Add basic yaml config resolver

77 files changed, 53995 insertions, 0 deletions

diff --git a/contrib/libs/CMakeLists.darwin.txt b/contrib/libs/CMakeLists.darwin.txt
index 2fb1191e81..7ade8a27a6 100644
--- a/contrib/libs/CMakeLists.darwin.txt
+++ b/contrib/libs/CMakeLists.darwin.txt
@@ -31,6 +31,7 @@ add_subdirectory(jwt-cpp)
 add_subdirectory(libbz2)
 add_subdirectory(libc_compat)
 add_subdirectory(libevent)
+add_subdirectory(libfyaml)
 add_subdirectory(libunwind)
 add_subdirectory(libxml)
 add_subdirectory(linuxvdso)
diff --git a/contrib/libs/CMakeLists.linux-aarch64.txt b/contrib/libs/CMakeLists.linux-aarch64.txt
index 45a9446c60..e803770d22 100644
--- a/contrib/libs/CMakeLists.linux-aarch64.txt
+++ b/contrib/libs/CMakeLists.linux-aarch64.txt
@@ -30,6 +30,7 @@ add_subdirectory(jwt-cpp)
 add_subdirectory(libbz2)
 add_subdirectory(libc_compat)
 add_subdirectory(libevent)
+add_subdirectory(libfyaml)
 add_subdirectory(libunwind)
 add_subdirectory(liburing)
 add_subdirectory(libxml)
diff --git a/contrib/libs/CMakeLists.linux.txt b/contrib/libs/CMakeLists.linux.txt
index 664626ecec..1e23ebb355 100644
--- a/contrib/libs/CMakeLists.linux.txt
+++ b/contrib/libs/CMakeLists.linux.txt
@@ -31,6 +31,7 @@ add_subdirectory(jwt-cpp)
 add_subdirectory(libbz2)
 add_subdirectory(libc_compat)
 add_subdirectory(libevent)
+add_subdirectory(libfyaml)
 add_subdirectory(libunwind)
 add_subdirectory(liburing)
 add_subdirectory(libxml)
diff --git a/contrib/libs/libfyaml/AUTHORS b/contrib/libs/libfyaml/AUTHORS
new file mode 100644
index 0000000000..ffb66c786c
--- /dev/null
+++ b/contrib/libs/libfyaml/AUTHORS
@@ -0,0 +1 @@
+Pantelis Antoniou <pantelis.antoniou@konsulko.com>
diff --git a/contrib/libs/libfyaml/CMakeLists.darwin.txt b/contrib/libs/libfyaml/CMakeLists.darwin.txt
new file mode 100644
index 0000000000..2548b20ffa
--- /dev/null
+++ b/contrib/libs/libfyaml/CMakeLists.darwin.txt
@@ -0,0 +1,45 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_library(contrib-libs-libfyaml)
+target_compile_options(contrib-libs-libfyaml PRIVATE
+  -DHAVE_CONFIG_H
+  -Wno-everything
+)
+target_include_directories(contrib-libs-libfyaml PRIVATE
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/include
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib
+  ${CMAKE_SOURCE_DIR}/contrib/libs/xxhash
+)
+target_link_libraries(contrib-libs-libfyaml PUBLIC
+  contrib-libs-xxhash
+)
+target_sources(contrib-libs-libfyaml PRIVATE
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-accel.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-atom.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-composer.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-ctype.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-diag.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-doc.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-docbuilder.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-docstate.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-dump.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-emit.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-event.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-input.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-parse.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-path.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-token.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-types.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-utf8.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-utils.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-walk.c
+)
diff --git a/contrib/libs/libfyaml/CMakeLists.linux-aarch64.txt b/contrib/libs/libfyaml/CMakeLists.linux-aarch64.txt
new file mode 100644
index 0000000000..1b0e026cf6
--- /dev/null
+++ b/contrib/libs/libfyaml/CMakeLists.linux-aarch64.txt
@@ -0,0 +1,46 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_library(contrib-libs-libfyaml)
+target_compile_options(contrib-libs-libfyaml PRIVATE
+  -DHAVE_CONFIG_H
+  -Wno-everything
+)
+target_include_directories(contrib-libs-libfyaml PRIVATE
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/include
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib
+  ${CMAKE_SOURCE_DIR}/contrib/libs/xxhash
+)
+target_link_libraries(contrib-libs-libfyaml PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-xxhash
+)
+target_sources(contrib-libs-libfyaml PRIVATE
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-accel.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-atom.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-composer.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-ctype.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-diag.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-doc.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-docbuilder.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-docstate.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-dump.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-emit.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-event.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-input.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-parse.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-path.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-token.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-types.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-utf8.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-utils.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-walk.c
+)
diff --git a/contrib/libs/libfyaml/CMakeLists.linux.txt b/contrib/libs/libfyaml/CMakeLists.linux.txt
new file mode 100644
index 0000000000..1b0e026cf6
--- /dev/null
+++ b/contrib/libs/libfyaml/CMakeLists.linux.txt
@@ -0,0 +1,46 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_library(contrib-libs-libfyaml)
+target_compile_options(contrib-libs-libfyaml PRIVATE
+  -DHAVE_CONFIG_H
+  -Wno-everything
+)
+target_include_directories(contrib-libs-libfyaml PRIVATE
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/include
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib
+  ${CMAKE_SOURCE_DIR}/contrib/libs/xxhash
+)
+target_link_libraries(contrib-libs-libfyaml PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-xxhash
+)
+target_sources(contrib-libs-libfyaml PRIVATE
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-accel.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-atom.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-composer.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-ctype.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-diag.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-doc.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-docbuilder.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-docstate.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-dump.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-emit.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-event.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-input.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-parse.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-path.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-token.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-types.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-utf8.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-utils.c
+  ${CMAKE_SOURCE_DIR}/contrib/libs/libfyaml/src/lib/fy-walk.c
+)
diff --git a/contrib/libs/libfyaml/CMakeLists.txt b/contrib/libs/libfyaml/CMakeLists.txt
new file mode 100644
index 0000000000..5bb4faffb4
--- /dev/null
+++ b/contrib/libs/libfyaml/CMakeLists.txt
@@ -0,0 +1,15 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+if (CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux-aarch64.txt)
+elseif (APPLE AND CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
+  include(CMakeLists.darwin.txt)
+elseif (CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux.txt)
+endif()
diff --git a/contrib/libs/libfyaml/LICENSE b/contrib/libs/libfyaml/LICENSE
new file mode 100644
index 0000000000..7403da9783
--- /dev/null
+++ b/contrib/libs/libfyaml/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/contrib/libs/libfyaml/README.md b/contrib/libs/libfyaml/README.md
new file mode 100644
index 0000000000..72e9c9a0e0
--- /dev/null
+++ b/contrib/libs/libfyaml/README.md
@@ -0,0 +1,466 @@
+# libfyaml &middot; ![](https://github.com/pantoniou/libfyaml/workflows/Standard%20Automake%20CI/badge.svg)
+
+A fancy 1.2 YAML and JSON parser/writer.
+
+Fully feature complete YAML parser and emitter, supporting the latest YAML spec and
+passing the full YAML testsuite.
+
+It is designed to be very efficient, avoiding copies of data, and
+has no artificial limits like the 1024 character limit for implicit keys.
+
+libfyaml is using https://github.com/yaml/yaml-test-suite as a core part
+of it's testsuite.
+
+## Features
+* Fully supports YAML version 1.2.
+* Attempts to adhere to features coming with YAML version 1.3 so that it
+  will be ready.
+* Zero content copy operation, which means that content is never copied to
+  internal structures. On input types that support it (mmap files and
+  constant strings) that means that memory usage is kept low, and arbitrary
+  large content can be manipulated without problem.
+* Parser may be used in event mode (like libyaml) or in document generating mode.
+* Extensive programmable API capable of manipulating parsed YAML documents or
+  creating them from scratch.
+* YAML emitter with programmable options, supporting colored output.
+* Extensive testsuite for the API, the full YAML test-suite and correct
+  emitter operation.
+* Easy printf/scanf based YAML creation and data extraction API.
+* Accurate and descriptive error messages, in standard compiler format that 
+  can be parsed by editors and developer GUIs.
+* Testsuite supports running under valgrind and checking for memory leaks. No
+  leaks should be possible under normal operation, so it is usable for long-
+  running applications.
+
+## Contents
+- [Features](#features)
+- [Prerequisites](#prerequisites)
+- [Building](#building)
+- [Usage and examples](#usage-and-examples)
+- [API documentation](#api-documentation)
+- [fy-tool reference](#fy-tool-reference)
+- [Missing Features](#missing-features)
+
+## Prerequisites
+
+libfyaml is primarily developed on Linux based debian distros but Apple MacOS X builds
+(using homebrew) are supported as well.
+
+On a based debian distro (i.e. ubuntu 19.04 disco) you should install the following
+dependencies:
+
+* `sudo apt-get install gcc autoconf automake libtool git make libltdl-dev pkg-config`
+
+To enable the libyaml comparison checker:
+
+* `sudo apt-get install libyaml-dev`
+
+For the API testsuite libcheck is required:
+
+* `sudo apt-get install check`
+
+And finally in order to build the sphinx based documentation:
+
+* `sudo apt-get install python3 python3-pip python3-setuptools`
+* `pip3 install wheel sphinx git+http://github.com/return42/linuxdoc.git sphinx\_rtd\_theme sphinx-markdown-builder`
+
+Note that some older distros (like xenial) do not have a sufficiently recent
+sphinx in their repos. In that case you can create a virtual environment
+using scripts/create-virtual-env
+
+## Building
+
+``libfyaml`` uses a standard autotools based build scheme so:
+
+* `./bootstrap.sh`
+* `./configure`
+* `make`
+
+Will build the library and `fy-tool`.
+
+* `make check`
+
+Will run the test-suite.
+
+Binaries, libraries, header files and pkgconfig files maybe installed with
+
+* `make install`
+
+By default, the installation prefix will be `/usr/local`, which you can change
+with the `--prefix <dir>` option during configure.
+
+To build the documentation API in HTML format use:
+
+* `make doc-html`
+
+The documentation for the public API will be found in doc/\_build/html
+
+* `make doc-latexpdf`
+
+Will generate a single pdf containing everything.
+
+## Usage and examples
+
+Usage of libfyaml is somewhat similar to libyaml, but with a few notable differences.
+
+1. The objects of the library are opaque, they are pointers that may be used but
+   may not be derefenced via library users. This makes the public API not be dependent of
+   internal changes in the library structures.
+
+2. The object pointers used are guaranteed to not 'move' like libyaml object pointers
+   so you may embed them freely in your own structures.
+
+3. The convenience methods of libyaml allow you to avoid tedious iteration and code
+   duplication. While fully manual YAML document tree manipulation is available, if your
+   application is not performance sensitive when manipulating YAML, you are advised to
+   use the helpers.
+
+### Using libfyaml in your projects
+
+Typically you only have to include the single header file `libfyaml.h` and
+link against the correct fyaml-\<major\>-\<minor\> library.
+
+It is recommended to use pkg-config, i.e.
+
+```make
+CFLAGS+= `pkg-config --cflags libfyaml`
+LDFLAGS+= `pkg-config --libs libfyaml`
+```
+
+For use in an automake based project you may use the following fragment
+```bash
+PKG_CHECK_MODULES(LIBFYAML, [ libfyaml ], HAVE_LIBFYAML=1, HAVE_LIBFYAML=0)
+
+if test "x$HAVE_LIBFYAML" != "x1" ; then
+	AC_MSG_ERROR([failed to find libfyaml])
+fi
+
+AC_SUBST(HAVE_LIBFYAML)
+AC_SUBST(LIBFYAML_CFLAGS)
+AC_SUBST(LIBFYAML_LIBS)
+AC_DEFINE_UNQUOTED([HAVE_LIBFYAML], [$HAVE_LIBFYAML], [Define to 1 if you have libfyaml available])
+AM_CONDITIONAL([HAVE_LIBFYAML], [ test x$HAVE_LIBFYAML = x1 ])
+```
+
+The examples that follow will make things clear.
+
+### Display libfyaml version example
+
+This is the minimal example that checks that you've compiled against the correct libfyaml.
+
+```c
+/*
+ * fy-version.c - libfyaml version example
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <libfyaml.h>
+
+int main(int argc, char *argv[])
+{
+	printf("%s\n", fy_library_version());
+	return EXIT_SUCCESS;
+}
+```
+
+### libfyaml example using simplified inprogram YAML generation
+
+This example simply parses an in-program YAML string and displays
+a string.
+
+The standard header plus variables definition.
+
+```c
+/*
+ * inprogram.c - libfyaml inprogram YAML example
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+
+#include <libfyaml.h>
+
+int main(int argc, char *argv[])
+{
+	static const char *yaml = 
+		"invoice: 34843\n"
+		"date   : !!str 2001-01-23\n"
+		"bill-to: &id001\n"
+		"    given  : Chris\n"
+		"    family : Dumars\n"
+		"    address:\n"
+		"        lines: |\n"
+		"            458 Walkman Dr.\n"
+		"            Suite #292\n";
+	struct fy_document *fyd = NULL;
+	int rc, count, ret = EXIT_FAILURE;
+	unsigned int invoice_nr;
+	char given[256 + 1];
+```
+
+Parsing and creating a YAML document from either the built-in
+YAML, or an invoice file given on the command line:
+
+```c
+	if (argc == 1)
+		fyd = fy_document_build_from_string(NULL, yaml, FY_NT);
+	else
+		fyd = fy_document_build_from_file(NULL, argv[1]);
+	if (!fyd) {
+		fprintf(stderr, "failed to build document");
+		goto fail;
+	}
+```
+
+Get the invoice number and the given name using a single call.
+
+```c
+	/* get the invoice number and the given name */
+	count = fy_document_scanf(fyd,
+			"/invoice %u "
+			"/bill-to/given %256s",
+			&invoice_nr, given);
+	if (count != 2) {
+		fprintf(stderr, "Failed to retreive the two items\n");
+		goto fail;
+	}
+
+	/* print them as comments in the emitted YAML */
+	printf("# invoice number was %u\n", invoice_nr);
+	printf("# given name is %s\n", given);
+```
+
+In sequence, increase the invoice number, add a spouse and a secondary
+address.
+
+```c
+	rc =
+		/* set increased invoice number (modify existing node) */
+		fy_document_insert_at(fyd, "/invoice", FY_NT,
+			fy_node_buildf(fyd, "%u", invoice_nr + 1)) ||
+		/* add spouse (create new mapping pair) */
+		fy_document_insert_at(fyd, "/bill-to", FY_NT,
+			fy_node_buildf(fyd, "spouse: %s", "Doris")) ||
+		/* add a second address */
+		fy_document_insert_at(fyd, "/bill-to", FY_NT,
+			fy_node_buildf(fyd, "delivery-address:\n"
+				            "  lines: |\n"
+					    "    1226 Windward Ave.\n"));
+	if (rc) {
+		fprintf(stderr, "failed to insert to document\n");
+		goto fail;
+	}
+```
+
+Emit the document to standard output (while sorting the keys)
+
+```c
+	/* emit the document to stdout (but sorted) */
+	rc = fy_emit_document_to_fp(fyd, FYECF_DEFAULT | FYECF_SORT_KEYS, stdout);
+	if (rc) {
+		fprintf(stderr, "failed to emit document to stdout");
+		goto fail;
+	}
+```
+
+Finally exit and report condition.
+
+```c
+	ret = EXIT_SUCCESS;
+fail:
+	fy_document_destroy(fyd);	/* NULL is OK */
+
+	return ret;
+}
+```
+
+## API documentation
+
+For complete documentation of libfyaml API, visit https://pantoniou.github.io/libfyaml/
+
+## fy-tool reference
+
+A YAML manipulation tool is included in libfyaml, aptly name `fy-tool`.
+It's a multi tool application, acting differently according to the name it has
+when it's invoked. There are four tool modes, namely:
+
+* fy-testsuite: Used for outputing a test-suite specific event stream which is
+  used for comparison with the expected output of the suite.
+* fy-dump: General purpose YAML parser and dumper, with syntax coloring support,
+  visible whitespace options, and a number of output modes.
+* fy-filter: YAML filtering tool allows to extract information out of a YAML
+  document.
+* fy-join: YAML flexible join tool.
+
+### fy-testsuite usage
+
+A number of options are common in every fy-tool invocation:
+
+```
+Usage : fy-tool [options] [args]
+
+Options:
+
+	--include, -I <path>     : Add directory to include path (default path "")
+	--debug-level, -d <lvl>  : Set debug level to <lvl>(default level 3)
+	--indent, -i <indent>    : Set dump indent to <indent> (default indent 2)
+	--width, -w <width>      : Set dump width to <width> (default width 80)
+	--resolve, -r            : Perform anchor and merge key resolution (default false)
+	--color, -C <mode>       : Color output can be one of on, off, auto (default auto)
+	--visible, -V            : Make all whitespace and linebreaks visible (default false)
+	--follow, -l             : Follow aliases when using paths (default false)
+	--strip-labels           : Strip labels when emitting (default false)
+	--strip-tags             : Strip tags when emitting (default false)
+	--strip-doc              : Strip document headers and indicators when emitting (default false)
+	--quiet, -q              : Quiet operation, do not output messages (default false)
+	--version, -v            : Display libfyaml version
+	--help, -h               : Display  help message
+
+```
+
+```
+Usage: fy-testsuite [options] [args]
+
+	[common options]
+
+	Parse and dump test-suite event format
+	$ fy-testsuite input.yaml
+	...
+
+	Parse and dump of event example
+	$ echo "foo: bar" | fy-testsuite -
+	+STR
+	+DOC
+	+MAP
+	=VAL :foo
+	=VAL :bar
+	-MAP
+	-DOC
+	-STR
+```
+
+### fy-dump usage
+
+```
+Usage: fy-dump [options] [args]
+
+Options:
+
+	[common options]
+
+	--sort, -s               : Perform mapping key sort (valid for dump) (default false)
+	--comment, -c            : Output comments (experimental) (default false)
+	--mode, -m <mode>        : Output mode can be one of original, block, flow, flow-oneline, json, json-tp, json-oneline (default original)
+	--streaming              : Use streaming output mode (default false)
+
+	[common options]
+
+	Parse and dump generated YAML document tree in the original YAML form
+	$ fy-dump input.yaml
+	...
+
+	Parse and dump generated YAML document tree in block YAML form (and make whitespace visible)
+	$ fy-dump -V -mblock input.yaml
+	...
+
+	Parse and dump generated YAML document from the input string
+	$ fy-dump -mjson ">foo: bar"
+	{
+	  "foo": "bar"
+	}
+
+	Parse and dump generated YAML document from the input string (using streaming mode)
+	$ fy-dump --streaming ">foo: bar"
+	foo: bar
+
+	Note that streaming mode can not perform document validity checks, like duplicate keys nor
+        support the sort keys option.
+```
+
+### fy-filter usage
+
+```
+Usage: fy-filter [options] [args]
+
+Options:
+
+	[common options]
+
+	--sort, -s               : Perform mapping key sort (valid for dump) (default false)
+	--comment, -c            : Output comments (experimental) (default false)
+	--mode, -m <mode>        : Output mode can be one of original, block, flow, flow-oneline, json, json-tp, json-oneline (default original)
+	--file, -f <file>        : Use given file instead of <stdin>
+	                           Note that using a string with a leading '>' is equivalent to a file with the trailing content
+	                           --file ">foo: bar" is as --file file.yaml with file.yaml "foo: bar"
+
+	Parse and filter YAML document tree starting from the '/foo' path followed by the '/bar' path
+	$ fy-filter --file input.yaml /foo /bar
+	...
+
+	Parse and filter for two paths (note how a multi-document stream is produced)
+	$ fy-filter --file -mblock --filter --file ">{ foo: bar, baz: [ frooz, whee ] }" /foo /baz
+	bar
+	---
+	- frooz
+	- whee
+
+	Parse and filter YAML document in stdin (note how the key may be complex)
+	$ echo "{ foo: bar }: baz" | fy-filter "/{foo: bar}/"
+	baz
+```
+
+### fy-join usage
+
+```
+Usage: fy-join [options] [args]
+
+Options:
+
+	[common options]
+
+	--sort, -s               : Perform mapping key sort (valid for dump) (default false)
+	--comment, -c            : Output comments (experimental) (default false)
+	--mode, -m <mode>        : Output mode can be one of original, block, flow, flow-oneline, json, json-tp, json-oneline (default original)
+	--file, -f <file>        : Use given file instead of <stdin>
+	                           Note that using a string with a leading '>' is equivalent to a file with the trailing content
+	                           --file ">foo: bar" is as --file file.yaml with file.yaml "foo: bar"
+	--to, -T <path>          : Join to <path> (default /)
+	--from, -F <path>        : Join from <path> (default /)
+	--trim, -t <path>        : Output given path (default /)
+
+	Parse and join two YAML files
+	$ fy-join file1.yaml file2.yaml
+	...
+
+	Parse and join two YAML maps
+	$ fy-join ">foo: bar" ">baz: frooz"
+	foo: bar
+	baz: frooz
+```
+
+## Missing features and omissions
+
+1. Windows - libfyaml is not supporting windows yet.
+2. Unicode - libfyaml only supports UTF8 and has no support for wide character input.
+
+## Development and contributing
+Feel free to send pull requests and raise issues.
diff --git a/contrib/libs/libfyaml/config.h b/contrib/libs/libfyaml/config.h
new file mode 100644
index 0000000000..283720047d
--- /dev/null
+++ b/contrib/libs/libfyaml/config.h
@@ -0,0 +1,244 @@
+/* config.h.  Generated from config.h.in by configure.  */
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* Define if building universal (internal helper macro) */
+/* #undef AC_APPLE_UNIVERSAL_BUILD */
+
+/* Define to 1 if you have check available */
+#define HAVE_CHECK 0
+
+/* Define to 1 if you have a compatible version of check available */
+#define HAVE_COMPATIBLE_CHECK 0
+
+/* Define to 1 if you have the declaration of `environ', and to 0 if you
+   don't. */
+#define HAVE_DECL_ENVIRON 1
+
+/* Define to 1 if developer mode is enabled */
+#define HAVE_DEVMODE 1
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#define HAVE_DLFCN_H 1
+
+/* Define to 1 if you have git available */
+#define HAVE_GIT 0
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#define HAVE_INTTYPES_H 1
+
+/* Define to 1 if you have jq available */
+#define HAVE_JQ 0
+
+/* Define to 1 if you have libyaml available */
+#define HAVE_LIBYAML 0
+
+/* Define to 1 if you have the <minix/config.h> header file. */
+/* #undef HAVE_MINIX_CONFIG_H */
+
+/* Define if you have POSIX threads libraries and header files. */
+#define HAVE_PTHREAD 1
+
+/* Have PTHREAD_PRIO_INHERIT. */
+#define HAVE_PTHREAD_PRIO_INHERIT 1
+
+/* Define to 1 if you have qsort_r available */
+#define HAVE_QSORT_R 1
+
+/* Define to 1 if you have sphinx (and all required packages) available */
+#define HAVE_SPHINX 0
+
+/* Define to 1 if the system has the type `ssize_t'. */
+#define HAVE_SSIZE_T 1
+
+/* Define to 1 if static linking is available */
+#define HAVE_STATIC 0
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#define HAVE_STDINT_H 1
+
+/* Define to 1 if you have the <stdio.h> header file. */
+#define HAVE_STDIO_H 1
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#define HAVE_STDLIB_H 1
+
+/* Define to 1 if you have the <strings.h> header file. */
+#define HAVE_STRINGS_H 1
+
+/* Define to 1 if you have the <string.h> header file. */
+#define HAVE_STRING_H 1
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#define HAVE_SYS_STAT_H 1
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#define HAVE_SYS_TYPES_H 1
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#define HAVE_UNISTD_H 1
+
+/* Define to 1 if you have the <wchar.h> header file. */
+#define HAVE_WCHAR_H 1
+
+/* Define to the sub-directory where libtool stores uninstalled libraries. */
+#define LT_OBJDIR ".libs/"
+
+/* Define if debugging is disabled */
+#define NDEBUG 1
+
+/* Name of package */
+#define PACKAGE "libfyaml"
+
+/* Define to the address where bug reports for this package should be sent. */
+#define PACKAGE_BUGREPORT "pantelis.antoniou@konsulko.com"
+
+/* Define to the full name of this package. */
+#define PACKAGE_NAME "libfyaml"
+
+/* Define to the full name and version of this package. */
+#define PACKAGE_STRING "libfyaml 0.7.12"
+
+/* Define to the one symbol short name of this package. */
+#define PACKAGE_TARNAME "libfyaml"
+
+/* Define to the home page for this package. */
+#define PACKAGE_URL ""
+
+/* Define to the version of this package. */
+#define PACKAGE_VERSION "0.7.12"
+
+/* Define to necessary symbol if this constant uses a non-standard name on
+   your system. */
+/* #undef PTHREAD_CREATE_JOINABLE */
+
+/* Define as the return type of signal handlers (`int' or `void'). */
+#define RETSIGTYPE void
+
+/* Define to 1 if all of the C90 standard headers exist (not just the ones
+   required in a freestanding environment). This macro is provided for
+   backward compatibility; new code need not use it. */
+#define STDC_HEADERS 1
+
+/* Enable extensions on AIX 3, Interix.  */
+#ifndef _ALL_SOURCE
+# define _ALL_SOURCE 1
+#endif
+/* Enable general extensions on macOS.  */
+#ifndef _DARWIN_C_SOURCE
+# define _DARWIN_C_SOURCE 1
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# define __EXTENSIONS__ 1
+#endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE 1
+#endif
+/* Enable X/Open compliant socket functions that do not require linking
+   with -lxnet on HP-UX 11.11.  */
+#ifndef _HPUX_ALT_XOPEN_SOCKET_API
+# define _HPUX_ALT_XOPEN_SOCKET_API 1
+#endif
+/* Identify the host operating system as Minix.
+   This macro does not affect the system headers' behavior.
+   A future release of Autoconf may stop defining this macro.  */
+#ifndef _MINIX
+/* # undef _MINIX */
+#endif
+/* Enable general extensions on NetBSD.
+   Enable NetBSD compatibility extensions on Minix.  */
+#ifndef _NETBSD_SOURCE
+# define _NETBSD_SOURCE 1
+#endif
+/* Enable OpenBSD compatibility extensions on NetBSD.
+   Oddly enough, this does nothing on OpenBSD.  */
+#ifndef _OPENBSD_SOURCE
+# define _OPENBSD_SOURCE 1
+#endif
+/* Define to 1 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_SOURCE
+/* # undef _POSIX_SOURCE */
+#endif
+/* Define to 2 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_1_SOURCE
+/* # undef _POSIX_1_SOURCE */
+#endif
+/* Enable POSIX-compatible threading on Solaris.  */
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# define _POSIX_PTHREAD_SEMANTICS 1
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-5:2014.  */
+#ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+# define __STDC_WANT_IEC_60559_ATTRIBS_EXT__ 1
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-1:2014.  */
+#ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+# define __STDC_WANT_IEC_60559_BFP_EXT__ 1
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-2:2015.  */
+#ifndef __STDC_WANT_IEC_60559_DFP_EXT__
+# define __STDC_WANT_IEC_60559_DFP_EXT__ 1
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-4:2015.  */
+#ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
+# define __STDC_WANT_IEC_60559_FUNCS_EXT__ 1
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-3:2015.  */
+#ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
+# define __STDC_WANT_IEC_60559_TYPES_EXT__ 1
+#endif
+/* Enable extensions specified by ISO/IEC TR 24731-2:2010.  */
+#ifndef __STDC_WANT_LIB_EXT2__
+# define __STDC_WANT_LIB_EXT2__ 1
+#endif
+/* Enable extensions specified by ISO/IEC 24747:2009.  */
+#ifndef __STDC_WANT_MATH_SPEC_FUNCS__
+# define __STDC_WANT_MATH_SPEC_FUNCS__ 1
+#endif
+/* Enable extensions on HP NonStop.  */
+#ifndef _TANDEM_SOURCE
+# define _TANDEM_SOURCE 1
+#endif
+/* Enable X/Open extensions.  Define to 500 only if necessary
+   to make mbstate_t available.  */
+#ifndef _XOPEN_SOURCE
+/* # undef _XOPEN_SOURCE */
+#endif
+
+
+/* Version number of package */
+#define VERSION "0.7.12"
+
+/* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
+   significant byte first (like Motorola and SPARC, unlike Intel). */
+#if defined AC_APPLE_UNIVERSAL_BUILD
+# if defined __BIG_ENDIAN__
+#  define WORDS_BIGENDIAN 1
+# endif
+#else
+# ifndef WORDS_BIGENDIAN
+/* #  undef WORDS_BIGENDIAN */
+# endif
+#endif
+
+/* Define to empty if `const' does not conform to ANSI C. */
+/* #undef const */
+
+/* Define to `int' if <sys/types.h> doesn't define. */
+/* #undef gid_t */
+
+/* Define to `long int' if <sys/types.h> does not define. */
+/* #undef off_t */
+
+/* Define as a signed integer type capable of holding a process identifier. */
+/* #undef pid_t */
+
+/* Define to `unsigned int' if <sys/types.h> does not define. */
+/* #undef size_t */
+
+/* Define ssize_t if it is not done by the standard libs. */
+/* #undef ssize_t */
+
+/* Define to `int' if <sys/types.h> doesn't define. */
+/* #undef uid_t */
diff --git a/contrib/libs/libfyaml/include/libfyaml.h b/contrib/libs/libfyaml/include/libfyaml.h
new file mode 100644
index 0000000000..0d68ff8257
--- /dev/null
+++ b/contrib/libs/libfyaml/include/libfyaml.h
@@ -0,0 +1,7326 @@
+/*
+ * libfyaml.h - Main header file of the public interface
+ *
+ * Copyright (c) 2019-2021 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef LIBFYAML_H
+#define LIBFYAML_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <unistd.h>
+#define FY_ALLOCA(x) alloca(x)
+#elif defined(_MSC_VER)
+#include <BaseTsd.h>
+typedef SSIZE_T ssize_t;
+#define FY_ALLOCA(x) _alloca(x)
+#endif
+
+/* opaque types for the user */
+struct fy_token;
+struct fy_document_state;
+struct fy_parser;
+struct fy_emitter;
+struct fy_document;
+struct fy_node;
+struct fy_node_pair;
+struct fy_anchor;
+struct fy_node_mapping_sort_ctx;
+struct fy_token_iter;
+struct fy_diag;
+struct fy_path_parser;
+struct fy_path_expr;
+struct fy_path_exec;
+struct fy_path_component;
+struct fy_path;
+struct fy_document_iterator;
+
+
+#ifndef FY_BIT
+#define FY_BIT(x) (1U << (x))
+#endif
+
+/* NULL terminated string length specifier */
+#define FY_NT	((size_t)-1)
+
+#if defined(__GNUC__) && __GNUC__ >= 4
+#define FY_ATTRIBUTE(attr) __attribute ((attr))
+#define FY_EXPORT __attribute__ ((visibility ("default")))
+#define FY_DEPRECATED __attribute__ ((deprecated))
+#else
+#define FY_ATTRIBUTE(attr) /* nothing */
+#define FY_EXPORT /* nothing */
+#define FY_DEPRECATED /* nothing */
+#endif
+
+/* make a copy of an allocated string and return it on stack
+ * note that this is a convenience, and should not be called
+ * in a loop. The string is always '\0' terminated.
+ * If the _str pointer is NULL, then NULL will be returned
+ */
+#ifndef FY_ALLOCA_COPY_FREE
+#define FY_ALLOCA_COPY_FREE(_str, _len, _res)			\
+	do {							\
+		char *__res, *__str = (char*)(_str);		\
+	        size_t __len = (size_t)(_len);			\
+		__res = NULL;					\
+								\
+		if (__str) {					\
+			if (__len == FY_NT)			\
+				__len = strlen(__str);		\
+			__res = FY_ALLOCA(__len + 1);		\
+			memcpy(__res, __str, __len);		\
+			(__res[__len]) = '\0';			\
+			free(__str);				\
+		}						\
+	        *(_res) = __res;				\
+	} while(false)
+#endif
+
+/* same as above but when _str == NULL return "" */
+#ifndef FY_ALLOCA_COPY_FREE_NO_NULL
+#define FY_ALLOCA_COPY_FREE_NO_NULL(_str, _len, _res)		\
+	do {							\
+		FY_ALLOCA_COPY_FREE(_str, _len, _res);  	\
+		if (!*(_res))					\
+			*(_res) = "";				\
+	} while(false)
+#endif
+
+/**
+ * DOC: libfyaml public API
+ *
+ */
+
+/**
+ * struct fy_version - The YAML version
+ *
+ * @major: Major version number
+ * @minor: Major version number
+ *
+ * The parser fills it according to the \%YAML directive
+ * found in the document.
+ */
+struct fy_version {
+	int major;
+	int minor;
+};
+
+/* Build a fy_version * from the given major and minor */
+#define fy_version_make(_maj, _min) (&(struct fy_version){ (_maj), (_min) })
+
+/**
+ * fy_version_compare() - Compare two yaml versions
+ *
+ * Compare the versions
+ *
+ * @va: The first version, if NULL use default version
+ * @vb: The second version, if NULL use default version
+ *
+ * Returns:
+ * 0 if versions are equal, > 0 if version va is higher than vb
+ * < 0 if version va is lower than vb
+ */
+int
+fy_version_compare(const struct fy_version *va, const struct fy_version *vb)
+	FY_EXPORT;
+
+/**
+ * fy_version_default() - Get the default version of the library
+ *
+ * Return the default version of the library, i.e. the highest
+ * stable version that is supported.
+ *
+ * Returns:
+ * The default YAML version of this library
+ */
+const struct fy_version *
+fy_version_default(void)
+	FY_EXPORT;
+
+/**
+ * fy_version_is_supported() - Check if supported version
+ *
+ * Check if the given YAML version is supported.
+ *
+ * @vers: The version to check, NULL means default version.
+ *
+ * Returns:
+ * true if version supported, false otherwise.
+ */
+bool
+fy_version_is_supported(const struct fy_version *vers)
+	FY_EXPORT;
+
+/**
+ * fy_version_supported_iterate() - Iterate over the supported YAML versions
+ *
+ * This method iterates over the supported YAML versions of this ibrary.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * @prevp: The previous version iterator
+ *
+ * Returns:
+ * The next node in sequence or NULL at the end of the sequence.
+ */
+const struct fy_version *
+fy_version_supported_iterate(void **prevp)
+	FY_EXPORT;
+
+/**
+ * struct fy_tag - The YAML tag structure.
+ *
+ * @handle: Handle of the tag (i.e. `"!!"` )
+ * @prefix: The prefix of the tag (i.e. `"tag:yaml.org,2002:"`
+ *
+ * The parser fills it according to the \%TAG directives
+ * encountered during parsing.
+ */
+struct fy_tag {
+	const char *handle;
+	const char *prefix;
+};
+
+/**
+ * struct fy_mark - marker holding information about a location
+ *		    in a &struct fy_input
+ *
+ * @input_pos: Position of the mark (from the start of the current input)
+ * @line: Line position (0 index based)
+ * @column: Column position (0 index based)
+ */
+struct fy_mark {
+	size_t input_pos;
+	int line;
+	int column;
+};
+
+/**
+ * enum fy_error_type - The supported diagnostic/error types
+ *
+ * @FYET_DEBUG: Debug level (disabled if library is not compiled in debug mode)
+ * @FYET_INFO: Informational level
+ * @FYET_NOTICE: Notice level
+ * @FYET_WARNING: Warning level
+ * @FYET_ERROR: Error level - error reporting is using this level
+ * @FYET_MAX: Non inclusive maximum fy_error_type value
+ *
+ */
+enum fy_error_type {
+	FYET_DEBUG,
+	FYET_INFO,
+	FYET_NOTICE,
+	FYET_WARNING,
+	FYET_ERROR,
+	FYET_MAX,
+};
+
+/**
+ * enum fy_error_module - Module which generated the diagnostic/error
+ *
+ * @FYEM_UNKNOWN: Unknown, default if not specific
+ * @FYEM_ATOM: Atom module, used by atom chunking
+ * @FYEM_SCAN: Scanner module
+ * @FYEM_PARSE: Parser module
+ * @FYEM_DOC: Document module
+ * @FYEM_BUILD: Build document module (after tree is constructed)
+ * @FYEM_INTERNAL: Internal error/diagnostic module
+ * @FYEM_SYSTEM: System error/diagnostic module
+ * @FYEM_MAX: Non inclusive maximum fy_error_module value
+ */
+enum fy_error_module {
+	FYEM_UNKNOWN,
+	FYEM_ATOM,
+	FYEM_SCAN,
+	FYEM_PARSE,
+	FYEM_DOC,
+	FYEM_BUILD,
+	FYEM_INTERNAL,
+	FYEM_SYSTEM,
+	FYEM_MAX,
+};
+
+/* Shift amount of the default version */
+#define FYPCF_DEFAULT_VERSION_SHIFT	9
+/* Mask of the default version */
+#define FYPCF_DEFAULT_VERSION_MASK	((1U << 5) - 1)
+/* Build a default version */
+#define FYPCF_DEFAULT_VERSION(x)	(((unsigned int)(x) & FYPCF_DEFAULT_VERSION_MASK) << FYPCF_DEFAULT_VERSION_SHIFT)
+
+/* Shift amount of the JSON input mode */
+#define FYPCF_JSON_SHIFT		16
+/* Mask of the JSON input mode */
+#define FYPCF_JSON_MASK			((1U << 2) - 1)
+/* Build a JSON input mode option */
+#define FYPCF_JSON(x)			(((unsigned int)(x) & FYPCF_JSON_MASK) << FYPCF_JSON_SHIFT)
+
+/* guaranteed minimum depth limit for generated document */
+/* the actual limit is larger depending on the platform */
+#define FYPCF_GUARANTEED_MINIMUM_DEPTH_LIMIT	64
+
+/**
+ * enum fy_parse_cfg_flags - Parse configuration flags
+ *
+ * These flags control the operation of the parse and the debugging
+ * output/error reporting via filling in the &fy_parse_cfg->flags member.
+ *
+ * @FYPCF_QUIET: Quiet, do not output any information messages
+ * @FYPCF_COLLECT_DIAG: Collect diagnostic/error messages
+ * @FYPCF_RESOLVE_DOCUMENT: When producing documents, automatically resolve them
+ * @FYPCF_DISABLE_MMAP_OPT: Disable mmap optimization
+ * @FYPCF_DISABLE_RECYCLING: Disable recycling optimization
+ * @FYPCF_PARSE_COMMENTS: Enable parsing of comments (experimental)
+ * @FYPCF_DISABLE_DEPTH_LIMIT: Disable depth limit check, use with enlarged stack
+ * @FYPCF_DISABLE_ACCELERATORS: Disable use of access accelerators (saves memory)
+ * @FYPCF_DISABLE_BUFFERING: Disable use of buffering where possible
+ * @FYPCF_DEFAULT_VERSION_AUTO: Automatically use the most recent version the library supports
+ * @FYPCF_DEFAULT_VERSION_1_1: Default version is YAML 1.1
+ * @FYPCF_DEFAULT_VERSION_1_2: Default version is YAML 1.2
+ * @FYPCF_DEFAULT_VERSION_1_3: Default version is YAML 1.3 (experimental)
+ * @FYPCF_SLOPPY_FLOW_INDENTATION: Allow sloppy indentation in flow mode
+ * @FYPCF_PREFER_RECURSIVE: Prefer recursive algorighms instead of iterative whenever possible
+ * @FYPCF_JSON_AUTO: Automatically enable JSON mode (when extension is .json)
+ * @FYPCF_JSON_NONE: Never enable JSON input mode
+ * @FYPCF_JSON_FORCE: Force JSON mode always
+ * @FYPCF_YPATH_ALIASES: Enable YPATH aliases mode
+ * @FYPCF_ALLOW_DUPLICATE_KEYS: Allow duplicate keys on mappings
+ */
+enum fy_parse_cfg_flags {
+	FYPCF_QUIET			= FY_BIT(0),
+	FYPCF_COLLECT_DIAG		= FY_BIT(1),
+	FYPCF_RESOLVE_DOCUMENT		= FY_BIT(2),
+	FYPCF_DISABLE_MMAP_OPT		= FY_BIT(3),
+	FYPCF_DISABLE_RECYCLING		= FY_BIT(4),
+	FYPCF_PARSE_COMMENTS		= FY_BIT(5),
+	FYPCF_DISABLE_DEPTH_LIMIT	= FY_BIT(6),
+	FYPCF_DISABLE_ACCELERATORS	= FY_BIT(7),
+	FYPCF_DISABLE_BUFFERING		= FY_BIT(8),
+	FYPCF_DEFAULT_VERSION_AUTO	= FYPCF_DEFAULT_VERSION(0),
+	FYPCF_DEFAULT_VERSION_1_1	= FYPCF_DEFAULT_VERSION(1),
+	FYPCF_DEFAULT_VERSION_1_2	= FYPCF_DEFAULT_VERSION(2),
+	FYPCF_DEFAULT_VERSION_1_3	= FYPCF_DEFAULT_VERSION(3),
+	FYPCF_SLOPPY_FLOW_INDENTATION	= FY_BIT(14),
+	FYPCF_PREFER_RECURSIVE		= FY_BIT(15),
+	FYPCF_JSON_AUTO			= FYPCF_JSON(0),
+	FYPCF_JSON_NONE			= FYPCF_JSON(1),
+	FYPCF_JSON_FORCE		= FYPCF_JSON(2),
+	FYPCF_YPATH_ALIASES		= FY_BIT(18),
+	FYPCF_ALLOW_DUPLICATE_KEYS	= FY_BIT(19),
+};
+
+#define FYPCF_DEFAULT_PARSE	(0)
+
+#define FYPCF_DEFAULT_DOC	(FYPCF_QUIET | FYPCF_DEFAULT_PARSE)
+
+/*
+ * The FYPCF_DEBUG and FYPCF_COLOR flags have been removed, however
+ * to help with backwards compatibility we will define them as 0
+ * so that code can continue to compile.
+ *
+ * You will need to eventualy modify the code if you actually depended
+ * on the old behaviour.
+ */
+#define FYPCF_MODULE_SHIFT		0
+#define FYPCF_MODULE_MASK		0
+#define FYPCF_DEBUG_LEVEL_SHIFT		0
+#define FYPCF_DEBUG_LEVEL_MASK		0
+#define FYPCF_DEBUG_LEVEL(x)		0
+#define FYPCF_DEBUG_DIAG_SHIFT		0
+#define FYPCF_DEBUG_DIAG_MASK		0
+#define FYPCF_DEBUG_DIAG_ALL		0
+#define FYPCF_DEBUG_DIAG_DEFAULT	0
+#define FYPCF_DEBUG_UNKNOWN		0
+#define FYPCF_DEBUG_ATOM		0
+#define FYPCF_DEBUG_SCAN		0
+#define FYPCF_DEBUG_PARSE		0
+#define FYPCF_DEBUG_DOC			0
+#define FYPCF_DEBUG_BUILD		0
+#define FYPCF_DEBUG_INTERNAL		0
+#define FYPCF_DEBUG_SYSTEM		0
+#define FYPCF_DEBUG_LEVEL_DEBUG		0
+#define FYPCF_DEBUG_LEVEL_INFO		0
+#define FYPCF_DEBUG_LEVEL_NOTICE	0
+#define FYPCF_DEBUG_LEVEL_WARNING	0
+#define FYPCF_DEBUG_LEVEL_ERROR		0
+#define FYPCF_DEBUG_DIAG_SOURCE		0
+#define FYPCF_DEBUG_DIAG_POSITION	0
+#define FYPCF_DEBUG_DIAG_TYPE		0
+#define FYPCF_DEBUG_DIAG_MODULE		0
+#define FYPCF_DEBUG_ALL			0
+#define FYPCF_DEBUG_DEFAULT		0
+#define FYPCF_COLOR_SHIFT		0
+#define FYPCF_COLOR_MASK		0
+#define FYPCF_COLOR(x)			0
+#define FYPCF_COLOR_AUTO		0
+#define FYPCF_COLOR_NONE		0
+#define FYPCF_COLOR_FORCE		0
+
+/**
+ * struct fy_parse_cfg - parser configuration structure.
+ *
+ * Argument to the fy_parser_create() method which
+ * perform parsing of YAML files.
+ *
+ * @search_path: Search path when accessing files, seperate with ':'
+ * @flags: Configuration flags
+ * @userdata: Opaque user data pointer
+ * @diag: Optional diagnostic interface to use
+ */
+struct fy_parse_cfg {
+	const char *search_path;
+	enum fy_parse_cfg_flags flags;
+	void *userdata;
+	struct fy_diag *diag;
+};
+
+/**
+ * enum fy_event_type - Event types
+ *
+ * @FYET_NONE: No event
+ * @FYET_STREAM_START: Stream start event
+ * @FYET_STREAM_END: Stream end event
+ * @FYET_DOCUMENT_START: Document start event
+ * @FYET_DOCUMENT_END: Document end event
+ * @FYET_MAPPING_START: YAML mapping start event
+ * @FYET_MAPPING_END: YAML mapping end event
+ * @FYET_SEQUENCE_START: YAML sequence start event
+ * @FYET_SEQUENCE_END: YAML sequence end event
+ * @FYET_SCALAR: YAML scalar event
+ * @FYET_ALIAS: YAML alias event
+ */
+enum fy_event_type {
+	FYET_NONE,
+	FYET_STREAM_START,
+	FYET_STREAM_END,
+	FYET_DOCUMENT_START,
+	FYET_DOCUMENT_END,
+	FYET_MAPPING_START,
+	FYET_MAPPING_END,
+	FYET_SEQUENCE_START,
+	FYET_SEQUENCE_END,
+	FYET_SCALAR,
+	FYET_ALIAS,
+};
+
+/**
+ * fy_event_type_get_text() - Return text of an event type
+ *
+ * @type: The event type to get text from
+ *
+ * Returns:
+ * A pointer to a text, i.e for FYET_SCALAR "=VAL".
+ */
+const char *
+fy_event_type_get_text(enum fy_event_type type)
+	FY_EXPORT;
+
+/**
+ * enum fy_scalar_style - Scalar styles supported by the parser/emitter
+ *
+ * @FYSS_ANY: Any scalar style, not generated by the parser.
+ * 	      Lets the emitter to choose
+ * @FYSS_PLAIN: Plain scalar style
+ * @FYSS_SINGLE_QUOTED: Single quoted style
+ * @FYSS_DOUBLE_QUOTED: Double quoted style
+ * @FYSS_LITERAL: YAML literal block style
+ * @FYSS_FOLDED: YAML folded block style
+ * @FYSS_MAX: marks end of scalar styles
+ */
+enum fy_scalar_style {
+	FYSS_ANY = -1,
+	FYSS_PLAIN,
+	FYSS_SINGLE_QUOTED,
+	FYSS_DOUBLE_QUOTED,
+	FYSS_LITERAL,
+	FYSS_FOLDED,
+	FYSS_MAX,
+};
+
+/**
+ * struct fy_event_stream_start_data - stream start event data
+ *
+ * @stream_start: The token that started the stream
+ */
+struct fy_event_stream_start_data {
+	struct fy_token *stream_start;
+};
+
+/*
+ * struct fy_event_stream_end_data - stream end event data
+ *
+ * @stream_end: The token that ended the stream
+ */
+struct fy_event_stream_end_data {
+	struct fy_token *stream_end;
+};
+
+/*
+ * struct fy_event_document_start_data - doument start event data
+ *
+ * @document_start: The token that started the document, or NULL if
+ * 		    the document was implicitly started.
+ * @document_state: The state of the document (i.e. information about
+ * 		    the YAML version and configured tags)
+ * @implicit: True if the document started implicitly
+ */
+struct fy_event_document_start_data {
+	struct fy_token *document_start;
+	struct fy_document_state *document_state;
+	bool implicit;
+};
+
+/*
+ * struct fy_event_document_end_data - doument end event data
+ *
+ * @document_end: The token that ended the document, or NULL if the
+ * 	          document was implicitly ended
+ * @implicit: True if the document ended implicitly
+ */
+struct fy_event_document_end_data {
+	struct fy_token *document_end;
+	bool implicit;
+};
+
+/*
+ * struct fy_event_alias_data - alias event data
+ *
+ * @anchor: The anchor token definining this alias.
+ */
+struct fy_event_alias_data {
+	struct fy_token *anchor;
+};
+
+/*
+ * struct fy_event_scalar_data - scalar event data
+ *
+ * @.anchor: anchor token or NULL
+ * @tag: tag token or NULL
+ * @value: scalar value token (cannot be NULL)
+ * @tag_implicit: true if the tag was implicit or explicit
+ */
+struct fy_event_scalar_data {
+	struct fy_token *anchor;
+	struct fy_token *tag;
+	struct fy_token *value;
+	bool tag_implicit;
+};
+
+/*
+ * struct fy_event_sequence_start_data - sequence start event data
+ *
+ * @anchor: anchor token or NULL
+ * @tag: tag token or NULL
+ * @sequence_start: sequence start value token or NULL if the sequence
+ * 		    was started implicitly
+ */
+struct fy_event_sequence_start_data {
+	struct fy_token *anchor;
+	struct fy_token *tag;
+	struct fy_token *sequence_start;
+};
+
+/*
+ * struct fy_event_sequence_end_data - sequence end event data
+ *
+ * @sequence_end: The token that ended the sequence, or NULL if
+ * 		  the sequence was implicitly ended
+ */
+struct fy_event_sequence_end_data {
+	struct fy_token *sequence_end;
+};
+
+/*
+ * struct fy_event_mapping_start_data - mapping start event data
+ *
+ * @anchor: anchor token or NULL
+ * @tag: tag token or NULL
+ * @mapping_start: mapping start value token or NULL if the mapping
+ * 		    was started implicitly
+ */
+struct fy_event_mapping_start_data {
+	struct fy_token *anchor;
+	struct fy_token *tag;
+	struct fy_token *mapping_start;
+};
+
+/*
+ * struct fy_event_mapping_end_data - mapping end event data
+ *
+ * @mapping_end: The token that ended the mapping, or NULL if
+ * 		  the mapping was implicitly ended
+ */
+struct fy_event_mapping_end_data {
+	struct fy_token *mapping_end;
+};
+
+/**
+ * struct fy_event - Event generated by the parser
+ *
+ * This structure is generated by the parser by each call
+ * to fy_parser_parse() and release by fy_parser_event_free()
+ *
+ * @type: Type of the event, see &enum fy_event_type
+ *
+ * @stream_start: Stream start information, it is valid when
+ *                &fy_event->type is &enum FYET_STREAM_START
+ * @stream_end: Stream end information, it is valid when
+ *                &fy_event->type is &enum FYET_STREAM_END
+ * @document_start: Document start information, it is valid when
+ *                  &fy_event->type is &enum FYET_DOCUMENT_START
+ * @document_end: Document end information, it is valid when
+ *                &fy_event->type is &enum FYET_DOCUMENT_END
+ * @alias: Alias information, it is valid when
+ *         &fy_event->type is &enum FYET_ALIAS
+ * @scalar: Scalar information, it is valid when
+ *          &fy_event->type is &enum FYET_SCALAR
+ * @sequence_start: Sequence start information, it is valid when
+ *                  &fy_event->type is &enum FYET_SEQUENCE_START
+ * @sequence_end: Sequence end information, it is valid when
+ *                &fy_event->type is &enum FYET_SEQUENCE_END
+ * @mapping_start: Mapping start information, it is valid when
+ *                 &fy_event->type is &enum FYET_MAPPING_START
+ * @mapping_end: Mapping end information, it is valid when
+ *               &fy_event->type is &enum FYET_MAPPING_END
+ */
+struct fy_event {
+	enum fy_event_type type;
+	/* anonymous union */
+	union {
+		struct fy_event_stream_start_data stream_start;
+		struct fy_event_stream_end_data stream_end;
+		struct fy_event_document_start_data document_start;
+		struct fy_event_document_end_data document_end;
+		struct fy_event_alias_data alias;
+		struct fy_event_scalar_data scalar;
+		struct fy_event_sequence_start_data sequence_start;
+		struct fy_event_sequence_end_data sequence_end;
+		struct fy_event_mapping_start_data mapping_start;
+		struct fy_event_mapping_end_data mapping_end;
+	};
+};
+
+/**
+ * fy_event_data() - Get a pointer to the event data
+ *
+ * Some languages *cough*golang*cough* really don't like
+ * unions, and anonymous unions in particular.
+ *
+ * You should not have to use this in other language bindings.
+ *
+ * @fye: The event
+ *
+ * Returns:
+ * A pointer to the event data structure, or NULL if the
+ * event is invalid
+ */
+static inline void *
+fy_event_data(struct fy_event *fye)
+{
+	if (!fye)
+		return NULL;
+
+	/* note that the unions should all be laid out
+	 * at the same address, but play it straight and
+	 * hope the optimizer will figure this is all
+	 * the same...
+	 */
+	switch (fye->type) {
+	case FYET_STREAM_START:
+		return &fye->stream_start;
+	case FYET_STREAM_END:
+		return &fye->stream_end;
+	case FYET_DOCUMENT_START:
+		return &fye->document_start;
+	case FYET_DOCUMENT_END:
+		return &fye->document_end;
+	case FYET_ALIAS:
+		return &fye->alias;
+	case FYET_SCALAR:
+		return &fye->scalar;
+	case FYET_SEQUENCE_START:
+		return &fye->sequence_start;
+	case FYET_SEQUENCE_END:
+		return &fye->sequence_end;
+	case FYET_MAPPING_START:
+		return &fye->mapping_start;
+	case FYET_MAPPING_END:
+		return &fye->mapping_end;
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+/**
+ * fy_library_version() - Return the library version string
+ *
+ * Returns:
+ * A pointer to a version string of the form
+ * <MAJOR>.<MINOR>[[.<PATCH>][-EXTRA-VERSION-INFO]]
+ */
+const char *
+fy_library_version(void)
+	FY_EXPORT;
+
+/**
+ * fy_string_to_error_type() - Return the error type from a string
+ *
+ * @str: The string to convert to an error type
+ *
+ * Returns:
+ * The error type if greater or equal to zero, FYET_MAX otherwise
+ */
+enum fy_error_type fy_string_to_error_type(const char *str)
+	FY_EXPORT;
+
+/**
+ * fy_error_type_to_string() - Convert an error type to string
+ *
+ * @type: The error type to convert
+ *
+ * Returns:
+ * The string value of the error type or the empty string "" on error
+ */
+const char *fy_error_type_to_string(enum fy_error_type type)
+	FY_EXPORT;
+
+/**
+ * fy_string_to_error_module() - Return the error module from a string
+ *
+ * @str: The string to convert to an error module
+ *
+ * Returns:
+ * The error type if greater or equal to zero, FYEM_MAX otherwise
+ */
+enum fy_error_module fy_string_to_error_module(const char *str)
+	FY_EXPORT;
+
+/**
+ * fy_error_module_to_string() - Convert an error module to string
+ *
+ * @module: The error module to convert
+ *
+ * Returns:
+ * The string value of the error module or the empty string "" on error
+ */
+const char *fy_error_module_to_string(enum fy_error_module module)
+	FY_EXPORT;
+
+/**
+ * fy_event_is_implicit() - Check whether the given event is an implicit one
+ *
+ * @fye: A pointer to a &struct fy_event to check.
+ *
+ * Returns:
+ * true if the event is an implicit one.
+ */
+bool
+fy_event_is_implicit(struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_document_event_is_implicit() - Check whether the given document event is an implicit one
+ *
+ * @fye: A pointer to a &struct fy_event to check.
+ *       It must be either a document start or document end event.
+ *
+ * Returns:
+ * true if the event is an implicit one.
+ */
+bool
+fy_document_event_is_implicit(const struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_parser_create() - Create a parser.
+ *
+ * Creates a parser with its configuration @cfg
+ * The parser may be destroyed by a corresponding call to
+ * fy_parser_destroy().
+ *
+ * @cfg: The configuration for the parser
+ *
+ * Returns:
+ * A pointer to the parser or NULL in case of an error.
+ */
+struct fy_parser *
+fy_parser_create(const struct fy_parse_cfg *cfg)
+	FY_EXPORT;
+
+/**
+ * fy_parser_destroy() - Destroy the given parser
+ *
+ * Destroy a parser created earlier via fy_parser_create().
+ *
+ * @fyp: The parser to destroy
+ */
+void
+fy_parser_destroy(struct fy_parser *fyp)
+	FY_EXPORT;
+
+/**
+ * fy_parser_get_cfg() - Get the configuration of a parser
+ *
+ * @fyp: The parser
+ *
+ * Returns:
+ * The configuration of the parser
+ */
+const struct fy_parse_cfg *
+fy_parser_get_cfg(struct fy_parser *fyp)
+	FY_EXPORT;
+
+/**
+ * fy_parser_get_diag() - Get the diagnostic object of a parser
+ *
+ * Return a pointer to the diagnostic object of a parser object.
+ * Note that the returned diag object has a reference taken so
+ * you should fy_diag_unref() it when you're done with it.
+ *
+ * @fyp: The parser to get the diagnostic object
+ *
+ * Returns:
+ * A pointer to a ref'ed diagnostic object or NULL in case of an
+ * error.
+ */
+struct fy_diag *
+fy_parser_get_diag(struct fy_parser *fyp)
+	FY_EXPORT;
+
+/**
+ * fy_parser_set_diag() - Set the diagnostic object of a parser
+ *
+ * Replace the parser's current diagnostic object with the one
+ * given as an argument. The previous diagnostic object will be
+ * unref'ed (and freed if its reference gets to 0).
+ * Also note that the diag argument shall take a reference too.
+ *
+ * @fyp: The parser to replace the diagnostic object
+ * @diag: The parser's new diagnostic object, NULL for default
+ *
+ * Returns:
+ * 0 if everything OK, -1 otherwise
+ */
+int
+fy_parser_set_diag(struct fy_parser *fyp, struct fy_diag *diag)
+	FY_EXPORT;
+
+/**
+ * fy_parser_reset() - Reset a parser completely
+ *
+ * Completely reset a parser, including after an error
+ * that caused a parser error to be emitted.
+ *
+ * @fyp: The parser to reset
+ *
+ * Returns:
+ * 0 if the reset was successful, -1 otherwise
+ */
+int
+fy_parser_reset(struct fy_parser *fyp)
+	FY_EXPORT;
+
+/**
+ * fy_parser_set_input_file() - Set the parser to process the given file
+ *
+ * Point the parser to the given @file for processing. The file
+ * is located by honoring the search path of the configuration set
+ * by the earlier call to fy_parser_create().
+ * While the parser is in use the file will must be available.
+ *
+ * @fyp: The parser
+ * @file: The file to parse.
+ *
+ * Returns:
+ * zero on success, -1 on error
+ */
+int
+fy_parser_set_input_file(struct fy_parser *fyp, const char *file)
+	FY_EXPORT;
+
+/**
+ * fy_parser_set_string() - Set the parser to process the given string.
+ *
+ * Point the parser to the given (NULL terminated) string. Note that
+ * while the parser is active the string must not go out of scope.
+ *
+ * @fyp: The parser
+ * @str: The YAML string to parse.
+ * @len: The length of the string (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * zero on success, -1 on error
+ */
+int
+fy_parser_set_string(struct fy_parser *fyp, const char *str, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_parser_set_malloc_string() - Set the parser to process the given malloced string.
+ *
+ * Point the parser to the given (possible NULL terminated) string. Note that
+ * the string is expected to be allocated via malloc(3) and ownership is transferred
+ * to the created input. When the input is free'ed the memory will be automatically
+ * freed.
+ *
+ * In case of an error the string is not freed.
+ *
+ * @fyp: The parser
+ * @str: The YAML string to parse (allocated).
+ * @len: The length of the string (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * zero on success, -1 on error
+ */
+int
+fy_parser_set_malloc_string(struct fy_parser *fyp, char *str, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_parser_set_input_fp() - Set the parser to process the given file
+ *
+ * Point the parser to use @fp for processing.
+ *
+ * @fyp: The parser
+ * @name: The label of the stream
+ * @fp: The FILE pointer, it must be open in read mode.
+ *
+ * Returns:
+ * zero on success, -1 on error
+ */
+int
+fy_parser_set_input_fp(struct fy_parser *fyp, const char *name, FILE *fp)
+	FY_EXPORT;
+
+/**
+ * fy_parser_set_input_callback() - Set the parser to process via a callback
+ *
+ * Point the parser to use a callback for input.
+ *
+ * @fyp: The parser
+ * @user: The user data pointer
+ * @callback: The callback method to request data with
+ *
+ * Returns:
+ * zero on success, -1 on error
+ */
+int fy_parser_set_input_callback(struct fy_parser *fyp, void *user,
+		ssize_t (*callback)(void *user, void *buf, size_t count))
+	FY_EXPORT;
+
+/**
+ * fy_parser_set_input_db() - Set the parser to process the given file descriptor
+ *
+ * Point the parser to use @fd for processing.
+ *
+ * @fyp: The parser
+ * @fd: The file descriptor to use
+ *
+ * Returns:
+ * zero on success, -1 on error
+ */
+int
+fy_parser_set_input_fd(struct fy_parser *fyp, int fd)
+	FY_EXPORT;
+
+/**
+ * fy_parser_parse() - Parse and return the next event.
+ *
+ * Each call to fy_parser_parse() returns the next event from
+ * the configured input of the parser, or NULL at the end of
+ * the stream. The returned event must be released via
+ * a matching call to fy_parser_event_free().
+ *
+ * @fyp: The parser
+ *
+ * Returns:
+ * The next event in the stream or NULL.
+ */
+struct fy_event *
+fy_parser_parse(struct fy_parser *fyp)
+	FY_EXPORT;
+
+/**
+ * fy_parser_event_free() - Free an event
+ *
+ * Free a previously returned event from fy_parser_parse().
+ *
+ * @fyp: The parser
+ * @fye: The event to free (may be NULL)
+ */
+void
+fy_parser_event_free(struct fy_parser *fyp, struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_parser_get_stream_error() - Check the parser for stream errors
+ *
+ * @fyp: The parser
+ *
+ * Returns:
+ * true in case of a stream error, false otherwise.
+ */
+bool
+fy_parser_get_stream_error(struct fy_parser *fyp)
+	FY_EXPORT;
+
+/**
+ * fy_token_scalar_style() - Get the style of a scalar token
+ *
+ * @fyt: The scalar token to get it's style. Note that a NULL
+ *       token is a &enum FYSS_PLAIN.
+ *
+ * Returns:
+ * The scalar style of the token, or FYSS_PLAIN on each other case
+ */
+enum fy_scalar_style
+fy_token_scalar_style(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_token_get_text() - Get text (and length of it) of a token
+ *
+ * This method will return a pointer to the text of a token
+ * along with the length of it. Note that this text is *not*
+ * NULL terminated. If you need a NULL terminated pointer
+ * use fy_token_get_text0().
+ *
+ * In case that the token is 'simple' enough (i.e. a plain scalar)
+ * or something similar the returned pointer is a direct pointer
+ * to the space of the input that contains the token.
+ *
+ * That means that the pointer is *not* guaranteed to be valid
+ * after the parser is destroyed.
+ *
+ * If the token is 'complex' enough, then space shall be allocated,
+ * filled and returned.
+ *
+ * Note that the concept of 'simple' and 'complex' is vague, and
+ * that's on purpose.
+ *
+ * @fyt: The token out of which the text pointer will be returned.
+ * @lenp: Pointer to a variable that will hold the returned length
+ *
+ * Returns:
+ * A pointer to the text representation of the token, while
+ * @lenp will be assigned the character length of said representation.
+ * NULL in case of an error.
+ */
+const char *
+fy_token_get_text(struct fy_token *fyt, size_t *lenp)
+	FY_EXPORT;
+
+/**
+ * fy_token_get_text0() - Get zero terminated text of a token
+ *
+ * This method will return a pointer to the text of a token
+ * which is zero terminated. It will allocate memory to hold
+ * it in the token structure so try to use fy_token_get_text()
+ * instead if possible.
+ *
+ * @fyt: The token out of which the text pointer will be returned.
+ *
+ * Returns:
+ * A pointer to a zero terminated text representation of the token.
+ * NULL in case of an error.
+ */
+const char *
+fy_token_get_text0(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_token_get_text_length() - Get length of the text of a token
+ *
+ * This method will return the length of the text representation
+ * of a token.
+ *
+ * @fyt: The token
+ *
+ * Returns:
+ * The size of the text representation of a token, -1 in case of an error.
+ * Note that the NULL token will return a length of zero.
+ */
+size_t
+fy_token_get_text_length(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_token_get_utf8_length() - Get length of the text of a token
+ *
+ * This method will return the length of the text representation
+ * of a token as a utf8 string.
+ *
+ * @fyt: The token
+ *
+ * Returns:
+ * The size of the utf8 text representation of a token, -1 in case of an error.
+ * Note that the NULL token will return a length of zero.
+ */
+size_t
+fy_token_get_utf8_length(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * enum fy_comment_placement - Comment placement relative to token
+ *
+ * @fycp_top: Comment on top of token
+ * @fycp_right: Comment to the right of the token
+ * @fycp_bottom: Comment to the bottom of the token
+ */
+enum fy_comment_placement {
+	fycp_top,
+	fycp_right,
+	fycp_bottom
+};
+#define fycp_max (fycp_bottom + 1)
+
+/**
+ * fy_token_get_comment() - Get zero terminated comment of a token
+ *
+ * @fyt: The token out of which the comment text will be returned.
+ * @buf: The buffer to be filled with the contents of the token
+ * @maxsz: The maximum size of the comment buffer
+ * @which: The comment placement
+ *
+ * Returns:
+ * A pointer to a zero terminated text representation of the token comment.
+ * NULL in case of an error or if the token has no comment.
+ */
+const char *
+fy_token_get_comment(struct fy_token *fyt, char *buf, size_t maxsz,
+		     enum fy_comment_placement which)
+	FY_EXPORT;
+
+/**
+ * struct fy_iter_chunk - An iteration chunk
+ *
+ * @str: Pointer to the start of the chunk
+ * @len: The size of the chunk
+ *
+ * The iterator produces a stream of chunks which
+ * cover the whole object.
+ */
+struct fy_iter_chunk {
+	const char *str;
+	size_t len;
+};
+
+/**
+ * fy_token_iter_create() - Create a token iterator
+ *
+ * Create an iterator for operating on the given token, or
+ * a generic iterator for use with fy_token_iter_start().
+ * The iterator must be destroyed with a matching call to
+ * fy_token_iter_destroy().
+ *
+ * @fyt: The token to iterate, or NULL.
+ *
+ * Returns:
+ * A pointer to the newly created iterator, or NULL in case of
+ * an error.
+ */
+struct fy_token_iter *
+fy_token_iter_create(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_destroy() - Destroy the iterator
+ *
+ * Destroy the iterator created by fy_token_iter_create().
+ *
+ * @iter: The iterator to destroy.
+ */
+void
+fy_token_iter_destroy(struct fy_token_iter *iter)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_start() - Start iterating over the contents of a token
+ *
+ * Prepare an iterator for operating on the given token.
+ * The iterator must be created via a previous call to fy_token_iter_create()
+ * for user level API access.
+ *
+ * @fyt: The token to iterate over
+ * @iter: The iterator to prepare.
+ */
+void
+fy_token_iter_start(struct fy_token *fyt, struct fy_token_iter *iter)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_finish() - Stop iterating over the contents of a token
+ *
+ * Stop the iteration operation.
+ *
+ * @iter: The iterator.
+ */
+void
+fy_token_iter_finish(struct fy_token_iter *iter)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_peek_chunk() - Peek at the next iterator chunk
+ *
+ * Peek at the next iterator chunk
+ *
+ * @iter: The iterator.
+ *
+ * Returns:
+ * A pointer to the next iterator chunk, or NULL in case there's
+ * no other.
+ */
+const struct fy_iter_chunk *
+fy_token_iter_peek_chunk(struct fy_token_iter *iter)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_chunk_next() - Get next iterator chunk
+ *
+ * Get the next iterator chunk in sequence,
+ *
+ * @iter: The iterator.
+ * @curr: The current chunk, or NULL for the first one.
+ * @errp: Pointer to an error return value or NULL
+ *
+ * Returns:
+ * A pointer to the next iterator chunk, or NULL in case there's
+ * no other. When the return value is NULL, the errp variable
+ * will be filled with 0 for normal end, or -1 in case of an error.
+ */
+const struct fy_iter_chunk *
+fy_token_iter_chunk_next(struct fy_token_iter *iter,
+			 const struct fy_iter_chunk *curr, int *errp)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_advance() - Advance the iterator position
+ *
+ * Advance the read pointer of the iterator.
+ * Note that mixing calls of this with any call of fy_token_iter_ungetc() /
+ * fy_token_iter_utf8_unget() in a single iterator sequence leads
+ * to undefined behavior.
+ *
+ * @iter: The iterator.
+ * @len: Number of bytes to advance the iterator position
+ */
+void
+fy_token_iter_advance(struct fy_token_iter *iter, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_read() - Read a block from an iterator
+ *
+ * Read a block from an iterator. Note than mixing calls of this
+ * and any of the ungetc methods leads to undefined behavior.
+ *
+ * @iter: The iterator.
+ * @buf: Pointer to a block of memory to receive the data. Must be at
+ *       least count bytes long.
+ * @count: Amount of bytes to read.
+ *
+ * Returns:
+ * The amount of data read, or -1 in case of an error.
+ */
+ssize_t
+fy_token_iter_read(struct fy_token_iter *iter, void *buf, size_t count)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_getc() - Get a single character from an iterator
+ *
+ * Reads a single character from an iterator. If the iterator is
+ * finished, it will return -1. If any calls to ungetc have pushed
+ * a character in the iterator it shall return that.
+ *
+ * @iter: The iterator.
+ *
+ * Returns:
+ * The next character in the iterator, or -1 in case of an error, or
+ * end of stream.
+ */
+int
+fy_token_iter_getc(struct fy_token_iter *iter)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_ungetc() - Ungets a single character from an iterator
+ *
+ * Pushes back a single character to an iterator stream. It will be
+ * returned in subsequent calls of fy_token_iter_getc(). Currently
+ * only a single character is allowed to be pushed back, and any
+ * further calls to ungetc will return an error.
+ *
+ * @iter: The iterator.
+ * @c: The character to push back, or -1 to reset the pushback buffer.
+ *
+ * Returns:
+ * The pushed back character given as argument, or -1 in case of an error.
+ * If the pushed back character was -1, then 0 will be returned.
+ */
+int
+fy_token_iter_ungetc(struct fy_token_iter *iter, int c)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_peekc() - Peeks at single character from an iterator
+ *
+ * Peeks at the next character to get from an iterator. If the iterator is
+ * finished, it will return -1. If any calls to ungetc have pushed
+ * a character in the iterator it shall return that. The character is not
+ * removed from the iterator stream.
+ *
+ * @iter: The iterator.
+ *
+ * Returns:
+ * The next character in the iterator, or -1 in case of an error, or end
+ * of stream.
+ */
+int
+fy_token_iter_peekc(struct fy_token_iter *iter)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_utf8_get() - Get a single utf8 character from an iterator
+ *
+ * Reads a single utf8 character from an iterator. If the iterator is
+ * finished, it will return -1. If any calls to ungetc have pushed
+ * a character in the iterator it shall return that.
+ *
+ * @iter: The iterator.
+ *
+ * Returns:
+ * The next utf8 character in the iterator, or -1 in case of an error, or end
+ * of stream.
+ */
+int
+fy_token_iter_utf8_get(struct fy_token_iter *iter)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_utf8_unget() - Ungets a single utf8 character from an iterator
+ *
+ * Pushes back a single utf8 character to an iterator stream. It will be
+ * returned in subsequent calls of fy_token_iter_utf8_getc(). Currently
+ * only a single character is allowed to be pushed back, and any
+ * further calls to ungetc will return an error.
+ *
+ * @iter: The iterator.
+ * @c: The character to push back, or -1 to reset the pushback buffer.
+ *
+ * Returns:
+ * The pushed back utf8 character given as argument, or -1 in case of an error.
+ * If the pushed back utf8 character was -1, then 0 will be returned.
+ */
+int
+fy_token_iter_utf8_unget(struct fy_token_iter *iter, int c)
+	FY_EXPORT;
+
+/**
+ * fy_token_iter_utf8_peek() - Peeks at single utf8 character from an iterator
+ *
+ * Peeks at the next utf8 character to get from an iterator. If the iterator is
+ * finished, it will return -1. If any calls to ungetc have pushed
+ * a character in the iterator it shall return that. The character is not
+ * removed from the iterator stream.
+ *
+ * @iter: The iterator.
+ *
+ * Returns:
+ * The next utf8 character in the iterator, or -1 in case of an error, or end
+ * of stream.
+ */
+int
+fy_token_iter_utf8_peek(struct fy_token_iter *iter)
+	FY_EXPORT;
+
+/**
+ * fy_parse_load_document() - Parse the next document from the parser stream
+ *
+ * This method performs parsing on a parser stream and returns the next
+ * document. This means that for a compound document with multiple
+ * documents, each call will return the next document.
+ *
+ * @fyp: The parser
+ *
+ * Returns:
+ * The next document from the parser stream.
+ */
+struct fy_document *
+fy_parse_load_document(struct fy_parser *fyp)
+	FY_EXPORT;
+
+/**
+ * fy_parse_document_destroy() - Destroy a document created by fy_parse_load_document()
+ *
+ * @fyp: The parser
+ * @fyd: The document to destroy
+ */
+void
+fy_parse_document_destroy(struct fy_parser *fyp, struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_resolve() - Resolve anchors and merge keys
+ *
+ * This method performs resolution of the given document,
+ * by replacing references to anchors with their contents
+ * and handling merge keys (<<)
+ *
+ * @fyd: The document to resolve
+ *
+ * Returns:
+ * zero on success, -1 on error
+ */
+int
+fy_document_resolve(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_has_directives() - Document directive check
+ *
+ * Checks whether the given document has any directives, i.e.
+ * %TAG or %VERSION.
+ *
+ * @fyd: The document to check for directives existence
+ *
+ * Returns:
+ * true if directives exist, false if not
+ */
+bool
+fy_document_has_directives(const struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_has_explicit_document_start() - Explicit document start check
+ *
+ * Checks whether the given document has an explicit document start marker,
+ * i.e. ---
+ *
+ * @fyd: The document to check for explicit start marker
+ *
+ * Returns:
+ * true if document has an explicit document start marker, false if not
+ */
+bool
+fy_document_has_explicit_document_start(const struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_has_explicit_document_end() - Explicit document end check
+ *
+ * Checks whether the given document has an explicit document end marker,
+ * i.e. ...
+ *
+ * @fyd: The document to check for explicit end marker
+ *
+ * Returns:
+ * true if document has an explicit document end marker, false if not
+ */
+bool
+fy_document_has_explicit_document_end(const struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_node_document() - Retreive the document the node belong to
+ *
+ * Returns the document of the node; note that while the node may not
+ * be reachable via a path expression, it may still be member of a
+ * document.
+ *
+ * @fyn: The node to retreive it's document
+ *
+ * Returns:
+ * The document of the node, or NULL in case of an error, or
+ * when the node has no document attached.
+ */
+struct fy_document *
+fy_node_document(struct fy_node *fyn)
+	FY_EXPORT;
+
+/*
+ * enum fy_emitter_write_type - Type of the emitted output
+ *
+ * Describes the kind of emitted output, which makes it
+ * possible to colorize the output, or do some other content related
+ * filtering.
+ *
+ * @fyewt_document_indicator: Output chunk is a document indicator
+ * @fyewt_tag_directive: Output chunk is a tag directive
+ * @fyewt_version_directive: Output chunk is a version directive
+ * @fyewt_indent: Output chunk is a document indicator
+ * @fyewt_indicator: Output chunk is an indicator
+ * @fyewt_whitespace: Output chunk is white space
+ * @fyewt_plain_scalar: Output chunk is a plain scalar
+ * @fyewt_single_quoted_scalar: Output chunk is a single quoted scalar
+ * @fyewt_double_quoted_scalar: Output chunk is a double quoted scalar
+ * @fyewt_literal_scalar: Output chunk is a literal block scalar
+ * @fyewt_folded_scalar: Output chunk is a folded block scalar
+ * @fyewt_anchor: Output chunk is an anchor
+ * @fyewt_tag: Output chunk is a tag
+ * @fyewt_linebreak: Output chunk is a linebreak
+ * @fyewt_alias: Output chunk is an alias
+ * @fyewt_terminating_zero: Output chunk is a terminating zero
+ * @fyewt_plain_scalar_key: Output chunk is an plain scalar key
+ * @fyewt_single_quoted_scalar_key: Output chunk is an single quoted scalar key
+ * @fyewt_double_quoted_scalar_key: Output chunk is an double quoted scalar key
+ * @fyewt_comment: Output chunk is a comment
+ *
+ */
+enum fy_emitter_write_type {
+	fyewt_document_indicator,
+	fyewt_tag_directive,
+	fyewt_version_directive,
+	fyewt_indent,
+	fyewt_indicator,
+	fyewt_whitespace,
+	fyewt_plain_scalar,
+	fyewt_single_quoted_scalar,
+	fyewt_double_quoted_scalar,
+	fyewt_literal_scalar,
+	fyewt_folded_scalar,
+	fyewt_anchor,
+	fyewt_tag,
+	fyewt_linebreak,
+	fyewt_alias,
+	fyewt_terminating_zero,
+	fyewt_plain_scalar_key,
+	fyewt_single_quoted_scalar_key,
+	fyewt_double_quoted_scalar_key,
+	fyewt_comment,
+};
+
+#define FYECF_INDENT_SHIFT	8
+#define FYECF_INDENT_MASK	0xf
+#define FYECF_INDENT(x)	(((x) & FYECF_INDENT_MASK) << FYECF_INDENT_SHIFT)
+
+#define FYECF_WIDTH_SHIFT	12
+#define FYECF_WIDTH_MASK	0xff
+#define FYECF_WIDTH(x)		(((x) & FYECF_WIDTH_MASK) << FYECF_WIDTH_SHIFT)
+
+#define FYECF_MODE_SHIFT	20
+#define FYECF_MODE_MASK		0xf
+#define FYECF_MODE(x)		(((x) & FYECF_MODE_MASK) << FYECF_MODE_SHIFT)
+
+#define FYECF_DOC_START_MARK_SHIFT	24
+#define FYECF_DOC_START_MARK_MASK	0x3
+#define FYECF_DOC_START_MARK(x)		(((x) & FYECF_DOC_START_MARK_MASK) << FYECF_DOC_START_MARK_SHIFT)
+
+#define FYECF_DOC_END_MARK_SHIFT	26
+#define FYECF_DOC_END_MARK_MASK		0x3
+#define FYECF_DOC_END_MARK(x)		(((x) & FYECF_DOC_END_MARK_MASK) << FYECF_DOC_END_MARK_SHIFT)
+
+#define FYECF_VERSION_DIR_SHIFT		28
+#define FYECF_VERSION_DIR_MASK		0x3
+#define FYECF_VERSION_DIR(x)		(((x) & FYECF_VERSION_DIR_MASK) << FYECF_VERSION_DIR_SHIFT)
+
+#define FYECF_TAG_DIR_SHIFT		30
+#define FYECF_TAG_DIR_MASK		0x3
+#define FYECF_TAG_DIR(x)		(((unsigned int)(x) & FYECF_TAG_DIR_MASK) << FYECF_TAG_DIR_SHIFT)
+
+/**
+ * enum fy_emitter_cfg_flags - Emitter configuration flags
+ *
+ * These flags control the operation of the emitter
+ *
+ * @FYECF_SORT_KEYS: Sort key when emitting
+ * @FYECF_OUTPUT_COMMENTS: Output comments (experimental)
+ * @FYECF_STRIP_LABELS: Strip labels when emitting
+ * @FYECF_STRIP_TAGS: Strip tags when emitting
+ * @FYECF_STRIP_DOC: Strip document tags and markers when emitting
+ * @FYECF_NO_ENDING_NEWLINE: Do not output ending new line (useful for single line mode)
+ * @FYECF_STRIP_EMPTY_KV: Remove all keys with empty values from the output (not available in streaming mode)
+ * @FYECF_INDENT_DEFAULT: Default emit output indent
+ * @FYECF_INDENT_1: Output indent is 1
+ * @FYECF_INDENT_2: Output indent is 2
+ * @FYECF_INDENT_3: Output indent is 3
+ * @FYECF_INDENT_4: Output indent is 4
+ * @FYECF_INDENT_5: Output indent is 5
+ * @FYECF_INDENT_6: Output indent is 6
+ * @FYECF_INDENT_7: Output indent is 7
+ * @FYECF_INDENT_8: Output indent is 8
+ * @FYECF_INDENT_9: Output indent is 9
+ * @FYECF_WIDTH_DEFAULT: Default emit output width
+ * @FYECF_WIDTH_80: Output width is 80
+ * @FYECF_WIDTH_132: Output width is 132
+ * @FYECF_WIDTH_INF: Output width is infinite
+ * @FYECF_MODE_ORIGINAL: Emit using the same flow mode as the original
+ * @FYECF_MODE_BLOCK: Emit using only the block mode
+ * @FYECF_MODE_FLOW: Emit using only the flow mode
+ * @FYECF_MODE_FLOW_ONELINE: Emit using only the flow mode (in one line)
+ * @FYECF_MODE_JSON: Emit using JSON mode (non type preserving)
+ * @FYECF_MODE_JSON_TP: Emit using JSON mode (type preserving)
+ * @FYECF_MODE_JSON_ONELINE: Emit using JSON mode (non type preserving, one line)
+ * @FYECF_MODE_DEJSON: Emit YAML trying to pretify JSON
+ * @FYECF_MODE_PRETTY: Emit YAML that tries to look good
+ * @FYECF_DOC_START_MARK_AUTO: Automatically generate document start markers if required
+ * @FYECF_DOC_START_MARK_OFF: Do not generate document start markers
+ * @FYECF_DOC_START_MARK_ON: Always generate document start markers
+ * @FYECF_DOC_END_MARK_AUTO: Automatically generate document end markers if required
+ * @FYECF_DOC_END_MARK_OFF: Do not generate document end markers
+ * @FYECF_DOC_END_MARK_ON: Always generate document end markers
+ * @FYECF_VERSION_DIR_AUTO: Automatically generate version directive
+ * @FYECF_VERSION_DIR_OFF: Never generate version directive
+ * @FYECF_VERSION_DIR_ON: Always generate version directive
+ * @FYECF_TAG_DIR_AUTO: Automatically generate tag directives
+ * @FYECF_TAG_DIR_OFF: Never generate tag directives
+ * @FYECF_TAG_DIR_ON: Always generate tag directives
+ * @FYECF_DEFAULT: The default emitter configuration
+ */
+enum fy_emitter_cfg_flags {
+	FYECF_SORT_KEYS			= FY_BIT(0),
+	FYECF_OUTPUT_COMMENTS		= FY_BIT(1),
+	FYECF_STRIP_LABELS		= FY_BIT(2),
+	FYECF_STRIP_TAGS		= FY_BIT(3),
+	FYECF_STRIP_DOC			= FY_BIT(4),
+	FYECF_NO_ENDING_NEWLINE		= FY_BIT(5),
+	FYECF_STRIP_EMPTY_KV		= FY_BIT(6),
+	FYECF_INDENT_DEFAULT		= FYECF_INDENT(0),
+	FYECF_INDENT_1			= FYECF_INDENT(1),
+	FYECF_INDENT_2			= FYECF_INDENT(2),
+	FYECF_INDENT_3			= FYECF_INDENT(3),
+	FYECF_INDENT_4			= FYECF_INDENT(4),
+	FYECF_INDENT_5			= FYECF_INDENT(5),
+	FYECF_INDENT_6			= FYECF_INDENT(6),
+	FYECF_INDENT_7			= FYECF_INDENT(7),
+	FYECF_INDENT_8			= FYECF_INDENT(8),
+	FYECF_INDENT_9			= FYECF_INDENT(9),
+	FYECF_WIDTH_DEFAULT		= FYECF_WIDTH(80),
+	FYECF_WIDTH_80			= FYECF_WIDTH(80),
+	FYECF_WIDTH_132			= FYECF_WIDTH(132),
+	FYECF_WIDTH_INF			= FYECF_WIDTH(255),
+	FYECF_MODE_ORIGINAL		= FYECF_MODE(0),
+	FYECF_MODE_BLOCK		= FYECF_MODE(1),
+	FYECF_MODE_FLOW			= FYECF_MODE(2),
+	FYECF_MODE_FLOW_ONELINE 	= FYECF_MODE(3),
+	FYECF_MODE_JSON			= FYECF_MODE(4),
+	FYECF_MODE_JSON_TP		= FYECF_MODE(5),
+	FYECF_MODE_JSON_ONELINE 	= FYECF_MODE(6),
+	FYECF_MODE_DEJSON 		= FYECF_MODE(7),
+	FYECF_MODE_PRETTY 		= FYECF_MODE(8),
+	FYECF_DOC_START_MARK_AUTO	= FYECF_DOC_START_MARK(0),
+	FYECF_DOC_START_MARK_OFF	= FYECF_DOC_START_MARK(1),
+	FYECF_DOC_START_MARK_ON		= FYECF_DOC_START_MARK(2),
+	FYECF_DOC_END_MARK_AUTO		= FYECF_DOC_END_MARK(0),
+	FYECF_DOC_END_MARK_OFF		= FYECF_DOC_END_MARK(1),
+	FYECF_DOC_END_MARK_ON		= FYECF_DOC_END_MARK(2),
+	FYECF_VERSION_DIR_AUTO		= FYECF_VERSION_DIR(0),
+	FYECF_VERSION_DIR_OFF		= FYECF_VERSION_DIR(1),
+	FYECF_VERSION_DIR_ON		= FYECF_VERSION_DIR(2),
+	FYECF_TAG_DIR_AUTO		= FYECF_TAG_DIR(0),
+	FYECF_TAG_DIR_OFF		= FYECF_TAG_DIR(1),
+	FYECF_TAG_DIR_ON		= FYECF_TAG_DIR(2),
+
+	FYECF_DEFAULT			= FYECF_WIDTH_INF |
+					  FYECF_MODE_ORIGINAL |
+					  FYECF_INDENT_DEFAULT,
+};
+
+/**
+ * struct fy_emitter_cfg - emitter configuration structure.
+ *
+ * Argument to the fy_emitter_create() method which
+ * is the way to convert a runtime document structure back to YAML.
+ *
+ * @flags: Configuration flags
+ * @output: Pointer to the method that will perform output.
+ * @userdata: Opaque user data pointer
+ * @diag: Diagnostic interface
+ */
+struct fy_emitter_cfg {
+	enum fy_emitter_cfg_flags flags;
+	int (*output)(struct fy_emitter *emit, enum fy_emitter_write_type type,
+		      const char *str, int len, void *userdata);
+	void *userdata;
+	struct fy_diag *diag;
+};
+
+/**
+ * fy_emitter_create() - Create an emitter
+ *
+ * Creates an emitter using the supplied configuration
+ *
+ * @cfg: The emitter configuration
+ *
+ * Returns:
+ * The newly created emitter or NULL on error.
+ */
+struct fy_emitter *
+fy_emitter_create(const struct fy_emitter_cfg *cfg)
+	FY_EXPORT;
+
+/**
+ * fy_emitter_destroy() - Destroy an emitter
+ *
+ * Destroy an emitter previously created by fy_emitter_create()
+ *
+ * @emit: The emitter to destroy
+ */
+void
+fy_emitter_destroy(struct fy_emitter *emit)
+	FY_EXPORT;
+
+/**
+ * fy_emitter_get_cfg() - Get the configuration of an emitter
+ *
+ * @emit: The emitter
+ *
+ * Returns:
+ * The configuration of the emitter
+ */
+const struct fy_emitter_cfg *
+fy_emitter_get_cfg(struct fy_emitter *emit)
+	FY_EXPORT;
+
+/**
+ * fy_emitter_get_diag() - Get the diagnostic object of an emitter
+ *
+ * Return a pointer to the diagnostic object of an emitter object.
+ * Note that the returned diag object has a reference taken so
+ * you should fy_diag_unref() it when you're done with it.
+ *
+ * @emit: The emitter to get the diagnostic object
+ *
+ * Returns:
+ * A pointer to a ref'ed diagnostic object or NULL in case of an
+ * error.
+ */
+struct fy_diag *
+fy_emitter_get_diag(struct fy_emitter *emit)
+	FY_EXPORT;
+
+/**
+ * fy_emitter_set_diag() - Set the diagnostic object of an emitter
+ *
+ * Replace the emitters's current diagnostic object with the one
+ * given as an argument. The previous diagnostic object will be
+ * unref'ed (and freed if its reference gets to 0).
+ * Also note that the diag argument shall take a reference too.
+ *
+ * @emit: The emitter to replace the diagnostic object
+ * @diag: The emitter's new diagnostic object, NULL for default
+ *
+ * Returns:
+ * 0 if everything OK, -1 otherwise
+ */
+int
+fy_emitter_set_diag(struct fy_emitter *emit, struct fy_diag *diag)
+	FY_EXPORT;
+
+/**
+ * fy_emitter_set_finalizer() - Set emitter finalizer
+ *
+ * Set a method callback to be called when the emitter
+ * is disposed of. If finalizer is NULL, then the method
+ * is removed.
+ *
+ * @emit: The emitter to replace the diagnostic object
+ * @finalizer: The finalizer callback
+ */
+void
+fy_emitter_set_finalizer(struct fy_emitter *emit,
+		void (*finalizer)(struct fy_emitter *emit))
+	FY_EXPORT;
+
+/**
+ * struct fy_emitter_default_output_data - emitter default output configuration
+ *
+ * This is the argument to the default output method of the emitter.
+ *
+ * @fp: File where the output is directed to
+ * @colorize: Use ANSI color sequences to colorize the output
+ * @visible: Make whitespace visible (requires a UTF8 capable terminal)
+ */
+struct fy_emitter_default_output_data {
+	FILE *fp;
+	bool colorize;
+	bool visible;
+};
+
+/**
+ * fy_emitter_default_output() - The default colorizing output method
+ *
+ * This is the default colorizing output method.
+ * Will be used when the output field of the emitter configuration is NULL.
+ *
+ * @fye: The emitter
+ * @type: Type of the emitted output
+ * @str: Pointer to the string to output
+ * @len: Length of the string
+ * @userdata: Must point to a fy_emitter_default_output_data structure
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emitter_default_output(struct fy_emitter *fye, enum fy_emitter_write_type type,
+			  const char *str, int len, void *userdata)
+	FY_EXPORT;
+
+/**
+ * fy_document_default_emit_to_fp() - Emit a document to a file, using defaults
+ *
+ * Simple one shot emitter to a file, using the default emitter output.
+ * The output will be colorized if the the file points to a tty.
+ *
+ * @fyd: The document to emit
+ * @fp: The file where the output is sent
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_document_default_emit_to_fp(struct fy_document *fyd, FILE *fp)
+	FY_EXPORT;
+
+/**
+ * fy_emit_event() - Queue (and possibly emit) an event
+ *
+ * Queue and output using the emitter. This is the streaming
+ * output method which does not require creating a document.
+ *
+ * @emit: The emitter to use
+ * @fye: The event to queue for emission
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_event(struct fy_emitter *emit, struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_emit_event_from_parser() - Queue (and possibly emit) an event
+ * 			  	 generated by the parser.
+ *
+ * Queue and output using the emitter. This is the streaming
+ * output method which does not require creating a document.
+ * Similar to fy_emit_event() but it is more efficient.
+ *
+ * @emit: The emitter to use
+ * @fyp: The parser that generated the event
+ * @fye: The event to queue for emission
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_event_from_parser(struct fy_emitter *emit, struct fy_parser *fyp, struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_emit_document() - Emit the document using the emitter
+ *
+ * Emits a document in YAML format using the emitter.
+ *
+ * @emit: The emitter
+ * @fyd: The document to emit
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_document(struct fy_emitter *emit, struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_emit_document_start() - Emit document start using the emitter
+ *
+ * Emits a document start using the emitter. This is used in case
+ * you need finer control over the emitting output.
+ *
+ * @emit: The emitter
+ * @fyd: The document to use for emitting it's start
+ * @fyn: The root (or NULL for using the document's root)
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_document_start(struct fy_emitter *emit, struct fy_document *fyd,
+		       struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_emit_document_end() - Emit document end using the emitter
+ *
+ * Emits a document end using the emitter. This is used in case
+ * you need finer control over the emitting output.
+ *
+ * @emit: The emitter
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_document_end(struct fy_emitter *emit)
+	FY_EXPORT;
+
+/**
+ * fy_emit_node() - Emit a single node using the emitter
+ *
+ * Emits a single node using the emitter. This is used in case
+ * you need finer control over the emitting output.
+ *
+ * @emit: The emitter
+ * @fyn: The node to emit
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_node(struct fy_emitter *emit, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_emit_root_node() - Emit a single root node using the emitter
+ *
+ * Emits a single root node using the emitter. This is used in case
+ * you need finer control over the emitting output.
+ *
+ * @emit: The emitter
+ * @fyn: The root node to emit
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_root_node(struct fy_emitter *emit, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_emit_explicit_document_end() - Emit an explicit document end
+ *
+ * Emits an explicit document end, i.e. ... . Use this if you
+ * you need finer control over the emitting output.
+ *
+ * @emit: The emitter
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_explicit_document_end(struct fy_emitter *emit)
+	FY_EXPORT;
+
+/**
+ * fy_emit_document_to_fp() - Emit a document to an file pointer
+ *
+ * Emits a document from the root to the given file pointer.
+ *
+ * @fyd: The document to emit
+ * @flags: The emitter flags to use
+ * @fp: The file pointer to output to
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_document_to_fp(struct fy_document *fyd,
+		       enum fy_emitter_cfg_flags flags, FILE *fp)
+	FY_EXPORT;
+
+/**
+ * fy_emit_document_to_file() - Emit a document to file
+ *
+ * Emits a document from the root to the given file.
+ * The file will be fopen'ed using a "wa" mode.
+ *
+ * @fyd: The document to emit
+ * @flags: The emitter flags to use
+ * @filename: The filename to output to, or NULL for stdout
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_document_to_file(struct fy_document *fyd,
+			 enum fy_emitter_cfg_flags flags,
+			 const char *filename)
+	FY_EXPORT;
+
+/**
+ * fy_emit_document_to_fd() - Emit a document to a file descriptor
+ *
+ * Emits a document from the root to the given file descriptor
+ *
+ * @fyd: The document to emit
+ * @flags: The emitter flags to use
+ * @fd: The file descriptor to output to
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_emit_document_to_fd(struct fy_document *fyd,
+		       enum fy_emitter_cfg_flags flags, int fd)
+	FY_EXPORT;
+
+/**
+ * fy_emit_document_to_buffer() - Emit a document to a buffer
+ *
+ * Emits an document from the root to the given buffer.
+ * If the document does not fit, an error will be returned.
+ *
+ * @fyd: The document to emit
+ * @flags: The emitter flags to use
+ * @buf: Pointer to the buffer area to fill
+ * @size: Size of the buffer
+ *
+ * Returns:
+ * A positive number, which is the size of the emitted document
+ * on the buffer on success, -1 on error
+ */
+int
+fy_emit_document_to_buffer(struct fy_document *fyd,
+			   enum fy_emitter_cfg_flags flags,
+			   char *buf, size_t size)
+	FY_EXPORT;
+
+/**
+ * fy_emit_document_to_string() - Emit a document to an allocated string
+ *
+ * Emits an document from the root to a string which will be dynamically
+ * allocated.
+ *
+ * @fyd: The document to emit
+ * @flags: The emitter flags to use
+ *
+ * Returns:
+ * A pointer to the allocated string, or NULL in case of an error
+ */
+char *
+fy_emit_document_to_string(struct fy_document *fyd,
+			   enum fy_emitter_cfg_flags flags)
+	FY_EXPORT;
+
+#define fy_emit_document_to_string_alloca(_fyd, _flags, _res) \
+	FY_ALLOCA_COPY_FREE(fy_emit_document_to_string((_fyd), (_flags)), FY_NT, (_res))
+
+/**
+ * fy_emit_node_to_buffer() - Emit a node (recursively) to a buffer
+ *
+ * Emits a node recursively to the given buffer.
+ * If the document does not fit, an error will be returned.
+ *
+ * @fyn: The node to emit
+ * @flags: The emitter flags to use
+ * @buf: Pointer to the buffer area to fill
+ * @size: Size of the buffer
+ *
+ * Returns:
+ * A positive number, which is the size of the emitted node
+ * on the buffer on success, -1 on error
+ */
+int
+fy_emit_node_to_buffer(struct fy_node *fyn, enum fy_emitter_cfg_flags flags,
+		       char *buf, size_t size)
+	FY_EXPORT;
+
+/**
+ * fy_emit_node_to_string() - Emit a node to an allocated string
+ *
+ * Emits a node recursively to a string which will be dynamically
+ * allocated.
+ *
+ * @fyn: The node to emit
+ * @flags: The emitter flags to use
+ *
+ * Returns:
+ * A pointer to the allocated string, or NULL in case of an error
+ */
+char *
+fy_emit_node_to_string(struct fy_node *fyn, enum fy_emitter_cfg_flags flags)
+	FY_EXPORT;
+
+#define fy_emit_node_to_string_alloca(_fyn, _flags, _res) \
+	FY_ALLOCA_COPY_FREE(fy_emit_node_to_string((_fyn), (_flags)), FY_NT, (_res))
+
+/**
+ * fy_emit_to_buffer() - Create an emitter for buffer output.
+ *
+ * Creates a special purpose emitter for buffer output.
+ * Calls to fy_emit_event() populate the buffer.
+ * The contents are retreived by a call to fy_emit_to_buffer_collect()
+ *
+ * @flags: The emitter flags to use
+ * @buf: Pointer to the buffer area to fill
+ * @size: Size of the buffer
+ *
+ * Returns:
+ * The newly created emitter or NULL on error.
+ */
+struct fy_emitter *
+fy_emit_to_buffer(enum fy_emitter_cfg_flags flags, char *buf, size_t size)
+	FY_EXPORT;
+
+/**
+ * fy_emit_to_buffer_collect() - Collect the buffer emitter output
+ *
+ * Collects the output of the emitter which was created by
+ * fy_emit_to_buffer() and populated using fy_emit_event() calls.
+ * The NULL terminated returned buffer is the same as the one used in the
+ * fy_emit_to_buffer() call and the sizep argument will be filled with
+ * the size of the buffer.
+ *
+ * @emit: The emitter
+ * @sizep: Pointer to the size to be filled
+ *
+ * Returns:
+ * The buffer or NULL in case of an error.
+ */
+char *
+fy_emit_to_buffer_collect(struct fy_emitter *emit, size_t *sizep)
+	FY_EXPORT;
+
+/**
+ * fy_emit_to_string() - Create an emitter to create a dynamically
+ *                       allocated string.
+ *
+ * Creates a special purpose emitter for output to a dynamically
+ * allocated string.
+ * Calls to fy_emit_event() populate the buffer.
+ * The contents are retreived by a call to fy_emit_to_string_collect()
+ *
+ * @flags: The emitter flags to use
+ *
+ * Returns:
+ * The newly created emitter or NULL on error.
+ */
+struct fy_emitter *
+fy_emit_to_string(enum fy_emitter_cfg_flags flags)
+	FY_EXPORT;
+
+/**
+ * fy_emit_to_string_collect() - Collect the string emitter output
+ *
+ * Collects the output of the emitter which was created by
+ * fy_emit_to_string() and populated using fy_emit_event() calls.
+ * The NULL terminated returned buffer is dynamically allocated
+ * and must be freed via a call to free().
+ * The sizep argument will be filled with the size of the buffer.
+ *
+ * @emit: The emitter
+ * @sizep: Pointer to the size to be filled
+ *
+ * Returns:
+ * The dynamically allocated string or NULL in case of an error.
+ */
+char *
+fy_emit_to_string_collect(struct fy_emitter *emit, size_t *sizep)
+	FY_EXPORT;
+
+/**
+ * fy_node_copy() - Copy a node, associating the new node with the given document
+ *
+ * Make a deep copy of a node, associating the copy with the given document.
+ * Note that no content copying takes place as the contents of the nodes
+ * are reference counted. This means that the operation is relatively inexpensive.
+ *
+ * Note that the copy includes all anchors contained in the subtree of the
+ * source, so this call will register them with the document.
+ *
+ * @fyd: The document which the resulting node will be associated with
+ * @fyn_from: The source node to recursively copy
+ *
+ * Returns:
+ * The copied node on success, NULL on error
+ */
+struct fy_node *
+fy_node_copy(struct fy_document *fyd, struct fy_node *fyn_from)
+	FY_EXPORT;
+
+/**
+ * fy_document_clone() - Clones a document
+ *
+ * Clone a document, by making a deep copy of the source.
+ * Note that no content copying takes place as the contents of the nodes
+ * are reference counted. This means that the operation is relatively inexpensive.
+ *
+ * @fydsrc: The source document to clone
+ *
+ * Returns:
+ * The newly created clone document, or NULL in case of an error
+ */
+struct fy_document *
+fy_document_clone(struct fy_document *fydsrc)
+	FY_EXPORT;
+
+/**
+ * fy_node_insert() - Insert a node to the given node
+ *
+ * Insert a node to another node. If @fyn_from is NULL then this
+ * operation will delete the @fyn_to node.
+ *
+ * The operation varies according to the types of the arguments:
+ *
+ * from: scalar
+ *
+ * to: another-scalar -> scalar
+ * to: { key: value } -> scalar
+ * to: [ seq0, seq1 ] -> scalar
+ *
+ * from: [ seq2 ]
+ * to: scalar -> [ seq2 ]
+ * to: { key: value } -> [ seq2 ]
+ * to: [ seq0, seq1 ] -> [ seq0, seq1, sec2 ]
+ *
+ * from: { another-key: another-value }
+ * to: scalar -> { another-key: another-value }
+ * to: { key: value } -> { key: value, another-key: another-value }
+ * to: [ seq0, seq1 ] -> { another-key: another-value }
+ *
+ * from: { key: another-value }
+ * to: scalar -> { key: another-value }
+ * to: { key: value } -> { key: another-value }
+ * to: [ seq0, seq1 ] -> { key: another-value }
+ *
+ * The rules are:
+ * - If target node changes type, source ovewrites target.
+ * - If source or target node are scalars, source it overwrites target.
+ * - If target and source are sequences the items of the source sequence
+ *   are appended to the target sequence.
+ * - If target and source are maps the key, value pairs of the source
+ *   are appended to the target map. If the target map contains a
+ *   key-value pair that is present in the source map, it is overwriten
+ *   by it.
+ *
+ * @fyn_to: The target node
+ * @fyn_from: The source node
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_insert(struct fy_node *fyn_to, struct fy_node *fyn_from)
+	FY_EXPORT;
+
+/**
+ * fy_document_insert_at() - Insert a node to the given path in the document
+ *
+ * Insert a node to a given point in the document. If @fyn is NULL then this
+ * operation will delete the target node.
+ *
+ * Please see fy_node_insert for details of operation.
+ *
+ * Note that in any case the fyn node will be unref'ed.
+ * So if the operation fails, and the reference is 0
+ * the node will be freed. If you want it to stick around
+ * take a reference before.
+ *
+ * @fyd: The document
+ * @path: The path where the insert operation will target
+ * @pathlen: The length of the path (or -1 if '\0' terminated)
+ * @fyn: The source node
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_document_insert_at(struct fy_document *fyd,
+		      const char *path, size_t pathlen,
+		      struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * enum fy_node_type - Node type
+ *
+ * Each node may be one of the following types
+ *
+ * @FYNT_SCALAR: Node is a scalar
+ * @FYNT_SEQUENCE: Node is a sequence
+ * @FYNT_MAPPING: Node is a mapping
+ */
+enum fy_node_type {
+	FYNT_SCALAR,
+	FYNT_SEQUENCE,
+	FYNT_MAPPING,
+};
+
+/**
+ * enum fy_node_style - Node style
+ *
+ * A node may contain a hint of how it should be
+ * rendered, encoded as a style.
+ *
+ * @FYNS_ANY: No hint, let the emitter decide
+ * @FYNS_FLOW: Prefer flow style (for sequence/mappings)
+ * @FYNS_BLOCK: Prefer block style (for sequence/mappings)
+ * @FYNS_PLAIN: Plain style preferred
+ * @FYNS_SINGLE_QUOTED: Single quoted style preferred
+ * @FYNS_DOUBLE_QUOTED: Double quoted style preferred
+ * @FYNS_LITERAL: Literal style preferred (valid in block context)
+ * @FYNS_FOLDED: Folded style preferred (valid in block context)
+ * @FYNS_ALIAS: It's an alias
+ */
+enum fy_node_style {
+	FYNS_ANY = -1,
+	FYNS_FLOW,
+	FYNS_BLOCK,
+	FYNS_PLAIN,
+	FYNS_SINGLE_QUOTED,
+	FYNS_DOUBLE_QUOTED,
+	FYNS_LITERAL,
+	FYNS_FOLDED,
+	FYNS_ALIAS,
+};
+
+/* maximum depth is 256 */
+#define FYNWF_MAXDEPTH_SHIFT	4
+#define FYNWF_MAXDEPTH_MASK	0xff
+#define FYNWF_MAXDEPTH(x)	(((x) & FYNWF_MAXDEPTH_MASK) << FYNWF_MAXDEPTH_SHIFT)
+#define FYNWF_MARKER_SHIFT	12
+#define FYNWF_MARKER_MASK	0x1f
+#define FYNWF_MARKER(x)		(((x) & FYNWF_MARKER_MASK) << FYNWF_MARKER_SHIFT)
+#define FYNWF_PTR_SHIFT		16
+#define FYNWF_PTR_MASK		0x03
+#define FYNWF_PTR(x)		(((x) & FYNWF_PTR_MASK) << FYNWF_PTR_SHIFT)
+
+/**
+ * enum fy_node_walk_flags - Node walk flags
+ *
+ * @FYNWF_DONT_FOLLOW: Don't follow aliases during pathwalk
+ * @FYNWF_FOLLOW: Follow aliases during pathwalk
+ * @FYNWF_PTR_YAML: YAML pointer path walks
+ * @FYNWF_PTR_JSON: JSON pointer path walks
+ * @FYNWF_PTR_RELJSON: Relative JSON pointer path walks
+ * @FYNWF_PTR_YPATH: YPATH pointer path walks
+ * @FYNWF_URI_ENCODED: The path is URI encoded
+ * @FYNWF_MAXDEPTH_DEFAULT: Max follow depth is automatically determined
+ * @FYNWF_MARKER_DEFAULT: Default marker to use when scanning
+ * @FYNWF_PTR_DEFAULT: Default path type
+ */
+enum fy_node_walk_flags {
+	FYNWF_DONT_FOLLOW = 0,
+	FYNWF_FOLLOW = FY_BIT(0),
+	FYNWF_PTR_YAML = FYNWF_PTR(0),
+	FYNWF_PTR_JSON = FYNWF_PTR(1),
+	FYNWF_PTR_RELJSON = FYNWF_PTR(2),
+	FYNWF_PTR_YPATH = FYNWF_PTR(3),
+	FYNWF_URI_ENCODED = FY_BIT(18),
+	FYNWF_MAXDEPTH_DEFAULT = FYNWF_MAXDEPTH(0),
+	FYNWF_MARKER_DEFAULT = FYNWF_MARKER(0),
+	FYNWF_PTR_DEFAULT = FYNWF_PTR(0),
+};
+
+/* the maximum user marker */
+#define FYNWF_MAX_USER_MARKER	24
+
+/**
+ * fy_node_style_from_scalar_style() - Convert from scalar to node style
+ *
+ * Convert a scalar style to a node style.
+ *
+ * @sstyle: The input scalar style
+ *
+ * Returns:
+ * The matching node style
+ */
+static inline enum fy_node_style
+fy_node_style_from_scalar_style(enum fy_scalar_style sstyle)
+{
+	if (sstyle == FYSS_ANY)
+		return FYNS_ANY;
+	return (enum fy_node_style)(FYNS_PLAIN + (sstyle - FYSS_PLAIN));
+}
+
+/**
+ * typedef fy_node_mapping_sort_fn - Mapping sorting method function
+ *
+ * @fynp_a: The first node_pair used in the comparison
+ * @fynp_b: The second node_pair used in the comparison
+ * @arg: The opaque user provided pointer to the sort operation
+ *
+ * Returns:
+ * <0 if @fynp_a is less than @fynp_b
+ * 0 if @fynp_a is equal to fynp_b
+ * >0 if @fynp_a is greater than @fynp_b
+ */
+typedef int (*fy_node_mapping_sort_fn)(const struct fy_node_pair *fynp_a,
+				       const struct fy_node_pair *fynp_b,
+				       void *arg);
+
+/**
+ * typedef fy_node_scalar_compare_fn - Node compare method function for scalars
+ *
+ * @fyn_a: The first scalar node used in the comparison
+ * @fyn_b: The second scalar node used in the comparison
+ * @arg: The opaque user provided pointer to the compare operation
+ *
+ * Returns:
+ * <0 if @fyn_a is less than @fyn_b
+ * 0 if @fyn_a is equal to fyn_b
+ * >0 if @fyn_a is greater than @fyn_b
+ */
+typedef int (*fy_node_scalar_compare_fn)(struct fy_node *fyn_a,
+					 struct fy_node *fyn_b,
+					 void *arg);
+
+/**
+ * fy_node_compare() - Compare two nodes for equality
+ *
+ * Compare two nodes for equality.
+ * The comparison is 'deep', i.e. it recurses in subnodes,
+ * and orders the keys of maps using default libc strcmp
+ * ordering. For scalar the comparison is performed after
+ * any escaping so it's a true content comparison.
+ *
+ * @fyn1: The first node to use in the comparison
+ * @fyn2: The second node to use in the comparison
+ *
+ * Returns:
+ * true if the nodes contain the same content, false otherwise
+ */
+bool
+fy_node_compare(struct fy_node *fyn1, struct fy_node *fyn2)
+	FY_EXPORT;
+
+/**
+ * fy_node_compare_user() - Compare two nodes for equality using
+ * 			    user supplied sort and scalar compare methods
+ *
+ * Compare two nodes for equality using user supplied sot and scalar
+ * compare methods.
+ * The comparison is 'deep', i.e. it recurses in subnodes,
+ * and orders the keys of maps using the supplied mapping sort method for
+ * ordering. For scalars the comparison is performed using the supplied
+ * scalar node compare methods.
+ *
+ * @fyn1: The first node to use in the comparison
+ * @fyn2: The second node to use in the comparison
+ * @sort_fn: The method to use for sorting maps, or NULL for the default
+ * @sort_fn_arg: The extra user supplied argument to the @sort_fn
+ * @cmp_fn: The method to use for comparing scalars, or NULL for the default
+ * @cmp_fn_arg: The extra user supplied argument to the @cmp_fn
+ *
+ * Returns:
+ * true if the nodes contain the same content, false otherwise
+ */
+bool
+fy_node_compare_user(struct fy_node *fyn1, struct fy_node *fyn2,
+		     fy_node_mapping_sort_fn sort_fn, void *sort_fn_arg,
+		     fy_node_scalar_compare_fn cmp_fn, void *cmp_fn_arg)
+	FY_EXPORT;
+
+/**
+ * fy_node_compare_string() - Compare a node for equality with a YAML string
+ *
+ * Compare a node for equality with a YAML string.
+ * The comparison is performed using fy_node_compare() with the
+ * first node supplied as an argument and the second being generated
+ * by calling fy_document_build_from_string with the YAML string.
+ *
+ * @fyn: The node to use in the comparison
+ * @str: The YAML string to compare against
+ * @len: The length of the string (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * true if the node and the string are equal.
+ */
+bool
+fy_node_compare_string(struct fy_node *fyn, const char *str, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_compare_token() - Compare a node for equality against a token
+ *
+ * Compare a node for equality with a token.
+ * Both the node and the tokens must be a scalars.
+ *
+ * @fyn: The node to use in the comparison
+ * @fyt: The scalar token
+ *
+ * Returns:
+ * true if the node and the token are equal.
+ */
+bool
+fy_node_compare_token(struct fy_node *fyn, struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_node_compare_text() - Compare a node for equality with a raw C text
+ *
+ * Compare a node for equality with a raw C string.
+ * The node must be a scalar.
+ *
+ * @fyn: The node to use in the comparison
+ * @text: The raw C text to compare against
+ * @len: The length of the text (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * true if the node and the text are equal.
+ */
+bool
+fy_node_compare_text(struct fy_node *fyn, const char *text, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_document_create() - Create an empty document
+ *
+ * Create an empty document using the provided parser configuration.
+ * If NULL use the default parse configuration.
+ *
+ * @cfg: The parse configuration to use or NULL for the default.
+ *
+ * Returns:
+ * The created empty document, or NULL on error.
+ */
+struct fy_document *
+fy_document_create(const struct fy_parse_cfg *cfg)
+	FY_EXPORT;
+
+/**
+ * fy_document_destroy() - Destroy a document previously created via
+ *                         fy_document_create()
+ *
+ * Destroy a document (along with all children documents)
+ *
+ * @fyd: The document to destroy
+ *
+ */
+void
+fy_document_destroy(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_get_cfg() - Get the configuration of a document
+ *
+ * @fyd: The document
+ *
+ * Returns:
+ * The configuration of the document
+ */
+const struct fy_parse_cfg *
+fy_document_get_cfg(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_get_diag() - Get the diagnostic object of a document
+ *
+ * Return a pointer to the diagnostic object of a document object.
+ * Note that the returned diag object has a reference taken so
+ * you should fy_diag_unref() it when you're done with it.
+ *
+ * @fyd: The document to get the diagnostic object
+ *
+ * Returns:
+ * A pointer to a ref'ed diagnostic object or NULL in case of an
+ * error.
+ */
+struct fy_diag *
+fy_document_get_diag(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_set_diag() - Set the diagnostic object of a document
+ *
+ * Replace the documents's current diagnostic object with the one
+ * given as an argument. The previous diagnostic object will be
+ * unref'ed (and freed if its reference gets to 0).
+ * Also note that the diag argument shall take a reference too.
+ *
+ * @fyd: The document to replace the diagnostic object
+ * @diag: The document's new diagnostic object, NULL for default
+ *
+ * Returns:
+ * 0 if everything OK, -1 otherwise
+ */
+int
+fy_document_set_diag(struct fy_document *fyd, struct fy_diag *diag)
+	FY_EXPORT;
+
+/**
+ * fy_document_set_parent() - Make a document a child of another
+ *
+ * Set the parent of @fyd_child document to be @fyd
+ *
+ * @fyd: The parent document
+ * @fyd_child: The child document
+ *
+ * Returns:
+ * 0 if all OK, -1 on error.
+ */
+int
+fy_document_set_parent(struct fy_document *fyd, struct fy_document *fyd_child)
+	FY_EXPORT;
+
+/**
+ * fy_document_build_from_string() - Create a document using the provided YAML source.
+ *
+ * Create a document parsing the provided string as a YAML source.
+ *
+ * @cfg: The parse configuration to use or NULL for the default.
+ * @str: The YAML source to use.
+ * @len: The length of the string (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The created document, or NULL on error.
+ */
+struct fy_document *
+fy_document_build_from_string(const struct fy_parse_cfg *cfg,
+			      const char *str, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_document_build_from_malloc_string() - Create a document using the provided YAML source which was malloced.
+ *
+ * Create a document parsing the provided string as a YAML source. The string is expected to have been
+ * allocated by malloc(3) and when the document is destroyed it will be automatically freed.
+ *
+ * @cfg: The parse configuration to use or NULL for the default.
+ * @str: The YAML source to use.
+ * @len: The length of the string (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The created document, or NULL on error.
+ */
+struct fy_document *
+fy_document_build_from_malloc_string(const struct fy_parse_cfg *cfg,
+				     char *str, size_t len)
+	FY_EXPORT;
+/**
+ * fy_document_build_from_file() - Create a document parsing the given file
+ *
+ * Create a document parsing the provided file as a YAML source.
+ *
+ * @cfg: The parse configuration to use or NULL for the default.
+ * @file: The name of the file to parse
+ *
+ * Returns:
+ * The created document, or NULL on error.
+ */
+struct fy_document *
+fy_document_build_from_file(const struct fy_parse_cfg *cfg, const char *file)
+	FY_EXPORT;
+
+/**
+ * fy_document_build_from_fp() - Create a document parsing the given file pointer
+ *
+ * Create a document parsing the provided file pointer as a YAML source.
+ *
+ * @cfg: The parse configuration to use or NULL for the default.
+ * @fp: The file pointer
+ *
+ * Returns:
+ * The created document, or NULL on error.
+ */
+struct fy_document *
+fy_document_build_from_fp(const struct fy_parse_cfg *cfg, FILE *fp)
+	FY_EXPORT;
+
+/**
+ * fy_document_vbuildf() - Create a document using the provided YAML via vprintf formatting
+ *
+ * Create a document parsing the provided string as a YAML source. The string
+ * is created by applying vprintf formatting.
+ *
+ * @cfg: The parse configuration to use or NULL for the default.
+ * @fmt: The format string creating the YAML source to use.
+ * @ap: The va_list argument pointer
+ *
+ * Returns:
+ * The created document, or NULL on error.
+ */
+struct fy_document *
+fy_document_vbuildf(const struct fy_parse_cfg *cfg,
+		    const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_document_buildf() - Create a document using the provided YAML source via printf formatting
+ *
+ * Create a document parsing the provided string as a YAML source. The string
+ * is created by applying printf formatting.
+ *
+ * @cfg: The parse configuration to use or NULL for the default.
+ * @fmt: The format string creating the YAML source to use.
+ * @...: The printf arguments
+ *
+ * Returns:
+ * The created document, or NULL on error.
+ */
+struct fy_document *
+fy_document_buildf(const struct fy_parse_cfg *cfg, const char *fmt, ...)
+	FY_ATTRIBUTE(format(printf, 2, 3))
+	FY_EXPORT;
+
+/**
+ * fy_flow_document_build_from_string() - Create a document using the provided YAML source.
+ *
+ * Create a document parsing the provided string as a YAML source.
+ *
+ * The document is a flow document, i.e. does not contain any block content
+ * and is usually laid out in a single line.
+ *
+ * Example of flow documents:
+ *
+ * plain-scalar
+ * "double-quoted-scalar"
+ * 'single-quoted-scalar'
+ * { foo: bar }
+ * [ 0, 1, 2 ]
+ *
+ * A flow document is important because parsing stops at the end
+ * of it, and so can be placed in other non-yaml content.
+ *
+ * @cfg: The parse configuration to use or NULL for the default.
+ * @str: The YAML source to use.
+ * @len: The length of the string (or -1 if '\0' terminated)
+ * @consumed: A pointer to the consumed amount
+ *
+ * Returns:
+ * The created document, or NULL on error.
+ */
+struct fy_document *
+fy_flow_document_build_from_string(const struct fy_parse_cfg *cfg,
+				   const char *str, size_t len, size_t *consumed)
+	FY_EXPORT;
+
+/**
+ * fy_document_root() - Return the root node of the document
+ *
+ * Returns the root of the document. If the document is empty
+ * NULL will be returned instead.
+ *
+ * @fyd: The document
+ *
+ * Returns:
+ * The root of the document, or NULL if the document is empty.
+ */
+struct fy_node *
+fy_document_root(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_set_root() - Set the root of the document
+ *
+ * Set the root of a document. If the document was not empty
+ * the old root will be freed. If @fyn is NULL then the
+ * document is set to empty.
+ *
+ * @fyd: The document
+ * @fyn: The new root of the document.
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_document_set_root(struct fy_document *fyd, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_type() - Get the node type
+ *
+ * Retrieve the node type. It is one of FYNT_SCALAR, FYNT_SEQUENCE
+ * or FYNT_MAPPING. A NULL node argument is a FYNT_SCALAR.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The node type
+ */
+enum fy_node_type
+fy_node_get_type(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_style() - Get the node style
+ *
+ * Retrieve the node rendering style.
+ * If the node is NULL then the style is FYNS_PLAIN.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The node style
+ */
+enum fy_node_style
+fy_node_get_style(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_is_scalar() - Check whether the node is a scalar
+ *
+ * Convenience method for checking whether a node is a scalar.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * true if the node is a scalar, false otherwise
+ */
+static inline bool
+fy_node_is_scalar(struct fy_node *fyn)
+{
+	return fy_node_get_type(fyn) == FYNT_SCALAR;
+}
+
+/**
+ * fy_node_is_sequence() - Check whether the node is a sequence
+ *
+ * Convenience method for checking whether a node is a sequence.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * true if the node is a sequence, false otherwise
+ */
+static inline bool
+fy_node_is_sequence(struct fy_node *fyn)
+{
+	return fy_node_get_type(fyn) == FYNT_SEQUENCE;
+}
+
+/**
+ * fy_node_is_mapping() - Check whether the node is a mapping
+ *
+ * Convenience method for checking whether a node is a mapping.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * true if the node is a mapping, false otherwise
+ */
+static inline bool
+fy_node_is_mapping(struct fy_node *fyn)
+{
+	return fy_node_get_type(fyn) == FYNT_MAPPING;
+}
+
+/**
+ * fy_node_is_alias() - Check whether the node is an alias
+ *
+ * Convenience method for checking whether a node is an alias.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * true if the node is an alias, false otherwise
+ */
+static inline bool
+fy_node_is_alias(struct fy_node *fyn)
+{
+	return fy_node_get_type(fyn) == FYNT_SCALAR &&
+	       fy_node_get_style(fyn) == FYNS_ALIAS;
+}
+
+/**
+ * fy_node_is_null() - Check whether the node is a NULL
+ *
+ * Convenience method for checking whether a node is a NULL scalar..
+ * Note that a NULL node argument returns true...
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * true if the node is a NULL scalar, false otherwise
+ */
+bool
+fy_node_is_null(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_is_attached() - Check whether the node is attached
+ *
+ * Checks whether a node is attached in a document structure.
+ * An attached node may not be freed, before being detached.
+ * Note that there is no method that explicitly detaches
+ * a node, since this is handled internaly by the sequence
+ * and mapping removal methods.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * true if the node is attached, false otherwise
+ */
+bool
+fy_node_is_attached(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_tag_token() - Gets the tag token of a node (if it exists)
+ *
+ * Gets the tag token of a node, if it exists
+ *
+ * @fyn: The node which has the tag token to be returned
+ *
+ * Returns:
+ * The tag token of the given node, or NULL if the tag does not
+ * exist.
+ */
+struct fy_token *
+fy_node_get_tag_token(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_scalar_token() - Gets the scalar token of a node (if it exists)
+ *
+ * Gets the scalar token of a node, if it exists and the node is a valid scalar
+ * node. Note that aliases are scalars, so if this call is issued on an alias
+ * node the return shall be of an alias token.
+ *
+ * @fyn: The node which has the scalar token to be returned
+ *
+ * Returns:
+ * The scalar token of the given node, or NULL if the node is not a scalar.
+ */
+struct fy_token *
+fy_node_get_scalar_token(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_resolve_alias() - Resolve an alias node
+ *
+ * Resolve an alias node, following any subsequent aliases until
+ * a non alias node has been found. This call performs cycle detection
+ * and excessive redirections checks so it's safe to call in any
+ * context.
+ *
+ * @fyn: The alias node to be resolved
+ *
+ * Returns:
+ * The resolved alias node, or NULL if either fyn is not an alias, or
+ * resolution fails due to a graph cycle.
+ */
+struct fy_node *
+fy_node_resolve_alias(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_dereference() - Dereference a single alias node
+ *
+ * Dereference an alias node. This is different than resolution
+ * in that will only perform a single alias follow call and
+ * it will fail if the input is not an alias.
+ * This call performs cycle detection
+ * and excessive redirections checks so it's safe to call in any
+ * context.
+ *
+ * @fyn: The alias node to be dereferenced
+ *
+ * Returns:
+ * The dereferenced alias node, or NULL if either fyn is not an alias, or
+ * resolution fails due to a graph cycle.
+ */
+struct fy_node *
+fy_node_dereference(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_free() - Free a node
+ *
+ * Recursively frees the given node releasing the memory it uses, removing
+ * any anchors on the document it contains, and releasing references
+ * on the tokens it contains.
+ *
+ * This method will return an error if the node is attached, or
+ * if not NULL it is not a member of a document.
+ *
+ * @fyn: The node to free
+ *
+ * Returns:
+ * 0 on success, -1 on error.
+ */
+int
+fy_node_free(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_build_from_string() - Create a node using the provided YAML source.
+ *
+ * Create a node parsing the provided string as a YAML source. The
+ * node created will be associated with the provided document.
+ *
+ * @fyd: The document
+ * @str: The YAML source to use.
+ * @len: The length of the string (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_build_from_string(struct fy_document *fyd,
+			  const char *str, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_build_from_malloc_string() - Create a node using the provided YAML source which was malloced.
+ *
+ * Create a node parsing the provided string as a YAML source. The
+ * node created will be associated with the provided document. The string is expected to have been
+ * allocated by malloc(3) and when the document is destroyed it will be automatically freed.
+ *
+ * @fyd: The document
+ * @str: The YAML source to use.
+ * @len: The length of the string (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_build_from_malloc_string(struct fy_document *fyd,
+				 char *str, size_t len)
+	FY_EXPORT;
+
+
+/**
+ * fy_node_build_from_file() - Create a node using the provided YAML file.
+ *
+ * Create a node parsing the provided file as a YAML source. The
+ * node created will be associated with the provided document.
+ *
+ * @fyd: The document
+ * @file: The name of the file to parse
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_build_from_file(struct fy_document *fyd, const char *file)
+	FY_EXPORT;
+
+/**
+ * fy_node_build_from_fp() - Create a node using the provided file pointer.
+ *
+ * Create a node parsing the provided file pointer as a YAML source. The
+ * node created will be associated with the provided document.
+ *
+ * @fyd: The document
+ * @fp: The file pointer
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_build_from_fp(struct fy_document *fyd, FILE *fp)
+	FY_EXPORT;
+
+/**
+ * fy_node_vbuildf() - Create a node using the provided YAML source via vprintf formatting
+ *
+ * Create a node parsing the resulting string as a YAML source. The string
+ * is created by applying vprintf formatting.
+ *
+ * @fyd: The document
+ * @fmt: The format string creating the YAML source to use.
+ * @ap: The va_list argument pointer
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_vbuildf(struct fy_document *fyd, const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_node_buildf() - Create a node using the provided YAML source via printf formatting
+ *
+ * Create a node parsing the resulting string as a YAML source. The string
+ * is created by applying printf formatting.
+ *
+ * @fyd: The document
+ * @fmt: The format string creating the YAML source to use.
+ * @...: The printf arguments
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_buildf(struct fy_document *fyd, const char *fmt, ...)
+	FY_ATTRIBUTE(format(printf, 2, 3))
+	FY_EXPORT;
+
+/**
+ * fy_node_by_path() - Retrieve a node using the provided path spec.
+ *
+ * This method will retrieve a node relative to the given node using
+ * the provided path spec.
+ *
+ * Path specs are comprised of keys seperated by slashes '/'.
+ * Keys are either regular YAML expressions in flow format for traversing
+ * mappings, or indexes in brackets for traversing sequences.
+ * Path specs may start with '/' which is silently ignored.
+ *
+ * A few examples will make this clear
+ *
+ * fyn = { foo: bar } - fy_node_by_path(fyn, "/foo") -> bar
+ * fyn = [ foo, bar ] - fy_node_by_path(fyn, "1") -> bar
+ * fyn = { { foo: bar }: baz } - fy_node_by_path(fyn, "{foo: bar}") -> baz
+ * fyn = [ foo, { bar: baz } } - fy_node_by_path(fyn, "1/bar") -> baz
+ *
+ * Note that the special characters /{}[] are not escaped in plain style,
+ * so you will not be able to use them as path traversal keys.
+ * In that case you can easily use either the single, or double quoted forms:
+ *
+ * fyn = { foo/bar: baz } - fy_node_by_path(fyn, "'foo/bar'") -> baz
+ *
+ * @fyn: The node to use as start of the traversal operation
+ * @path: The path spec to use in the traversal operation
+ * @len: The length of the path (or -1 if '\0' terminated)
+ * @flags: The extra path walk flags
+ *
+ * Returns:
+ * The retrieved node, or NULL if not possible to be found.
+ */
+struct fy_node *
+fy_node_by_path(struct fy_node *fyn, const char *path, size_t len,
+		enum fy_node_walk_flags flags)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_path() - Get the path of this node
+ *
+ * Retrieve the given node's path address relative to the document root.
+ * The address is dynamically allocated and should be freed when
+ * you're done with it.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The node's address, or NULL if fyn is the root.
+ */
+char *
+fy_node_get_path(struct fy_node *fyn)
+	FY_EXPORT;
+
+#define fy_node_get_path_alloca(_fyn, _res) \
+	FY_ALLOCA_COPY_FREE_NO_NULL(fy_node_get_path((_fyn)), FY_NT, (_res))
+
+/**
+ * fy_node_get_parent() - Get the parent node of a node
+ *
+ * Get the parent node of a node. The parent of a document's root
+ * is NULL, and so is the parent of the root of a key node's of a mapping.
+ * This is because the nodes of a key may not be addressed using a
+ * path expression.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The node's parent, or NULL if fyn is the root, or the root of a key mapping.
+ */
+struct fy_node *
+fy_node_get_parent(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_document_parent() - Get the document parent node of a node
+ *
+ * Get the document parent node of a node. The document parent differs
+ * than the regular parent in that a key's root node of a mapping is not
+ * NULL, rather it points to the actual node parent.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The node's document parent, or NULL if fyn is the root
+ */
+struct fy_node *
+fy_node_get_document_parent(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_parent_address() - Get the path address of this node's parent
+ *
+ * Retrieve the given node's parent path address
+ * The address is dynamically allocated and should be freed when
+ * you're done with it.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The parent's address, or NULL if fyn is the root.
+ */
+char *
+fy_node_get_parent_address(struct fy_node *fyn)
+	FY_EXPORT;
+
+#define fy_node_get_parent_address_alloca(_fyn, _res) \
+	FY_ALLOCA_COPY_FREE_NO_NULL(fy_node_get_parent_address((_fyn)), FY_NT, (_res))
+
+/**
+ * fy_node_get_path_relative_to() - Get a path address of a node
+ *                                  relative to one of it's parents
+ *
+ * Retrieve the given node's path address relative to an arbitrary
+ * parent in the tree.
+ * The address is dynamically allocated and should be freed when
+ * you're done with it.
+ *
+ * @fyn_parent: The node parent/grandparent...
+ * @fyn: The node
+ *
+ * Returns:
+ * The relative address from the parent to the node
+ */
+char *
+fy_node_get_path_relative_to(struct fy_node *fyn_parent, struct fy_node *fyn)
+	FY_EXPORT;
+
+#define fy_node_get_path_relative_to_alloca(_fynp, _fyn, _res) \
+	FY_ALLOCA_COPY_FREE_NO_NULL(fy_node_get_path_relative_to((_fynp), (_fyn)), FY_NT, (_res))
+
+/**
+ * fy_node_get_short_path() - Get a path address of a node in the shortest
+ *                            path possible
+ *
+ * Retrieve the given node's short path address relative to the
+ * closest anchor (either on this node, or it's parent).
+ * If no such parent is found then returns the absolute path
+ * from the start of the document.
+ *
+ *   --- &foo
+ *   foo: &bar
+ *       bar
+ *   baz
+ *
+ * - The short path of /foo is \*foo
+ * - The short path of /foo/bar is \*bar
+ * - The short path of /baz is \*foo/baz
+ *
+ * The address is dynamically allocated and should be freed when
+ * you're done with it.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The shortest path describing the node
+ */
+char *
+fy_node_get_short_path(struct fy_node *fyn)
+	FY_EXPORT;
+
+#define fy_node_get_short_path_alloca(_fyn, _res) \
+	FY_ALLOCA_COPY_FREE_NO_NULL(fy_node_get_short_path((_fyn)), FY_NT, (_res))
+
+/**
+ * fy_node_get_reference() - Get a textual reference to a node
+ *
+ * Retrieve the given node's textual reference. If the node
+ * contains an anchor the expression that references the anchor
+ * will be returned, otherwise an absolute path reference relative
+ * to the root of the document will be returned.
+ *
+ * The address is dynamically allocated and should be freed when
+ * you're done with it.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The node's text reference.
+ */
+char *
+fy_node_get_reference(struct fy_node *fyn)
+	FY_EXPORT;
+
+#define fy_node_get_reference_alloca(_fyn, _res) \
+	FY_ALLOCA_COPY_FREE_NO_NULL(fy_node_get_reference((_fyn)), FY_NT, (_res))
+
+/**
+ * fy_node_create_reference() - Create an alias reference node
+ *
+ * Create an alias node reference. If the node
+ * contains an anchor the expression that references the alias will
+ * use the anchor, otherwise an absolute path reference relative
+ * to the root of the document will be created.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * An alias node referencing the argument node
+ */
+struct fy_node *
+fy_node_create_reference(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_relative_reference() - Get a textual reference to a node
+ * 				      relative to a base node.
+ *
+ * Retrieve the given node's textual reference as generated using
+ * another parent (or grand parent) as a base.
+ * If the node contains an anchor the expression that references the anchor
+ * will be returned.
+ * If the base node contains an anchor the reference will be relative to it
+ * otherwise an absolute path reference will be returned.
+ *
+ * The address is dynamically allocated and should be freed when
+ * you're done with it.
+ *
+ * @fyn_base: The base node
+ * @fyn: The node
+ *
+ * Returns:
+ * The node's text reference.
+ */
+char *
+fy_node_get_relative_reference(struct fy_node *fyn_base, struct fy_node *fyn)
+	FY_EXPORT;
+
+#define fy_node_get_relative_reference_alloca(_fynb, _fyn, _res) \
+	FY_ALLOCA_COPY_FREE_NO_NULL(fy_node_get_relative_reference((_fynb), (_fyn)), FY_NT, (_res))
+
+/**
+ * fy_node_create_relative_reference() - Create an alias reference node
+ *
+ * Create a relative alias node reference using
+ * another parent (or grand parent) as a base.
+ * If the node contains an anchor the alias will reference the anchor.
+ * If the base node contains an anchor the alias will be relative to it
+ * otherwise an absolute path reference will be created.
+ *
+ * @fyn_base: The base node
+ * @fyn: The node
+ *
+ * Returns:
+ * An alias node referencing the argument node relative to the base
+ */
+struct fy_node *
+fy_node_create_relative_reference(struct fy_node *fyn_base, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_create_scalar() - Create a scalar node.
+ *
+ * Create a scalar node using the provided memory area as input.
+ * The input is expected to be regular utf8 encoded. It may contain
+ * escaped characters in which case the style of the scalar will be
+ * set to double quoted.
+ *
+ * Note that the data are not copied, merely a reference is taken, so
+ * it must be available while the node is in use.
+ *
+ * @fyd: The document which the resulting node will be associated with
+ * @data: Pointer to the data area
+ * @size: Size of the data area, or (size_t)-1 for '\0' terminated data.
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_create_scalar(struct fy_document *fyd,
+		      const char *data, size_t size)
+	FY_EXPORT;
+
+/**
+ * fy_node_create_scalar_copy() - Create a scalar node copying the data.
+ *
+ * Create a scalar node using the provided memory area as input.
+ * The input is expected to be regular utf8 encoded. It may contain
+ * escaped characters in which case the style of the scalar will be
+ * set to double quoted.
+ *
+ * A copy of the data will be made, so it is safe to free the data
+ * after the call.
+ *
+ * @fyd: The document which the resulting node will be associated with
+ * @data: Pointer to the data area
+ * @size: Size of the data area, or (size_t)-1 for '\0' terminated data.
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_create_scalar_copy(struct fy_document *fyd,
+			   const char *data, size_t size)
+	FY_EXPORT;
+
+/**
+ * fy_node_create_vscalarf() - vprintf interface for creating scalars
+ *
+ * Create a scalar node using a vprintf interface.
+ * The input is expected to be regular utf8 encoded. It may contain
+ * escaped characters in which case the style of the scalar will be
+ * set to double quoted.
+ *
+ * @fyd: The document which the resulting node will be associated with
+ * @fmt: The printf based format string
+ * @ap: The va_list containing the arguments
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_create_vscalarf(struct fy_document *fyd, const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_node_create_scalarf() - printf interface for creating scalars
+ *
+ * Create a scalar node using a printf interface.
+ * The input is expected to be regular utf8 encoded. It may contain
+ * escaped characters in which case the style of the scalar will be
+ * set to double quoted.
+ *
+ * @fyd: The document which the resulting node will be associated with
+ * @fmt: The printf based format string
+ * @...: The arguments
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_create_scalarf(struct fy_document *fyd, const char *fmt, ...)
+	FY_EXPORT
+	FY_ATTRIBUTE(format(printf, 2, 3));
+
+/**
+ * fy_node_create_sequence() - Create an empty sequence node.
+ *
+ * Create an empty sequence node associated with the given document.
+ *
+ * @fyd: The document which the resulting node will be associated with
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_create_sequence(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_node_create_mapping() - Create an empty mapping node.
+ *
+ * Create an empty mapping node associated with the given document.
+ *
+ * @fyd: The document which the resulting node will be associated with
+ *
+ * Returns:
+ * The created node, or NULL on error.
+ */
+struct fy_node *
+fy_node_create_mapping(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_node_set_tag() - Set the tag of node
+ *
+ * Manually set the tag of a node. The tag must be a valid one for
+ * the document the node belongs to.
+ *
+ * Note that the data are not copied, merely a reference is taken, so
+ * it must be available while the node is in use.
+ *
+ * If the node already contains a tag it will be overwriten.
+ *
+ * @fyn: The node to set it's tag.
+ * @data: Pointer to the tag data.
+ * @len: Size of the tag data, or (size_t)-1 for '\0' terminated.
+ *
+ * Returns:
+ * 0 on success, -1 on error.
+ */
+int
+fy_node_set_tag(struct fy_node *fyn, const char *data, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_remove_tag() - Remove the tag of node
+ *
+ * Remove the tag of a node.
+ *
+ * @fyn: The node to remove it's tag.
+ *
+ * Returns:
+ * 0 on success, -1 on error.
+ */
+int
+fy_node_remove_tag(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_tag() - Get the tag of the node
+ *
+ * This method will return a pointer to the text of a tag
+ * along with the length of it. Note that this text is *not*
+ * NULL terminated.
+ *
+ * @fyn: The node
+ * @lenp: Pointer to a variable that will hold the returned length
+ *
+ * Returns:
+ * A pointer to the tag of the node, while @lenp will be assigned the
+ * length of said tag.
+ * A NULL will be returned in case of an error.
+ */
+const char *
+fy_node_get_tag(struct fy_node *fyn, size_t *lenp)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_scalar() - Get the scalar content of the node
+ *
+ * This method will return a pointer to the text of the scalar
+ * content of a node along with the length of it.
+ * Note that this pointer is *not* NULL terminated.
+ *
+ * @fyn: The scalar node
+ * @lenp: Pointer to a variable that will hold the returned length
+ *
+ * Returns:
+ * A pointer to the scalar content of the node, while @lenp will be assigned the
+ * length of said content.
+ * A NULL will be returned in case of an error, i.e. the node is not
+ * a scalar.
+ */
+const char *
+fy_node_get_scalar(struct fy_node *fyn, size_t *lenp)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_scalar0() - Get the scalar content of the node
+ *
+ * This method will return a pointer to the text of the scalar
+ * content of a node as a null terminated string.
+ * Note that this call will allocate memory to hold the null terminated
+ * string so if possible use fy_node_get_scalar()
+ *
+ * @fyn: The scalar node
+ *
+ * Returns:
+ * A pointer to the scalar content of the node or NULL in returned in case of an error.
+ */
+const char *
+fy_node_get_scalar0(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_scalar_length() - Get the length of the scalar content
+ *
+ * This method will return the size of the scalar content of the node.
+ * If the node is not a scalar it will return 0.
+ *
+ * @fyn: The scalar node
+ *
+ * Returns:
+ * The size of the scalar content, or 0 if node is not scalar.
+ */
+size_t
+fy_node_get_scalar_length(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_scalar_utf8_length() - Get the length of the scalar content
+ * 				      in utf8 characters
+ *
+ * This method will return the size of the scalar content of the node in
+ * utf8 characters.
+ * If the node is not a scalar it will return 0.
+ *
+ * @fyn: The scalar node
+ *
+ * Returns:
+ * The size of the scalar content in utf8 characters, or 0 if node is not scalar.
+ */
+size_t
+fy_node_get_scalar_utf8_length(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_iterate() - Iterate over a sequence node
+ *
+ * This method iterates over all the item nodes in the sequence node.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * @fyn: The sequence node
+ * @prevp: The previous sequence iterator
+ *
+ * Returns:
+ * The next node in sequence or NULL at the end of the sequence.
+ */
+struct fy_node *
+fy_node_sequence_iterate(struct fy_node *fyn, void **prevp)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_reverse_iterate() - Iterate over a sequence node in reverse
+ *
+ * This method iterates in reverse over all the item nodes in the sequence node.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * @fyn: The sequence node
+ * @prevp: The previous sequence iterator
+ *
+ * Returns:
+ * The next node in reverse sequence or NULL at the end of the sequence.
+ */
+struct fy_node *
+fy_node_sequence_reverse_iterate(struct fy_node *fyn, void **prevp)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_item_count() - Return the item count of the sequence
+ *
+ * Get the item count of the sequence.
+ *
+ * @fyn: The sequence node
+ *
+ * Returns:
+ * The count of items in the sequence or -1 in case of an error.
+ */
+int
+fy_node_sequence_item_count(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_is_empty() - Check whether the sequence is empty
+ *
+ * Check whether the sequence contains items.
+ *
+ * @fyn: The sequence node
+ *
+ * Returns:
+ * true if the node is a sequence containing items, false otherwise
+ */
+bool
+fy_node_sequence_is_empty(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_get_by_index() - Return a sequence item by index
+ *
+ * Retrieve a node in the sequence using it's index. If index
+ * is positive or zero the count is from the start of the sequence,
+ * while if negative from the end. I.e. -1 returns the last item
+ * in the sequence.
+ *
+ * @fyn: The sequence node
+ * @index: The index of the node to retrieve.
+ *         - >= 0 counting from the start
+ *         - < 0 counting from the end
+ *
+ * Returns:
+ * The node at the specified index or NULL if no such item exist.
+ */
+struct fy_node *
+fy_node_sequence_get_by_index(struct fy_node *fyn, int index)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_append() - Append a node item to a sequence
+ *
+ * Append a node item to a sequence.
+ *
+ * @fyn_seq: The sequence node
+ * @fyn: The node item to append
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_sequence_append(struct fy_node *fyn_seq, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_prepend() - Append a node item to a sequence
+ *
+ * Prepend a node item to a sequence.
+ *
+ * @fyn_seq: The sequence node
+ * @fyn: The node item to prepend
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int fy_node_sequence_prepend(struct fy_node *fyn_seq, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_insert_before() - Insert a node item before another
+ *
+ * Insert a node item before another in the sequence.
+ *
+ * @fyn_seq: The sequence node
+ * @fyn_mark: The node item which the node will be inserted before.
+ * @fyn: The node item to insert in the sequence.
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_sequence_insert_before(struct fy_node *fyn_seq,
+			       struct fy_node *fyn_mark, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_insert_after() - Insert a node item after another
+ *
+ * Insert a node item after another in the sequence.
+ *
+ * @fyn_seq: The sequence node
+ * @fyn_mark: The node item which the node will be inserted after.
+ * @fyn: The node item to insert in the sequence.
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_sequence_insert_after(struct fy_node *fyn_seq,
+			      struct fy_node *fyn_mark, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_remove() - Remove an item from a sequence
+ *
+ * Remove a node item from a sequence and return it.
+ *
+ * @fyn_seq: The sequence node
+ * @fyn: The node item to remove from the sequence.
+ *
+ * Returns:
+ * The removed node item fyn, or NULL in case of an error.
+ */
+struct fy_node *
+fy_node_sequence_remove(struct fy_node *fyn_seq, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_iterate() - Iterate over a mapping node
+ *
+ * This method iterates over all the node pairs in the mapping node.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * Note that while a mapping is an unordered collection of key/values
+ * the order of which they are created is important for presentation
+ * purposes.
+ *
+ * @fyn: The mapping node
+ * @prevp: The previous sequence iterator
+ *
+ * Returns:
+ * The next node pair in the mapping or NULL at the end of the mapping.
+ */
+struct fy_node_pair *
+fy_node_mapping_iterate(struct fy_node *fyn, void **prevp)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_reverse_iterate() - Iterate over a mapping node in reverse
+ *
+ * This method iterates in reverse over all the node pairs in the mapping node.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * Note that while a mapping is an unordered collection of key/values
+ * the order of which they are created is important for presentation
+ * purposes.
+ *
+ * @fyn: The mapping node
+ * @prevp: The previous sequence iterator
+ *
+ * Returns:
+ * The next node pair in reverse sequence in the mapping or NULL at the end of the mapping.
+ */
+struct fy_node_pair *
+fy_node_mapping_reverse_iterate(struct fy_node *fyn, void **prevp)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_item_count() - Return the node pair count of the mapping
+ *
+ * Get the count of the node pairs in the mapping.
+ *
+ * @fyn: The mapping node
+ *
+ * Returns:
+ * The count of node pairs in the mapping or -1 in case of an error.
+ */
+int
+fy_node_mapping_item_count(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_is_empty() - Check whether the mapping is empty
+ *
+ * Check whether the mapping contains any node pairs.
+ *
+ * @fyn: The mapping node
+ *
+ * Returns:
+ * true if the node is a mapping containing node pairs, false otherwise
+ */
+bool
+fy_node_mapping_is_empty(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_get_by_index() - Return a node pair by index
+ *
+ * Retrieve a node pair in the mapping using its index. If index
+ * is positive or zero the count is from the start of the sequence,
+ * while if negative from the end. I.e. -1 returns the last node pair
+ * in the mapping.
+ *
+ * @fyn: The mapping node
+ * @index: The index of the node pair to retrieve.
+ *         - >= 0 counting from the start
+ *         - < 0 counting from the end
+ *
+ * Returns:
+ * The node pair at the specified index or NULL if no such item exist.
+ */
+struct fy_node_pair *
+fy_node_mapping_get_by_index(struct fy_node *fyn, int index)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_lookup_pair_by_string() - Lookup a node pair in mapping by string
+ *
+ * This method will return the node pair that contains the same key
+ * from the YAML node created from the @key argument. The comparison of the
+ * node is using fy_node_compare()
+ *
+ * @fyn: The mapping node
+ * @key: The YAML source to use as key
+ * @len: The length of the key (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The value matching the given key, or NULL if not found.
+ */
+struct fy_node_pair *
+fy_node_mapping_lookup_pair_by_string(struct fy_node *fyn,
+				      const char *key, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_lookup_by_string() - Lookup a node value in mapping by string
+ *
+ * This method will return the value of node pair that contains the same key
+ * from the YAML node created from the @key argument. The comparison of the
+ * node is using fy_node_compare()
+ *
+ * @fyn: The mapping node
+ * @key: The YAML source to use as key
+ * @len: The length of the key (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The value matching the given key, or NULL if not found.
+ */
+struct fy_node *
+fy_node_mapping_lookup_by_string(struct fy_node *fyn,
+				 const char *key, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_lookup_value_by_string() - Lookup a node value in mapping by string
+ *
+ * This method will return the value of node pair that contains the same key
+ * from the YAML node created from the @key argument. The comparison of the
+ * node is using fy_node_compare()
+ *
+ * It is synonymous with fy_node_mapping_lookup_by_string().
+ *
+ * @fyn: The mapping node
+ * @key: The YAML source to use as key
+ * @len: The length of the key (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The value matching the given key, or NULL if not found.
+ */
+struct fy_node *
+fy_node_mapping_lookup_value_by_string(struct fy_node *fyn,
+				       const char *key, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_lookup_key_by_string() - Lookup a node key in mapping by string
+ *
+ * This method will return the key of node pair that contains the same key
+ * from the YAML node created from the @key argument. The comparison of the
+ * node is using fy_node_compare()
+ *
+ * @fyn: The mapping node
+ * @key: The YAML source to use as key
+ * @len: The length of the key (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The key matching the given key, or NULL if not found.
+ */
+struct fy_node *
+fy_node_mapping_lookup_key_by_string(struct fy_node *fyn,
+				     const char *key, size_t len)
+	FY_EXPORT;
+
+
+/**
+ * fy_node_mapping_lookup_pair_by_simple_key() - Lookup a node pair in mapping by simple string
+ *
+ * This method will return the node pair that contains the same key
+ * from the YAML node created from the @key argument. The comparison of the
+ * node is using by comparing the strings for identity.
+ *
+ * @fyn: The mapping node
+ * @key: The string to use as key
+ * @len: The length of the key (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The node pair matching the given key, or NULL if not found.
+ */
+struct fy_node_pair *
+fy_node_mapping_lookup_pair_by_simple_key(struct fy_node *fyn,
+					  const char *key, size_t len)
+	FY_EXPORT;
+/**
+ * fy_node_mapping_lookup_value_by_simple_key() - Lookup a node value in mapping by simple string
+ *
+ * This method will return the value of node pair that contains the same key
+ * from the YAML node created from the @key argument. The comparison of the
+ * node is using by comparing the strings for identity.
+ *
+ * @fyn: The mapping node
+ * @key: The string to use as key
+ * @len: The length of the key (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The value matching the given key, or NULL if not found.
+ */
+struct fy_node *
+fy_node_mapping_lookup_value_by_simple_key(struct fy_node *fyn,
+					   const char *key, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_lookup_pair_by_null_key() - Lookup a node pair in mapping that has a NULL key
+ *
+ * This method will return the node pair that has a NULL key.
+ * Note this method is not using the mapping accelerator
+ * and arguably NULL keys should not exist. Alas...
+ *
+ * @fyn: The mapping node
+ *
+ * Returns:
+ * The node pair with a NULL key, NULL otherwise
+ */
+struct fy_node_pair *
+fy_node_mapping_lookup_pair_by_null_key(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_lookup_value_by_null_key() - Lookup a node value with a NULL key.
+ *
+ * Return the value of a node pair that has a NULL key.
+ *
+ * @fyn: The mapping node
+ *
+ * Returns:
+ * The value matching the null key, NULL otherwise.
+ * Note that the value may be NULL too, but for that pathological case
+ * use the node pair method instead.
+ */
+struct fy_node *
+fy_node_mapping_lookup_value_by_null_key(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_lookup_scalar_by_simple_key() - Lookup a scalar in mapping by simple string
+ *
+ * This method will return the scalar contents that contains the same key
+ * from the YAML node created from the @key argument. The comparison of the
+ * node is using by comparing the strings for identity.
+ *
+ * @fyn: The mapping node
+ * @lenp: Pointer to a variable that will hold the returned length
+ * @key: The string to use as key
+ * @keylen: The length of the key (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The scalar contents matching the given key, or NULL if not found.
+ */
+const char *
+fy_node_mapping_lookup_scalar_by_simple_key(struct fy_node *fyn, size_t *lenp,
+					    const char *key, size_t keylen)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_lookup_scalar0_by_simple_key() - Lookup a scalar in mapping by simple string
+ * 						    returning a '\0' terminated scalar
+ *
+ * This method will return the NUL terminated scalar contents that contains the same key
+ * from the YAML node created from the @key argument. The comparison of the
+ * node is using by comparing the strings for identity.
+ *
+ * @fyn: The mapping node
+ * @key: The string to use as key
+ * @keylen: The length of the key (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The NUL terminated scalar contents matching the given key, or NULL if not found.
+ */
+const char *
+fy_node_mapping_lookup_scalar0_by_simple_key(struct fy_node *fyn,
+					     const char *key, size_t keylen)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_lookup_pair() - Lookup a node pair matching the provided key
+ *
+ * This method will return the node pair that matches the provided @fyn_key
+ *
+ * @fyn: The mapping node
+ * @fyn_key: The node to use as key
+ *
+ * Returns:
+ * The node pair matching the given key, or NULL if not found.
+ */
+struct fy_node_pair *
+fy_node_mapping_lookup_pair(struct fy_node *fyn, struct fy_node *fyn_key)
+	FY_EXPORT;
+
+
+/**
+ * fy_node_mapping_lookup_value_by_key() - Lookup a node pair's value matching the provided key
+ *
+ * This method will return the node pair that matches the provided @fyn_key
+ * The key may be collection and a content match check is performed recursively
+ * in order to find the right key.
+ *
+ * @fyn: The mapping node
+ * @fyn_key: The node to use as key
+ *
+ * Returns:
+ * The node value matching the given key, or NULL if not found.
+ */
+struct fy_node *
+fy_node_mapping_lookup_value_by_key(struct fy_node *fyn, struct fy_node *fyn_key);
+
+/**
+ * fy_node_mapping_lookup_key_by_key() - Lookup a node pair's key matching the provided key
+ *
+ * This method will return the node pair that matches the provided @fyn_key
+ * The key may be collection and a content match check is performed recursively
+ * in order to find the right key.
+ *
+ * @fyn: The mapping node
+ * @fyn_key: The node to use as key
+ *
+ * Returns:
+ * The node key matching the given key, or NULL if not found.
+ */
+struct fy_node *
+fy_node_mapping_lookup_key_by_key(struct fy_node *fyn, struct fy_node *fyn_key);
+
+/**
+ * fy_node_mapping_get_pair_index() - Return the node pair index in the mapping
+ *
+ * This method will return the node pair index in the mapping of the given
+ * node pair argument.
+ *
+ * @fyn: The mapping node
+ * @fynp: The node pair
+ *
+ * Returns:
+ * The index of the node pair in the mapping or -1 in case of an error.
+ */
+int
+fy_node_mapping_get_pair_index(struct fy_node *fyn,
+			       const struct fy_node_pair *fynp)
+	FY_EXPORT;
+
+/**
+ * fy_node_pair_key() - Return the key of a node pair
+ *
+ * This method will return the node pair's key.
+ * Note that this may be NULL, which is returned also in case
+ * the node pair argument is NULL, so you should protect against
+ * such a case.
+ *
+ * @fynp: The node pair
+ *
+ * Returns:
+ * The node pair key
+ */
+struct fy_node *
+fy_node_pair_key(struct fy_node_pair *fynp)
+	FY_EXPORT;
+
+/**
+ * fy_node_pair_value() - Return the value of a node pair
+ *
+ * This method will return the node pair's value.
+ * Note that this may be NULL, which is returned also in case
+ * the node pair argument is NULL, so you should protect against
+ * such a case.
+ *
+ * @fynp: The node pair
+ *
+ * Returns:
+ * The node pair value
+ */
+struct fy_node *
+fy_node_pair_value(struct fy_node_pair *fynp)
+	FY_EXPORT;
+
+/**
+ * fy_node_pair_set_key() - Sets the key of a node pair
+ *
+ * This method will set the key part of the node pair.
+ * It will ovewrite any previous key.
+ *
+ * Note that no checks for duplicate keys are going to be
+ * performed.
+ *
+ * @fynp: The node pair
+ * @fyn: The key node
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_pair_set_key(struct fy_node_pair *fynp, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_pair_set_value() - Sets the value of a node pair
+ *
+ * This method will set the value part of the node pair.
+ * It will ovewrite any previous value.
+ *
+ * @fynp: The node pair
+ * @fyn: The value node
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_pair_set_value(struct fy_node_pair *fynp, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_append() - Append a node item to a mapping
+ *
+ * Append a node pair to a mapping.
+ *
+ * @fyn_map: The mapping node
+ * @fyn_key: The node pair's key
+ * @fyn_value: The node pair's value
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_mapping_append(struct fy_node *fyn_map,
+		       struct fy_node *fyn_key, struct fy_node *fyn_value)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_prepend() - Prepend a node item to a mapping
+ *
+ * Prepend a node pair to a mapping.
+ *
+ * @fyn_map: The mapping node
+ * @fyn_key: The node pair's key
+ * @fyn_value: The node pair's value
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_mapping_prepend(struct fy_node *fyn_map,
+			struct fy_node *fyn_key, struct fy_node *fyn_value)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_remove() - Remove a node pair from a mapping
+ *
+ * Remove node pair from a mapping.
+ *
+ * @fyn_map: The mapping node
+ * @fynp: The node pair to remove
+ *
+ * Returns:
+ * 0 on success, -1 on failure.
+ */
+int
+fy_node_mapping_remove(struct fy_node *fyn_map, struct fy_node_pair *fynp)
+	FY_EXPORT;
+
+/**
+ * fy_node_mapping_remove_by_key() - Remove a node pair from a mapping returning the value
+ *
+ * Remove node pair from a mapping using the supplied key.
+ *
+ * @fyn_map: The mapping node
+ * @fyn_key: The node pair's key
+ *
+ * Returns:
+ * The value part of removed node pair, or NULL in case of an error.
+ */
+struct fy_node *
+fy_node_mapping_remove_by_key(struct fy_node *fyn_map, struct fy_node *fyn_key)
+	FY_EXPORT;
+
+/**
+ * fy_node_sort() - Recursively sort node
+ *
+ * Recursively sort all mappings of the given node, using the given
+ * comparison method (if NULL use the default one).
+ *
+ * @fyn: The node to sort
+ * @key_cmp: The comparison method
+ * @arg: An opaque user pointer for the comparison method
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_sort(struct fy_node *fyn, fy_node_mapping_sort_fn key_cmp, void *arg)
+	FY_EXPORT;
+
+/**
+ * fy_node_vscanf() - Retrieve data via vscanf
+ *
+ * This method easily retrieves data using a familiar vscanf interface.
+ * The format string is a regular scanf format string with the following format.
+ *
+ *   "pathspec %opt pathspec %opt..."
+ *
+ * Each pathspec is separated with space from the scanf option
+ *
+ * For example:
+ * fyn = { foo: 3 } -> fy_node_scanf(fyn, "/foo %d", &var) -> var = 3
+ *
+ *
+ * @fyn: The node to use as a pathspec root
+ * @fmt: The scanf based format string
+ * @ap: The va_list containing the arguments
+ *
+ * Returns:
+ * The number of scanned arguments, or -1 on error.
+ */
+int fy_node_vscanf(struct fy_node *fyn, const char *fmt, va_list ap);
+
+/**
+ * fy_node_scanf() - Retrieve data via scanf
+ *
+ * This method easily retrieves data using a familiar vscanf interface.
+ * The format string is a regular scanf format string with the following format.
+ *
+ *   "pathspec %opt pathspec %opt..."
+ *
+ * Each pathspec is separated with space from the scanf option
+ *
+ * For example:
+ * fyn = { foo: 3 } -> fy_node_scanf(fyn, "/foo %d", &var) -> var = 3
+ *
+ *
+ * @fyn: The node to use as a pathspec root
+ * @fmt: The scanf based format string
+ * @...: The arguments
+ *
+ * Returns:
+ * The number of scanned arguments, or -1 on error.
+ */
+int
+fy_node_scanf(struct fy_node *fyn, const char *fmt, ...)
+	FY_ATTRIBUTE(format(scanf, 2, 3))
+	FY_EXPORT;
+
+/**
+ * fy_document_vscanf() - Retrieve data via vscanf relative to document root
+ *
+ * This method easily retrieves data using a familiar vscanf interface.
+ * The format string is a regular scanf format string with the following format.
+ *
+ *   "pathspec %opt pathspec %opt..."
+ *
+ * Each pathspec is separated with space from the scanf option
+ *
+ * For example:
+ * fyd = { foo: 3 } -> fy_document_scanf(fyd, "/foo %d", &var) -> var = 3
+ *
+ *
+ * @fyd: The document
+ * @fmt: The scanf based format string
+ * @ap: The va_list containing the arguments
+ *
+ * Returns:
+ * The number of scanned arguments, or -1 on error.
+ */
+int
+fy_document_vscanf(struct fy_document *fyd, const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_document_scanf() - Retrieve data via scanf relative to document root
+ *
+ * This method easily retrieves data using a familiar vscanf interface.
+ * The format string is a regular scanf format string with the following format.
+ *
+ *   "pathspec %opt pathspec %opt..."
+ *
+ * Each pathspec is separated with space from the scanf option
+ *
+ * For example:
+ * fyn = { foo: 3 } -> fy_node_scanf(fyd, "/foo %d", &var) -> var = 3
+ *
+ *
+ * @fyd: The document
+ * @fmt: The scanf based format string
+ * @...: The arguments
+ *
+ * Returns:
+ * The number of scanned arguments, or -1 on error.
+ */
+int
+fy_document_scanf(struct fy_document *fyd, const char *fmt, ...)
+	FY_ATTRIBUTE(format(scanf, 2, 3))
+	FY_EXPORT;
+
+/**
+ * fy_document_tag_directive_iterate() - Iterate over a document's tag directives
+ *
+ * This method iterates over all the documents tag directives.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * @fyd: The document
+ * @prevp: The previous state of the iterator
+ *
+ * Returns:
+ * The next tag directive token in the document or NULL at the end of them.
+ */
+struct fy_token *
+fy_document_tag_directive_iterate(struct fy_document *fyd, void **prevp)
+	FY_EXPORT;
+
+/**
+ * fy_document_tag_directive_lookup() - Retreive a document's tag directive
+ *
+ * Retreives the matching tag directive token of the document matching the handle.
+ *
+ * @fyd: The document
+ * @handle: The handle to look for
+ *
+ * Returns:
+ * The tag directive token with the given handle or NULL if not found
+ */
+struct fy_token *
+fy_document_tag_directive_lookup(struct fy_document *fyd, const char *handle)
+	FY_EXPORT;
+
+/**
+ * fy_tag_directive_token_handle() - Get a tag directive handle
+ *
+ * Retreives the tag directives token handle value. Only valid on
+ * tag directive tokens.
+ *
+ * @fyt: The tag directive token
+ * @lenp: Pointer to a variable that will hold the returned length
+ *
+ * Returns:
+ * A pointer to the tag directive's handle, while @lenp will be assigned the
+ * length of said handle.
+ * A NULL will be returned in case of an error.
+ */
+const char *
+fy_tag_directive_token_handle(struct fy_token *fyt, size_t *lenp)
+	FY_EXPORT;
+
+/**
+ * fy_tag_directive_token_prefix() - Get a tag directive prefix
+ *
+ * Retreives the tag directives token prefix value. Only valid on
+ * tag directive tokens.
+ *
+ * @fyt: The tag directive token
+ * @lenp: Pointer to a variable that will hold the returned length
+ *
+ * Returns:
+ * A pointer to the tag directive's prefix, while @lenp will be assigned the
+ * length of said prefix.
+ * A NULL will be returned in case of an error.
+ */
+const char *
+fy_tag_directive_token_prefix(struct fy_token *fyt, size_t *lenp)
+	FY_EXPORT;
+
+/**
+ * fy_document_tag_directive_add() - Add a tag directive to a document
+ *
+ * Add tag directive to the document.
+ *
+ * @fyd: The document
+ * @handle: The handle of the tag directive
+ * @prefix: The prefix of the tag directive
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_document_tag_directive_add(struct fy_document *fyd,
+			      const char *handle, const char *prefix)
+	FY_EXPORT;
+
+/**
+ * fy_document_tag_directive_remove() - Remove a tag directive
+ *
+ * Remove a tag directive from a document.
+ * Note that removal is prohibited if any node is still using this tag directive.
+ *
+ * @fyd: The document
+ * @handle: The handle of the tag directive to remove.
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_document_tag_directive_remove(struct fy_document *fyd, const char *handle)
+	FY_EXPORT;
+
+/**
+ * fy_document_lookup_anchor() - Lookup an anchor
+ *
+ * Lookup for an anchor having the name provided
+ *
+ * @fyd: The document
+ * @anchor: The anchor to look for
+ * @len: The length of the anchor (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The anchor if found, NULL otherwise
+ */
+struct fy_anchor *
+fy_document_lookup_anchor(struct fy_document *fyd,
+			  const char *anchor, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_document_lookup_anchor_by_token() - Lookup an anchor by token text
+ *
+ * Lookup for an anchor having the name provided from the text of the token
+ *
+ * @fyd: The document
+ * @anchor: The token contains the anchor text to look for
+ *
+ * Returns:
+ * The anchor if found, NULL otherwise
+ */
+struct fy_anchor *
+fy_document_lookup_anchor_by_token(struct fy_document *fyd,
+				   struct fy_token *anchor)
+	FY_EXPORT;
+
+/**
+ * fy_document_lookup_anchor_by_node() - Lookup an anchor by node
+ *
+ * Lookup for an anchor located in the given node
+ *
+ * @fyd: The document
+ * @fyn: The node
+ *
+ * Returns:
+ * The anchor if found, NULL otherwise
+ */
+struct fy_anchor *
+fy_document_lookup_anchor_by_node(struct fy_document *fyd,
+				  struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_anchor_get_text() - Get the text of an anchor
+ *
+ * This method will return a pointer to the text of an anchor
+ * along with the length of it. Note that this text is *not*
+ * NULL terminated.
+ *
+ * @fya: The anchor
+ * @lenp: Pointer to a variable that will hold the returned length
+ *
+ * Returns:
+ * A pointer to the text of the anchor, while @lenp will be assigned the
+ * length of said anchor.
+ * A NULL will be returned in case of an error.
+ */
+const char *
+fy_anchor_get_text(struct fy_anchor *fya, size_t *lenp)
+	FY_EXPORT;
+
+/**
+ * fy_anchor_node() - Get the node of an anchor
+ *
+ * This method returns the node associated with the anchor.
+ *
+ * @fya: The anchor
+ *
+ * Returns:
+ * The node of the anchor, or NULL in case of an error.
+ */
+struct fy_node *
+fy_anchor_node(struct fy_anchor *fya)
+	FY_EXPORT;
+
+/**
+ * fy_document_anchor_iterate() - Iterate over a document's anchors
+ *
+ * This method iterates over all the documents anchors.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * @fyd: The document
+ * @prevp: The previous state of the iterator
+ *
+ * Returns:
+ * The next anchor in the document or NULL at the end of them.
+ */
+struct fy_anchor *
+fy_document_anchor_iterate(struct fy_document *fyd, void **prevp)
+	FY_EXPORT;
+
+/**
+ * fy_document_set_anchor() - Place an anchor
+ *
+ * Places an anchor to the node with the give text name.
+ *
+ * Note that the data are not copied, merely a reference is taken, so
+ * it must be available while the node is in use.
+ *
+ * Also not that this method is deprecated; use fy_node_set_anchor()
+ * instead.
+ *
+ * @fyd: The document
+ * @fyn: The node to set the anchor to
+ * @text: Pointer to the anchor text
+ * @len: Size of the anchor text, or (size_t)-1 for '\0' terminated.
+ *
+ * Returns:
+ * 0 on success, -1 on error.
+ */
+int
+fy_document_set_anchor(struct fy_document *fyd, struct fy_node *fyn,
+		       const char *text, size_t len)
+	FY_EXPORT FY_DEPRECATED;
+
+/**
+ * fy_node_set_anchor() - Place an anchor to the node
+ *
+ * Places an anchor to the node with the give text name.
+ *
+ * Note that the data are not copied, merely a reference is taken, so
+ * it must be available while the node is in use.
+ *
+ * This is similar to fy_document_set_anchor() with the document set
+ * to the document of the @fyn node.
+ *
+ * @fyn: The node to set the anchor to
+ * @text: Pointer to the anchor text
+ * @len: Size of the anchor text, or (size_t)-1 for '\0' terminated.
+ *
+ * Returns:
+ * 0 on success, -1 on error.
+ */
+int
+fy_node_set_anchor(struct fy_node *fyn, const char *text, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_set_anchor_copy() - Place an anchor to the node copying the text
+ *
+ * Places an anchor to the node with the give text name, which
+ * will be copied, so it's safe to dispose the text after the call.
+ *
+ * @fyn: The node to set the anchor to
+ * @text: Pointer to the anchor text
+ * @len: Size of the anchor text, or (size_t)-1 for '\0' terminated.
+ *
+ * Returns:
+ * 0 on success, -1 on error.
+ */
+int
+fy_node_set_anchor_copy(struct fy_node *fyn, const char *text, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_set_vanchorf() - Place an anchor to the node using a vprintf interface.
+ *
+ * Places an anchor to the node with the give text name as created
+ * via vprintf'ing the arguments.
+ *
+ * @fyn: The node to set the anchor to
+ * @fmt: Pointer to the anchor format string
+ * @ap: The argument list.
+ *
+ * Returns:
+ * 0 on success, -1 on error.
+ */
+int
+fy_node_set_vanchorf(struct fy_node *fyn, const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_node_set_anchorf() - Place an anchor to the node using a printf interface.
+ *
+ * Places an anchor to the node with the give text name as created
+ * via printf'ing the arguments.
+ *
+ * @fyn: The node to set the anchor to
+ * @fmt: Pointer to the anchor format string
+ * @...: The extra arguments.
+ *
+ * Returns:
+ * 0 on success, -1 on error.
+ */
+int
+fy_node_set_anchorf(struct fy_node *fyn, const char *fmt, ...)
+	FY_EXPORT FY_ATTRIBUTE(format(printf, 2, 3));
+
+/**
+ * fy_node_remove_anchor() - Remove an anchor
+ *
+ * Remove an anchor for the given node (if it exists)
+ *
+ * @fyn: The node to remove anchors from
+ *
+ * Returns:
+ * 0 on success, -1 on error.
+ */
+int
+fy_node_remove_anchor(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_anchor() - Get the anchor of a node
+ *
+ * Retrieve the anchor of the given node (if it exists)
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The anchor if there's one at the node, or NULL otherwise
+ */
+struct fy_anchor *
+fy_node_get_anchor(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_nearest_anchor() - Get the nearest anchor of the node
+ *
+ * Retrieve the anchor of the nearest parent of the given node or
+ * the given node if it has one.
+ *
+ * @fyn: The node
+ *
+ * Returns:
+ * The nearest anchor if there's one, or NULL otherwise
+ */
+struct fy_anchor *
+fy_node_get_nearest_anchor(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_nearest_child_of() - Get the nearest node which is a
+ * 				    child of the base
+ *
+ * Retrieve the nearest node which is a child of fyn_base starting
+ * at fyn and working upwards.
+ *
+ * @fyn_base: The base node
+ * @fyn: The node to start from
+ *
+ * Returns:
+ * The nearest child of the base if there's one, or NULL otherwise
+ */
+struct fy_node *
+fy_node_get_nearest_child_of(struct fy_node *fyn_base, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_create_alias() - Create an alias node
+ *
+ * Create an alias on the given document
+ *
+ * Note that the data are not copied, merely a reference is taken, so
+ * it must be available while the node is in use.
+ *
+ * @fyd: The document
+ * @alias: The alias text
+ * @len: The length of the alias (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The created alias node, or NULL in case of an error
+ */
+struct fy_node *
+fy_node_create_alias(struct fy_document *fyd,
+		     const char *alias, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_create_alias_copy() - Create an alias node copying the data
+ *
+ * Create an alias on the given document
+ *
+ * A copy of the data will be made, so it is safe to free the data
+ * after the call.
+ *
+ * @fyd: The document
+ * @alias: The alias text
+ * @len: The length of the alias (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The created alias node, or NULL in case of an error
+ */
+struct fy_node *
+fy_node_create_alias_copy(struct fy_document *fyd,
+			  const char *alias, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_node_get_meta() - Get the meta pointer of a node
+ *
+ * Return the meta pointer of a node.
+ *
+ * @fyn: The node to get meta data from
+ *
+ * Returns:
+ * The stored meta data pointer
+ */
+void *
+fy_node_get_meta(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_set_meta() - Set the meta pointer of a node
+ *
+ * Set the meta pointer of a node. If @meta is NULL
+ * then clear the meta data.
+ *
+ * @fyn: The node to set meta data
+ * @meta: The meta data pointer
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_set_meta(struct fy_node *fyn, void *meta)
+	FY_EXPORT;
+
+/**
+ * fy_node_clear_meta() - Clear the meta data of a node
+ *
+ * Clears the meta data of a node.
+ *
+ * @fyn: The node to clear meta data
+ */
+void
+fy_node_clear_meta(struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * typedef fy_node_meta_clear_fn - Meta data clear method
+ *
+ * This is the callback called when meta data are cleared.
+ *
+ * @fyn: The node which the meta data is being cleared
+ * @meta: The meta data of the node assigned via fy_node_set_meta()
+ * @user: The user pointer of fy_document_register_meta()
+ *
+ */
+typedef void (*fy_node_meta_clear_fn)(struct fy_node *fyn, void *meta, void *user);
+
+/**
+ * fy_document_register_meta() - Register a meta cleanup hook
+ *
+ * Register a meta data cleanup hook, to be called when
+ * the node is freed via a final call to fy_node_free().
+ * The hook is active for all nodes belonging to the document.
+ *
+ * @fyd: The document which the hook is registered to
+ * @clear_fn: The clear hook method
+ * @user: Opaque user provided pointer to the clear method
+ *
+ * Returns:
+ * 0 on success, -1 if another hook is already registered.
+ */
+int
+fy_document_register_meta(struct fy_document *fyd,
+			  fy_node_meta_clear_fn clear_fn, void *user)
+	FY_EXPORT;
+
+/**
+ * fy_document_unregister_meta() - Unregister a meta cleanup hook
+ *
+ * Unregister the currently active meta cleanup hook.
+ * The previous cleanup hook will be called for every node in
+ * the document.
+ *
+ * @fyd: The document to unregister it's meta cleanup hook.
+ */
+void
+fy_document_unregister_meta(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_node_set_marker() - Set a marker of a node
+ *
+ * Sets the marker of the given node, while returning
+ * the previous state of the marker. Note that the
+ * markers use the same space as the node follow markers.
+ *
+ * @fyn: The node
+ * @marker: The marker to set
+ *
+ * Returns:
+ * The previous value of the marker
+ */
+bool
+fy_node_set_marker(struct fy_node *fyn, unsigned int marker)
+	FY_EXPORT;
+
+/**
+ * fy_node_clear_marker() - Clear a marker of a node
+ *
+ * Clears the marker of the given node, while returning
+ * the previous state of the marker. Note that the
+ * markers use the same space as the node follow markers.
+ *
+ * @fyn: The node
+ * @marker: The marker to clear
+ *
+ * Returns:
+ * The previous value of the marker
+ */
+bool
+fy_node_clear_marker(struct fy_node *fyn, unsigned int marker)
+	FY_EXPORT;
+
+/**
+ * fy_node_is_marker_set() - Checks whether a marker is set
+ *
+ * Check the state of the given marker.
+ *
+ * @fyn: The node
+ * @marker: The marker index (must be less that FYNWF_MAX_USER_MARKER)
+ *
+ * Returns:
+ * The value of the marker (invalid markers return false)
+ */
+bool
+fy_node_is_marker_set(struct fy_node *fyn, unsigned int marker)
+	FY_EXPORT;
+
+/**
+ * fy_node_vreport() - Report about a node vprintf style
+ *
+ * Output a report about the given node via the specific
+ * error type, and using the reporting configuration of the node's
+ * document.
+ *
+ * @fyn: The node
+ * @type: The error type
+ * @fmt: The printf format string
+ * @ap: The argument list
+ */
+void
+fy_node_vreport(struct fy_node *fyn, enum fy_error_type type,
+		const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_node_report() - Report about a node printf style
+ *
+ * Output a report about the given node via the specific
+ * error type, and using the reporting configuration of the node's
+ * document.
+ *
+ * @fyn: The node
+ * @type: The error type
+ * @fmt: The printf format string
+ * @...: The extra arguments.
+ */
+void
+fy_node_report(struct fy_node *fyn, enum fy_error_type type,
+	       const char *fmt, ...)
+	FY_ATTRIBUTE(format(printf, 3, 4))
+	FY_EXPORT;
+
+/**
+ * fy_node_override_vreport() - Report about a node vprintf style,
+ * 				overriding file, line and column info
+ *
+ * Output a report about the given node via the specific
+ * error type, and using the reporting configuration of the node's
+ * document. This method will use the overrides provided in order
+ * to massage the reporting information.
+ * If @file is NULL, no file location will be reported.
+ * If either @line or @column is negative no location will be reported.
+ *
+ * @fyn: The node
+ * @type: The error type
+ * @file: The file override
+ * @line: The line override
+ * @column: The column override
+ * @fmt: The printf format string
+ * @ap: The argument list
+ */
+void
+fy_node_override_vreport(struct fy_node *fyn, enum fy_error_type type,
+			 const char *file, int line, int column,
+			 const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_node_override_report() - Report about a node printf style,
+ * 				overriding file, line and column info
+ *
+ * Output a report about the given node via the specific
+ * error type, and using the reporting configuration of the node's
+ * document. This method will use the overrides provided in order
+ * to massage the reporting information.
+ * If @file is NULL, no file location will be reported.
+ * If either @line or @column is negative no location will be reported.
+ *
+ * @fyn: The node
+ * @type: The error type
+ * @file: The file override
+ * @line: The line override
+ * @column: The column override
+ * @fmt: The printf format string
+ * @...: The extra arguments.
+ */
+void
+fy_node_override_report(struct fy_node *fyn, enum fy_error_type type,
+			const char *file, int line, int column,
+			const char *fmt, ...)
+	FY_ATTRIBUTE(format(printf, 6, 7))
+	FY_EXPORT;
+
+typedef void (*fy_diag_output_fn)(struct fy_diag *diag, void *user,
+				  const char *buf, size_t len);
+
+/**
+ * struct fy_diag_cfg - The diagnostics configuration
+ *
+ * @fp: File descriptor of the error output
+ * @output_fn: Callback to use when fp is NULL
+ * @user: User pointer to pass to the output_fn
+ * @level: The minimum debugging level
+ * @module_mask: A bitmask of the enabled modules
+ * @colorize: true if output should be colorized using ANSI sequences
+ * @show_source: true if source location should be displayed
+ * @show_position: true if position should be displayed
+ * @show_type: true if the type should be displayed
+ * @show_module: true if the module should be displayed
+ * @source_width: Width of the source field
+ * @position_width: Width of the position field
+ * @type_width: Width of the type field
+ * @module_width: Width of the module field
+ *
+ * This structure contains the configuration of the
+ * diagnostic object.
+ */
+struct fy_diag_cfg {
+	FILE *fp;
+	fy_diag_output_fn output_fn;
+	void *user;
+	enum fy_error_type level;
+	unsigned int module_mask;
+	bool colorize : 1;
+	bool show_source : 1;
+	bool show_position : 1;
+	bool show_type : 1;
+	bool show_module : 1;
+	int source_width;
+	int position_width;
+	int type_width;
+	int module_width;
+};
+
+/**
+ * struct fy_diag_error - A collected diagnostic error
+ *
+ * @type: Error type
+ * @module: The module
+ * @fyt: The token (may be NULL)
+ * @msg: The message to be output alongside
+ * @file: The file which contained the input
+ * @line: The line at the error
+ * @column: The column at the error
+ *
+ * This structure contains information about an error
+ * being collected by the diagnostic object.
+ */
+struct fy_diag_error {
+	enum fy_error_type type;
+	enum fy_error_module module;
+	struct fy_token *fyt;
+	const char *msg;
+	const char *file;
+	int line;
+	int column;
+};
+
+/**
+ * fy_diag_create() - Create a diagnostic object
+ *
+ * Creates a diagnostic object using the provided configuration.
+ *
+ * @cfg: The configuration for the diagnostic object (NULL is default)
+ *
+ * Returns:
+ * A pointer to the diagnostic object or NULL in case of an error.
+ */
+struct fy_diag *
+fy_diag_create(const struct fy_diag_cfg *cfg)
+	FY_EXPORT;
+
+/**
+ * fy_diag_destroy() - Destroy a diagnostic object
+ *
+ * Destroy a diagnostic object; note that the actual
+ * destruction only occurs when no more references to the
+ * object are present. However no output will be generated
+ * after this call.
+ *
+ * @diag: The diagnostic object to destroy
+ */
+void
+fy_diag_destroy(struct fy_diag *diag)
+	FY_EXPORT;
+
+/**
+ * fy_diag_get_cfg() - Get a diagnostic object's configuration
+ *
+ * Return the current configuration of a diagnostic object
+ *
+ * @diag: The diagnostic object
+ *
+ * Returns:
+ * A const pointer to the diagnostic object configuration, or NULL
+ * in case where diag is NULL
+ */
+const struct fy_diag_cfg *
+fy_diag_get_cfg(struct fy_diag *diag)
+	FY_EXPORT;
+
+/**
+ * fy_diag_set_cfg() - Set a diagnostic object's configuration
+ *
+ * Replace the current diagnostic configuration with the given
+ * configuration passed as an argument.
+ *
+ * @diag: The diagnostic object
+ * @cfg: The diagnostic configuration
+ */
+void
+fy_diag_set_cfg(struct fy_diag *diag, const struct fy_diag_cfg *cfg)
+	FY_EXPORT;
+
+/**
+ * fy_diag_set_level() - Set a diagnostic object's debug error level
+ *
+ * @diag: The diagnostic object
+ * @level: The debugging level to set
+ */
+void
+fy_diag_set_level(struct fy_diag *diag, enum fy_error_type level);
+
+/**
+ * fy_diag_set_colorize() - Set a diagnostic object's colorize option
+ *
+ * @diag: The diagnostic object
+ * @colorize: The colorize option
+ */
+void
+fy_diag_set_colorize(struct fy_diag *diag, bool colorize);
+
+/**
+ * fy_diag_ref() - Increment that reference counter of a diagnostic object
+ *
+ * Increment the reference.
+ *
+ * @diag: The diagnostic object to reference
+ *
+ * Returns:
+ * Always returns the @diag argument
+ */
+struct fy_diag *
+fy_diag_ref(struct fy_diag *diag)
+	FY_EXPORT;
+
+/**
+ * fy_diag_unref() - Take away a ref from a diagnostic object
+ *
+ * Take away a reference, if it gets to 0, the diagnostic object
+ * is freed.
+ *
+ * @diag: The diagnostic object to unref
+ */
+void
+fy_diag_unref(struct fy_diag *diag)
+	FY_EXPORT;
+
+/**
+ * fy_diag_got_error() - Test whether an error level diagnostic
+ *                       has been produced
+ *
+ * Tests whether an error diagnostic has been produced.
+ *
+ * @diag: The diagnostic object
+ *
+ * Returns:
+ * true if an error has been produced, false otherwise
+ */
+bool
+fy_diag_got_error(struct fy_diag *diag)
+	FY_EXPORT;
+
+/**
+ * fy_diag_reset_error() - Reset the error flag of
+ * 			   the diagnostic object
+ *
+ * Clears the error flag which was set by an output
+ * of an error level diagnostic
+ *
+ * @diag: The diagnostic object
+ */
+void
+fy_diag_reset_error(struct fy_diag *diag)
+	FY_EXPORT;
+
+/**
+ * fy_diag_set_collect_errors() - Collect errors instead of outputting
+ *
+ * Set the collect errors mode. When true instead of outputting to
+ * the diagnostic interface, errors are collected for later
+ * retrieval.
+ *
+ * @diag: The diagnostic object
+ * @collect_errors: The collect errors mode
+ */
+void
+fy_diag_set_collect_errors(struct fy_diag *diag, bool collect_errors)
+	FY_EXPORT;
+
+/**
+ * fy_diag_cfg_default() - Fill in the configuration structure
+ * 			   with defaults
+ *
+ * Fills the configuration structure with defaults. The default
+ * always associates the file descriptor to stderr.
+ *
+ * @cfg: The diagnostic configuration structure
+ */
+void
+fy_diag_cfg_default(struct fy_diag_cfg *cfg)
+	FY_EXPORT;
+
+/**
+ * fy_diag_cfg_from_parser_flags() - Fill partial diagnostic config
+ * 				     structure from parser config flags
+ *
+ * Fills in part of the configuration structure using parser flags.
+ * Since the parser flags do not contain debugging flags anymore this
+ * method is deprecated.
+ *
+ * @cfg: The diagnostic configuration structure
+ * @pflags: The parser flags
+ */
+void
+fy_diag_cfg_from_parser_flags(struct fy_diag_cfg *cfg,
+			      enum fy_parse_cfg_flags pflags)
+	FY_EXPORT FY_DEPRECATED;
+
+/**
+ * fy_diag_vprintf() - vprintf raw interface to diagnostics
+ *
+ * Raw output to the diagnostic object using a standard
+ * vprintf interface. Note that this is the lowest level
+ * interface, and as such is not recommended for use, since
+ * no formatting or coloring will take place.
+ *
+ * @diag: The diagnostic object to use
+ * @fmt: The vprintf format string
+ * @ap: The arguments
+ *
+ * Returns:
+ * The number of characters output, or -1 in case of an error
+ * Note that 0 shall be returned if the diagnostic object has
+ * been destroyed but not yet freed.
+ */
+int
+fy_diag_vprintf(struct fy_diag *diag, const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_diag_printf() - printf raw interface to diagnostics
+ *
+ * Raw output to the diagnostic object using a standard
+ * printf interface. Note that this is the lowest level
+ * interface, and as such is not recommended for use, since
+ * no formatting or coloring will take place.
+ *
+ * @diag: The diagnostic object to use
+ * @fmt: The printf format string
+ * @...: The arguments
+ *
+ * Returns:
+ * The number of characters output, or -1 in case of an error
+ * Note that 0 shall be returned if the diagnostic object has
+ * been destroyed but not yet freed.
+ */
+int
+fy_diag_printf(struct fy_diag *diag, const char *fmt, ...)
+	FY_EXPORT
+	FY_ATTRIBUTE(format(printf, 2, 3));
+
+/**
+ * struct fy_diag_ctx - The diagnostics context
+ *
+ * @level: The level of the diagnostic
+ * @module: The module of the diagnostic
+ * @source_func: The source function
+ * @source_file: The source file
+ * @source_line: The source line
+ * @file: The file that caused the error
+ * @line: The line where the diagnostic occured
+ * @column: The column where the diagnostic occured
+ *
+ * This structure contains the diagnostic context
+ */
+struct fy_diag_ctx {
+	enum fy_error_type level;
+	enum fy_error_module module;
+	const char *source_func;
+	const char *source_file;
+	int source_line;
+	const char *file;
+	int line;
+	int column;
+};
+
+/**
+ * fy_vdiag() - context aware diagnostic output like vprintf
+ *
+ * Context aware output to the diagnostic object using a standard
+ * vprintf interface.
+ *
+ * @diag: The diagnostic object to use
+ * @fydc: The diagnostic context
+ * @fmt: The vprintf format string
+ * @ap: The arguments
+ *
+ * Returns:
+ * The number of characters output, or -1 in case of an error
+ * Note that 0 shall be returned if the diagnostic object has
+ * been destroyed but not yet freed.
+ */
+int
+fy_vdiag(struct fy_diag *diag, const struct fy_diag_ctx *fydc,
+	 const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_diagf() - context aware diagnostic output like printf
+ *
+ * Context aware output to the diagnostic object using a standard
+ * printf interface.
+ *
+ * @diag: The diagnostic object to use
+ * @fydc: The diagnostic context
+ * @fmt: The vprintf format string
+ *
+ * Returns:
+ * The number of characters output, or -1 in case of an error
+ * Note that 0 shall be returned if the diagnostic object has
+ * been destroyed but not yet freed.
+ */
+int
+fy_diagf(struct fy_diag *diag, const struct fy_diag_ctx *fydc,
+	 const char *fmt, ...)
+	FY_EXPORT
+	FY_ATTRIBUTE(format(printf, 3, 4));
+
+int fy_diag_diag(struct fy_diag *diag, enum fy_error_type level, const char* fmt, ...);
+
+#ifndef NDEBUG
+
+#define fy_debug(_diag, _fmt, ...) \
+	fy_diag_diag((_diag), FYET_DEBUG, (_fmt) , ## __VA_ARGS__)
+#else
+
+#define fy_debug(_diag, _fmt, ...) \
+	do { } while(0)
+
+#endif
+
+#define fy_info(_diag, _fmt, ...) \
+	fy_diag_diag((_diag), FYET_INFO, (_fmt) , ## __VA_ARGS__)
+#define fy_notice(_diag, _fmt, ...) \
+	fy_diag_diag((_diag), FYET_NOTICE, (_fmt) , ## __VA_ARGS__)
+#define fy_warning(_diag, _fmt, ...) \
+	fy_diag_diag((_diag), FYET_WARNING, (_fmt) , ## __VA_ARGS__)
+#define fy_error(_diag, _fmt, ...) \
+	fy_diag_diag((_diag), FYET_ERROR, (_fmt) , ## __VA_ARGS__)
+
+/**
+ * fy_diag_node_vreport() - Report about a node vprintf style using
+ *                          the given diagnostic object
+ *
+ * Output a report about the given node via the specific
+ * error type, and using the reporting configuration of the node's
+ * document.
+ *
+ * @diag: The diag object
+ * @fyn: The node
+ * @type: The error type
+ * @fmt: The printf format string
+ * @ap: The argument list
+ */
+void
+fy_diag_node_vreport(struct fy_diag *diag, struct fy_node *fyn,
+		     enum fy_error_type type, const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_diag_node_report() - Report about a node printf style using
+ *                          the given diagnostic object
+ *
+ * Output a report about the given node via the specific
+ * error type, and using the reporting configuration of the node's
+ * document.
+ *
+ * @diag: The diag object
+ * @fyn: The node
+ * @type: The error type
+ * @fmt: The printf format string
+ * @...: The extra arguments.
+ */
+void
+fy_diag_node_report(struct fy_diag *diag, struct fy_node *fyn,
+		    enum fy_error_type type, const char *fmt, ...)
+	FY_ATTRIBUTE(format(printf, 4, 5))
+	FY_EXPORT;
+
+/**
+ * fy_diag_node_override_vreport() - Report about a node vprintf style,
+ * 				     overriding file, line and column info using
+ * 				     the given diagnostic object
+ *
+ * Output a report about the given node via the specific
+ * error type, and using the reporting configuration of the node's
+ * document. This method will use the overrides provided in order
+ * to massage the reporting information.
+ * If @file is NULL, no file location will be reported.
+ * If either @line or @column is negative no location will be reported.
+ *
+ * @diag: The diag object
+ * @fyn: The node
+ * @type: The error type
+ * @file: The file override
+ * @line: The line override
+ * @column: The column override
+ * @fmt: The printf format string
+ * @ap: The argument list
+ */
+void
+fy_diag_node_override_vreport(struct fy_diag *diag, struct fy_node *fyn,
+			      enum fy_error_type type, const char *file,
+			      int line, int column, const char *fmt, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_diag_node_override_report() - Report about a node printf style,
+ * 				    overriding file, line and column info using
+ * 				    the given diagnostic object
+ *
+ * Output a report about the given node via the specific
+ * error type, and using the reporting configuration of the node's
+ * document. This method will use the overrides provided in order
+ * to massage the reporting information.
+ * If @file is NULL, no file location will be reported.
+ * If either @line or @column is negative no location will be reported.
+ *
+ * @diag: The diag object
+ * @fyn: The node
+ * @type: The error type
+ * @file: The file override
+ * @line: The line override
+ * @column: The column override
+ * @fmt: The printf format string
+ * @...: The extra arguments.
+ */
+void
+fy_diag_node_override_report(struct fy_diag *diag, struct fy_node *fyn,
+			     enum fy_error_type type, const char *file,
+			     int line, int column, const char *fmt, ...)
+	FY_ATTRIBUTE(format(printf, 7, 8))
+	FY_EXPORT;
+
+/**
+ * fy_diag_errors_iterate() - Iterate over the errors of a diagnostic object
+ *
+ * This method iterates over all the errors collected on the diagnostic object.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * @diag: The diagnostic object
+ * @prevp: The previous result iterator
+ *
+ * Returns:
+ * The next errors or NULL when there are not any more.
+ */
+struct fy_diag_error *
+fy_diag_errors_iterate(struct fy_diag *diag, void **prevp)
+	FY_EXPORT;
+
+/**
+ * enum fy_path_parse_cfg_flags - Path parse configuration flags
+ *
+ * These flags control the operation of the path parse
+ *
+ * @FYPPCF_QUIET: Quiet, do not output any information messages
+ * @FYPPCF_DISABLE_RECYCLING: Disable recycling optimization
+ * @FYPPCF_DISABLE_ACCELERATORS: Disable use of access accelerators (saves memory)
+ */
+enum fy_path_parse_cfg_flags {
+	FYPPCF_QUIET			= FY_BIT(0),
+	FYPPCF_DISABLE_RECYCLING	= FY_BIT(1),
+	FYPPCF_DISABLE_ACCELERATORS	= FY_BIT(2),
+};
+
+/**
+ * struct fy_path_parse_cfg - path parser configuration structure.
+ *
+ * Argument to the fy_path_parser_create() method which
+ * performs parsing of a ypath expression
+ *
+ * @flags: Configuration flags
+ * @userdata: Opaque user data pointer
+ * @diag: Optional diagnostic interface to use
+ */
+struct fy_path_parse_cfg {
+	enum fy_path_parse_cfg_flags flags;
+	void *userdata;
+	struct fy_diag *diag;
+};
+
+/**
+ * fy_path_parser_create() - Create a ypath parser.
+ *
+ * Creates a path parser with its configuration @cfg
+ * The path parser may be destroyed by a corresponding call to
+ * fy_path_parser_destroy().
+ *
+ * @cfg: The configuration for the path parser
+ *
+ * Returns:
+ * A pointer to the path parser or NULL in case of an error.
+ */
+struct fy_path_parser *
+fy_path_parser_create(const struct fy_path_parse_cfg *cfg)
+	FY_EXPORT;
+
+/**
+ * fy_path_parser_destroy() - Destroy the given path parser
+ *
+ * Destroy a path parser created earlier via fy_path_parser_create().
+ *
+ * @fypp: The path parser to destroy
+ */
+void
+fy_path_parser_destroy(struct fy_path_parser *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_parser_reset() - Reset a path parser completely
+ *
+ * Completely reset a path parser, including after an error
+ * that caused a parser error to be emitted.
+ *
+ * @fypp: The path parser to reset
+ *
+ * Returns:
+ * 0 if the reset was successful, -1 otherwise
+ */
+int
+fy_path_parser_reset(struct fy_path_parser *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_parse_expr_from_string() - Parse an expression from a given string
+ *
+ * Create a path expression from a string using the provided path parser.
+ *
+ * @fypp: The path parser to use
+ * @str: The ypath source to use.
+ * @len: The length of the string (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The created path expression or NULL on error.
+ */
+struct fy_path_expr *
+fy_path_parse_expr_from_string(struct fy_path_parser *fypp,
+			       const char *str, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_path_expr_build_from_string() - Parse an expression from a given string
+ *
+ * Create a path expression from a string using the provided path parser
+ * configuration.
+ *
+ * @pcfg: The path parser configuration to use, or NULL for default
+ * @str: The ypath source to use.
+ * @len: The length of the string (or -1 if '\0' terminated)
+ *
+ * Returns:
+ * The created path expression or NULL on error.
+ */
+struct fy_path_expr *
+fy_path_expr_build_from_string(const struct fy_path_parse_cfg *pcfg,
+			       const char *str, size_t len)
+	FY_EXPORT;
+
+/**
+ * fy_path_expr_free() - Free a path expression
+ *
+ * Free a previously returned expression from any of the path parser
+ * methods like fy_path_expr_build_from_string()
+ *
+ * @expr: The expression to free (may be NULL)
+ */
+void
+fy_path_expr_free(struct fy_path_expr *expr)
+	FY_EXPORT;
+
+/**
+ * fy_path_expr_dump() - Dump the contents of a path expression to
+ * 			 the diagnostic object
+ *
+ * Dumps the expression using the provided error level.
+ *
+ * @expr: The expression to dump
+ * @diag: The diagnostic object to use
+ * @errlevel: The error level which the diagnostic will use
+ * @level: The nest level; should be set to 0
+ * @banner: The banner to display on level 0
+ */
+void
+fy_path_expr_dump(struct fy_path_expr *expr, struct fy_diag *diag,
+		  enum fy_error_type errlevel, int level, const char *banner)
+	FY_EXPORT;
+
+/**
+ * fy_path_expr_to_document() - Converts the path expression to a YAML document
+ *
+ * Converts the expression to a YAML document which is useful for
+ * understanding what the expression evaluates to.
+ *
+ * @expr: The expression to convert to a document
+ *
+ * Returns:
+ * The document of the expression or NULL on error.
+ */
+struct fy_document *
+fy_path_expr_to_document(struct fy_path_expr *expr)
+	FY_EXPORT;
+
+/**
+ * enum fy_path_exec_cfg_flags - Path executor configuration flags
+ *
+ * These flags control the operation of the path expression executor
+ *
+ * @FYPXCF_QUIET: Quiet, do not output any information messages
+ * @FYPXCF_DISABLE_RECYCLING: Disable recycling optimization
+ * @FYPXCF_DISABLE_ACCELERATORS: Disable use of access accelerators (saves memory)
+ */
+enum fy_path_exec_cfg_flags {
+	FYPXCF_QUIET			= FY_BIT(0),
+	FYPXCF_DISABLE_RECYCLING	= FY_BIT(1),
+	FYPXCF_DISABLE_ACCELERATORS	= FY_BIT(2),
+};
+
+/**
+ * struct fy_path_exec_cfg - path expression executor configuration structure.
+ *
+ * Argument to the fy_path_exec_create() method which
+ * performs execution of a ypath expression
+ *
+ * @flags: Configuration flags
+ * @userdata: Opaque user data pointer
+ * @diag: Optional diagnostic interface to use
+ */
+struct fy_path_exec_cfg {
+	enum fy_path_exec_cfg_flags flags;
+	void *userdata;
+	struct fy_diag *diag;
+};
+
+/**
+ * fy_path_exec_create() - Create a ypath expression executor.
+ *
+ * Creates a ypath expression parser with its configuration @cfg
+ * The executor may be destroyed by a corresponding call to
+ * fy_path_exec_destroy().
+ *
+ * @xcfg: The configuration for the executor
+ *
+ * Returns:
+ * A pointer to the executor or NULL in case of an error.
+ */
+struct fy_path_exec *
+fy_path_exec_create(const struct fy_path_exec_cfg *xcfg)
+	FY_EXPORT;
+
+/**
+ * fy_path_exec_destroy() - Destroy the given path expression executor
+ *
+ * Destroy ane executor  created earlier via fy_path_exec_create().
+ *
+ * @fypx: The path parser to destroy
+ */
+void
+fy_path_exec_destroy(struct fy_path_exec *fypx)
+	FY_EXPORT;
+
+/**
+ * fy_path_exec_reset() - Reset an executor
+ *
+ * Completely reset an executor without releasing it.
+ *
+ * @fypx: The executor to reset
+ *
+ * Returns:
+ * 0 if the reset was successful, -1 otherwise
+ */
+int
+fy_path_exec_reset(struct fy_path_exec *fypx)
+	FY_EXPORT;
+
+/**
+ * fy_path_exec_execute() - Execute a path expression starting at
+ *                          the given start node
+ *
+ * Execute the expression starting at fyn_start. If execution
+ * is successful the results are available via fy_path_exec_results_iterate()
+ *
+ * Note that it is illegal to modify the state of the document that the
+ * results reside between this call and the results collection.
+ *
+ * @fypx: The executor to use
+ * @expr: The expression to use
+ * @fyn_start: The node on which the expression will begin.
+ *
+ * Returns:
+ * 0 if the execution was successful, -1 otherwise
+ *
+ * Note that the execution may be successful but no results were
+ * produced, in which case the iterator will return NULL.
+ */
+int
+fy_path_exec_execute(struct fy_path_exec *fypx, struct fy_path_expr *expr,
+		     struct fy_node *fyn_start)
+	FY_EXPORT;
+
+/**
+ * fy_path_exec_results_iterate() - Iterate over the results of execution
+ *
+ * This method iterates over all the results in the executor.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * @fypx: The executor
+ * @prevp: The previous result iterator
+ *
+ * Returns:
+ * The next node in the result set or NULL at the end of the results.
+ */
+struct fy_node *
+fy_path_exec_results_iterate(struct fy_path_exec *fypx, void **prevp)
+	FY_EXPORT;
+
+/*
+ * Helper methods for binding implementers
+ * Note that users of the library do not need to know these details.
+ * However bindings that were developed against libyaml expect these
+ * to be exported, so provide a shim here
+ */
+
+/**
+ * enum fy_token_type - Token types
+ *
+ * The available token types that the tokenizer produces.
+ *
+ * @FYTT_NONE: No token
+ * @FYTT_STREAM_START: Stream start
+ * @FYTT_STREAM_END: Stream end
+ * @FYTT_VERSION_DIRECTIVE: Version directive
+ * @FYTT_TAG_DIRECTIVE: Tag directive
+ * @FYTT_DOCUMENT_START: Document start
+ * @FYTT_DOCUMENT_END: Document end
+ * @FYTT_BLOCK_SEQUENCE_START: Start of a block sequence
+ * @FYTT_BLOCK_MAPPING_START: Start of a block mapping
+ * @FYTT_BLOCK_END: End of a block mapping or a sequence
+ * @FYTT_FLOW_SEQUENCE_START: Start of a flow sequence
+ * @FYTT_FLOW_SEQUENCE_END: End of a flow sequence
+ * @FYTT_FLOW_MAPPING_START: Start of a flow mapping
+ * @FYTT_FLOW_MAPPING_END: End of a flow mapping
+ * @FYTT_BLOCK_ENTRY: A block entry
+ * @FYTT_FLOW_ENTRY: A flow entry
+ * @FYTT_KEY: A key of a mapping
+ * @FYTT_VALUE: A value of a mapping
+ * @FYTT_ALIAS: An alias
+ * @FYTT_ANCHOR: An anchor
+ * @FYTT_TAG: A tag
+ * @FYTT_SCALAR: A scalar
+ * @FYTT_INPUT_MARKER: Internal input marker token
+ * @FYTT_PE_SLASH: A slash
+ * @FYTT_PE_ROOT: A root
+ * @FYTT_PE_THIS: A this
+ * @FYTT_PE_PARENT: A parent
+ * @FYTT_PE_MAP_KEY: A map key
+ * @FYTT_PE_SEQ_INDEX: A sequence index
+ * @FYTT_PE_SEQ_SLICE: A sequence slice
+ * @FYTT_PE_SCALAR_FILTER: A scalar filter
+ * @FYTT_PE_COLLECTION_FILTER: A collection filter
+ * @FYTT_PE_SEQ_FILTER: A sequence filter
+ * @FYTT_PE_MAP_FILTER: A mapping filter
+ * @FYTT_PE_UNIQUE_FILTER: Filters out duplicates
+ * @FYTT_PE_EVERY_CHILD: Every child
+ * @FYTT_PE_EVERY_CHILD_R: Every child recursive
+ * @FYTT_PE_ALIAS: An alias
+ * @FYTT_PE_SIBLING: A sibling marker
+ * @FYTT_PE_COMMA: A comma
+ * @FYTT_PE_BARBAR: A ||
+ * @FYTT_PE_AMPAMP: A &&
+ * @FYTT_PE_LPAREN: A left parenthesis
+ * @FYTT_PE_RPAREN: A right parenthesis
+ * @FYTT_PE_EQEQ: Equality operator
+ * @FYTT_PE_NOTEQ: Non-equality operator
+ * @FYTT_PE_LT: Less than operator
+ * @FYTT_PE_GT: Greater than operator
+ * @FYTT_PE_LTE: Less or equal than operator
+ * @FYTT_PE_GTE: Greater or equal than operator
+ * @FYTT_SE_PLUS: Plus operator
+ * @FYTT_SE_MINUS: Minus operator
+ * @FYTT_SE_MULT: Multiply operator
+ * @FYTT_SE_DIV: Divide operator
+ * @FYTT_PE_METHOD: Path expression method (chained)
+ * @FYTT_SE_METHOD: Scalar expression method (non chained)
+ */
+enum fy_token_type {
+	/* non-content token types */
+	FYTT_NONE,
+	FYTT_STREAM_START,
+	FYTT_STREAM_END,
+	FYTT_VERSION_DIRECTIVE,
+	FYTT_TAG_DIRECTIVE,
+	FYTT_DOCUMENT_START,
+	FYTT_DOCUMENT_END,
+	/* content token types */
+	FYTT_BLOCK_SEQUENCE_START,
+	FYTT_BLOCK_MAPPING_START,
+	FYTT_BLOCK_END,
+	FYTT_FLOW_SEQUENCE_START,
+	FYTT_FLOW_SEQUENCE_END,
+	FYTT_FLOW_MAPPING_START,
+	FYTT_FLOW_MAPPING_END,
+	FYTT_BLOCK_ENTRY,
+	FYTT_FLOW_ENTRY,
+	FYTT_KEY,
+	FYTT_VALUE,
+	FYTT_ALIAS,
+	FYTT_ANCHOR,
+	FYTT_TAG,
+	FYTT_SCALAR,
+
+	/* special error reporting */
+	FYTT_INPUT_MARKER,
+
+	/* path expression tokens */
+	FYTT_PE_SLASH,
+	FYTT_PE_ROOT,
+	FYTT_PE_THIS,
+	FYTT_PE_PARENT,
+	FYTT_PE_MAP_KEY,
+	FYTT_PE_SEQ_INDEX,
+	FYTT_PE_SEQ_SLICE,
+	FYTT_PE_SCALAR_FILTER,
+	FYTT_PE_COLLECTION_FILTER,
+	FYTT_PE_SEQ_FILTER,
+	FYTT_PE_MAP_FILTER,
+	FYTT_PE_UNIQUE_FILTER,
+	FYTT_PE_EVERY_CHILD,
+	FYTT_PE_EVERY_CHILD_R,
+	FYTT_PE_ALIAS,
+	FYTT_PE_SIBLING,
+	FYTT_PE_COMMA,
+	FYTT_PE_BARBAR,
+	FYTT_PE_AMPAMP,
+	FYTT_PE_LPAREN,
+	FYTT_PE_RPAREN,
+
+	/* comparison operators */
+	FYTT_PE_EQEQ,		/* == */
+	FYTT_PE_NOTEQ,		/* != */
+	FYTT_PE_LT,		/* <  */
+	FYTT_PE_GT,		/* >  */
+	FYTT_PE_LTE,		/* <= */
+	FYTT_PE_GTE,		/* >= */
+
+	/* scalar expression tokens */
+	FYTT_SE_PLUS,
+	FYTT_SE_MINUS,
+	FYTT_SE_MULT,
+	FYTT_SE_DIV,
+
+	FYTT_PE_METHOD,		/* path expr method (chained) */
+	FYTT_SE_METHOD,		/* scalar expr method (non chained) */
+};
+
+/* The number of token types available */
+#define FYTT_COUNT	(FYTT_SE_METHOD+1)
+
+/**
+ * fy_token_type_is_valid() - Check token type validity
+ *
+ * Check if argument token type is a valid one.
+ *
+ * @type: The token type
+ *
+ * Returns:
+ * true if the token type is valid, false otherwise
+ */
+static inline bool
+fy_token_type_is_valid(enum fy_token_type type)
+{
+	return type >= FYTT_NONE && type < FYTT_COUNT;
+}
+
+/**
+ * fy_token_type_is_yaml() - Check if token type is valid for YAML
+ *
+ * Check if argument token type is a valid YAML one.
+ *
+ * @type: The token type
+ *
+ * Returns:
+ * true if the token type is a valid YAML one, false otherwise
+ */
+static inline bool
+fy_token_type_is_yaml(enum fy_token_type type)
+{
+	return type >= FYTT_STREAM_START && type <= FYTT_SCALAR;
+}
+
+/**
+ * fy_token_type_is_content() - Check if token type is
+ *                              valid for YAML content
+ *
+ * Check if argument token type is a valid YAML content one.
+ *
+ * @type: The token type
+ *
+ * Returns:
+ * true if the token type is a valid YAML content one, false otherwise
+ */
+static inline bool
+fy_token_type_is_content(enum fy_token_type type)
+{
+	return type >= FYTT_BLOCK_SEQUENCE_START && type <= FYTT_SCALAR;
+}
+
+/**
+ * fy_token_type_is_path_expr() - Check if token type is
+ *                                valid for a YPATH expression
+ *
+ * Check if argument token type is a valid YPATH parse expression token
+ *
+ * @type: The token type
+ *
+ * Returns:
+ * true if the token type is a valid YPATH one, false otherwise
+ */
+static inline bool
+fy_token_type_is_path_expr(enum fy_token_type type)
+{
+	return type >= FYTT_PE_SLASH && type <= FYTT_PE_GTE;
+}
+
+/**
+ * fy_token_type_is_scalar_expr() - Check if token type is
+ *                                  valid for a YPATH scalar expression
+ *
+ * Check if argument token type is a valid YPATH parse scalar expression token
+ *
+ * @type: The token type
+ *
+ * Returns:
+ * true if the token type is a valid YPATH scalar one, false otherwise
+ */
+static inline bool
+fy_token_type_is_scalar_expr(enum fy_token_type type)
+{
+	return type >= FYTT_SE_PLUS && type <= FYTT_SE_DIV;
+}
+
+/**
+ * fy_token_get_type() - Return the token's type
+ *
+ * Return the token's type; if NULL then FYTT_NONE is returned
+ *
+ * @fyt: The token
+ *
+ * Returns:
+ * The token's type; FYTT_NONE if not a valid token (or NULL)
+ */
+enum fy_token_type
+fy_token_get_type(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_token_start_mark() - Get token's start marker
+ *
+ * Return the token's start marker if it exists. Note
+ * it is permissable for some token types to have no
+ * start marker because they are without content.
+ *
+ * @fyt: The token to get its start marker
+ *
+ * Returns:
+ * The token's start marker, NULL if not available.
+ */
+const struct fy_mark *
+fy_token_start_mark(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_token_end_mark() - Get token's end marker
+ *
+ * Return the token's end marker if it exists. Note
+ * it is permissable for some token types to have no
+ * end marker because they are without content.
+ *
+ * @fyt: The token to get its end marker
+ *
+ * Returns:
+ * The token's end marker, NULL if not available.
+ */
+const struct fy_mark *
+fy_token_end_mark(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_scan() - Low level access to the scanner
+ *
+ * Return the next scanner token. Note this is a very
+ * low level interface, intended for users that want/need
+ * to implement their own YAML parser. The returned
+ * token is expected to be disposed using fy_scan_token_free()
+ *
+ * @fyp: The parser to get the next token from.
+ *
+ * Returns:
+ * The next token, or NULL if no more tokens are available.
+ */
+struct fy_token *
+fy_scan(struct fy_parser *fyp)
+	FY_EXPORT;
+
+/**
+ * fy_scan_token_free() - Free the token returned by fy_scan()
+ *
+ * Free the token returned by fy_scan().
+ *
+ * @fyp: The parser of which the token was returned by fy_scan()
+ * @fyt: The token to free
+ */
+void
+fy_scan_token_free(struct fy_parser *fyp, struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_tag_directive_token_prefix0() - Get the prefix contained in the
+ * 				      tag directive token as zero terminated
+ * 				      string
+ *
+ * Retrieve the tag directive's prefix contents as a zero terminated string.
+ * It is similar to fy_tag_directive_token_prefix(), with the difference
+ * that the returned string is zero terminated and memory may be allocated
+ * to hold it associated with the token.
+ *
+ * @fyt: The tag directive token out of which the prefix pointer
+ *       will be returned.
+ *
+ * Returns:
+ * A pointer to the zero terminated text representation of the prefix token.
+ * NULL in case of an error.
+ */
+const char *
+fy_tag_directive_token_prefix0(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_tag_directive_token_handle0() - Get the handle contained in the
+ * 				      tag directive token as zero terminated
+ * 				      string
+ *
+ * Retrieve the tag directive's handle contents as a zero terminated string.
+ * It is similar to fy_tag_directive_token_handle(), with the difference
+ * that the returned string is zero terminated and memory may be allocated
+ * to hold it associated with the token.
+ *
+ * @fyt: The tag directive token out of which the handle pointer
+ *       will be returned.
+ *
+ * Returns:
+ * A pointer to the zero terminated text representation of the handle token.
+ * NULL in case of an error.
+ */
+const char *
+fy_tag_directive_token_handle0(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_tag_token_handle() - Get the handle contained in the
+ * 			   tag token
+ *
+ * Retrieve the tag handle contents. Will fail if
+ * token is not a tag token, or if a memory error happens.
+ *
+ * @fyt: The tag token out of which the handle pointer
+ *       will be returned.
+ * @lenp: Pointer to a variable that will hold the returned length
+ *
+ * Returns:
+ * A pointer to the text representation of the handle token, while
+ * @lenp will be assigned the character length of said representation.
+ * NULL in case of an error.
+ */
+const char *
+fy_tag_token_handle(struct fy_token *fyt, size_t *lenp)
+	FY_EXPORT;
+
+/**
+ * fy_tag_token_suffix() - Get the suffix contained in the
+ * 			   tag token
+ *
+ * Retrieve the tag suffix contents. Will fail if
+ * token is not a tag token, or if a memory error happens.
+ *
+ * @fyt: The tag token out of which the suffix pointer
+ *       will be returned.
+ * @lenp: Pointer to a variable that will hold the returned length
+ *
+ * Returns:
+ * A pointer to the text representation of the suffix token, while
+ * @lenp will be assigned the character length of said representation.
+ * NULL in case of an error.
+ */
+const char *
+fy_tag_token_suffix(struct fy_token *fyt, size_t *lenp)
+	FY_EXPORT;
+
+/**
+ * fy_tag_token_handle0() - Get the handle contained in the
+ * 			    tag token as zero terminated string
+ *
+ * Retrieve the tag handle contents as a zero terminated string.
+ * It is similar to fy_tag_token_handle(), with the difference
+ * that the returned string is zero terminated and memory may be allocated
+ * to hold it associated with the token.
+ *
+ * @fyt: The tag token out of which the handle pointer will be returned.
+ *
+ * Returns:
+ * A pointer to the zero terminated text representation of the handle token.
+ * NULL in case of an error.
+ */
+const char *
+fy_tag_token_handle0(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_tag_token_suffix0() - Get the suffix contained in the
+ * 			    tag token as zero terminated string
+ *
+ * Retrieve the tag suffix contents as a zero terminated string.
+ * It is similar to fy_tag_token_suffix(), with the difference
+ * that the returned string is zero terminated and memory may be allocated
+ * to hold it associated with the token.
+ *
+ * @fyt: The tag token out of which the suffix pointer will be returned.
+ *
+ * Returns:
+ * A pointer to the zero terminated text representation of the suffix token.
+ * NULL in case of an error.
+ */
+const char *
+fy_tag_token_suffix0(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_version_directive_token_version() - Return the version of a version
+ * 					  directive token
+ *
+ * Retrieve the version stored in a version directive token.
+ *
+ * @fyt: The version directive token
+ *
+ * Returns:
+ * A pointer to the version stored in the version directive token, or
+ * NULL in case of an error, or the token not being a version directive token.
+ */
+const struct fy_version *
+fy_version_directive_token_version(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_scalar_token_get_style() - Return the style of a scalar token
+ *
+ * Retrieve the style of a scalar token.
+ *
+ * @fyt: The scalar token
+ *
+ * Returns:
+ * The scalar style of the token, or FYSS_ANY for an error
+ */
+enum fy_scalar_style
+fy_scalar_token_get_style(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_tag_token_tag() - Get tag of a tag token
+ *
+ * Retrieve the tag of a tag token.
+ *
+ * @fyt: The tag token
+ *
+ * Returns:
+ * A pointer to the tag or NULL in case of an error
+ */
+const struct fy_tag *
+fy_tag_token_tag(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_tag_directive_token_tag() - Get tag of a tag directive token
+ *
+ * Retrieve the tag of a tag directive token.
+ *
+ * @fyt: The tag directive token
+ *
+ * Returns:
+ * A pointer to the tag or NULL in case of an error
+ */
+const struct fy_tag *
+fy_tag_directive_token_tag(struct fy_token *fyt)
+	FY_EXPORT;
+
+/**
+ * fy_event_get_token() - Return the main token of an event
+ *
+ * Retrieve the main token (i.e. not the tag or the anchor) of
+ * an event. It may be NULL in case of an implicit event.
+ *
+ * @fye: The event to get its main token
+ *
+ * Returns:
+ * The main token if it exists, NULL otherwise or in case of an error
+ */
+struct fy_token *
+fy_event_get_token(struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_event_get_anchor_token() - Return the anchor token of an event
+ *
+ * Retrieve the anchor token if it exists. Only valid for
+ * mapping/sequence start and scalar events.
+ *
+ * @fye: The event to get its anchor token
+ *
+ * Returns:
+ * The anchor token if it exists, NULL otherwise or in case of an error
+ */
+struct fy_token *
+fy_event_get_anchor_token(struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_event_get_tag_token() - Return the tag token of an event
+ *
+ * Retrieve the tag token if it exists. Only valid for
+ * mapping/sequence start and scalar events.
+ *
+ * @fye: The event to get its tag token
+ *
+ * Returns:
+ * The tag token if it exists, NULL otherwise or in case of an error
+ */
+struct fy_token *
+fy_event_get_tag_token(struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_event_start_mark() - Get event's start marker
+ *
+ * Return the event's start marker if it exists. The
+ * start marker is the one of the event's main token.
+ *
+ * @fye: The event to get its start marker
+ *
+ * Returns:
+ * The event's start marker, NULL if not available.
+ */
+const struct fy_mark *
+fy_event_start_mark(struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_event_end_mark() - Get event's end marker
+ *
+ * Return the event's end marker if it exists. The
+ * end marker is the one of the event's main token.
+ *
+ * @fye: The event to get its end marker
+ *
+ * Returns:
+ * The event's end marker, NULL if not available.
+ */
+const struct fy_mark *
+fy_event_end_mark(struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_event_get_node_style() - Get the node style of an event
+ *
+ * Return the node style (FYNS_*) of an event. May return
+ * FYNS_ANY if the event is implicit.
+ * For collection start events the only possible values is
+ * FYNS_ANY, FYNS_FLOW, FYNS_BLOCK.
+ * A scalar event may return any.
+ *
+ * @fye: The event to get it's node style
+ *
+ * Returns:
+ * The event's end marker, NULL if not available.
+ */
+enum fy_node_style
+fy_event_get_node_style(struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_document_start_event_version() - Return the version of a document
+ * 				       start event
+ *
+ * Retrieve the version stored in a document start event
+ *
+ * @fye: The document start event
+ *
+ * Returns:
+ * A pointer to the version, or NULL in case of an error, or the event
+ * not being a document start event.
+ */
+const struct fy_version *
+fy_document_start_event_version(struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_version() - Return the version of a document state
+ * 				 object
+ *
+ * Retrieve the version stored in a document state object
+ *
+ * @fyds: The document state object
+ *
+ * Returns:
+ * A pointer to the version, or NULL in case of an error
+ */
+const struct fy_version *
+fy_document_state_version(struct fy_document_state *fyds)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_start_mark() - Get document state's start mark
+ *
+ * Return the document state's start mark (if it exists).
+ * Note that purely synthetic documents do not contain one
+ *
+ * @fyds: The document state object
+ *
+ * Returns:
+ * The document's start marker, NULL if not available.
+ */
+const struct fy_mark *
+fy_document_state_start_mark(struct fy_document_state *fyds)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_end_mark() - Get document state's end mark
+ *
+ * Return the document state's end mark (if it exists).
+ * Note that purely synthetic documents do not contain one
+ *
+ * @fyds: The document state object
+ *
+ * Returns:
+ * The document's end marker, NULL if not available.
+ */
+const struct fy_mark *
+fy_document_state_end_mark(struct fy_document_state *fyds)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_version_explicit() - Version explicit?
+ *
+ * Find out if a document state object's version was explicitly
+ * set in the document.
+ * Note that for synthetic documents this method returns false.
+ *
+ * @fyds: The document state object
+ *
+ * Returns:
+ * true if version was set explicitly, false otherwise
+ */
+bool
+fy_document_state_version_explicit(struct fy_document_state *fyds)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_tags_explicit() - Tags explicit?
+ *
+ * Find out if a document state object's tags were explicitly
+ * set in the document.
+ * Note that for synthetic documents this method returns false.
+ *
+ * @fyds: The document state object
+ *
+ * Returns:
+ * true if document had tags set explicitly, false otherwise
+ */
+bool
+fy_document_state_tags_explicit(struct fy_document_state *fyds)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_start_implicit() - Started implicitly?
+ *
+ * Find out if a document state object's document was
+ * started implicitly.
+ * Note that for synthetic documents this method returns false.
+ *
+ * @fyds: The document state object
+ *
+ * Returns:
+ * true if document was started implicitly, false otherwise
+ */
+bool
+fy_document_state_start_implicit(struct fy_document_state *fyds)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_end_implicit() - Started implicitly?
+ *
+ * Find out if a document state object's document was
+ * ended implicitly.
+ * Note that for synthetic documents this method returns false.
+ *
+ * @fyds: The document state object
+ *
+ * Returns:
+ * true if document was ended implicitly, false otherwise
+ */
+bool
+fy_document_state_end_implicit(struct fy_document_state *fyds)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_json_mode() - Input was JSON?
+ *
+ * Find out if a document state object's document was
+ * created by a JSON input.
+ * Note that for synthetic documents this method returns false.
+ *
+ * @fyds: The document state object
+ *
+ * Returns:
+ * true if document was created in JSON mode, false otherwise
+ */
+bool
+fy_document_state_json_mode(struct fy_document_state *fyds)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_tag_directive_iterate() - Iterate over the tag
+ * 					       directives of a document state
+ * 					       object
+ *
+ * This method iterates over all the tag directives nodes in the document state
+ * object.
+ * The start of the iteration is signalled by a NULL in \*prevp.
+ *
+ * @fyds: The document state
+ * @prevp: The previous iterator
+ *
+ * Returns:
+ * The next tag or NULL at the end of the iteration sequence.
+ */
+const struct fy_tag *
+fy_document_state_tag_directive_iterate(struct fy_document_state *fyds, void **prevp)
+	FY_EXPORT;
+
+/**
+ * fy_document_state_tag_is_default() - Test whether the given tag is a default one
+ *
+ * Test whether a tag is a default (i.e. impliciticly set)
+ *
+ * @fyds: The document state
+ * @tag: The tag to check
+ *
+ * Returns:
+ * true in case that the tag is a default one, false otherwise
+ */
+bool
+fy_document_state_tag_is_default(struct fy_document_state *fyds, const struct fy_tag *tag)
+	FY_EXPORT;
+
+/**
+ * fy_parser_get_document_state() - Get the document state of a parser object
+ *
+ * Retrieve the document state object of a parser. Note that this is only
+ * valid during parsing.
+ *
+ * @fyp: The parser
+ *
+ * Returns:
+ * The active document state object of the parser, NULL otherwise
+ */
+struct fy_document_state *
+fy_parser_get_document_state(struct fy_parser *fyp)
+	FY_EXPORT;
+
+/**
+ * fy_document_get_document_state() - Get the document state of a document
+ *
+ * Retrieve the document state object of a document.
+ *
+ * @fyd: The document
+ *
+ * Returns:
+ * The document state object of the document, NULL otherwise
+ */
+struct fy_document_state *
+fy_document_get_document_state(struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_set_document_state() - Set the document state of a document
+ *
+ * Set the document state of a document
+ *
+ * @fyd: The document
+ * @fyds: The document state to use, or NULL for default
+ *
+ * Returns:
+ * 0 if set operation was successful, -1 otherwise
+ */
+int
+fy_document_set_document_state(struct fy_document *fyd, struct fy_document_state *fyds)
+	FY_EXPORT;
+
+/**
+ * fy_document_create_from_event() - Create an empty document using the event
+ *
+ * Create an empty document using the FYET_DOCUMENT_START event generated
+ * by the parser.
+ *
+ * @fyp: The parser
+ * @fye: The event
+ *
+ * Returns:
+ * The created empty document, or NULL on error.
+ */
+struct fy_document *
+fy_document_create_from_event(struct fy_parser *fyp, struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_document_update_from_event() - Update the document with the event
+ *
+ * Update the document using the FYET_DOCUMENT_END event generated
+ * by the parser.
+ *
+ * @fyd: The document
+ * @fyp: The parser
+ * @fye: The event
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_document_update_from_event(struct fy_document *fyd, struct fy_parser *fyp, struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_node_create_from_event() - Create a node using the event
+ *
+ * Create a new node using the supplied event.
+ * Allowed events are FYET_SCALAR, FYET_ALIAS, FYET_MAPPING_START & FYET_SEQUENCE_START
+ *
+ * @fyd: The document
+ * @fyp: The parser
+ * @fye: The event
+ *
+ * Returns:
+ * The newly created node, or NULL on error
+ */
+struct fy_node *
+fy_node_create_from_event(struct fy_document *fyd, struct fy_parser *fyp, struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_node_update_from_event() - Update a node using the event
+ *
+ * Update information of node created using fy_node_create_from_event()
+ * Allowed events are FYET_MAPPING_END & FYET_SEQUENCE_END
+ *
+ * @fyn: The node
+ * @fyp: The parser
+ * @fye: The event
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_update_from_event(struct fy_node *fyn, struct fy_parser *fyp, struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_node_pair_create_with_key() - Create a new node pair and set it's key
+ *
+ * Create a new node pair using the supplied fyn_parent mapping and fyn node as
+ * a key. Note that the nodes _must_ have been created by fy_node_create_from_event
+ * and they are not interchangeable with other node pair methods.
+ *
+ * The node pair will be added to the fyn_parent mapping with a subsequent call
+ * to fy_node_pair_update_with_value().
+ *
+ * @fyd: The document
+ * @fyn_parent: The mapping
+ * @fyn: The node pair key
+ *
+ * Returns:
+ * The newly created node pair, or NULL on error
+ */
+struct fy_node_pair *
+fy_node_pair_create_with_key(struct fy_document *fyd, struct fy_node *fyn_parent, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_pair_update_with_value() - Update a node pair with a value and add it to the parent mapping
+ *
+ * Update the node pair with the given value and add it to the parent mapping.
+ * Note that the fyn node _must_ have been created by fy_node_create_from_event
+ * and the node pair created by fy_node_pair_create_with_key().
+ * Do not intermix other node pair manipulation methods.
+ *
+ * @fynp: The node pair
+ * @fyn: The node pair value
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_pair_update_with_value(struct fy_node_pair *fynp, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_node_sequence_add_item() - Add an item node to a sequence node
+ *
+ * Add an item to the end of the sequence node fyn_parent.
+ * Note that the fyn_parent and fyn nodes _must_ have been created by
+ * fy_node_create_from_event.
+ * Do not intermix other sequence node manipulation methods.
+ *
+ * @fyn_parent: The parent sequence node
+ * @fyn: The node pair item
+ *
+ * Returns:
+ * 0 on success, -1 on error
+ */
+int
+fy_node_sequence_add_item(struct fy_node *fyn_parent, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_emitter_get_document_state() - Get the document state of an emitter  object
+ *
+ * Retrieve the document state object of an emitter. Note that this is only
+ * valid during emitting.
+ *
+ * @emit: The emitter
+ *
+ * Returns:
+ * The active document state object of the emitter, NULL otherwise
+ */
+struct fy_document_state *
+fy_emitter_get_document_state(struct fy_emitter *emit)
+	FY_EXPORT;
+
+/**
+ * fy_emit_event_create() - Create an emit event.
+ *
+ * Create an emit event to pass to fy_emit_event()
+ * The extra arguments differ according to the event to be created
+ *
+ * FYET_STREAM_START:
+ * 	- None
+ *
+ * FYET_STREAM_END:
+ * 	- None
+ *
+ * FYET_DOCUMENT_START:
+ * 	- int implicit
+ * 		true if document start should be marked implicit
+ * 		false if document start should not be marked implicit
+ * 	- const struct fy_version \*vers
+ * 		Pointer to version to use for the document, or NULL for default
+ * 	- const struct fy_tag \* const \*tags
+ * 		Pointer to a NULL terminated array of tag pointers (like argv)
+ * 		NULL if no extra tags are to be used
+ *
+ * FYET_DOCUMENT_END:
+ * 	- int implicit
+ * 		true if document end should be marked implicit
+ * 		false if document end should not be marked implicit
+ *
+ * FYET_MAPPING_START:
+ * 	- enum fy_node_style style
+ * 		Style of the mapping (one of FYNS_ANY, FYNS_BLOCK or FYNS_FLOW)
+ *	- const char \*anchor
+ *		Anchor to place at the mapping, or NULL for none
+ *	- const char \*tag
+ *		Tag to place at the mapping, or NULL for none
+ *
+ * FYET_MAPPING_END:
+ * 	- None
+ *
+ * FYET_SEQUENCE_START:
+ * 	- enum fy_node_style style
+ * 		Style of the sequence (one of FYNS_ANY, FYNS_BLOCK or FYNS_FLOW)
+ *	- const char \*anchor
+ *		Anchor to place at the sequence, or NULL for none
+ *	- const char \*tag
+ *		Tag to place at the sequence, or NULL for none
+ *
+ * FYET_SEQUENCE_END:
+ * 	- None
+ *
+ * FYET_SCALAR:
+ * 	- enum fy_scalar_style style
+ * 		Style of the scalar, any valid FYSS_* value
+ * 		Note that certain styles may not be used according to the
+ * 		contents of the data
+ *	- const char \*value
+ *		Pointer to the scalar contents.
+ *	- size_t len
+ *		Length of the scalar contents, of FY_NT (-1) for strlen(value)
+ *	- const char \*anchor
+ *		Anchor to place at the scalar, or NULL for none
+ *	- const char \*tag
+ *		Tag to place at the scalar, or NULL for none
+ *
+ * FYET_ALIAS:
+ *	- const char \*value
+ *		Pointer to the alias.
+ *
+ * @emit: The emitter
+ * @type: The event type to create
+ *
+ * Returns:
+ * The created event or NULL in case of an error
+ */
+struct fy_event *
+fy_emit_event_create(struct fy_emitter *emit, enum fy_event_type type, ...)
+	FY_EXPORT;
+
+/**
+ * fy_emit_event_vcreate() - Create an emit event using varargs.
+ *
+ * Create an emit event to pass to fy_emit_event()
+ * The varargs analogous to fy_emit_event_create().
+ *
+ * @emit: The emitter
+ * @type: The event type to create
+ * @ap: The variable argument list pointer.
+ *
+ * Returns:
+ * The created event or NULL in case of an error
+ */
+struct fy_event *
+fy_emit_event_vcreate(struct fy_emitter *emit, enum fy_event_type type, va_list ap)
+	FY_EXPORT;
+
+/**
+ * fy_emit_event_free() - Free an event created via fy_emit_event_create()
+ *
+ * Free an event previously created via fy_emit_event_create(). Note
+ * that usually you don't have to call this method since if you pass
+ * the event to fy_emit_event() it shall be disposed properly.
+ * Only use is error recovery and cleanup.
+ *
+ * @emit: The emitter
+ * @fye: The event to free
+ */
+void
+fy_emit_event_free(struct fy_emitter *emit, struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_parse_event_create() - Create an emit event.
+ *
+ * See fy_emit_event_create()...
+ *
+ * @fyp: The parser
+ * @type: The event type to create
+ *
+ * Returns:
+ * The created event or NULL in case of an error
+ */
+struct fy_event *
+fy_parse_event_create(struct fy_parser *fyp, enum fy_event_type type, ...)
+	FY_EXPORT;
+
+/**
+ * fy_parse_event_vcreate() - Create an emit event using varargs.
+ *
+ * Create an emit event to pass to fy_emit_event()
+ * The varargs analogous to fy_parse_event_create().
+ *
+ * @fyp: The parser
+ * @type: The event type to create
+ * @ap: The variable argument list pointer.
+ *
+ * Returns:
+ * The created event or NULL in case of an error
+ */
+struct fy_event *
+fy_parse_event_vcreate(struct fy_parser *fyp, enum fy_event_type type, va_list ap)
+	FY_EXPORT;
+
+/**
+ * enum fy_composer_return - The returns of the composer callback
+ *
+ * @FYCR_OK_CONTINUE: continue processing, event processed
+ * @FYCR_OK_STOP: stop processing, event processed
+ * @FYCR_OK_START_SKIP: start skip object(s), event processed
+ * @FYCR_OK_STOP_SKIP: stop skipping of objects, event processed
+ * @FYCR_ERROR: error, stop processing
+ */
+enum fy_composer_return {
+	FYCR_OK_CONTINUE = 0,
+	FYCR_OK_STOP = 1,
+	FYCR_OK_START_SKIP = 2,
+	FYCR_OK_STOP_SKIP = 3,
+	FYCR_ERROR = -1,
+};
+
+/**
+ * fy_composer_return_is_ok() - Check if the return code is OK
+ *
+ * Convenience method for checking if it's OK to continue
+ *
+ * @ret: the composer return to check
+ *
+ * Returns:
+ * true if non error or skip condition
+ */
+static inline bool
+fy_composer_return_is_ok(enum fy_composer_return ret)
+{
+	return ret == FYCR_OK_CONTINUE || ret == FYCR_OK_STOP;
+}
+
+/**
+ * typedef fy_parse_composer_cb - composer callback method
+ *
+ * This method is called by the fy_parse_compose() method
+ * when an event must be processed.
+ *
+ * @fyp: The parser
+ * @fye: The event
+ * @path: The path that the parser is processing
+ * @userdata: The user data of the fy_parse_compose() method
+ *
+ * Returns:
+ * fy_composer_return code telling the parser what to do
+ */
+typedef enum fy_composer_return
+(*fy_parse_composer_cb)(struct fy_parser *fyp, struct fy_event *fye,
+			struct fy_path *path, void *userdata);
+
+/**
+ * fy_parse_compose() - Parse using a compose callback
+ *
+ * Alternative parsing method using a composer callback.
+ *
+ * The parser will construct a path argument that is used
+ * by the callback to make intelligent decisions about
+ * creating a document and/or DOM.
+ *
+ * @fyp: The parser
+ * @cb: The callback that will be called
+ * @userdata: user pointer to pass to the callback
+ *
+ * Returns:
+ * 0 if no error occured
+ * -1 on error
+ */
+int
+fy_parse_compose(struct fy_parser *fyp, fy_parse_composer_cb cb,
+		 void *userdata)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_is_mapping() - Check if the component is a mapping
+ *
+ * @fypc: The path component to check
+ *
+ * Returns:
+ * true if the path component is a mapping, false otherwise
+ */
+bool
+fy_path_component_is_mapping(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_is_sequence() - Check if the component is a sequence
+ *
+ * @fypc: The path component to check
+ *
+ * Returns:
+ * true if the path component is a sequence, false otherwise
+ */
+bool
+fy_path_component_is_sequence(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_sequence_get_index() - Get the index of sequence path component
+ *
+ * @fypc: The sequence path component to return it's index value
+ *
+ * Returns:
+ * >= 0 the sequence index
+ * -1 if the component is either not in the proper mode, or not a sequence
+ */
+int
+fy_path_component_sequence_get_index(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_mapping_get_scalar_key() - Get the scalar key of a mapping
+ *
+ * @fypc: The mapping path component to return it's scalar key
+ *
+ * Returns:
+ * a non NULL scalar or alias token if the mapping contains a scalar key
+ * NULL in case of an error, or if the component has a complex key
+ */
+struct fy_token *
+fy_path_component_mapping_get_scalar_key(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_mapping_get_scalar_key_tag() - Get the scalar key's tag of a mapping
+ *
+ * @fypc: The mapping path component to return it's scalar key's tag
+ *
+ * Returns:
+ * a non NULL tag token if the mapping contains a scalar key with a tag or
+ * NULL in case of an error, or if the component has a complex key
+ */
+struct fy_token *
+fy_path_component_mapping_get_scalar_key_tag(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_mapping_get_complex_key() - Get the complex key of a mapping
+ *
+ * @fypc: The mapping path component to return it's complex key
+ *
+ * Returns:
+ * a non NULL document if the mapping contains a complex key
+ * NULL in case of an error, or if the component has a simple key
+ */
+struct fy_document *
+fy_path_component_mapping_get_complex_key(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_get_text() - Get the textual representation of a path component
+ *
+ * Given a path component, return a malloc'ed string which contains
+ * the textual representation of it.
+ *
+ * Note that this method will only return fully completed components and not
+ * ones that are in the building process.
+ *
+ * @fypc: The path component to get it's textual representation
+ *
+ * Returns:
+ * The textual representation of the path component, NULL on error, or
+ * if the component has not been completely built during the composition
+ * of a complex key.
+ * The string must be free'ed using free.
+ */
+char *
+fy_path_component_get_text(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+#define fy_path_component_get_text_alloca(_fypc, _res) \
+	FY_ALLOCA_COPY_FREE(fy_path_component_get_text((_fypc)), FY_NT, (_res))
+/**
+ * fy_path_depth() - Get the depth of a path
+ *
+ * @fypp: The path to query
+ *
+ * Returns:
+ * The depth of the path, or -1 on error
+ */
+int
+fy_path_depth(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_parent() - Get the parent of a path
+ *
+ * Paths may contain parents when traversing complex keys.
+ * This method returns the immediate parent.
+ *
+ * @fypp: The path to return it's parent
+ *
+ * Returns:
+ * The path parent or NULL on error, if it doesn't exist
+ */
+struct fy_path *
+fy_path_parent(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_get_text() - Get the textual representation of a path
+ *
+ * Given a path, return a malloc'ed string which contains
+ * the textual representation of it.
+ *
+ * Note that during processing, complex key paths are simply
+ * indicative and not to be used for addressing.
+ *
+ * @fypp: The path to get it's textual representation
+ *
+ * Returns:
+ * The textual representation of the path, NULL on error.
+ * The string must be free'ed using free.
+ */
+char *
+fy_path_get_text(struct fy_path *fypp)
+	FY_EXPORT;
+
+#define fy_path_get_text_alloca(_fypp, _res) \
+	FY_ALLOCA_COPY_FREE(fy_path_get_text((_fypp)), FY_NT, (_res))
+
+/**
+ * fy_path_in_root() - Check if the path is in the root of the document
+ *
+ * @fypp: The path
+ *
+ * Returns:
+ * true if the path is located within the root of the document
+ */
+bool
+fy_path_in_root(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_in_mapping() - Check if the path is in a mapping
+ *
+ * @fypp: The path
+ *
+ * Returns:
+ * true if the path is located within a mapping
+ */
+bool
+fy_path_in_mapping(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_in_sequence() - Check if the path is in a sequence
+ *
+ * @fypp: The path
+ *
+ * Returns:
+ * true if the path is located within a sequence
+ */
+bool
+fy_path_in_sequence(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_in_mapping_key() - Check if the path is in a mapping key state
+ *
+ * @fypp: The path
+ *
+ * Returns:
+ * true if the path is located within a mapping key state
+ */
+bool
+fy_path_in_mapping_key(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_in_mapping_value() - Check if the path is in a mapping value state
+ *
+ * @fypp: The path
+ *
+ * Returns:
+ * true if the path is located within a mapping value state
+ */
+bool
+fy_path_in_mapping_value(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_in_collection_root() - Check if the path is in a collection root
+ *
+ * A collection root state is when the path points to a sequence or mapping
+ * but the state does not allow setting keys, values or adding items.
+ *
+ * This occurs on MAPPING/SEQUENCE START/END events.
+ *
+ * @fypp: The path
+ *
+ * Returns:
+ * true if the path is located within a collectin root state
+ */
+bool
+fy_path_in_collection_root(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_get_root_user_data() - Return the userdata associated with the path root
+ *
+ * @fypp: The path
+ *
+ * Returns:
+ * The user data associated with the root of the path, or NULL if no path
+ */
+void *
+fy_path_get_root_user_data(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_set_root_user_data() - Set the user data associated with the root
+ *
+ * Note, no error condition if not a path
+ *
+ * @fypp: The path
+ * @data: The data to set as root data
+ */
+void
+fy_path_set_root_user_data(struct fy_path *fypp, void *data)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_get_mapping_user_data() - Return the userdata associated with the mapping
+ *
+ * @fypc: The path component
+ *
+ * Returns:
+ * The user data associated with the mapping, or NULL if not a mapping or the user data are NULL
+ */
+void *
+fy_path_component_get_mapping_user_data(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_get_mapping_key_user_data() - Return the userdata associated with the mapping key
+ *
+ * @fypc: The path component
+ *
+ * Returns:
+ * The user data associated with the mapping key, or NULL if not a mapping or the user data are NULL
+ */
+void *
+fy_path_component_get_mapping_key_user_data(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_get_sequence_user_data() - Return the userdata associated with the sequence
+ *
+ * @fypc: The path component
+ *
+ * Returns:
+ * The user data associated with the sequence, or NULL if not a sequence or the user data are NULL
+ */
+void *
+fy_path_component_get_sequence_user_data(struct fy_path_component *fypc)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_set_mapping_user_data() - Set the user data associated with a mapping
+ *
+ * Note, no error condition if not a mapping
+ *
+ * @fypc: The path component
+ * @data: The data to set as mapping data
+ */
+void
+fy_path_component_set_mapping_user_data(struct fy_path_component *fypc, void *data)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_set_mapping_key_user_data() - Set the user data associated with a mapping key
+ *
+ * Note, no error condition if not in a mapping key state
+ *
+ * @fypc: The path component
+ * @data: The data to set as mapping key data
+ */
+void
+fy_path_component_set_mapping_key_user_data(struct fy_path_component *fypc, void *data)
+	FY_EXPORT;
+
+/**
+ * fy_path_component_set_sequence_user_data() - Set the user data associated with a sequence
+ *
+ * Note, no error condition if not a sequence
+ *
+ * @fypc: The path component
+ * @data: The data to set as sequence data
+ */
+void
+fy_path_component_set_sequence_user_data(struct fy_path_component *fypc, void *data)
+	FY_EXPORT;
+
+/**
+ * fy_path_last_component() - Get the very last component of a path
+ *
+ * Returns the last component of a path.
+ *
+ * @fypp: The path
+ *
+ * Returns:
+ * The last path component (which may be a collection root component), or NULL
+ * if it does not exist
+ */
+struct fy_path_component *
+fy_path_last_component(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_path_last_not_collection_root_component() - Get the last non collection root component of a path
+ *
+ * Returns the last non collection root component of a path. This may not be the
+ * last component that is returned by fy_path_last_component().
+ *
+ * The difference is present on MAPPING/SEQUENCE START/END events where the
+ * last component is present but not usuable as a object parent.
+ *
+ * @fypp: The path
+ *
+ * Returns:
+ * The last non collection root component, or NULL if it does not exist
+ */
+struct fy_path_component *
+fy_path_last_not_collection_root_component(struct fy_path *fypp)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_create() - Create a document iterator
+ *
+ * Creates a document iterator, that can trawl through a document
+ * without using recursion.
+ *
+ * Returns:
+ * The newly created document iterator or NULL on error
+ */
+struct fy_document_iterator *
+fy_document_iterator_create(void)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_destroy() - Destroy the given document iterator
+ *
+ * Destroy a document iterator created earlier via fy_document_iterator_create().
+ *
+ * @fydi: The document iterator to destroy
+ */
+void
+fy_document_iterator_destroy(struct fy_document_iterator *fydi)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_event_free() - Free an event that was created by a document iterator
+ *
+ * Free (possibly recycling) an event that was created by a document iterator.
+ *
+ * @fydi: The document iterator that created the event
+ * @fye: The event
+ */
+void
+fy_document_iterator_event_free(struct fy_document_iterator *fydi, struct fy_event *fye)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_stream_start() - Create a stream start event using the iterator
+ *
+ * Creates a stream start event on the document iterator and advances the internal state
+ * of it accordingly.
+ *
+ * @fydi: The document iterator to create the event
+ *
+ * Returns:
+ * The newly created stream start event, or NULL on error.
+ */
+struct fy_event *
+fy_document_iterator_stream_start(struct fy_document_iterator *fydi)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_stream_end() - Create a stream end event using the iterator
+ *
+ * Creates a stream end event on the document iterator and advances the internal state
+ * of it accordingly.
+ *
+ * @fydi: The document iterator to create the event
+ *
+ * Returns:
+ * The newly created stream end event, or NULL on error.
+ */
+struct fy_event *
+fy_document_iterator_stream_end(struct fy_document_iterator *fydi)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_document_start() - Create a document start event using the iterator
+ *
+ * Creates a document start event on the document iterator and advances the internal state
+ * of it accordingly. The document must not be released until an error, cleanup or a call
+ * to fy_document_iterator_document_end().
+ *
+ * @fydi: The document iterator to create the event
+ * @fyd: The document containing the document state that is used in the event
+ *
+ * Returns:
+ * The newly created document start event, or NULL on error.
+ */
+struct fy_event *
+fy_document_iterator_document_start(struct fy_document_iterator *fydi, struct fy_document *fyd)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_document_end() - Create a document end event using the iterator
+ *
+ * Creates a document end event on the document iterator and advances the internal state
+ * of it accordingly. The document that was used earlier in the call of
+ * fy_document_iterator_document_start() can now be released.
+ *
+ * @fydi: The document iterator to create the event
+ *
+ * Returns:
+ * The newly created document end event, or NULL on error.
+ */
+struct fy_event *
+fy_document_iterator_document_end(struct fy_document_iterator *fydi)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_body_next() - Create document body events until the end
+ *
+ * Creates the next document body, depth first until the end of the document.
+ * The events are created depth first and are in same exact sequence that the
+ * original events that created the document.
+ *
+ * That means that the finite event stream that generated the document is losslesly
+ * preserved in such a way that the document tree representation is functionally
+ * equivalent.
+ *
+ * Repeated calls to this function will generate a stream of SCALAR, ALIAS, SEQUENCE
+ * START, SEQUENCE END, MAPPING START and MAPPING END events, returning NULL at the
+ * end of the body event stream.
+ *
+ * @fydi: The document iterator to create the event
+ *
+ * Returns:
+ * The newly created document body event or NULL at an error, or an end of the
+ * event stream. Use fy_document_iterator_get_error() to check if an error occured.
+ */
+struct fy_event *
+fy_document_iterator_body_next(struct fy_document_iterator *fydi)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_node_start() - Start a document node iteration run using a starting point
+ *
+ * Starts an iteration run starting at the given node.
+ *
+ * @fydi: The document iterator to run with
+ * @fyn: The iterator root for the iteration
+ */
+void
+fy_document_iterator_node_start(struct fy_document_iterator *fydi, struct fy_node *fyn)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_node_next() - Return the next node in the iteration sequence
+ *
+ * Returns a pointer to the next node iterating using as a start the node given
+ * at fy_document_iterator_node_start(). The first node returned will be that,
+ * followed by all the remaing nodes in the subtree.
+ *
+ * @fydi: The document iterator to use for the iteration
+ *
+ * Returns:
+ * The next node in the iteration sequence or NULL at the end, or if an error occured.
+ */
+struct fy_node *
+fy_document_iterator_node_next(struct fy_document_iterator *fydi)
+	FY_EXPORT;
+
+/**
+ * fy_document_iterator_get_error() - Get the error state of the document iterator
+ *
+ * Returns the error state of the iterator. If it's in error state, return true
+ * and reset the iterator to the state just after creation.
+ *
+ * @fydi: The document iterator to use for checking it's error state.
+ *
+ * Returns:
+ * true if it was in an error state, false otherwise.
+ */
+bool
+fy_document_iterator_get_error(struct fy_document_iterator *fydi)
+	FY_EXPORT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-accel.c b/contrib/libs/libfyaml/src/lib/fy-accel.c
new file mode 100644
index 0000000000..1b1ac99f32
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-accel.c
@@ -0,0 +1,416 @@
+/*
+ * fy-accel.c - YAML accelerated access methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <limits.h>
+#include <string.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-doc.h"
+
+#include "fy-accel.h"
+
+#define XXH_STATIC_LINKING_ONLY
+#include "xxhash.h"
+
+/* powers of two and the closest primes before
+ *
+ * pow2:  1 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768 65536
+ * prime: 1 2 3 7 13 31 61 127 251 509 1021 2039 4093 8191 16381 32749 65521
+ *
+ * pow2:  131072 262144 524288
+ * prime: 130657 262051 524201
+ */
+
+/* 64K bucket should be enough for everybody */
+static const uint32_t prime_lt_pow2[] = {
+	1, 2, 3, 7, 13, 31, 61, 127, 251, 509, 1021,
+	2039, 4093, 8191, 16381, 32749, 65521,
+	130657, 262051, 524201
+};
+
+static inline unsigned int
+fy_accel_hash_to_pos(struct fy_accel *xl, const void *hash, unsigned int nbuckets)
+{
+	uint64_t pos;
+
+	switch (xl->hd->size) {
+	case 1:
+		pos = *(const uint8_t *)hash;
+		break;
+	case 2:
+		assert(!((uintptr_t)hash & 1));
+		pos = *(const uint16_t *)hash;
+		break;
+	case 4:
+		assert(!((uintptr_t)hash & 3));
+		pos = *(const uint32_t *)hash;
+		break;
+	case 8:
+		assert(!((uintptr_t)hash & 7));
+		pos = *(const uint64_t *)hash;
+		break;
+	default:
+		/* sigh, what ever */
+		pos = XXH32(hash, xl->hd->size, 0);
+		break;
+	}
+
+	return (unsigned int)(pos % nbuckets);
+}
+
+static inline bool
+fy_accel_hash_eq(struct fy_accel *xl, const void *hash1, const void *hash2)
+{
+	switch (xl->hd->size) {
+	case 1:
+		return *(const uint8_t *)hash1 == *(const uint8_t *)hash2;
+	case 2:
+		assert(!((uintptr_t)hash1 & 1));
+		assert(!((uintptr_t)hash2 & 1));
+		return *(const uint16_t *)hash1 == *(const uint16_t *)hash2;
+	case 4:
+		assert(!((uintptr_t)hash1 & 3));
+		assert(!((uintptr_t)hash2 & 3));
+		return *(const uint32_t *)hash1 == *(const uint32_t *)hash2;
+	case 8:
+		assert(!((uintptr_t)hash1 & 7));
+		assert(!((uintptr_t)hash2 & 7));
+		return *(const uint64_t *)hash1 == *(const uint64_t *)hash2;
+	default:
+		break;
+	}
+
+	return !memcmp(hash1, hash2, xl->hd->size);
+}
+
+int fy_accel_resize(struct fy_accel *xl, unsigned int min_buckets)
+{
+	unsigned int next_pow2, exp, i, nbuckets, pos;
+	struct fy_accel_entry_list *xlel;
+	struct fy_accel_entry *xle;
+	struct fy_accel_entry_list *buckets_new;
+
+	/* get the next power of two larger or equal */
+	next_pow2 = 1;
+	exp = 0;
+	while (next_pow2 < min_buckets &&
+	       exp < sizeof(prime_lt_pow2)/sizeof(prime_lt_pow2[0])) {
+		next_pow2 <<= 1;
+		exp++;
+	}
+
+	nbuckets = prime_lt_pow2[exp];
+	if (nbuckets == xl->nbuckets)
+		return 0;
+
+	buckets_new = malloc(sizeof(*buckets_new) * nbuckets);
+	if (!buckets_new)
+		return -1;
+
+	for (i = 0, xlel = buckets_new; i < nbuckets; i++, xlel++)
+		fy_accel_entry_list_init(xlel);
+
+	if (xl->buckets) {
+		for (i = 0, xlel = xl->buckets; i < xl->nbuckets; i++, xlel++) {
+			while ((xle = fy_accel_entry_list_pop(xlel)) != NULL) {
+				pos = fy_accel_hash_to_pos(xl, xle->hash, nbuckets);
+				fy_accel_entry_list_add_tail(&buckets_new[pos], xle);
+			}
+		}
+		free(xl->buckets);
+	}
+	xl->buckets = buckets_new;
+	xl->nbuckets = nbuckets;
+	xl->next_exp2 = exp;
+
+	return 0;
+}
+
+int fy_accel_grow(struct fy_accel *xl)
+{
+	if (!xl)
+		return -1;
+
+	/* should not grow indefinetely */
+	if (xl->next_exp2 >= sizeof(prime_lt_pow2)/sizeof(prime_lt_pow2[0]))
+		return -1;
+
+	return fy_accel_resize(xl, prime_lt_pow2[xl->next_exp2 + 1]);
+}
+
+int fy_accel_shrink(struct fy_accel *xl)
+{
+	if (!xl)
+		return -1;
+
+	/* should not shrink indefinetely */
+	if (xl->next_exp2 <= 0)
+		return -1;
+
+	return fy_accel_resize(xl, prime_lt_pow2[xl->next_exp2 - 1]);
+}
+
+int
+fy_accel_setup(struct fy_accel *xl,
+	       const struct fy_hash_desc *hd,
+	       void *userdata,
+	       unsigned int min_buckets)
+{
+	if (!xl || !hd || !hd->size || !hd->hash)
+		return -1;
+
+	memset(xl, 0, sizeof(*xl));
+	xl->hd = hd;
+	xl->userdata = userdata;
+	xl->count = 0;
+
+	return fy_accel_resize(xl, min_buckets);
+}
+
+void fy_accel_cleanup(struct fy_accel *xl)
+{
+	unsigned int i;
+	struct fy_accel_entry_list *xlel;
+	struct fy_accel_entry *xle;
+
+	if (!xl)
+		return;
+
+	for (i = 0, xlel = xl->buckets; i < xl->nbuckets; i++, xlel++) {
+		while ((xle = fy_accel_entry_list_pop(xlel)) != NULL) {
+			free(xle);
+			assert(xl->count > 0);
+			xl->count--;
+		}
+	}
+
+	free(xl->buckets);
+}
+
+struct fy_accel_entry *
+fy_accel_entry_insert(struct fy_accel *xl, const void *key, const void *value)
+{
+	struct fy_accel_entry *xle, *xlet;
+	struct fy_accel_entry_list *xlel;
+	unsigned int pos, bucket_size;
+	int rc;
+
+	if (!xl)
+		return NULL;
+
+	xle = malloc(sizeof(*xle) + xl->hd->size);
+	if (!xle)
+		goto err_out;
+
+	rc = xl->hd->hash(xl, key, xl->userdata, xle->hash);
+	if (rc)
+		goto err_out;
+	xle->key = key;
+	xle->value = value;
+
+	pos = fy_accel_hash_to_pos(xl, xle->hash, xl->nbuckets);
+	xlel = &xl->buckets[pos];
+
+	fy_accel_entry_list_add_tail(xlel, xle);
+
+	assert(xl->count < UINT_MAX);
+	xl->count++;
+
+	/* if we don't auto-resize, return */
+	if (xl->hd->max_bucket_grow_limit) {
+		bucket_size = 0;
+		for (xlet = fy_accel_entry_list_first(xlel); xlet; xlet = fy_accel_entry_next(xlel, xlet)) {
+			bucket_size++;
+			if (bucket_size >= xl->hd->max_bucket_grow_limit)
+				break;
+		}
+
+		/* we don't really care whether the grow up succeeds or not */
+		if (bucket_size >= xl->hd->max_bucket_grow_limit)
+			(void)fy_accel_grow(xl);
+	}
+
+	return xle;
+err_out:
+	if (xle)
+		free(xle);
+	return NULL;
+}
+
+struct fy_accel_entry *
+fy_accel_entry_lookup(struct fy_accel *xl, const void *key)
+{
+	struct fy_accel_entry_iter xli;
+	struct fy_accel_entry *xle;
+
+	xle = fy_accel_entry_iter_start(&xli, xl, key);
+	fy_accel_entry_iter_finish(&xli);
+
+	return xle;
+}
+
+struct fy_accel_entry *
+fy_accel_entry_lookup_key_value(struct fy_accel *xl, const void *key, const void *value)
+{
+	struct fy_accel_entry_iter xli;
+	struct fy_accel_entry *xle;
+
+	for (xle = fy_accel_entry_iter_start(&xli, xl, key); xle;
+	     xle = fy_accel_entry_iter_next(&xli)) {
+
+		if (xle->value == value)
+			break;
+	}
+	fy_accel_entry_iter_finish(&xli);
+
+	return xle;
+}
+
+void
+fy_accel_entry_remove(struct fy_accel *xl, struct fy_accel_entry *xle)
+{
+	unsigned int pos;
+
+	if (!xl || !xle)
+		return;
+
+	pos = fy_accel_hash_to_pos(xl, xle->hash, xl->nbuckets);
+
+	fy_accel_entry_list_del(&xl->buckets[pos], xle);
+
+	assert(xl->count > 0);
+	xl->count--;
+
+	free(xle);
+}
+
+int
+fy_accel_insert(struct fy_accel *xl, const void *key, const void *value)
+{
+	struct fy_accel_entry *xle;
+
+	xle = fy_accel_entry_lookup(xl, key);
+	if (xle)
+		return -1;	/* exists */
+
+	xle = fy_accel_entry_insert(xl, key, value);
+	if (!xle)
+		return -1;	/* failure to insert */
+
+	return 0;
+}
+
+const void *
+fy_accel_lookup(struct fy_accel *xl, const void *key)
+{
+	struct fy_accel_entry *xle;
+
+	xle = fy_accel_entry_lookup(xl, key);
+	return xle ? xle->value : NULL;
+}
+
+int
+fy_accel_remove(struct fy_accel *xl, const void *data)
+{
+	struct fy_accel_entry *xle;
+
+	xle = fy_accel_entry_lookup(xl, data);
+	if (!xle)
+		return -1;
+
+	fy_accel_entry_remove(xl, xle);
+
+	return 0;
+}
+
+struct fy_accel_entry *
+fy_accel_entry_iter_next_internal(struct fy_accel_entry_iter *xli)
+{
+	struct fy_accel *xl;
+	struct fy_accel_entry *xle;
+	struct fy_accel_entry_list *xlel;
+	const void *key;
+	void *hash;
+
+	if (!xli)
+		return NULL;
+
+	xl = xli->xl;
+	hash = xli->hash;
+	xlel = xli->xlel;
+	if (!xl || !hash || !xlel)
+		return NULL;
+	key = xli->key;
+
+	xle = !xli->xle ? fy_accel_entry_list_first(xlel) :
+			  fy_accel_entry_next(xlel, xli->xle);
+	for (; xle; xle = fy_accel_entry_next(xlel, xle)) {
+		if (fy_accel_hash_eq(xl, hash, xle->hash) &&
+		    xl->hd->eq(xl, hash, xle->key, key, xl->userdata))
+			break;
+	}
+	return xli->xle = xle;
+}
+
+struct fy_accel_entry *
+fy_accel_entry_iter_start(struct fy_accel_entry_iter *xli, struct fy_accel *xl, const void *key)
+{
+	unsigned int pos;
+	int rc;
+
+	if (!xli || !xl)
+		return NULL;
+	xli->xl = xl;
+	xli->key = key;
+	if (xl->hd->size <= sizeof(xli->hash_inline))
+		xli->hash = xli->hash_inline;
+	else
+		xli->hash = malloc(xl->hd->size);
+	xli->xlel = NULL;
+
+	if (!xli->hash)
+		goto err_out;
+
+	rc = xl->hd->hash(xl, key, xl->userdata, xli->hash);
+	if (rc)
+		goto err_out;
+
+	pos = fy_accel_hash_to_pos(xl, xli->hash, xl->nbuckets);
+	xli->xlel = &xl->buckets[pos];
+
+	xli->xle = NULL;
+
+	return fy_accel_entry_iter_next_internal(xli);
+
+err_out:
+	fy_accel_entry_iter_finish(xli);
+	return NULL;
+}
+
+void fy_accel_entry_iter_finish(struct fy_accel_entry_iter *xli)
+{
+	if (!xli)
+		return;
+
+	if (xli->hash && xli->hash != xli->hash_inline)
+		free(xli->hash);
+}
+
+struct fy_accel_entry *
+fy_accel_entry_iter_next(struct fy_accel_entry_iter *xli)
+{
+	if (!xli || !xli->xle)
+		return NULL;
+
+	return fy_accel_entry_iter_next_internal(xli);
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-accel.h b/contrib/libs/libfyaml/src/lib/fy-accel.h
new file mode 100644
index 0000000000..2e917cebfb
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-accel.h
@@ -0,0 +1,92 @@
+/*
+ * fy-accel.h - YAML accelerated access methods
+ *
+ * Copyright (c) 2020 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_ACCEL_H
+#define FY_ACCEL_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdbool.h>
+
+#include <libfyaml.h>
+
+#include "fy-list.h"
+#include "fy-typelist.h"
+
+struct fy_accel_entry {
+	struct fy_list_head node;
+	const void *key;
+	const void *value;
+	uint8_t hash[0];
+};
+FY_TYPE_FWD_DECL_LIST(accel_entry);
+FY_TYPE_DECL_LIST(accel_entry);
+
+struct fy_accel;
+
+struct fy_hash_desc {
+	unsigned int size;
+	unsigned int max_bucket_grow_limit;
+	bool unique;
+	int (*hash)(struct fy_accel *xl, const void *key, void *userdata, void *hash);
+	bool (*eq)(struct fy_accel *xl, const void *hash, const void *key1, const void *key2, void *userdata);
+};
+
+struct fy_accel {
+	const struct fy_hash_desc *hd;
+	void *userdata;
+	unsigned int count;
+	unsigned int nbuckets;
+	unsigned int next_exp2;
+	struct fy_accel_entry_list *buckets;
+};
+
+int
+fy_accel_setup(struct fy_accel *xl,
+	       const struct fy_hash_desc *hd,
+	       void *userdata,
+	       unsigned int min_buckets);
+
+void fy_accel_cleanup(struct fy_accel *xl);
+
+int fy_accel_resize(struct fy_accel *xl, unsigned int min_buckets);
+int fy_accel_grow(struct fy_accel *xl);
+int fy_accel_shrink(struct fy_accel *xl);
+
+int fy_accel_insert(struct fy_accel *xl, const void *key, const void *value);
+const void *fy_accel_lookup(struct fy_accel *xl, const void *key);
+int fy_accel_remove(struct fy_accel *xl, const void *key);
+
+struct fy_accel_entry_iter {
+	struct fy_accel *xl;
+	const void *key;
+	void *hash;
+	struct fy_accel_entry_list *xlel;
+	struct fy_accel_entry *xle;
+	uint64_t hash_inline[4];	/* to avoid allocation */
+};
+
+struct fy_accel_entry *
+fy_accel_entry_insert(struct fy_accel *xl, const void *key, const void *value);
+
+struct fy_accel_entry *
+fy_accel_entry_lookup(struct fy_accel *xl, const void *key);
+struct fy_accel_entry *
+fy_accel_entry_lookup_key_value(struct fy_accel *xl, const void *key, const void *value);
+
+void fy_accel_entry_remove(struct fy_accel *xl, struct fy_accel_entry *xle);
+
+struct fy_accel_entry *
+fy_accel_entry_iter_start(struct fy_accel_entry_iter *xli,
+			  struct fy_accel *xl, const void *key);
+void fy_accel_entry_iter_finish(struct fy_accel_entry_iter *xli);
+struct fy_accel_entry *
+fy_accel_entry_iter_next(struct fy_accel_entry_iter *xli);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-atom.c b/contrib/libs/libfyaml/src/lib/fy-atom.c
new file mode 100644
index 0000000000..a38e6fbf7b
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-atom.c
@@ -0,0 +1,1877 @@
+/*
+ * fy-atom.c - YAML atom methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <ctype.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-doc.h"
+
+struct fy_atom *fy_reader_fill_atom(struct fy_reader *fyr, int advance, struct fy_atom *handle)
+{
+	/* start mark */
+	fy_reader_fill_atom_start(fyr, handle);
+
+	/* advance the given number of characters */
+	if (advance > 0)
+		fy_reader_advance_by(fyr, advance);
+
+	fy_reader_fill_atom_end(fyr, handle);
+
+	return handle;
+}
+
+int fy_reader_advance_mark(struct fy_reader *fyr, int advance, struct fy_mark *m)
+{
+	int i, c, tabsize;
+	bool is_line_break;
+
+	tabsize = fy_reader_tabsize(fyr);
+	i = 0;
+	while (advance-- > 0) {
+		c = fy_reader_peek_at(fyr, i++);
+		if (c == -1)
+			return -1;
+		m->input_pos += fy_utf8_width(c);
+
+		/* first check for CR/LF */
+		if (c == '\r' && fy_reader_peek_at(fyr, i) == '\n') {
+			m->input_pos++;
+			i++;
+			is_line_break = true;
+		} else if (fy_reader_is_lb(fyr, c))
+			is_line_break = true;
+		else
+			is_line_break = false;
+
+		if (is_line_break) {
+			m->column = 0;
+			m->line++;
+		} else if (tabsize > 0 && fy_is_tab(c))
+			m->column += (tabsize - (fy_reader_column(fyr) % tabsize));
+		else
+			m->column++;
+	}
+
+	return 0;
+}
+
+struct fy_atom *fy_reader_fill_atom_mark(struct fy_reader *fyr,
+					 const struct fy_mark *start_mark,
+					 const struct fy_mark *end_mark,
+					 struct fy_atom *handle)
+{
+	if (!fyr || !start_mark || !end_mark || !handle)
+		return NULL;
+
+	memset(handle, 0, sizeof(*handle));
+
+	handle->start_mark = *start_mark;
+	handle->end_mark = *end_mark;
+	handle->fyi = fy_reader_current_input(fyr);
+	handle->fyi_generation = fy_reader_current_input_generation(fyr);
+
+	/* default is plain, modify at return */
+	handle->style = FYAS_PLAIN;
+	handle->chomp = FYAC_CLIP;
+	/* by default we don't do storage hints, it's the job of the caller */
+	handle->storage_hint = 0;
+	handle->storage_hint_valid = false;
+
+	return handle;
+}
+
+struct fy_atom *fy_reader_fill_atom_at(struct fy_reader *fyr, int advance, int count, struct fy_atom *handle)
+{
+	struct fy_mark start_mark, end_mark;
+	int rc;
+
+	if (!fyr || !handle)
+		return NULL;
+
+	/* start mark */
+	fy_reader_get_mark(fyr, &start_mark);
+	rc = fy_reader_advance_mark(fyr, advance, &start_mark);
+	(void)rc;
+	/* ignore the return, if the advance failed, it's the end of input */
+
+	/* end mark */
+	end_mark = start_mark;
+	rc = fy_reader_advance_mark(fyr, count, &end_mark);
+	(void)rc;
+	/* ignore the return, if the advance failed, it's the end of input */
+
+	return fy_reader_fill_atom_mark(fyr, &start_mark, &end_mark, handle);
+}
+
+static inline void
+fy_atom_iter_chunk_reset(struct fy_atom_iter *iter)
+{
+	iter->top = 0;
+	iter->read = 0;
+}
+
+static int
+fy_atom_iter_grow_chunk(struct fy_atom_iter *iter)
+{
+	struct fy_atom_iter_chunk *chunks, *c;
+	size_t asz;
+	const char *old_s, *old_e, *ss;
+	unsigned int i;
+	size_t offset;
+
+	old_s = (const char *)iter->chunks;
+	old_e = (const char *)(iter->chunks + iter->alloc);
+
+	asz = sizeof(*chunks) * iter->alloc * 2;
+	chunks = realloc(iter->chunks == iter->startup_chunks ? NULL : iter->chunks, asz);
+	if (!chunks)	/* out of memory */
+		return -1;
+	if (iter->chunks == iter->startup_chunks)
+		memcpy(chunks, iter->startup_chunks, sizeof(iter->startup_chunks));
+
+	/* for chunks that point to the inplace buffer, reassign pointers */
+	for (ss = old_s, c = chunks, i = 0; i < iter->top; ss += sizeof(*c), c++, i++) {
+		if (c->ic.str < old_s || c->ic.str >= old_e ||
+		    c->ic.len > sizeof(c->inplace_buf))
+			continue;
+
+		/* get offset */
+		offset = (size_t)(c->ic.str - ss);
+
+		/* verify that it points to the inplace_buf area */
+		assert(offset >= offsetof(struct fy_atom_iter_chunk, inplace_buf));
+		offset -= offsetof(struct fy_atom_iter_chunk, inplace_buf);
+
+		c->ic.str = c->inplace_buf + offset;
+	}
+
+	iter->alloc *= 2;
+	iter->chunks = chunks;
+
+	return 0;
+}
+
+static int
+_fy_atom_iter_add_chunk(struct fy_atom_iter *iter, const char *str, size_t len)
+{
+	struct fy_atom_iter_chunk *c;
+	int ret;
+
+	if (!len)
+		return 0;
+
+	/* grow iter chunks? */
+	if (iter->top >= iter->alloc) {
+		ret = fy_atom_iter_grow_chunk(iter);
+		if (ret)
+			return ret;
+	}
+	assert(iter->top < iter->alloc);
+	c = &iter->chunks[iter->top++];
+
+	c->ic.str = str;
+	c->ic.len = len;
+
+	return 0;
+}
+
+static int
+_fy_atom_iter_add_chunk_copy(struct fy_atom_iter *iter, const char *str, size_t len)
+{
+	struct fy_atom_iter_chunk *c;
+	int ret;
+
+	if (!len)
+		return 0;
+
+	assert(len <= sizeof(c->inplace_buf));
+
+	if (iter->top >= iter->alloc) {
+		ret = fy_atom_iter_grow_chunk(iter);
+		if (ret)
+			return ret;
+	}
+	assert(iter->top < iter->alloc);
+	c = &iter->chunks[iter->top++];
+
+	memcpy(c->inplace_buf, str, len);
+
+	c->ic.str = c->inplace_buf;
+	c->ic.len = len;
+
+	return 0;
+}
+
+/* keep it around without a warning even though it's unused */
+static int
+_fy_atom_iter_add_utf8(struct fy_atom_iter *iter, int c)
+	FY_ATTRIBUTE(__unused__);
+
+static int
+_fy_atom_iter_add_utf8(struct fy_atom_iter *iter, int c)
+{
+	char buf[FY_UTF8_FORMAT_BUFMIN];
+	char *e;
+
+	/* only fails if invalid utf8 */
+	e = fy_utf8_put(buf, sizeof(buf), c);
+	if (!e)
+		return -1;
+
+	return _fy_atom_iter_add_chunk_copy(iter, buf, e - buf);
+}
+
+/* optimized linebreaks */
+static int
+_fy_atom_iter_add_lb(struct fy_atom_iter *iter, int c)
+{
+	switch (c) {
+	/* those are generic linebreaks */
+	case '\r':
+	case '\n':
+	case 0x85:
+		return _fy_atom_iter_add_chunk(iter, "\n", 1);
+	/* these are specific linebreaks */
+	case 0x2028:
+		return _fy_atom_iter_add_chunk(iter, "\xe2\x80\xa8", 3);
+	case 0x2029:
+		return _fy_atom_iter_add_chunk(iter, "\xe2\x80\xa9", 3);
+	}
+	/* not a linebreak */
+	return -1;
+}
+
+// #define DEBUG_CHUNK
+
+#ifndef DEBUG_CHUNK
+#define fy_atom_iter_add_chunk _fy_atom_iter_add_chunk
+#define fy_atom_iter_add_chunk_copy _fy_atom_iter_add_chunk_copy
+#define fy_atom_iter_add_utf8 _fy_atom_iter_add_utf8
+#define fy_atom_iter_add_lb _fy_atom_iter_add_lb
+#else
+#define fy_atom_iter_add_chunk(_iter, _str, _len) \
+	({ \
+		const char *__str = (_str); \
+		size_t __len2 = (_len); \
+		char *__out = NULL; \
+		int __ret = 0; \
+		\
+		if (__len2 > 0) { \
+			__out = fy_utf8_format_text_alloc(__str, __len2, fyue_doublequote); \
+			assert(__out); \
+			fprintf(stderr, "%s:%d chunk #%zu \"%s\"\n", __func__, __LINE__, __len2, __out); \
+			__ret = _fy_atom_iter_add_chunk((_iter), __str, __len2); \
+			free(__out); \
+		} \
+		__ret; \
+	})
+
+#define fy_atom_iter_add_chunk_copy(_iter, _str, _len) \
+	({ \
+		const char *__str = (_str); \
+		size_t __len2 = (_len); \
+		char *__out = NULL; \
+		int __ret = 0; \
+		\
+		if (__len2 > 0) { \
+			__out = fy_utf8_format_text_alloc(__str, __len2, fyue_doublequote); \
+			assert(__out); \
+			fprintf(stderr, "%s:%d chunk-copy #%zu \"%s\"\n", __func__, __LINE__, __len2, __out); \
+			/* fprintf(stderr, "%s:%d chunk-copy \"%.*s\"\n", __func__, __LINE__, (int)__len, __str); */ \
+			__ret = _fy_atom_iter_add_chunk_copy((_iter), __str, __len2); \
+			free(__out); \
+		} \
+		__ret; \
+	})
+#define fy_atom_iter_add_utf8(_iter, _c) \
+	({ \
+		int __c = (_c); \
+		fprintf(stderr, "%s:%d utf8 %d\n", __func__, __LINE__, __c); \
+		_fy_atom_iter_add_utf8((_iter), (_c)); \
+	})
+#define fy_atom_iter_add_lb(_iter, _c) \
+	({ \
+		int __c = (_c); \
+		fprintf(stderr, "%s:%d lb 0x%02x\n", __func__, __LINE__, __c); \
+		_fy_atom_iter_add_lb((_iter), (_c)); \
+	})
+#endif
+
+static void
+fy_atom_iter_line_analyze(struct fy_atom_iter *iter, struct fy_atom_iter_line_info *li,
+			  const char *line_start, size_t len)
+{
+	const struct fy_atom *atom = iter->atom;
+	const char *s, *e, *ss;
+	int col, c, w, ts, cws, advws;
+	bool last_was_ws, is_block;
+	int lastc;
+
+	s = line_start;
+	e = line_start + len;
+
+	is_block = atom->style == FYAS_LITERAL || atom->style == FYAS_FOLDED;
+
+	/* short circuit non multiline, non ws atoms */
+	if ((atom->direct_output && !atom->has_lb && !atom->has_ws) ||
+	    atom->style == FYAS_DOUBLE_QUOTED_MANUAL) {
+		li->start = s;
+		li->end = e;
+		li->nws_start = s;
+		li->nws_end = e;
+		li->chomp_start = s;
+		li->final = true;
+		li->empty = atom->empty;
+		li->trailing_breaks = 0;
+		li->trailing_breaks_ws = false;
+		li->start_ws = 0;
+		li->end_ws = 0;
+		li->indented = false;
+		li->lb_end = is_block ? atom->ends_with_lb : false;
+		li->final = true;
+		li->actual_lb = -1;
+		li->s_tb = li->e_tb = NULL;
+		li->ends_with_backslash = false;
+		return;
+	}
+
+	li->start = s;
+	li->end = NULL;
+	li->nws_start = NULL;
+	li->nws_end = NULL;
+	li->chomp_start = NULL;
+	li->empty = true;
+	li->trailing_breaks = 0;
+	li->trailing_breaks_ws = false;
+	li->first = false;
+	li->start_ws = (size_t)-1;
+	li->end_ws = (size_t)-1;
+	li->indented = false;
+	li->lb_end = false;
+	li->final = false;
+	li->actual_lb = -1;
+	li->ends_with_backslash = false;
+
+	last_was_ws = false;
+
+	ts = atom->tabsize ? atom->tabsize : 8;	/* pick it up from the atom (if there is) */
+
+	/* consecutive whitespace */
+	cws = 0;
+
+	lastc = -1;
+	li->s_tb = s;
+	for (col = 0, ss = s; (c = fy_utf8_get(ss, (e - ss), &w)) >= 0; ss += w) {
+
+		lastc = c;
+
+		/* mark start of chomp */
+		if (is_block && !li->chomp_start && (unsigned int)col >= iter->chomp) {
+			li->chomp_start = ss;
+
+			/* if the character at the chomp point is whitespace
+			 * then we're indented
+			 */
+			li->indented = fy_is_ws(c);
+
+#if defined(DEBUG_CHUNK)
+			fprintf(stderr, "%s:%d chomp_start=%d\n", __FILE__, __LINE__, (int)(li->chomp_start - li->start));
+#endif
+
+		}
+
+		if (fy_is_lb_m(c, atom->lb_mode)) {
+
+#ifdef DEBUG_CHUNK
+			fprintf(stderr, "%s:%d lb=0x%x\n", __FILE__, __LINE__, c);
+#endif
+
+			col = 0;
+			if (!li->end) {
+
+				li->end = ss;
+				li->end_ws = cws;
+				li->lb_end = true;
+				li->actual_lb = c;
+
+#ifdef DEBUG_CHUNK
+				fprintf(stderr, "%s:%d set actual_lb=0x%x\n", __FILE__, __LINE__, li->actual_lb);
+#endif
+
+				cws = 0;
+			}
+
+			/* no chomp point hit, use whatever we have here */
+			if (is_block && !li->chomp_start) {
+				li->chomp_start = ss;
+#if defined(DEBUG_CHUNK)
+				fprintf(stderr, "%s:%d chomp_start=%d\n", __FILE__, __LINE__, (int)(li->chomp_start - li->start));
+#endif
+
+			}
+
+			if (!last_was_ws) {
+				cws = 0;
+				li->nws_end = ss;
+				last_was_ws = true;
+			}
+
+		} else if (fy_is_space(c)) {
+
+			col++;
+			cws++;
+
+			if (!last_was_ws) {
+				li->nws_end = ss;
+				last_was_ws = true;
+			}
+
+		} else if (fy_is_tab(c)) {
+
+			bool can_be_nws_end;
+
+			advws = ts - (col % ts);
+			col += advws;
+
+#if defined(DEBUG_CHUNK)
+			fprintf(stderr, "%s:%d tab col=%d chomp=%d\n", __FILE__, __LINE__, col, (int)(li->chomp_start - li->start));
+#endif
+
+			if (fy_atom_style_is_block(atom->style) && col >= (int)(li->chomp_start - li->start)) {
+#if defined(DEBUG_CHUNK)
+				fprintf(stderr, "%s:%d tab col=%d chomp=%d\n", __FILE__, __LINE__, col, (int)(li->chomp_start - li->start));
+#endif
+				goto do_nws;
+			}
+
+			cws += advws;
+
+			can_be_nws_end = true;
+			if (atom->style == FYAS_DOUBLE_QUOTED && ss > li->start && ss[-1] == '\\') {
+				can_be_nws_end = false;
+#ifdef DEBUG_CHUNK
+				fprintf(stderr, "%s:%d backslashed tab\n", __FILE__, __LINE__);
+#endif
+			}
+
+			if (can_be_nws_end && !last_was_ws) {
+				li->nws_end = ss;
+				last_was_ws = true;
+			}
+
+		} else {
+
+			col++;
+do_nws:
+			/* mark start of non whitespace */
+			if (!li->nws_start)
+				li->nws_start = ss;
+
+			if (li->empty)
+				li->empty = false;
+
+			if (li->start_ws == (size_t)-1)
+				li->start_ws = cws;
+
+			last_was_ws = false;
+			cws = 0;
+		}
+
+		/* if we got both break */
+		if (li->end && iter->chomp >= 0)
+			break;
+	}
+	li->e_tb = ss;
+
+	li->final = c < 0;
+
+	if (li->final && atom->ends_with_eof) {
+
+		/* mark start of chomp */
+		if (is_block && !li->chomp_start && (unsigned int)col >= iter->chomp) {
+			li->chomp_start = ss;
+
+			/* if the character at the chomp point is whitespace
+			 * then we're indented
+			 */
+			li->indented = fy_is_ws(lastc);
+#ifdef DEBUG_CHUNK
+			fprintf(stderr, "%s:%d is_block && !li->chomp_start && (unsigned int)col >= iter->chomp\n", __FILE__, __LINE__);
+#endif
+#if defined(DEBUG_CHUNK)
+			fprintf(stderr, "%s:%d chomp_start=%d\n", __FILE__, __LINE__, (int)(li->chomp_start - li->start));
+#endif
+
+		}
+
+		if (!li->end) {
+			li->end = ss;
+			li->end_ws = cws;
+			li->lb_end = true;
+
+#ifdef DEBUG_CHUNK
+			fprintf(stderr, "%s:%d li->final && atom->ends_with_eof && !li->end\n", __FILE__, __LINE__);
+#endif
+			cws = 0;
+		}
+
+		/* no chomp point hit, use whatever we have here */
+		if (is_block && !li->chomp_start) {
+			li->chomp_start = ss;
+#ifdef DEBUG_CHUNK
+			fprintf(stderr, "%s:%d li->final && atom->ends_with_eof && !li->chomp_start\n", __FILE__, __LINE__);
+#endif
+#if defined(DEBUG_CHUNK)
+			fprintf(stderr, "%s:%d chomp_start=%d\n", __FILE__, __LINE__, (int)(li->chomp_start - li->start));
+#endif
+		}
+
+		if (!last_was_ws) {
+			cws = 0;
+			li->nws_end = ss;
+			last_was_ws = true;
+#ifdef DEBUG_CHUNK
+			fprintf(stderr, "%s:%d li->final && atom->ends_with_eof && !last_was_ws\n", __FILE__, __LINE__);
+#endif
+		}
+	}
+
+	if (!last_was_ws)
+		li->nws_end = ss;
+
+	if (!li->nws_start)
+		li->nws_start = ss;
+
+	if (!li->nws_end)
+		li->nws_end = ss;
+
+	/* if we haven't hit the chomp, point use whatever we're now */
+	if (is_block && !li->chomp_start) {
+		li->chomp_start = ss;
+#if defined(DEBUG_CHUNK)
+		fprintf(stderr, "%s:%d chomp_start=%d\n", __FILE__, __LINE__, (int)(li->chomp_start - li->start));
+#endif
+	}
+
+	if (li->start_ws == (size_t)-1)
+		li->start_ws = 0;
+
+	if (li->end_ws == (size_t)-1)
+		li->end_ws = 0;
+
+	/* mark next line to the end if no linebreak found */
+	if (!li->end) {
+		li->end = iter->e;
+		li->last = true;
+		li->end_ws = cws;
+		li->lb_end = false;
+		goto out;
+	}
+
+	/* find out if any trailing breaks exist afterwards */
+	for (; (c = fy_utf8_get(ss, (e - ss), &w)) >= 0 && (fy_is_ws(c) || fy_is_lb_m(c, atom->lb_mode)); ss += w) {
+
+		if (!li->trailing_breaks_ws && is_block && (unsigned int)col > iter->chomp)
+			li->trailing_breaks_ws = true;
+
+		if (fy_is_lb_m(c, atom->lb_mode)) {
+			li->trailing_breaks++;
+			col = 0;
+		} else {
+			/* indented whitespace counts as break */
+			if (fy_is_tab(c))
+				col += (ts - (col % ts));
+			else
+				col++;
+		}
+
+	}
+
+	/* and mark as last if only whitespace and breaks after this point */
+	li->last = ss >= e;
+
+out:
+	assert(li->start);
+	assert(li->end);
+	assert(li->nws_start);
+	assert(li->nws_end);
+	assert(!is_block || li->chomp_start);
+
+	li->ends_with_backslash = atom->style == FYAS_DOUBLE_QUOTED &&
+				  !li->empty &&
+				  (li->nws_end > li->nws_start && li->nws_end[-1] == '\\') &&
+				  ((li->nws_end - li->nws_start) <= 1 || li->nws_end[-2] != '\\');
+#ifdef DEBUG_CHUNK
+	fprintf(stderr, "%s:%d ends_with_backslash=%s\n", __FILE__, __LINE__, li->ends_with_backslash ? "true" : "false");
+#endif
+}
+
+void fy_atom_iter_start(const struct fy_atom *atom, struct fy_atom_iter *iter)
+{
+	struct fy_atom_iter_line_info *li;
+	size_t len;
+
+	if (!atom || !iter)
+		return;
+
+	memset(iter, 0, sizeof(*iter));
+
+	iter->atom = atom;
+	iter->s = fy_atom_data(atom);
+	len = fy_atom_size(atom);
+	iter->e = iter->s + len;
+
+	iter->chomp = atom->increment;
+
+	/* default tab size is 8 */
+	iter->tabsize = atom->tabsize ? atom->tabsize: 8;
+
+	memset(iter->li, 0, sizeof(iter->li));
+	li = &iter->li[1];
+	fy_atom_iter_line_analyze(iter, li, iter->s, len);
+	li->first = true;
+
+	/* if there's single quote at the start of a line ending the atom */
+	iter->dangling_end_quote = atom->end_mark.column == 0;
+	iter->single_line = atom->start_mark.line == atom->end_mark.line;
+	iter->empty = atom->empty;
+	iter->last_ends_with_backslash = li->ends_with_backslash;
+#ifdef DEBUG_CHUNK
+	fprintf(stderr, "%s:%d single_line=%s empty=%s last_ends_with_backslash=%s\n", __FILE__, __LINE__,
+			iter->single_line ? "true" : "false",
+			iter->empty ? "true" : "false",
+			iter->last_ends_with_backslash ? "true" : "false");
+#endif
+
+	/* current is 0, next is 1 */
+	iter->current = 0;
+
+	iter->alloc = sizeof(iter->startup_chunks)/sizeof(iter->startup_chunks[0]);
+	iter->top = 0;
+	iter->read = 0;
+	iter->chunks = iter->startup_chunks;
+
+	iter->done = false;
+
+	iter->unget_c = -1;
+}
+
+void fy_atom_iter_finish(struct fy_atom_iter *iter)
+{
+	if (iter->chunks && iter->chunks != iter->startup_chunks)
+		free(iter->chunks);
+
+	iter->chunks = NULL;
+}
+
+static const struct fy_atom_iter_line_info *
+fy_atom_iter_line(struct fy_atom_iter *iter)
+{
+	const struct fy_atom *atom = iter->atom;
+	struct fy_atom_iter_line_info *li, *nli;
+	const char *ss;
+
+	/* return while there's a next line */
+	if (!iter)
+		return NULL;
+
+	/* make next line the current one */
+	iter->current = !iter->current;
+
+	li = &iter->li[iter->current];
+
+	/* if we're out, we're out */
+	if (li->start >= iter->e)
+		return NULL;
+
+	/* scan next line (special handling for '\r\n') */
+	ss = li->end;
+	if (ss < iter->e) {
+		if (*ss == '\r' && (ss + 1) < iter->e && ss[1] == '\n')
+			ss += 2;
+		else
+			ss += fy_utf8_width_by_first_octet((uint8_t)*ss);
+	}
+
+	/* get current and next line */
+	fy_atom_iter_line_analyze(iter, &iter->li[!iter->current], ss, iter->e - ss);
+
+	/* if no more, mark the next as NULL */
+	nli = &iter->li[!iter->current];
+	if (nli->start >= iter->e)
+		nli = NULL;
+
+	/* for quoted, output the white space start */
+	if (atom->style == FYAS_SINGLE_QUOTED || atom->style == FYAS_DOUBLE_QUOTED) {
+		li->s = li->first ? li->start : li->nws_start;
+		li->e = li->last ? li->end : li->nws_end;
+
+		/* just empty */
+		if (li->empty && li->first && li->last && !iter->single_line)
+			li->s = li->e;
+
+	} else if (atom->style == FYAS_LITERAL || atom->style == FYAS_FOLDED) {
+		li->s = li->chomp_start;
+		li->e = li->end;
+		if (li->empty && li->first && li->last)
+			li->s = li->e;
+	} else {
+		li->s = li->nws_start;
+		li->e = li->nws_end;
+	}
+
+	/* bah, I hate this, */
+	if (li->s > li->e)
+		li->s = li->e;
+
+	assert(li->s <= li->e);
+
+	/* we never fold LS or PS linebreaks (on yaml 1.1) */
+	li->need_nl = fy_is_lb_LS_PS(li->actual_lb) && fy_is_lb_m(li->actual_lb, iter->atom->lb_mode) && !li->ends_with_backslash;
+	li->need_sep = false;
+
+#ifdef DEBUG_CHUNK
+	fprintf(stderr, "%s:%d need_nl=%s\n", __FILE__, __LINE__, li->need_nl ? "true" : "false");
+#endif
+	if (li->need_nl)
+		return li;
+
+	switch (atom->style) {
+	case FYAS_PLAIN:
+	case FYAS_URI:
+		li->need_nl = !li->last && li->empty;
+		li->need_sep = !li->need_nl && nli && !nli->empty;
+		break;
+
+	case FYAS_DOUBLE_QUOTED_MANUAL:
+		li->need_nl = false;
+		li->need_sep = false;
+		break;
+
+	case FYAS_COMMENT:
+		li->need_nl = !li->final;
+		li->need_sep = false;
+		break;
+
+	case FYAS_DOUBLE_QUOTED:
+#ifdef DEBUG_CHUNK
+		fprintf(stderr, "%s:%d ends_with_backslash=%s\n", __FILE__, __LINE__, li->ends_with_backslash ? "true" : "false");
+#endif
+		if (li->ends_with_backslash) {
+
+			li->need_nl = false;
+			li->need_sep = false;
+			break;
+		}
+
+		/* fall-through */
+	case FYAS_SINGLE_QUOTED:
+		li->need_nl = (!li->last && !li->first && li->empty) ||
+				(nli && iter->empty && !li->first);
+
+		if (li->need_nl)
+			break;
+
+		li->need_sep = (nli && !nli->empty) ||
+				(!nli && li->last && iter->dangling_end_quote) ||
+				(nli && nli->final && nli->empty);
+
+		break;
+	case FYAS_LITERAL:
+		li->need_nl = true;
+		break;
+	case FYAS_FOLDED:
+		li->need_nl = !li->last && (li->empty || li->indented || li->trailing_breaks_ws || (nli && nli->indented));
+		if (li->need_nl)
+			break;
+		li->need_sep = nli && !nli->indented && !nli->empty;
+		break;
+	default:
+		break;
+	}
+
+	return li;
+}
+
+static int
+fy_atom_iter_format(struct fy_atom_iter *iter)
+{
+	const struct fy_atom *atom = iter->atom;
+	const struct fy_atom_iter_line_info *li;
+	const char *s, *e, *t;
+	int value, code_length, rlen, ret;
+	uint8_t code[4], *tt;
+	int j, pending_nl;
+	int *pending_lb = NULL, *pending_lb_new = NULL;
+	int pending_lb_size = 0;
+	enum fy_utf8_escape esc_mode;
+	size_t i;
+
+	/* done? */
+	li = fy_atom_iter_line(iter);
+	if (!li) {
+		iter->done = true;
+		return 0;
+	}
+	if (iter->done)
+		return 0;
+
+	s = li->s;
+	e = li->e;
+
+	switch (atom->style) {
+
+	case FYAS_LITERAL:
+	case FYAS_PLAIN:
+	case FYAS_FOLDED:
+	case FYAS_COMMENT:
+		if (s < e) {
+			ret = fy_atom_iter_add_chunk(iter, s, e - s);
+			if (ret)
+				goto out;
+		}
+
+		break;
+
+	case FYAS_SINGLE_QUOTED:
+		if (li->last)
+			e = li->nws_end;
+		while (s < e) {
+			/* find next single quote */
+			t = memchr(s, '\'', e - s);
+			rlen = (t ? t : e) - s;
+
+			ret = fy_atom_iter_add_chunk(iter, s, rlen);
+			if (ret)
+				goto out;
+
+			/* end of string */
+			if (!t)
+				break;
+
+			s = t;
+			/* next character single quote too */
+			if ((e - s) >= 2 && s[1] == '\'')
+				fy_atom_iter_add_chunk(iter, s, 1);
+
+			/* skip over this single quote char */
+			s++;
+		}
+		break;
+
+	case FYAS_DOUBLE_QUOTED:
+		if (li->last)
+			e = li->nws_end;
+
+		esc_mode = atom->json_mode ? fyue_doublequote_json :
+			   atom->lb_mode == fylb_cr_nl ? fyue_doublequote : fyue_doublequote_yaml_1_1;
+
+		while (s < e) {
+			/* find next escape */
+			t = memchr(s, '\\', e - s);
+			/* copy up to there (or end) */
+			rlen = (t ? t : e) - s;
+			ret = fy_atom_iter_add_chunk(iter, s, rlen);
+			if (ret)
+				goto out;
+
+			if (!t || (e - t) < 2)
+				break;
+
+			ret = fy_utf8_parse_escape(&t, e - t, esc_mode);
+			if (ret < 0)
+				goto out;
+			s = t;
+			value = ret;
+
+			tt = fy_utf8_put(code, sizeof(code), value);
+			if (!tt) {
+				ret = -1;
+				goto out;
+			}
+
+			ret = fy_atom_iter_add_chunk_copy(iter, (const char *)code, tt - code);
+			if (ret)
+				goto out;
+		}
+		break;
+
+	case FYAS_URI:
+		while (s < e) {
+			/* find next escape */
+			t = memchr(s, '%', e - s);
+			rlen = (t ? t : e) - s;
+			ret = fy_atom_iter_add_chunk(iter, s, rlen);
+			if (ret)
+				goto out;
+
+			/* end of string */
+			if (!t)
+				break;
+			s = t;
+
+			code_length = sizeof(code);
+			t = fy_uri_esc(s, e - s, code, &code_length);
+			if (!t) {
+				ret = -1;
+				goto out;
+			}
+
+			/* output escaped utf8 */
+			ret = fy_atom_iter_add_chunk_copy(iter, (const char *)code, code_length);
+			if (ret)
+				goto out;
+			s = t;
+		}
+		break;
+
+	case FYAS_DOUBLE_QUOTED_MANUAL:
+		/* manual scalar just goes out */
+		ret = fy_atom_iter_add_chunk(iter, s, e - s);
+		if (ret)
+			goto out;
+		s = e;
+		break;
+
+	default:
+		ret = -1;
+		goto out;
+	}
+
+	if (li->last) {
+
+		if (fy_atom_style_is_block(atom->style)) {
+
+			switch (atom->chomp) {
+			case FYAC_STRIP:
+			case FYAC_CLIP:
+
+				pending_lb_size = 16;
+				pending_lb = FY_ALLOCA(sizeof(*pending_lb) * pending_lb_size);
+
+				pending_nl = 0;
+				if (!li->empty) {
+					pending_lb[0] = li->actual_lb > 0 ? li->actual_lb : '\n';
+					pending_nl = 1;
+				}
+				while ((li = fy_atom_iter_line(iter)) != NULL) {
+					if (!iter->empty && li->chomp_start < li->end) {
+						for (j = 0; j < pending_nl; j++) {
+							ret = fy_atom_iter_add_lb(iter, pending_lb[j]);
+							if (ret)
+								goto out;
+						}
+						pending_nl = 0;
+
+						ret = fy_atom_iter_add_chunk(iter, li->chomp_start, li->end - li->chomp_start);
+						if (ret)
+							goto out;
+					}
+					if (li->lb_end && !iter->empty) {
+						if (pending_nl >= pending_lb_size) {
+							pending_lb_new = FY_ALLOCA(sizeof(*pending_lb) * pending_lb_size * 2);
+							memcpy(pending_lb_new, pending_lb, sizeof(*pending_lb) * pending_lb_size);
+							pending_lb_size *= 2;
+							pending_lb = pending_lb_new;
+						}
+						pending_lb[pending_nl] = li->actual_lb > 0 ? li->actual_lb : '\n';
+						pending_nl++;
+					}
+				}
+
+				if (atom->chomp == FYAC_CLIP && (pending_nl || atom->ends_with_eof)) {
+					ret = fy_atom_iter_add_lb(iter, pending_lb[0]);
+					if (ret)
+						goto out;
+				}
+				break;
+			case FYAC_KEEP:
+				if (li->lb_end || atom->ends_with_eof) {
+					ret = fy_atom_iter_add_lb(iter, li->actual_lb > 0 ? li->actual_lb : '\n');
+					if (ret)
+						goto out;
+				}
+
+				/* nothing more if it's an EOF */
+				if (atom->ends_with_eof && atom->empty)
+					break;
+
+				while ((li = fy_atom_iter_line(iter)) != NULL) {
+					if (!iter->empty && li->chomp_start < li->end) {
+						ret = fy_atom_iter_add_chunk(iter, li->chomp_start, li->end - li->chomp_start);
+						if (ret)
+							goto out;
+					}
+					if (li->lb_end) {
+						ret = fy_atom_iter_add_lb(iter, li->actual_lb > 0 ? li->actual_lb : '\n');
+						if (ret)
+							goto out;
+					}
+				}
+				break;
+			}
+
+			iter->done = true;
+
+		} else {
+
+#ifdef DEBUG_CHUNK
+			fprintf(stderr, "%s:%d trailing_breaks=%zu end_ws=%zu empty=%s\n", __func__, __LINE__,
+					li->trailing_breaks, li->end_ws,
+					li->empty ? "true" : "false");
+#endif
+
+			if (li->trailing_breaks == 0 && li->end_ws > 0) {
+				/* end of quote in a non-blank line having white space */
+				ret = fy_atom_iter_add_chunk(iter, li->nws_end, (size_t)(li->e - li->nws_end));
+				if (ret)
+					goto out;
+			} else if (li->trailing_breaks == 1) {
+
+				if (atom->style == FYAS_DOUBLE_QUOTED) {
+#ifdef DEBUG_CHUNK
+					fprintf(stderr, "%s:%d %s <>%d single trailing break %c\n", __FILE__, __LINE__, __func__,
+							(int)(li->s_tb - li->s), li->s_tb[-1]);
+#endif
+				}
+
+				if (!li->ends_with_backslash) {
+					ret = fy_atom_iter_add_chunk(iter, " ", 1);
+					if (ret)
+						goto out;
+				}
+			} else if (li->trailing_breaks > 1) {
+				for (i = 0; i < li->trailing_breaks - 1; i++) {
+					ret = fy_atom_iter_add_lb(iter, '\n');
+					if (ret)
+						goto out;
+				}
+			}
+
+			iter->done = true;
+		}
+
+	} else {
+		if (li->need_sep) {
+			ret = fy_atom_iter_add_chunk(iter, " ", 1);
+			if (ret)
+				goto out;
+		}
+
+		if (li->need_nl) {
+			ret = fy_atom_iter_add_lb(iter, li->actual_lb > 0 ? li->actual_lb : '\n');
+			if (ret)
+				goto out;
+		}
+	}
+
+	/* got more */
+	ret = 1;
+
+out:
+	return ret;
+}
+
+const struct fy_iter_chunk *
+fy_atom_iter_peek_chunk(struct fy_atom_iter *iter)
+{
+	if (iter->read >= iter->top)
+		return NULL;
+
+	return &iter->chunks[iter->read].ic;
+}
+
+void fy_atom_iter_advance(struct fy_atom_iter *iter, size_t len)
+{
+	struct fy_atom_iter_chunk *ac;
+	size_t rlen;
+
+	/* while more and not out */
+	while (len > 0 && iter->read < iter->top) {
+
+		ac = iter->chunks + iter->read;
+
+		/* get next run length */
+		rlen = len > ac->ic.len ? ac->ic.len : len;
+
+		/* remove from chunk */
+		ac->ic.str += rlen;
+		ac->ic.len -= rlen;
+
+		/* advance if out of data */
+		if (ac->ic.len == 0)
+			iter->read++;
+
+		/* remove run from length */
+		len -= rlen;
+	}
+
+	/* reset when everything is gone */
+	if (iter->read >= iter->top)
+		fy_atom_iter_chunk_reset(iter);
+}
+
+const struct fy_iter_chunk *
+fy_atom_iter_chunk_next(struct fy_atom_iter *iter, const struct fy_iter_chunk *curr, int *errp)
+{
+	const struct fy_iter_chunk *ic;
+	int ret;
+
+	ic = fy_atom_iter_peek_chunk(iter);
+	if (curr && curr == ic)
+		fy_atom_iter_advance(iter, ic->len);
+
+	/* need to pull in data? */
+	ic = fy_atom_iter_peek_chunk(iter);
+	if (!curr || !ic) {
+		fy_atom_iter_chunk_reset(iter);
+
+		do {
+			ret = fy_atom_iter_format(iter);
+
+			/* either end or error, means we don't have data */
+			if (ret <= 0) {
+				if (errp)
+					*errp = ret < 0 ? -1 : 0;
+				return NULL;
+			}
+
+		} while (!fy_atom_iter_peek_chunk(iter));
+	}
+	ic = fy_atom_iter_peek_chunk(iter);
+	if (errp)
+		*errp = 0;
+	return ic;
+}
+
+int fy_atom_format_text_length(struct fy_atom *atom)
+{
+	struct fy_atom_iter iter;
+	const struct fy_iter_chunk *ic;
+	size_t len;
+	int ret;
+
+	if (!atom)
+		return -1;
+
+	if (atom->storage_hint_valid)
+		return atom->storage_hint;
+
+	len = 0;
+	fy_atom_iter_start(atom, &iter);
+	ic = NULL;
+	while ((ic = fy_atom_iter_chunk_next(&iter, ic, &ret)) != NULL)
+		len += ic->len;
+	fy_atom_iter_finish(&iter);
+
+	/* something funky going on here */
+	if ((int)len < 0)
+		return -1;
+
+	if (ret != 0)
+		return ret;
+
+	atom->storage_hint = (size_t)len;
+	atom->storage_hint_valid = true;
+	return (int)len;
+}
+
+const char *fy_atom_format_text(struct fy_atom *atom, char *buf, size_t maxsz)
+{
+	struct fy_atom_iter iter;
+	const struct fy_iter_chunk *ic;
+	char *s, *e;
+	int ret;
+
+	if (!atom || !buf)
+		return NULL;
+
+	s = buf;
+	e = s + maxsz;
+	fy_atom_iter_start(atom, &iter);
+	ic = NULL;
+	while ((ic = fy_atom_iter_chunk_next(&iter, ic, &ret)) != NULL) {
+		/* must fit */
+		if ((size_t)(e - s) < ic->len)
+			return NULL;
+		memcpy(s, ic->str, ic->len);
+		s += ic->len;
+	}
+	fy_atom_iter_finish(&iter);
+
+	if (ret != 0 || s >= e)
+		return NULL;
+	*s = '\0';
+
+	return buf;
+}
+
+int fy_atom_format_utf8_length(struct fy_atom *atom)
+{
+	struct fy_atom_iter iter;
+	const struct fy_iter_chunk *ic;
+	const char *s, *e;
+	size_t len;
+	int ret, rem, run, w;
+
+	if (!atom)
+		return -1;
+
+	len = 0;
+	rem = 0;
+	fy_atom_iter_start(atom, &iter);
+	ic = NULL;
+	while ((ic = fy_atom_iter_chunk_next(&iter, ic, &ret)) != NULL) {
+		s = ic->str;
+		e = s + ic->len;
+
+		/* add the remainder */
+		run = (e - s) > rem ? rem : (e - s);
+		s += run;
+
+		/* count utf8 characters */
+		while (s < e) {
+			w = fy_utf8_width_by_first_octet(*(uint8_t *)s);
+
+			/* how many bytes of this run */
+			run = (e - s) > w ? w : (e - s);
+			/* the remainder of this run */
+			rem = w - run;
+			/* one more character */
+			len++;
+			/* and advance */
+			s += run;
+		}
+	}
+	fy_atom_iter_finish(&iter);
+
+	/* something funky going on here */
+	if ((int)len < 0)
+		return -1;
+
+	if (ret != 0)
+		return ret;
+
+	return (int)len;
+}
+
+
+struct fy_atom_iter *
+fy_atom_iter_create(const struct fy_atom *atom)
+{
+	struct fy_atom_iter *iter;
+
+	iter = malloc(sizeof(*iter));
+	if (!iter)
+		return NULL;
+	if (atom)
+		fy_atom_iter_start(atom, iter);
+	else
+		memset(iter, 0, sizeof(*iter));
+	return iter;
+}
+
+void fy_atom_iter_destroy(struct fy_atom_iter *iter)
+{
+	if (!iter)
+		return;
+
+	fy_atom_iter_finish(iter);
+	free(iter);
+}
+
+ssize_t fy_atom_iter_read(struct fy_atom_iter *iter, void *buf, size_t count)
+{
+	ssize_t nread;
+	size_t nrun;
+	const struct fy_iter_chunk *ic;
+	int ret;
+
+	if (!iter || !buf)
+		return -1;
+
+	ret = 0;
+	nread = 0;
+	while (count > 0) {
+		ic = fy_atom_iter_peek_chunk(iter);
+		if (ic) {
+			nrun = count > ic->len ? ic->len : count;
+			memcpy(buf, ic->str, nrun);
+			nread += nrun;
+			count -= nrun;
+			fy_atom_iter_advance(iter, nrun);
+			continue;
+		}
+
+		fy_atom_iter_chunk_reset(iter);
+		do {
+			ret = fy_atom_iter_format(iter);
+
+			/* either end or error, means we don't have data */
+			if (ret <= 0)
+				return ret == 0 ? nread : -1;
+
+		} while (!fy_atom_iter_peek_chunk(iter));
+	}
+
+	return nread;
+}
+
+int fy_atom_iter_getc(struct fy_atom_iter *iter)
+{
+	uint8_t buf;
+	ssize_t nread;
+	int c;
+
+	if (!iter)
+		return -1;
+
+	/* first try the pushed ungetc */
+	if (iter->unget_c != -1) {
+		c = iter->unget_c;
+		iter->unget_c = -1;
+		return c & 0xff;
+	}
+
+	/* read first octet */
+	nread = fy_atom_iter_read(iter, &buf, 1);
+	if (nread != 1)
+		return -1;
+
+	return (int)buf & 0xff;
+}
+
+int fy_atom_iter_ungetc(struct fy_atom_iter *iter, int c)
+{
+	if (!iter)
+		return -1;
+
+	if (iter->unget_c != -1)
+		return -1;
+	if (c == -1) {
+		iter->unget_c = -1;
+		return 0;
+	}
+	iter->unget_c = c & 0xff;
+	return c & 0xff;
+}
+
+int fy_atom_iter_peekc(struct fy_atom_iter *iter)
+{
+	int c;
+
+	c = fy_atom_iter_getc(iter);
+	if (c == -1)
+		return -1;
+
+	return fy_atom_iter_ungetc(iter, c);
+}
+
+int fy_atom_iter_utf8_get(struct fy_atom_iter *iter)
+{
+	uint8_t buf[4];	/* maximum utf8 is 4 octets */
+	ssize_t nread;
+	int c, w;
+
+	if (!iter)
+		return -1;
+
+	/* first try the pushed ungetc */
+	if (iter->unget_c != -1) {
+		c = iter->unget_c;
+		iter->unget_c = -1;
+		return c & 0xff;
+	}
+
+	/* read first octet */
+	nread = fy_atom_iter_read(iter, &buf[0], 1);
+	if (nread != 1)
+		return -1;
+
+	/* get width from it (0 means illegal) */
+	w = fy_utf8_width_by_first_octet(buf[0]);
+	if (!w)
+		return -1;
+
+	/* read the rest octets (if possible) */
+	if (w > 1) {
+		nread = fy_atom_iter_read(iter, buf + 1, w - 1);
+		if (nread != (w - 1))
+			return -1;
+	}
+
+	/* and return the decoded utf8 character */
+	return fy_utf8_get(buf, w, &w);
+}
+
+int fy_atom_iter_utf8_quoted_get(struct fy_atom_iter *iter, size_t *lenp, uint8_t *buf)
+{
+	ssize_t nread;
+	int c, w, ww;
+
+	if (!iter || !lenp || !buf || *lenp < 4)
+		return -1;
+
+	/* first try the pushed ungetc */
+	if (iter->unget_c != -1) {
+		c = iter->unget_c;
+		iter->unget_c = -1;
+		*lenp = 0;
+		return c & 0xff;
+	}
+
+	/* read first octet */
+	nread = fy_atom_iter_read(iter, &buf[0], 1);
+	if (nread != 1)
+		return -1;
+
+	/* get width from it (0 means illegal) - return it and mark it */
+	w = fy_utf8_width_by_first_octet(buf[0]);
+	if (!w) {
+		*lenp = 1;
+		return 0;
+	}
+
+	/* read the rest octets (if possible) */
+	if (w > 1) {
+		nread = fy_atom_iter_read(iter, buf + 1, w - 1);
+		if (nread != (w - 1)) {
+			if (nread != -1 && nread < (w - 1))
+				*lenp += nread;
+			return 0;
+		}
+	}
+
+	/* and return the decoded utf8 character */
+	c = fy_utf8_get(buf, w, &ww);
+	if (c >= 0) {
+		*lenp = 0;
+		return c;
+	}
+	*lenp = w;
+	return 0;
+}
+
+int fy_atom_iter_utf8_unget(struct fy_atom_iter *iter, int c)
+{
+	if (iter->unget_c != -1)
+		return -1;
+	if (c == -1) {
+		iter->unget_c = -1;
+		return 0;
+	}
+	iter->unget_c = c;
+	return c;
+}
+
+int fy_atom_iter_utf8_peek(struct fy_atom_iter *iter)
+{
+	int c;
+
+	c = fy_atom_iter_utf8_get(iter);
+	if (c == -1)
+		return -1;
+
+	return fy_atom_iter_utf8_unget(iter, c);
+}
+
+int fy_atom_memcmp(struct fy_atom *atom, const void *ptr, size_t len)
+{
+	const char *dstr, *str;
+	size_t dlen, tlen;
+	struct fy_atom_iter iter;
+	int c, ct, ret;
+
+	/* empty? just fine */
+	if (!atom && !ptr && !len)
+		return 0;
+
+	/* empty atom but not ptr */
+	if (!atom && (ptr || len))
+		return -1;
+
+	/* non empty atom and empty ptr */
+	if (atom && (!ptr || !len))
+		return 1;
+
+	/* direct output, nice */
+	if (atom->direct_output) {
+		dlen = fy_atom_size(atom);
+		dstr = fy_atom_data(atom);
+		tlen = dlen > len ? len : dlen;
+		ret = memcmp(dstr, ptr, tlen);
+		if (ret)
+			return ret;
+
+		return dlen == len ? 0 : len > dlen ? -1 : 1;
+	}
+
+	str = ptr;
+	ct = -1;
+	fy_atom_iter_start(atom, &iter);
+	while ((c = fy_atom_iter_getc(&iter)) >= 0 && len) {
+		ct = *str & 0xff;
+		if (ct != c)
+			break;
+		str++;
+		len--;
+	}
+	fy_atom_iter_finish(&iter);
+
+	/* out of data on both */
+	if (c == -1 && !len)
+		return 0;
+
+	return ct > c ? -1 : 1;
+}
+
+int fy_atom_strcmp(struct fy_atom *atom, const char *str)
+{
+	size_t len;
+
+	len = str ? strlen(str) : 0;
+
+	return fy_atom_memcmp(atom, str, len);
+}
+
+bool fy_atom_is_number(struct fy_atom *atom)
+{
+	struct fy_atom_iter iter;
+	int c, len, dec, fract, enot;
+	bool first_zero;
+
+	/* empty? just fine */
+	if (!atom || atom->size0)
+		return false;
+
+	len = 0;
+
+	fy_atom_iter_start(atom, &iter);
+
+	/* skip minus sign if it's there */
+	c = fy_atom_iter_peekc(&iter);
+	if (c == '-') {
+		(void)fy_atom_iter_getc(&iter);
+		len++;
+	}
+
+	/* skip digits */
+	first_zero = false;
+	dec = 0;
+	while ((c = fy_atom_iter_peekc(&iter)) >= 0 && isdigit(c)) {
+		if (dec == 0 && c == '0')
+			first_zero = true;
+		else if (dec == 1 && first_zero)
+			goto err_out;	/* 0[0-9] is bad */
+		(void)fy_atom_iter_getc(&iter);
+		dec++;
+		len++;
+	}
+
+	/* no digits is bad */
+	if (!dec)
+		goto err_out;
+
+	fract = 0;
+	/* dot? */
+	c = fy_atom_iter_peekc(&iter);
+	if (c == '.') {
+
+		(void)fy_atom_iter_getc(&iter);
+		len++;
+		/* skip decimal part */
+		while ((c = fy_atom_iter_peekc(&iter)) >= 0 && isdigit(c)) {
+			(void)fy_atom_iter_getc(&iter);
+			len++;
+			fract++;
+		}
+
+		/* . without fractional */
+		if (!fract)
+			goto err_out;
+	}
+
+	enot = 0;
+	/* scientific notation */
+	c = fy_atom_iter_peekc(&iter);
+	if (c == 'e' || c == 'E') {
+		(void)fy_atom_iter_getc(&iter);
+		len++;
+
+		/* skip sign if it's there */
+		c = fy_atom_iter_peekc(&iter);
+		if (c == '+' || c == '-') {
+			(void)fy_atom_iter_getc(&iter);
+			len++;
+		}
+
+		/* skip exponent part */
+		while ((c = fy_atom_iter_peekc(&iter)) >= 0 && isdigit(c)) {
+			(void)fy_atom_iter_getc(&iter);
+			len++;
+			enot++;
+		}
+
+		if (!enot)
+			goto err_out;
+	}
+
+	c = fy_atom_iter_peekc(&iter);
+
+	fy_atom_iter_finish(&iter);
+
+	/* everything must be consumed (and something must) */
+	return c < 0 && len > 0;
+
+err_out:
+	fy_atom_iter_finish(&iter);
+
+	return false;
+}
+
+int fy_atom_cmp(struct fy_atom *atom1, struct fy_atom *atom2)
+{
+	struct fy_atom_iter iter1, iter2;
+	const char *d1, *d2;
+	size_t l1, l2, l;
+	int c1, c2, ret;
+
+	/* handles NULL case too */
+	if (atom1 == atom2)
+		return true;
+
+	/* either null, can't do */
+	if (!atom1 || !atom2)
+		return false;
+
+	/* direct output? */
+	if (atom1->direct_output) {
+		d1 = fy_atom_data(atom1);
+		l1 = fy_atom_size(atom1);
+	} else {
+		d1 = NULL;
+		l1 = 0;
+	}
+	if (atom2->direct_output) {
+		d2 = fy_atom_data(atom2);
+		l2 = fy_atom_size(atom2);
+	} else {
+		d2 = NULL;
+		l2 = 0;
+	}
+
+	/* we have both atoms with direct output */
+	if (d1 && d2) {
+		l = l1 > l2 ? l2 : l1;
+		ret = memcmp(d1, d2, l);
+		if (ret)
+			return ret;
+		return l1 == l2 ? 0 : l2 > l1 ? -1 : 1;
+	}
+
+	/* only atom2 is direct */
+	if (d2)
+		return fy_atom_memcmp(atom1, d2, l2);
+
+	/* only atom1 is direct, (note reversing sign) */
+	if (d1)
+		return -fy_atom_memcmp(atom2, d1, l1);
+
+	/* neither is direct, do it with iterators */
+	fy_atom_iter_start(atom1, &iter1);
+	fy_atom_iter_start(atom2, &iter2);
+	do {
+		c1 = fy_atom_iter_getc(&iter1);
+		c2 = fy_atom_iter_getc(&iter2);
+	} while (c1 == c2 && c1 >= 0 && c2 >= 0);
+	fy_atom_iter_finish(&iter2);
+	fy_atom_iter_finish(&iter1);
+
+	if (c1 == -1 && c2 == -1)
+		return 0;
+
+	return c2 > c1 ? -1 : 1;
+}
+
+const struct fy_raw_line *
+fy_atom_raw_line_iter_next(struct fy_atom_raw_line_iter *iter)
+{
+	struct fy_raw_line *l;
+	int c, w, col, col8, count;
+	unsigned int ts;
+	const char *s;
+
+	if (!iter || !iter->rs || iter->rs > iter->ae)
+		return NULL;
+
+	l = &iter->line;
+
+	ts = iter->atom->tabsize;
+
+	/* track back to the start of the line */
+	s = iter->rs;
+
+	/* we allow a single zero size iteration */
+	if (l->lineno > 0 && iter->rs >= iter->ae)
+		return NULL;
+
+	while (s > iter->is) {
+		c = fy_utf8_get_right(iter->is, (int)(s - iter->is), &w);
+		if (c <= 0 || fy_is_lb_m(c, iter->atom->lb_mode))
+			break;
+		s -= w;
+	}
+
+	l->line_start = s;
+	col = col8 = 0;
+	count = 0;
+	c = -1;
+	w = 0;
+
+	/* track until the start of the content */
+	while (s < iter->as) {
+		c = fy_utf8_get(s, (int)(iter->ae - s), &w);
+		/* we should never hit that */
+		if (c <= 0)
+			return NULL;
+		if (fy_is_tab(c)) {
+			col8 += (8 - (col8 % 8));
+			if (ts)
+				col += (ts - (col % ts));
+			else
+				col++;
+		} else if (!fy_is_lb_m(c, iter->atom->lb_mode)) {
+			col++;
+			col8++;
+		} else
+			return NULL;
+		count++;
+
+		s += w;
+	}
+	/* mark start of content */
+	l->content_start = s;
+	l->content_start_col = col;
+	l->content_start_col8 = col8;
+	l->content_start_count = count;
+
+	/* track until the end of the content (or lb) */
+	while (s < iter->ae) {
+		c = fy_utf8_get(s, (int)(iter->ae - s), &w);
+		/* we should never hit that */
+		if (c <= 0)
+			return NULL;
+		if (fy_is_tab(c)) {
+			col8 += (8 - (col8 % 8));
+			if (ts)
+				col += (ts - (col % ts));
+			else
+				col++;
+		} else if (!fy_is_lb_m(c, iter->atom->lb_mode)) {
+			col++;
+			col8++;
+		} else
+			break;
+		count++;
+
+		s += w;
+	}
+
+	l->content_len = (size_t)(s - l->content_start);
+	l->content_count = count - l->content_start_count;
+	l->content_end_col = col;
+	l->content_end_col8 = col8;
+
+	/* if the stop was due to end of the atom */
+	if (s >= iter->ae) {
+		while (s < iter->ie) {
+			c = fy_utf8_get(s, (int)(iter->ie - s), &w);
+			/* just end of input */
+			if (c <= 0)
+				break;
+
+			if (fy_is_tab(c)) {
+				col8 += (8 - (col8 % 8));
+				if (ts)
+					col += (ts - (col % ts));
+				else
+					col++;
+			} else if (!fy_is_lb_m(c, iter->atom->lb_mode)) {
+				col++;
+				col8++;
+			} else
+				break;
+			count++;
+
+			s += w;
+		}
+	}
+
+	l->line_len = (size_t)(s - l->line_start);
+	l->line_count = count;
+
+	if (fy_is_lb_m(c, iter->atom->lb_mode)) {
+		s += w;
+		/* special case for MSDOS */
+		if (c == '\r' && (s < iter->ie && s[1] == '\n'))
+			s++;
+		/* len_lb includes the lb */
+		l->line_len_lb = (size_t)(s - l->line_start);
+	} else
+		l->line_len_lb = l->line_len;
+
+	/* start at line #1 */
+	l->lineno++;
+
+	iter->rs = s;
+
+	return l;
+}
+
+void fy_atom_raw_line_iter_start(const struct fy_atom *atom,
+				 struct fy_atom_raw_line_iter *iter)
+{
+	struct fy_input *fyi;
+
+	if (!atom || !iter)
+		return;
+
+	memset(iter, 0, sizeof(*iter));
+
+	fyi = atom->fyi;
+	if (!fyi)
+		return;
+
+	iter->atom = atom;
+
+	iter->as = fy_atom_data(atom);
+	iter->ae = iter->as + fy_atom_size(atom);
+
+	iter->is = fy_input_start(fyi);
+	iter->ie = iter->is + fy_input_size(fyi);
+
+	iter->rs = iter->as;
+}
+
+void fy_atom_raw_line_iter_finish(struct fy_atom_raw_line_iter *iter)
+{
+	/* nothing */
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-atom.h b/contrib/libs/libfyaml/src/lib/fy-atom.h
new file mode 100644
index 0000000000..2a8b563323
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-atom.h
@@ -0,0 +1,330 @@
+/*
+ * fy-atom.h - internal YAML atom methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef FY_ATOM_H
+#define FY_ATOM_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-list.h"
+#include "fy-input.h"
+
+struct fy_reader;
+struct fy_input;
+struct fy_node;
+
+enum fy_atom_style {
+	/* YAML atoms */
+	FYAS_PLAIN,
+	FYAS_SINGLE_QUOTED,
+	FYAS_DOUBLE_QUOTED,
+	FYAS_LITERAL,
+	FYAS_FOLDED,
+	FYAS_URI,	/* special style for URIs */
+	FYAS_DOUBLE_QUOTED_MANUAL,
+	FYAS_COMMENT	/* (possibly multi line) comment */
+};
+
+static inline bool fy_atom_style_is_quoted(enum fy_atom_style style)
+{
+	return style == FYAS_SINGLE_QUOTED || style == FYAS_DOUBLE_QUOTED;
+}
+
+static inline bool fy_atom_style_is_block(enum fy_atom_style style)
+{
+	return style == FYAS_LITERAL || style == FYAS_FOLDED;
+}
+
+enum fy_atom_chomp {
+	FYAC_STRIP,
+	FYAC_CLIP,
+	FYAC_KEEP,
+};
+
+struct fy_atom {
+	struct fy_mark start_mark;
+	struct fy_mark end_mark;
+	size_t storage_hint;	/* guaranteed to fit in this amount of bytes */
+	struct fy_input *fyi;	/* input on which atom is on */
+	uint64_t fyi_generation;	/* to detect reallocs */
+	unsigned int increment;
+	union {
+		uint64_t tozero;			/* fast way to zero everything here */
+		struct {
+			/* save a little bit of space with bitfields */
+			enum fy_atom_style style : 8;	/* note that it's a big perf win for bytes */
+			enum fy_atom_chomp chomp : 8;
+			unsigned int tabsize : 8;
+			enum fy_lb_mode lb_mode : 1;
+			enum fy_flow_ws_mode fws_mode : 1;
+			bool direct_output : 1;		/* can directly output */
+			bool storage_hint_valid : 1;
+			bool empty : 1;			/* atom contains whitespace and linebreaks only if length > 0 */
+			bool has_lb : 1;		/* atom contains at least one linebreak */
+			bool has_ws : 1;		/* atom contains at least one whitespace */
+			bool starts_with_ws : 1;	/* atom starts with whitespace */
+			bool starts_with_lb : 1;	/* atom starts with linebreak */
+			bool ends_with_ws : 1;		/* atom ends with whitespace */
+			bool ends_with_lb : 1;		/* atom ends with linebreak */
+			bool trailing_lb : 1;		/* atom ends with trailing linebreaks > 1 */
+			bool size0 : 1;			/* atom contains absolutely nothing */
+			bool valid_anchor : 1;		/* atom is a valid anchor */
+			bool json_mode : 1;		/* atom was read in json mode */
+			bool ends_with_eof : 1;		/* atom ends at EOF of input */
+		};
+	};
+};
+
+static inline bool fy_atom_is_set(const struct fy_atom *atom)
+{
+	return atom && atom->fyi;
+}
+
+static inline void fy_atom_reset(struct fy_atom *atom)
+{
+	if (atom)
+		atom->fyi = NULL;
+}
+
+static inline bool fy_atom_json_mode(struct fy_atom *handle)
+{
+	if (!handle)
+		return false;
+
+	return handle->json_mode;
+}
+
+static inline enum fy_lb_mode fy_atom_lb_mode(struct fy_atom *handle)
+{
+	if (!handle)
+		return fylb_cr_nl;
+
+	return handle->lb_mode;
+}
+
+static inline enum fy_flow_ws_mode fy_atom_flow_ws_mode(struct fy_atom *handle)
+{
+	if (!handle)
+		return fyfws_space_tab;
+
+	return handle->fws_mode;
+}
+
+/* all atoms are scalars so... */
+static inline bool fy_atom_is_lb(struct fy_atom *handle, int c)
+{
+	return fy_is_generic_lb_m(c, fy_atom_lb_mode(handle));
+}
+
+static inline bool fy_atom_is_flow_ws(struct fy_atom *handle, int c)
+{
+	return fy_is_flow_ws_m(c, fy_atom_flow_ws_mode(handle));
+}
+
+int fy_atom_format_text_length(struct fy_atom *atom);
+const char *fy_atom_format_text(struct fy_atom *atom, char *buf, size_t maxsz);
+
+int fy_atom_format_utf8_length(struct fy_atom *atom);
+
+static inline void
+fy_reader_fill_atom_start(struct fy_reader *fyr, struct fy_atom *handle)
+{
+	/* start mark */
+	fy_reader_get_mark(fyr, &handle->start_mark);
+	handle->fyi = fy_reader_current_input(fyr);
+	handle->fyi_generation = fy_reader_current_input_generation(fyr);
+
+	handle->increment = 0;
+	handle->tozero = 0;
+
+	/* note that handle->data may be zero for empty input */
+}
+
+static inline void
+fy_reader_fill_atom_end_at(struct fy_reader *fyr, struct fy_atom *handle, struct fy_mark *end_mark)
+{
+	if (end_mark)
+		handle->end_mark = *end_mark;
+	else
+		fy_reader_get_mark(fyr, &handle->end_mark);
+
+	/* default is plain, modify at return */
+	handle->style = FYAS_PLAIN;
+	handle->chomp = FYAC_CLIP;
+	/* by default we don't do storage hints, it's the job of the caller */
+	handle->storage_hint = 0;
+	handle->storage_hint_valid = false;
+	handle->tabsize = fy_reader_tabsize(fyr);
+	handle->json_mode = fy_reader_json_mode(fyr);
+	handle->lb_mode = fy_reader_lb_mode(fyr);
+	handle->fws_mode = fy_reader_flow_ws_mode(fyr);
+}
+
+static inline void
+fy_reader_fill_atom_end(struct fy_reader *fyr, struct fy_atom *handle)
+{
+	fy_reader_fill_atom_end_at(fyr, handle, NULL);
+}
+
+struct fy_atom *fy_reader_fill_atom(struct fy_reader *fyr, int advance, struct fy_atom *handle);
+struct fy_atom *fy_reader_fill_atom_mark(struct fy_reader *fyr, const struct fy_mark *start_mark,
+					 const struct fy_mark *end_mark, struct fy_atom *handle);
+struct fy_atom *fy_reader_fill_atom_at(struct fy_reader *fyr, int advance, int count, struct fy_atom *handle);
+
+#define fy_reader_fill_atom_a(_fyr, _advance)  fy_reader_fill_atom((_fyr), (_advance), FY_ALLOCA(sizeof(struct fy_atom)))
+
+struct fy_atom *fy_fill_node_atom(struct fy_node *fyn, struct fy_atom *handle);
+
+#define fy_fill_node_atom_a(_fyn)  fy_fill_node_atom((_fyn), FY_ALLOCA(sizeof(struct fy_atom)))
+
+struct fy_atom_iter_line_info {
+	const char *start;
+	const char *end;
+	const char *nws_start;
+	const char *nws_end;
+	const char *chomp_start;
+	bool empty : 1;
+	bool trailing_breaks_ws : 1;
+	bool first : 1;		/* first */
+	bool last : 1;		/* last (only ws/lb afterwards */
+	bool final : 1;		/* the final iterator */
+	bool indented : 1;
+	bool lb_end : 1;
+	bool need_nl : 1;
+	bool need_sep : 1;
+	bool ends_with_backslash : 1;	/* last ended in \\ */
+	size_t trailing_ws;
+	size_t trailing_breaks;
+	size_t start_ws, end_ws;
+	const char *s;
+	const char *e;
+	int actual_lb;		/* the line break */
+	const char *s_tb;	/* start of trailing breaks run */
+	const char *e_tb;	/* end of trailing breaks run */
+};
+
+struct fy_atom_iter_chunk {
+	struct fy_iter_chunk ic;
+	/* note that it is guaranteed for copied chunks to be
+	 * less or equal to 10 characters (the maximum digitbuf
+	 * for double quoted escapes */
+	char inplace_buf[10];	/* small copies in place */
+};
+
+#define NR_STARTUP_CHUNKS	8
+#define SZ_STARTUP_COPY_BUFFER	32
+
+struct fy_atom_iter {
+	const struct fy_atom *atom;
+	const char *s, *e;
+	unsigned int chomp;
+	int tabsize;
+	bool single_line : 1;
+	bool dangling_end_quote : 1;
+	bool last_ends_with_backslash : 1;
+	bool empty : 1;
+	bool current : 1;
+	bool done : 1;	/* last iteration (for block styles) */
+	struct fy_atom_iter_line_info li[2];
+	unsigned int alloc;
+	unsigned int top;
+	unsigned int read;
+	struct fy_atom_iter_chunk *chunks;
+	struct fy_atom_iter_chunk startup_chunks[NR_STARTUP_CHUNKS];
+	int unget_c;
+};
+
+void fy_atom_iter_start(const struct fy_atom *atom, struct fy_atom_iter *iter);
+void fy_atom_iter_finish(struct fy_atom_iter *iter);
+const struct fy_iter_chunk *fy_atom_iter_peek_chunk(struct fy_atom_iter *iter);
+const struct fy_iter_chunk *fy_atom_iter_chunk_next(struct fy_atom_iter *iter, const struct fy_iter_chunk *curr, int *errp);
+void fy_atom_iter_advance(struct fy_atom_iter *iter, size_t len);
+
+struct fy_atom_iter *fy_atom_iter_create(const struct fy_atom *atom);
+void fy_atom_iter_destroy(struct fy_atom_iter *iter);
+ssize_t fy_atom_iter_read(struct fy_atom_iter *iter, void *buf, size_t count);
+int fy_atom_iter_getc(struct fy_atom_iter *iter);
+int fy_atom_iter_ungetc(struct fy_atom_iter *iter, int c);
+int fy_atom_iter_peekc(struct fy_atom_iter *iter);
+int fy_atom_iter_utf8_get(struct fy_atom_iter *iter);
+int fy_atom_iter_utf8_quoted_get(struct fy_atom_iter *iter, size_t *lenp, uint8_t *buf);
+int fy_atom_iter_utf8_unget(struct fy_atom_iter *iter, int c);
+int fy_atom_iter_utf8_peek(struct fy_atom_iter *iter);
+
+int fy_atom_memcmp(struct fy_atom *atom, const void *ptr, size_t len);
+int fy_atom_strcmp(struct fy_atom *atom, const char *str);
+bool fy_atom_is_number(struct fy_atom *atom);
+int fy_atom_cmp(struct fy_atom *atom1, struct fy_atom *atom2);
+
+static inline const char *fy_atom_data(const struct fy_atom *atom)
+{
+	if (!atom)
+		return NULL;
+
+	return (char *)fy_input_start(atom->fyi) + atom->start_mark.input_pos;
+}
+
+static inline size_t fy_atom_size(const struct fy_atom *atom)
+{
+	if (!atom)
+		return 0;
+
+	return atom->end_mark.input_pos - atom->start_mark.input_pos;
+}
+
+static inline bool fy_plain_atom_streq(const struct fy_atom *atom, const char *str)
+{
+	size_t size = strlen(str);
+
+	if (!atom || !str || atom->style != FYAS_PLAIN || fy_atom_size(atom) != size)
+		return false;
+
+	return !memcmp(str, fy_atom_data(atom), size);
+}
+
+struct fy_raw_line {
+	int lineno;
+	const char *line_start;
+	size_t line_len;
+	size_t line_len_lb;
+	size_t line_count;
+	const char *content_start;
+	size_t content_len;
+	size_t content_start_count;
+	size_t content_count;
+	int content_start_col;
+	int content_start_col8;	/* this is the tab 8 */
+	int content_end_col;
+	int content_end_col8;
+};
+
+struct fy_atom_raw_line_iter {
+	const struct fy_atom *atom;
+	const char *is, *ie;	/* input start, end */
+	const char *as, *ae;	/* atom start, end */
+	const char *rs;
+	struct fy_raw_line line;
+};
+
+void fy_atom_raw_line_iter_start(const struct fy_atom *atom,
+			     struct fy_atom_raw_line_iter *iter);
+void fy_atom_raw_line_iter_finish(struct fy_atom_raw_line_iter *iter);
+
+const struct fy_raw_line *
+fy_atom_raw_line_iter_next(struct fy_atom_raw_line_iter *iter);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-composer.c b/contrib/libs/libfyaml/src/lib/fy-composer.c
new file mode 100644
index 0000000000..2202497d69
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-composer.c
@@ -0,0 +1,356 @@
+/*
+ * fy-composer.c - Composer support
+ *
+ * Copyright (c) 2021 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-doc.h"
+
+#include "fy-utils.h"
+
+struct fy_composer *
+fy_composer_create(struct fy_composer_cfg *cfg)
+{
+	struct fy_composer *fyc;
+	struct fy_path *fypp;
+
+	/* verify configuration and mandatory ops */
+	if (!cfg || !cfg->ops ||
+	    !cfg->ops->process_event)
+		return NULL;
+
+	fyc = malloc(sizeof(*fyc));
+	if (!fyc)
+		return NULL;
+	memset(fyc, 0, sizeof(*fyc));
+	fyc->cfg = *cfg;
+
+	fy_path_list_init(&fyc->paths);
+	fypp = fy_path_create();
+	if (!fypp)
+		goto err_no_path;
+	fy_path_list_add_tail(&fyc->paths, fypp);
+
+	return fyc;
+
+err_no_path:
+	free(fyc);
+	return NULL;
+}
+
+void fy_composer_destroy(struct fy_composer *fyc)
+{
+	struct fy_path *fypp;
+
+	if (!fyc)
+		return;
+
+	fy_diag_unref(fyc->cfg.diag);
+	while ((fypp = fy_path_list_pop(&fyc->paths)) != NULL)
+		fy_path_destroy(fypp);
+	free(fyc);
+}
+
+static enum fy_composer_return
+fy_composer_process_event_private(struct fy_composer *fyc, struct fy_event *fye, struct fy_path *fypp)
+{
+	const struct fy_composer_ops *ops;
+	struct fy_eventp *fyep;
+	struct fy_path_component *fypc, *fypc_last;
+	struct fy_path *fyppt;
+	struct fy_document *fyd;
+	bool is_collection, is_map, is_start, is_end;
+	int rc = 0;
+	enum fy_composer_return ret;
+	bool stop_req = false;
+
+	assert(fyc);
+	assert(fye);
+	assert(fypp);
+
+	fyep = fy_container_of(fye, struct fy_eventp, e);
+
+	ops = fyc->cfg.ops;
+	assert(ops);
+
+	rc = 0;
+
+	switch (fye->type) {
+	case FYET_MAPPING_START:
+		is_collection = true;
+		is_start = true;
+		is_end = false;
+		is_map = true;
+		break;
+
+	case FYET_MAPPING_END:
+		is_collection = true;
+		is_start = false;
+		is_end = true;
+		is_map = true;
+		break;
+
+	case FYET_SEQUENCE_START:
+		is_collection = true;
+		is_start = true;
+		is_end = false;
+		is_map = false;
+		break;
+
+	case FYET_SEQUENCE_END:
+		is_collection = true;
+		is_start = false;
+		is_end = true;
+		is_map = false;
+		break;
+
+	case FYET_SCALAR:
+		is_collection = false;
+		is_start = true;
+		is_end = true;
+		is_map = false;
+		break;
+
+	case FYET_ALIAS:
+		is_collection = false;
+		is_start = true;
+		is_end = true;
+		is_map = false;
+		break;
+
+	case FYET_STREAM_START:
+	case FYET_STREAM_END:
+	case FYET_DOCUMENT_START:
+	case FYET_DOCUMENT_END:
+		return ops->process_event(fyc, fypp, fye);
+
+	default:
+		return FYCR_OK_CONTINUE;
+	}
+
+	fypc_last = fy_path_component_list_tail(&fypp->components);
+
+	if (fy_path_component_is_mapping(fypc_last) && fypc_last->map.accumulating_complex_key) {
+
+		/* get the next one */
+		fyppt = fy_path_next(&fyc->paths, fypp);
+		assert(fyppt);
+		assert(fyppt != fypp);
+		assert(fyppt->parent == fypp);
+
+		/* and pass along */
+		ret = fy_composer_process_event_private(fyc, fye, fyppt);
+		if (!fy_composer_return_is_ok(ret)) {
+			/* XXX TODO handle skip */
+			return ret;
+		}
+		if (!stop_req)
+			stop_req = ret == FYCR_OK_STOP;
+
+		rc = fy_document_builder_process_event(fypp->fydb, fyep);
+		if (rc == 0)
+			return FYCR_OK_CONTINUE;
+		fyc_error_check(fyc, rc > 0, err_out,
+				"fy_document_builder_process_event() failed\n");
+
+		/* get the document */
+		fyd = fy_document_builder_take_document(fypp->fydb);
+		fyc_error_check(fyc, fyd, err_out,
+				"fy_document_builder_take_document() failed\n");
+
+		fypc_last->map.is_complex_key = true;
+		fypc_last->map.accumulating_complex_key = false;
+		fypc_last->map.complex_key = fyd;
+		fypc_last->map.has_key = true;
+		fypc_last->map.await_key = false;
+		fypc_last->map.complex_key_complete = true;
+		fypc_last->map.root = false;
+
+		fyppt = fy_path_list_pop_tail(&fyc->paths);
+		assert(fyppt);
+
+		fy_path_destroy(fyppt);
+
+		fyc_error_check(fyc, rc >= 0, err_out,
+				"fy_path_component_build_text() failed\n");
+
+		return !stop_req ? FYCR_OK_CONTINUE : FYCR_OK_STOP;
+	}
+
+	/* start of something on a mapping */
+	if (is_start && fy_path_component_is_mapping(fypc_last) && fypc_last->map.await_key && is_collection) {
+
+		/* the configuration must support a document builder for complex keys */
+		FYC_TOKEN_ERROR_CHECK(fyc, fy_event_get_token(fye), FYEM_DOC,
+				ops->create_document_builder, err_out,
+				"composer configuration does not support complex keys");
+
+		/* call out for creating the document builder */
+		fypp->fydb = ops->create_document_builder(fyc);
+		fyc_error_check(fyc, fypp->fydb, err_out,
+				"ops->create_document_builder() failed\n");
+
+		/* and pass the current event; must return 0 since we know it's a collection start */
+		rc = fy_document_builder_process_event(fypp->fydb, fyep);
+		fyc_error_check(fyc, !rc, err_out,
+				"fy_document_builder_process_event() failed\n");
+
+		fypc_last->map.is_complex_key = true;
+		fypc_last->map.accumulating_complex_key = true;
+		fypc_last->map.complex_key = NULL;
+		fypc_last->map.complex_key_complete = false;
+
+		/* create new path */
+		fyppt = fy_path_create();
+		fyc_error_check(fyc, fyppt, err_out,
+				"fy_path_create() failed\n");
+
+		/* append it to the end */
+		fyppt->parent = fypp;
+		fy_path_list_add_tail(&fyc->paths, fyppt);
+
+		/* and pass along */
+		ret = fy_composer_process_event_private(fyc, fye, fyppt);
+		if (!fy_composer_return_is_ok(ret)) {
+			/* XXX TODO handle skip */
+			return ret;
+		}
+		if (!stop_req)
+			stop_req = ret == FYCR_OK_STOP;
+
+		return !stop_req ? FYCR_OK_CONTINUE : FYCR_OK_STOP;
+	}
+
+	if (is_start && fy_path_component_is_sequence(fypc_last)) {	/* start in a sequence */
+
+		if (fypc_last->seq.idx < 0)
+			fypc_last->seq.idx = 0;
+		else
+			fypc_last->seq.idx++;
+	}
+
+	if (is_collection && is_start) {
+
+		/* collection start */
+		if (is_map) {
+			fypc = fy_path_component_create_mapping(fypp);
+			fyc_error_check(fyc, fypc, err_out,
+					"fy_path_component_create_mapping() failed\n");
+		} else {
+			fypc = fy_path_component_create_sequence(fypp);
+			fyc_error_check(fyc, fypc, err_out,
+					"fy_path_component_create_sequence() failed\n");
+		}
+
+		/* append to the tail */
+		fy_path_component_list_add_tail(&fypp->components, fypc);
+
+	} else if (is_collection && is_end) {
+
+		/* collection end */
+		assert(fypc_last);
+		fy_path_component_clear_state(fypc_last);
+
+	} else if (!is_collection && fy_path_component_is_mapping(fypc_last) && fypc_last->map.await_key) {
+
+		fypc_last->map.is_complex_key = false;
+		fypc_last->map.scalar.tag = fy_token_ref(fy_event_get_tag_token(fye));
+		fypc_last->map.scalar.key = fy_token_ref(fy_event_get_token(fye));
+		fypc_last->map.has_key = true;
+		fypc_last->map.root = false;
+
+	}
+
+	/* process the event */
+	ret = ops->process_event(fyc, fypp, fye);
+	if (!fy_composer_return_is_ok(ret)) {
+		/* XXX TODO handle skip */
+		return ret;
+	}
+	if (!stop_req)
+		stop_req = ret == FYCR_OK_STOP;
+
+	if (is_collection && is_end) {
+		/* for the end of a collection, pop the last component */
+		fypc = fy_path_component_list_pop_tail(&fypp->components);
+		assert(fypc);
+
+		assert(fypc == fypc_last);
+
+		fy_path_component_recycle(fypp, fypc);
+
+		/* and get the new last */
+		fypc_last = fy_path_component_list_tail(&fypp->components);
+	}
+
+	/* at the end of something */
+	if (is_end && fy_path_component_is_mapping(fypc_last)) {
+		if (!fypc_last->map.await_key) {
+			fy_path_component_clear_state(fypc_last);
+			fypc_last->map.await_key = true;
+		} else
+			fypc_last->map.await_key = false;
+	}
+
+	return !stop_req ? FYCR_OK_CONTINUE : FYCR_OK_STOP;
+
+err_out:
+	return FYCR_ERROR;
+}
+
+enum fy_composer_return
+fy_composer_process_event(struct fy_composer *fyc, struct fy_event *fye)
+{
+	struct fy_path *fypp;
+	int rc;
+
+	if (!fyc || !fye)
+		return -1;
+
+	/* start at the head */
+	fypp = fy_path_list_head(&fyc->paths);
+
+	/* no top? something's very out of order */
+	if (!fypp)
+		return -1;
+
+	rc = fy_composer_process_event_private(fyc, fye, fypp);
+
+	return rc;
+}
+
+struct fy_composer_cfg *fy_composer_get_cfg(struct fy_composer *fyc)
+{
+	if (!fyc)
+		return NULL;
+	return &fyc->cfg;
+}
+
+void *fy_composer_get_cfg_userdata(struct fy_composer *fyc)
+{
+	if (!fyc)
+		return NULL;
+	return fyc->cfg.userdata;
+}
+
+struct fy_diag *fy_composer_get_diag(struct fy_composer *fyc)
+{
+	if (!fyc)
+		return NULL;
+	return fyc->cfg.diag;
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-composer.h b/contrib/libs/libfyaml/src/lib/fy-composer.h
new file mode 100644
index 0000000000..d690f22622
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-composer.h
@@ -0,0 +1,57 @@
+/*
+ * fy-composer.h - YAML composer
+ *
+ * Copyright (c) 2021 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_COMPOSER_H
+#define FY_COMPOSER_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdbool.h>
+
+#include <libfyaml.h>
+
+#include "fy-list.h"
+#include "fy-typelist.h"
+
+#include "fy-emit-accum.h"
+#include "fy-path.h"
+
+struct fy_composer;
+struct fy_token;
+struct fy_diag;
+struct fy_event;
+struct fy_eventp;
+struct fy_document_builder;
+
+struct fy_composer_ops {
+	/* single process event callback */
+	enum fy_composer_return (*process_event)(struct fy_composer *fyc, struct fy_path *path, struct fy_event *fye);
+	struct fy_document_builder *(*create_document_builder)(struct fy_composer *fyc);
+};
+
+struct fy_composer_cfg {
+	const struct fy_composer_ops *ops;
+	void *userdata;
+	struct fy_diag *diag;
+};
+
+struct fy_composer {
+	struct fy_composer_cfg cfg;
+	struct fy_path_list paths;
+};
+
+struct fy_composer *fy_composer_create(struct fy_composer_cfg *cfg);
+void fy_composer_destroy(struct fy_composer *fyc);
+int fy_composer_process_event(struct fy_composer *fyc, struct fy_event *fye);
+
+struct fy_composer_cfg *fy_composer_get_cfg(struct fy_composer *fyc);
+void *fy_composer_get_cfg_userdata(struct fy_composer *fyc);
+struct fy_diag *fy_composer_get_diag(struct fy_composer *fyc);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-ctype.c b/contrib/libs/libfyaml/src/lib/fy-ctype.c
new file mode 100644
index 0000000000..560fec63fa
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-ctype.c
@@ -0,0 +1,66 @@
+/*
+ * fy-ctype.c - ctype utilities
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <libfyaml.h>
+
+#include "fy-ctype.h"
+
+const char *fy_uri_esc(const char *s, size_t len, uint8_t *code, int *code_len)
+{
+	const char *e = s + len;
+	int j, k, width;
+	uint8_t octet;
+	char c;
+
+	width = 0;
+	k = 0;
+	do {
+		/* check for enough space for %XX */
+		if ((e - s) < 3)
+			return NULL;
+
+		/* if more than one run, expect '%' */
+		if (s[0] != '%')
+			return NULL;
+
+		octet = 0;
+		for (j = 0; j < 2; j++) {
+			c = s[1 + j];
+			octet <<= 4;
+			if (c >= '0' && c <= '9')
+				octet |= c - '0';
+			else if (c >= 'a' && c <= 'f')
+				octet |= 10 + c - 'a';
+			else
+				octet |= 10 + c - 'A';
+		}
+		if (!width) {
+			width = fy_utf8_width_by_first_octet(octet);
+			if (!width)
+				return NULL;
+			k = 0;
+		}
+		if (k >= *code_len)
+			return NULL;
+
+		code[k++] = octet;
+
+		/* skip over the 3 character escape */
+		s += 3;
+
+	} while (--width > 0);
+
+	*code_len = k;
+
+	return s;
+}
+
diff --git a/contrib/libs/libfyaml/src/lib/fy-ctype.h b/contrib/libs/libfyaml/src/lib/fy-ctype.h
new file mode 100644
index 0000000000..8a8e7fb907
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-ctype.h
@@ -0,0 +1,339 @@
+/*
+ * fy-ctype.h - ctype like macros header
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_CTYPE_H
+#define FY_CTYPE_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include <libfyaml.h>
+
+#include "fy-utf8.h"
+
+enum fy_lb_mode {
+	fylb_cr_nl,			/* only \r, \n (json + >= yaml1.2 */
+	fylb_cr_nl_N_L_P,		/* NEL/LS/PS (yaml1.1) */
+};
+
+enum fy_flow_ws_mode {
+	fyfws_space_tab,		/* space + TAB (yaml) */
+	fyfws_space,			/* only space (json) */
+};
+
+static inline bool fy_is_first_alpha(int c)
+{
+	return (c >= 'a' && c <= 'z') ||
+	       (c >= 'A' && c <= 'Z') ||
+	       c == '_';
+}
+
+static inline bool fy_is_alpha(int c)
+{
+	return fy_is_first_alpha(c) || c == '-';
+}
+
+static inline bool fy_is_num(int c)
+{
+	return c >= '0' && c <= '9';
+}
+
+static inline bool fy_is_first_alnum(int c)
+{
+	return fy_is_first_alpha(c);
+}
+
+static inline bool fy_is_alnum(int c)
+{
+	return fy_is_alpha(c) || fy_is_num(c);
+}
+
+static inline bool fy_is_space(int c)
+{
+	return c == ' ';
+}
+
+static inline bool fy_is_tab(int c)
+{
+	return c == '\t';
+}
+
+static inline bool fy_is_ws(int c)
+{
+	return fy_is_space(c) || fy_is_tab(c);
+}
+
+static inline bool fy_is_hex(int c)
+{
+	return (c >= '0' && c <= '9') ||
+	       (c >= 'a' && c <= 'f') ||
+	       (c >= 'A' && c <= 'F');
+}
+
+static inline bool fy_is_uri(int c)
+{
+	return fy_is_alnum(c) || fy_utf8_strchr(";/?:@&=+$,.!~*\'()[]%", c);
+}
+
+static inline bool fy_is_lb_r_n(int c)
+{
+	return c == '\r' || c == '\n';
+}
+
+static inline bool fy_is_lb_NEL(int c)
+{
+	return c == 0x85;
+}
+
+static inline bool fy_is_lb_LS_PS(int c)
+{
+	return c == 0x2028 || c == 0x2029;
+}
+
+static inline bool fy_is_unicode_lb(int c)
+{
+	/* note that YAML1.1 supports NEL #x85, LS #x2028 and PS #x2029 as linebreaks */
+	/* YAML1.2 and higher does not */
+	return fy_is_lb_NEL(c) || fy_is_lb_LS_PS(c);
+}
+
+static inline bool fy_is_any_lb(int c)
+{
+	return fy_is_lb_r_n(c) || fy_is_unicode_lb(c);
+}
+
+static inline bool fy_is_z(int c)
+{
+	return c <= 0;
+}
+
+static inline bool fy_is_blank(int c)
+{
+	return c == ' ' || c == '\t';
+}
+
+#define FY_UTF8_BOM	0xfeff
+
+static inline bool fy_is_print(int c)
+{
+	return c == '\n' || c == '\r' ||
+	       (c >= 0x0020 && c <= 0x007e) ||
+	       (c >= 0x00a0 && c <= 0xd7ff) ||
+	       (c >= 0xe000 && c <= 0xfffd && c != FY_UTF8_BOM);
+}
+
+static inline bool fy_is_printq(int c)
+{
+	return c != '\t' && c != 0xa0 && !fy_is_any_lb(c) && fy_is_print(c);
+}
+
+static inline bool fy_is_nb_char(int c)
+{
+	return (c >= 0x0020 && c <= 0x007e) ||
+	       (c >= 0x00a0 && c <= 0xd7ff) ||
+	       (c >= 0xe000 && c <= 0xfffd && c != FY_UTF8_BOM);
+}
+
+static inline bool fy_is_ns_char(int c)
+{
+	return fy_is_nb_char(c) && !fy_is_ws(c);
+}
+
+static inline bool fy_is_indicator(int c)
+{
+	return !!fy_utf8_strchr("-?:,[]{}#&*!|>'\"%%@`", c);
+}
+
+static inline bool fy_is_flow_indicator(int c)
+{
+	return !!fy_utf8_strchr(",[]{}", c);
+}
+
+static inline bool fy_is_path_flow_scalar_start(int c)
+{
+	return c == '\'' || c == '"';
+}
+
+static inline bool fy_is_path_flow_key_start(int c)
+{
+	return c == '"' || c == '\'' || c == '{' || c == '[';
+}
+
+static inline bool fy_is_path_flow_key_end(int c)
+{
+	return c == '"' || c == '\'' || c == '}' || c == ']';
+}
+
+static inline bool fy_is_unicode_control(int c)
+{
+        return (c >= 0 && c <= 0x1f) || (c >= 0x80 && c <= 0x9f);
+}
+
+static inline bool fy_is_unicode_space(int c)
+{
+        return c == 0x20 || c == 0xa0 ||
+               (c >= 0x2000 && c <= 0x200a) ||
+               c == 0x202f || c == 0x205f || c == 0x3000;
+}
+
+static inline bool fy_is_json_unescaped(int c)
+{
+	return c >= 0x20 && c <= 0x110000 && c != '"' && c != '\\';
+}
+
+static inline bool fy_is_json_unescaped_range_only(int c)
+{
+	return c >= 0x20 && c <= 0x110000;
+}
+
+static inline bool fy_is_lb_m(int c, enum fy_lb_mode lb_mode)
+{
+	if (fy_is_lb_r_n(c))
+		return true;
+	return lb_mode == fylb_cr_nl_N_L_P && fy_is_unicode_lb(c);
+}
+
+static inline bool fy_is_generic_lb_m(int c, enum fy_lb_mode lb_mode)
+{
+	if (fy_is_lb_r_n(c))
+		return true;
+	return lb_mode == fylb_cr_nl_N_L_P && fy_is_lb_NEL(c);
+}
+
+static inline bool fy_is_lbz_m(int c, enum fy_lb_mode lb_mode)
+{
+	return fy_is_lb_m(c, lb_mode) || fy_is_z(c);
+}
+
+static inline bool fy_is_generic_lbz_m(int c, enum fy_lb_mode lb_mode)
+{
+	return fy_is_generic_lb_m(c, lb_mode) || fy_is_z(c);
+}
+
+static inline bool fy_is_blankz_m(int c, enum fy_lb_mode lb_mode)
+{
+	return fy_is_ws(c) || fy_is_lbz_m(c, lb_mode);
+}
+
+static inline bool fy_is_generic_blankz_m(int c, enum fy_lb_mode lb_mode)
+{
+	return fy_is_ws(c) || fy_is_generic_lbz_m(c, lb_mode);
+}
+
+static inline bool fy_is_flow_ws_m(int c, enum fy_flow_ws_mode fws_mode)
+{
+	return fy_is_space(c) || (fws_mode == fyfws_space_tab && fy_is_tab(c));
+}
+
+#define FY_CTYPE_AT_BUILDER(_kind) \
+static inline const void * \
+fy_find_ ## _kind (const void *s, size_t len) \
+{ \
+	const char *cs = (char *)s; \
+	const char *e = cs + len; \
+	int c, w; \
+	for (; cs < e && (c = fy_utf8_get(cs,  e - cs, &w)) >= 0; cs += w) { \
+		assert(w); \
+		if (fy_is_ ## _kind (c)) \
+			return cs; \
+	} \
+	return NULL; \
+} \
+static inline const void * \
+fy_find_non_ ## _kind (const void *s, size_t len) \
+{ \
+	const char *cs = (char *)s; \
+	const char *e = cs + len; \
+	int c, w; \
+	for (; cs < e && (c = fy_utf8_get(cs,  e - cs, &w)) >= 0; cs += w) { \
+		assert(w); \
+		if (!(fy_is_ ## _kind (c))) \
+			return cs; \
+		assert(w); \
+	} \
+	return NULL; \
+} \
+struct useless_struct_for_semicolon
+
+FY_CTYPE_AT_BUILDER(first_alpha);
+FY_CTYPE_AT_BUILDER(alpha);
+FY_CTYPE_AT_BUILDER(num);
+FY_CTYPE_AT_BUILDER(first_alnum);
+FY_CTYPE_AT_BUILDER(alnum);
+FY_CTYPE_AT_BUILDER(space);
+FY_CTYPE_AT_BUILDER(tab);
+FY_CTYPE_AT_BUILDER(ws);
+FY_CTYPE_AT_BUILDER(hex);
+FY_CTYPE_AT_BUILDER(uri);
+FY_CTYPE_AT_BUILDER(z);
+FY_CTYPE_AT_BUILDER(any_lb);
+FY_CTYPE_AT_BUILDER(blank);
+FY_CTYPE_AT_BUILDER(print);
+FY_CTYPE_AT_BUILDER(printq);
+FY_CTYPE_AT_BUILDER(nb_char);
+FY_CTYPE_AT_BUILDER(ns_char);
+FY_CTYPE_AT_BUILDER(indicator);
+FY_CTYPE_AT_BUILDER(flow_indicator);
+FY_CTYPE_AT_BUILDER(path_flow_key_start);
+FY_CTYPE_AT_BUILDER(path_flow_key_end);
+FY_CTYPE_AT_BUILDER(unicode_control);
+FY_CTYPE_AT_BUILDER(unicode_space);
+FY_CTYPE_AT_BUILDER(json_unescaped);
+
+/*
+ * Very special linebreak/ws methods
+ * Things get interesting due to \r\n and
+ * unicode linebreaks/spaces
+ */
+
+/* skip for a _single_ linebreak */
+static inline const void *fy_skip_lb(const void *ptr, int left)
+{
+	int c, width;
+
+	/* get the utf8 character at this point */
+	c = fy_utf8_get(ptr, left, &width);
+	if (c < 0 || !fy_is_any_lb(c))
+		return NULL;
+
+	/* MS-DOS: check if next character is '\n' */
+	if (c == '\r' && left > width && *(char *)ptr == '\n')
+		width++;
+
+	return (char *)ptr + width;
+}
+
+/* given a pointer to a chunk of memory, return pointer to first
+ * ws character after the last non-ws character, or the end
+ * of the chunk
+ */
+static inline const void *fy_last_non_ws(const void *ptr, int left)
+{
+	const char *s, *e;
+	int c;
+
+	s = ptr;
+	e = s + left;
+	while (e > s) {
+		c = e[-1];
+		if (c != ' ' && c != '\t')
+			return e;
+		e--;
+
+	}
+	return NULL;
+}
+
+const char *fy_uri_esc(const char *s, size_t len, uint8_t *code, int *code_len);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-diag.c b/contrib/libs/libfyaml/src/lib/fy-diag.c
new file mode 100644
index 0000000000..ca324fa5d0
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-diag.c
@@ -0,0 +1,1386 @@
+/*
+ * fy-diag.c - diagnostics
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#endif
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <ctype.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+
+static const char *error_type_txt[] = {
+	[FYET_DEBUG]   = "debug",
+	[FYET_INFO]    = "info",
+	[FYET_NOTICE]  = "notice",
+	[FYET_WARNING] = "warning",
+	[FYET_ERROR]   = "error",
+};
+
+int fy_diag_diag(struct fy_diag *diag, enum fy_error_type level, const char* fmt, ...)
+{
+    int ret;
+
+    va_list args;
+       struct fy_diag_ctx ctx = {
+               .level = level,
+               .module = FYEM_UNKNOWN,
+               .source_func = __func__,
+               .source_file = __FILE__,
+               .source_line = __LINE__,
+               .file = NULL,
+               .line = 0,
+               .column = 0,
+       };
+
+    va_start(args, fmt);
+    ret = fy_diagf(diag, &ctx, fmt, args);
+    va_end(args);
+
+    return ret;
+}
+
+const char *fy_error_type_to_string(enum fy_error_type type)
+{
+
+	if ((unsigned int)type >= FYET_MAX)
+		return "";
+	return error_type_txt[type];
+}
+
+enum fy_error_type fy_string_to_error_type(const char *str)
+{
+	unsigned int i;
+	int level;
+
+	if (!str)
+		return FYET_MAX;
+
+	if (isdigit(*str)) {
+		level = atoi(str);
+		if (level >= 0 && level < FYET_MAX)
+			return (enum fy_error_type)level;
+	}
+
+	for (i = 0; i < FYET_MAX; i++) {
+		if (!strcmp(str, error_type_txt[i]))
+			return (enum fy_error_type)i;
+	}
+
+	return FYET_MAX;
+}
+
+static const char *error_module_txt[] = {
+	[FYEM_UNKNOWN]	= "unknown",
+	[FYEM_ATOM]	= "atom",
+	[FYEM_SCAN]	= "scan",
+	[FYEM_PARSE]	= "parse",
+	[FYEM_DOC]	= "doc",
+	[FYEM_BUILD]	= "build",
+	[FYEM_INTERNAL]	= "internal",
+	[FYEM_SYSTEM]	= "system",
+};
+
+const char *fy_error_module_to_string(enum fy_error_module module)
+{
+
+	if ((unsigned int)module >= FYEM_MAX)
+		return "";
+	return error_module_txt[module];
+}
+
+enum fy_error_module fy_string_to_error_module(const char *str)
+{
+	unsigned int i;
+
+	if (!str)
+		return FYEM_MAX;
+
+	for (i = 0; i < FYEM_MAX; i++) {
+		if (!strcmp(str, error_module_txt[i]))
+			return (enum fy_error_module)i;
+	}
+
+	return FYEM_MAX;
+}
+
+static const char *fy_error_level_str(enum fy_error_type level)
+{
+	static const char *txt[] = {
+		[FYET_DEBUG]   = "DBG",
+		[FYET_INFO]    = "INF",
+		[FYET_NOTICE]  = "NOT",
+		[FYET_WARNING] = "WRN",
+		[FYET_ERROR]   = "ERR",
+	};
+
+	if ((unsigned int)level >= FYET_MAX)
+		return "*unknown*";
+	return txt[level];
+}
+
+static const char *fy_error_module_str(enum fy_error_module module)
+{
+	static const char *txt[] = {
+		[FYEM_UNKNOWN]	= "UNKWN",
+		[FYEM_ATOM]	= "ATOM ",
+		[FYEM_SCAN]	= "SCAN ",
+		[FYEM_PARSE]	= "PARSE",
+		[FYEM_DOC]	= "DOC  ",
+		[FYEM_BUILD]	= "BUILD",
+		[FYEM_INTERNAL]	= "INTRL",
+		[FYEM_SYSTEM]	= "SYSTM",
+	};
+
+	if ((unsigned int)module >= FYEM_MAX)
+		return "*unknown*";
+	return txt[module];
+}
+
+/* really concervative options */
+static const struct fy_diag_term_info default_diag_term_info_template = {
+	.rows		= 25,
+	.columns	= 80
+};
+
+static const struct fy_diag_cfg default_diag_cfg_template = {
+	.fp		= NULL,	/* must be overriden */
+	.level		= FYET_INFO,
+	.module_mask	= (1U << FYEM_MAX) - 1,	/* all modules */
+	.show_source	= false,
+	.show_position	= false,
+	.show_type	= true,
+	.show_module	= false,
+	.colorize	= false, /* can be overriden */
+	.source_width	= 50,
+	.position_width	= 10,
+	.type_width	= 5,
+	.module_width	= 6,
+};
+
+void fy_diag_cfg_default(struct fy_diag_cfg *cfg)
+{
+	if (!cfg)
+		return;
+
+	*cfg = default_diag_cfg_template;
+	cfg->fp = stderr;
+	cfg->colorize = isatty(fileno(stderr)) == 1;
+}
+
+void fy_diag_cfg_from_parser_flags(struct fy_diag_cfg *cfg, enum fy_parse_cfg_flags pflags)
+{
+	/* nothing */
+}
+
+static bool fy_diag_isatty(struct fy_diag *diag)
+{
+	return diag && diag->cfg.fp && isatty(fileno(diag->cfg.fp));
+}
+
+static void fy_diag_update_term_info(struct fy_diag *diag)
+{
+	int fd, rows, columns, ret;
+
+	/* start by setting things to the default */
+	diag->term_info = default_diag_term_info_template;
+
+	fd = diag->cfg.fp && isatty(fileno(diag->cfg.fp)) ?
+		fileno(diag->cfg.fp) : -1;
+
+	if (fd == -1)
+		goto out;
+
+	rows = columns = 0;
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+	ret = fy_term_query_size(fd, &rows, &columns);
+	if (ret != 0)
+		goto out;
+
+	if (rows > 0 && columns > 0) {
+		diag->term_info.rows = rows;
+		diag->term_info.columns = columns;
+	}
+#endif
+out:
+	diag->terminal_probed = true;
+}
+
+void fy_diag_errorp_free(struct fy_diag_errorp *errp)
+{
+	if (errp->space)
+		free(errp->space);
+	fy_token_unref(errp->e.fyt);
+	free(errp);
+}
+
+struct fy_diag *fy_diag_create(const struct fy_diag_cfg *cfg)
+{
+	struct fy_diag *diag;
+
+	diag = malloc(sizeof(*diag));
+	if (!diag)
+		return NULL;
+	memset(diag, 0, sizeof(*diag));
+
+	if (!cfg)
+		fy_diag_cfg_default(&diag->cfg);
+	else
+		diag->cfg = *cfg;
+	diag->on_error = false;
+	diag->refs = 1;
+
+	diag->terminal_probed = false;
+	if (!fy_diag_isatty(diag))
+		fy_diag_update_term_info(diag);
+
+	fy_diag_errorp_list_init(&diag->errors);
+
+	return diag;
+}
+
+void fy_diag_destroy(struct fy_diag *diag)
+{
+	struct fy_diag_errorp *errp;
+
+	if (!diag)
+		return;
+
+	diag->destroyed = true;
+
+	/* free everything */
+	while ((errp = fy_diag_errorp_list_pop(&diag->errors)) != NULL)
+		fy_diag_errorp_free(errp);
+
+	return fy_diag_unref(diag);
+}
+
+bool fy_diag_got_error(struct fy_diag *diag)
+{
+	return diag && diag->on_error;
+}
+
+void fy_diag_reset_error(struct fy_diag *diag)
+{
+	struct fy_diag_errorp *errp;
+
+	if (!diag)
+		return;
+
+	diag->on_error = false;
+
+	while ((errp = fy_diag_errorp_list_pop(&diag->errors)) != NULL)
+		fy_diag_errorp_free(errp);
+}
+
+void fy_diag_set_collect_errors(struct fy_diag *diag, bool collect_errors)
+{
+	struct fy_diag_errorp *errp;
+
+	if (!diag || diag->destroyed)
+		return;
+
+	diag->collect_errors = collect_errors;
+
+	/* clear collected errors on disable */
+	if (!diag->collect_errors) {
+		while ((errp = fy_diag_errorp_list_pop(&diag->errors)) != NULL)
+			fy_diag_errorp_free(errp);
+	}
+}
+
+struct fy_diag_error *fy_diag_errors_iterate(struct fy_diag *diag, void **prevp)
+{
+	struct fy_diag_errorp *errp;
+
+	if (!diag || !prevp)
+		return NULL;
+
+	if (!*prevp)
+		errp = fy_diag_errorp_list_head(&diag->errors);
+	else {
+		errp = *prevp;
+		errp = fy_diag_errorp_next(&diag->errors, errp);
+	}
+
+	if (!errp)
+		return NULL;
+	*prevp = errp;
+	return &errp->e;
+}
+
+void fy_diag_free(struct fy_diag *diag)
+{
+	if (!diag)
+		return;
+	free(diag);
+}
+
+const struct fy_diag_cfg *fy_diag_get_cfg(struct fy_diag *diag)
+{
+	if (!diag)
+		return NULL;
+	return &diag->cfg;
+}
+
+void fy_diag_set_cfg(struct fy_diag *diag, const struct fy_diag_cfg *cfg)
+{
+	if (!diag)
+		return;
+
+	if (!cfg)
+		fy_diag_cfg_default(&diag->cfg);
+	else
+		diag->cfg = *cfg;
+
+	fy_diag_update_term_info(diag);
+}
+
+void fy_diag_set_level(struct fy_diag *diag, enum fy_error_type level)
+{
+	if (!diag || (unsigned int)level >= FYET_MAX)
+		return;
+	diag->cfg.level = level;
+}
+
+void fy_diag_set_colorize(struct fy_diag *diag, bool colorize)
+{
+	if (!diag)
+		return;
+	diag->cfg.colorize = colorize;
+}
+
+struct fy_diag *fy_diag_ref(struct fy_diag *diag)
+{
+	if (!diag)
+		return NULL;
+
+	assert(diag->refs + 1 > 0);
+	diag->refs++;
+
+	return diag;
+}
+
+void fy_diag_unref(struct fy_diag *diag)
+{
+	if (!diag)
+		return;
+
+	assert(diag->refs > 0);
+
+	if (diag->refs == 1)
+		fy_diag_free(diag);
+	else
+		diag->refs--;
+}
+
+ssize_t fy_diag_write(struct fy_diag *diag, const void *buf, size_t count)
+{
+	size_t ret;
+
+	if (!diag || !buf)
+		return -1;
+
+	/* no more output */
+	if (diag->destroyed)
+		return 0;
+
+	ret = 0;
+	if (diag->cfg.fp) {
+		ret = fwrite(buf, 1, count, diag->cfg.fp);
+	} else if (diag->cfg.output_fn) {
+		diag->cfg.output_fn(diag, diag->cfg.user, buf, count);
+		ret = count;
+	}
+
+	return ret == count ? (ssize_t)count : -1;
+}
+
+int fy_diag_vprintf(struct fy_diag *diag, const char *fmt, va_list ap)
+{
+	char *buf;
+	int rc;
+
+	if (!diag || !fmt)
+		return -1;
+
+	/* no more output */
+	if (diag->destroyed)
+		return 0;
+
+	if (diag->cfg.fp)
+		return vfprintf(diag->cfg.fp, fmt, ap);
+
+	if (diag->cfg.output_fn) {
+		rc = vasprintf(&buf, fmt, ap);
+		if (rc < 0)
+			return rc;
+		diag->cfg.output_fn(diag, diag->cfg.user, buf, (size_t)rc);
+		free(buf);
+		return rc;
+	}
+
+	return -1;
+}
+
+int fy_diag_printf(struct fy_diag *diag, const char *fmt, ...)
+{
+	va_list ap;
+	int rc;
+
+	va_start(ap, fmt);
+	rc = fy_diag_vprintf(diag, fmt, ap);
+	va_end(ap);
+
+	return rc;
+}
+
+int fy_vdiag(struct fy_diag *diag, const struct fy_diag_ctx *fydc,
+	     const char *fmt, va_list ap)
+{
+	char *msg = NULL;
+	char *source = NULL, *position = NULL, *typestr = NULL, *modulestr = NULL;
+	const char *file_stripped = NULL;
+	const char *color_start = NULL, *color_end = NULL;
+	enum fy_error_type level;
+	int rc;
+
+	if (!diag || !fydc || !fmt)
+		return -1;
+
+	level = fydc->level;
+
+	/* turn errors into debugs while not reset */
+	if (level >= FYET_ERROR && diag->on_error)
+		level = FYET_DEBUG;
+
+	if (level < diag->cfg.level) {
+		rc = 0;
+		goto out;
+	}
+
+	/* check module enable mask */
+	if (!(diag->cfg.module_mask & FY_BIT(fydc->module))) {
+		rc = 0;
+		goto out;
+	}
+
+	alloca_vsprintf(&msg, fmt, ap);
+
+	/* source part */
+	if (diag->cfg.show_source) {
+		if (fydc->source_file) {
+			file_stripped = strrchr(fydc->source_file, '/');
+			if (!file_stripped)
+				file_stripped = fydc->source_file;
+			else
+				file_stripped++;
+		} else
+			file_stripped = "";
+		alloca_sprintf(&source, "%s:%d @%s()%s",
+				file_stripped, fydc->source_line, fydc->source_func, " ");
+	}
+
+	/* position part */
+	if (diag->cfg.show_position && fydc->line >= 0 && fydc->column >= 0)
+		alloca_sprintf(&position, "<%3d:%2d>%s", fydc->line, fydc->column, ": ");
+
+	/* type part */
+	if (diag->cfg.show_type)
+		alloca_sprintf(&typestr, "[%s]%s", fy_error_level_str(level), ": ");
+
+	/* module part */
+	if (diag->cfg.show_module)
+		alloca_sprintf(&modulestr, "<%s>%s", fy_error_module_str(fydc->module), ": ");
+
+	if (diag->cfg.colorize) {
+		switch (level) {
+		case FYET_DEBUG:
+			color_start = "\x1b[37m";	/* normal white */
+			break;
+		case FYET_INFO:
+			color_start = "\x1b[37;1m";	/* bright white */
+			break;
+		case FYET_NOTICE:
+			color_start = "\x1b[34;1m";	/* bright blue */
+			break;
+		case FYET_WARNING:
+			color_start = "\x1b[33;1m";	/* bright yellow */
+			break;
+		case FYET_ERROR:
+			color_start = "\x1b[31;1m";	/* bright red */
+			break;
+		default:	/* handles FYET_MAX */
+			break;
+		}
+		if (color_start)
+			color_end = "\x1b[0m";
+	}
+
+	rc = fy_diag_printf(diag, "%s" "%*s" "%*s" "%*s" "%*s" "%s" "%s\n",
+			color_start ? color_start : "",
+			source    ? diag->cfg.source_width : 0, source ? source : "",
+			position  ? diag->cfg.position_width : 0, position ? position : "",
+			typestr   ? diag->cfg.type_width : 0, typestr ? typestr : "",
+			modulestr ? diag->cfg.module_width : 0, modulestr ? modulestr : "",
+			msg,
+			color_end ? color_end : "");
+
+	if (rc > 0)
+		rc++;
+
+out:
+	/* if it's the first error we're generating set the
+	 * on_error flag until the top caller clears it
+	 */
+	if (!diag->on_error && fydc->level >= FYET_ERROR)
+		diag->on_error = true;
+
+	return rc;
+}
+
+int fy_diagf(struct fy_diag *diag, const struct fy_diag_ctx *fydc,
+	     const char *fmt, ...)
+{
+	va_list ap;
+	int rc;
+
+	va_start(ap, fmt);
+	rc = fy_vdiag(diag, fydc, fmt, ap);
+	va_end(ap);
+
+	return rc;
+}
+
+static void fy_diag_get_error_colors(struct fy_diag *diag, enum fy_error_type type,
+				     const char **start, const char **end, const char **white)
+{
+	if (!diag->cfg.colorize) {
+		*start = *end = *white = "";
+		return;
+	}
+
+	switch (type) {
+	case FYET_DEBUG:
+		*start = "\x1b[37m";	/* normal white */
+		break;
+	case FYET_INFO:
+		*start = "\x1b[37;1m";	/* bright white */
+		break;
+	case FYET_NOTICE:
+		*start = "\x1b[34;1m";	/* bright blue */
+		break;
+	case FYET_WARNING:
+		*start = "\x1b[33;1m";	/* bright yellow */
+		break;
+	case FYET_ERROR:
+		*start = "\x1b[31;1m";	/* bright red */
+		break;
+	default:
+		*start = "\x1b[0m";	/* catch-all reset */
+		break;
+	}
+	*end = "\x1b[0m";
+	*white = "\x1b[37;1m";
+}
+
+void fy_diag_error_atom_display(struct fy_diag *diag, enum fy_error_type type, struct fy_atom *atom)
+{
+	const struct fy_raw_line *l, *ln;
+	struct fy_raw_line l_tmp;
+	struct fy_atom_raw_line_iter iter;
+	int content_start_col, content_end_col, content_width;
+	int pass, cols, min_col, max_col, total_lines, max_line_count, max_line_col8, max_width;
+	int start_col, end_col;
+	const char *color_start, *color_end, *white;
+	bool first_line, last_line;
+	const char *display;
+	int display_len, line_shift;
+	char qc, first_mark;
+	char *rowbuf = NULL, *rbs = NULL, *rbe = NULL;
+	const char *s, *e;
+	int col8, c, w;
+	int tab8_len, tilde_start, tilde_width, tilde_width_m1;
+	size_t rowbufsz;
+
+	(void)end_col;
+
+	if (!diag || !atom)
+		return;
+
+	fy_diag_get_error_colors(diag, type, &color_start, &color_end, &white);
+
+	/* two passes, first one collects extents */
+
+	start_col = -1;
+	end_col = -1;
+	min_col = -1;
+	max_col = -1;
+	max_line_count = -1;
+	max_line_col8 = -1;
+	total_lines = 0;
+	line_shift = -1;
+	for (pass = 0; pass < 2; pass++) {
+
+		/* on the start of the second pass */
+		if (pass > 0) {
+
+			cols = 0;
+
+			/* if it's probed, use what's there */
+			if (diag->terminal_probed && diag->term_info.columns > 0)
+				cols = diag->term_info.columns;
+
+			/* heuristic, avoid probing terminal size if maximum column is less than 80
+			 * columns. This is faster and avoid problems with terminals...
+			 */
+			if (!cols && max_line_col8 < 80)
+				cols = 80;
+
+			/* no choice but to probe */
+			if (!cols) {
+				/* only need the terminal width when outputting an error */
+				if (!diag->terminal_probed && fy_diag_isatty(diag))
+					fy_diag_update_term_info(diag);
+
+				cols = diag->term_info.columns;
+			}
+
+			/* worse case utf8 + 2 color sequences + zero terminated */
+			rowbufsz = cols * 4 + 2 * 16 + 1;
+			rowbuf = FY_ALLOCA(rowbufsz);
+			rbe = rowbuf + rowbufsz;
+
+			/* if the maximum column number is less than the terminal
+			 * width everything fits, and we're fine */ 
+			if (max_line_col8 < cols) {
+				line_shift = 0;
+			} else {
+				max_width = max_col - min_col;
+
+				/* try to center */
+				line_shift = min_col + (max_width - cols) / 2;
+
+				/* the start of the content must always be included */
+				if (start_col < line_shift)
+					line_shift = start_col;
+			}
+		}
+
+		fy_atom_raw_line_iter_start(atom, &iter);
+		l = fy_atom_raw_line_iter_next(&iter);
+		for (; l != NULL; l = ln) {
+
+			/* save it */
+			l_tmp = *l;
+			l = &l_tmp;
+
+			/* get the next too */
+			ln = fy_atom_raw_line_iter_next(&iter);
+
+			first_line = l->lineno <= 1;
+			last_line = ln == NULL;
+
+			content_start_col = l->content_start_col8;
+			content_end_col = l->content_end_col8;
+
+			/* adjust for single and double quoted to include the quote marks (usually works) */
+			if (fy_atom_style_is_quoted(atom->style)) {
+				qc = atom->style == FYAS_SINGLE_QUOTED ? '\'' : '"';
+				if (first_line && l->content_start > l->line_start &&
+						l->content_start[-1] == qc)
+					content_start_col--;
+				if (last_line && (l->content_start + l->content_len) < (l->line_start + l->line_len) &&
+						l->content_start[l->content_len] == qc)
+					content_end_col++;
+			}
+
+			content_width = content_end_col - content_start_col;
+
+			if (pass == 0) {
+
+				total_lines++;
+
+				if (min_col < 0 || content_start_col < min_col)
+					min_col = content_start_col;
+				if (max_col < 0 || content_end_col > max_col)
+					max_col = content_end_col;
+				if (max_line_count < 0 || (int)l->line_count > max_line_count)
+					max_line_count = (int)l->line_count;
+				if (first_line)
+					start_col = content_start_col;
+				if (last_line)
+					end_col = content_end_col;
+
+				/* optimize by using the content end as a starting point */
+				s = l->content_start + l->content_len;
+				e = l->line_start + l->line_count;
+				col8 = l->content_end_col8;
+				while ((c = fy_utf8_get(s, (e - s), &w)) >= 0) {
+					s += w;
+					if (fy_is_tab(c))
+						col8 += 8 - (col8 % 8);
+					else
+						col8++;
+				}
+				/* update the max column number of the lines */
+				if (max_line_col8 < 0 || col8 > max_line_col8)
+					max_line_col8 = col8;
+
+				continue;
+			}
+
+			/* output pass */
+
+			/* the defaults if everything fits */
+			first_mark = first_line ? '^' : '~';
+
+			tab8_len = 0;
+
+			/* find the starting point */
+			s = l->line_start;
+			e = s + l->line_len;
+			col8 = 0;
+			while (col8 < line_shift && (c = fy_utf8_get(s, (e - s), &w)) >= 0) {
+				if (fy_is_tab(c))
+					col8 += 8 - (col8 % 8);
+				else
+					col8++;
+				s += w;
+			}
+			if (col8 > line_shift)
+				tab8_len = col8 - line_shift;	/* the remaining of the tab */
+			else
+				tab8_len = 0;
+
+			/* start filling the row buffer */
+			assert(rowbuf);
+			rbs = rowbuf;
+			rbe = rowbuf + rowbufsz;
+
+			/* remaining tabs */
+			while (tab8_len > 0) {
+				*rbs++ = ' ';
+				tab8_len--;
+			}
+
+			/* go forward until end of line or cols */
+			while (col8 < (line_shift + cols) && (c = fy_utf8_get(s, (e - s), &w)) >= 0 && rbs < rbe) {
+				if (fy_is_tab(c)) {
+					s++;
+					tab8_len = 8 - (col8 % 8);
+					col8 += tab8_len;
+					while (tab8_len > 0 && rbs < rbe) {
+						*rbs++ = ' ';
+						tab8_len--;
+					}
+				} else {
+					while (w > 0 && rbs < rbe) {
+						*rbs++ = *s++;
+						w--;
+					}
+					col8++;
+				}
+			}
+			display = rowbuf;
+			display_len = rbs - rowbuf;
+
+			tilde_start = content_start_col - line_shift;
+			tilde_width = content_width;
+			if (tilde_start + tilde_width > cols)
+				tilde_width = cols - tilde_start;
+			if ((size_t)tilde_width >= rowbufsz)
+				tilde_width = rowbufsz - 1;	/* guard */
+			tilde_width_m1 = tilde_width > 0 ? (tilde_width - 1) : 0;
+
+			/* output the line */
+			fy_diag_write(diag, display, display_len);
+
+			/* set the tildes */
+			assert((int)rowbufsz > tilde_width_m1 + 1);
+			memset(rowbuf, '~', tilde_width_m1);
+			rowbuf[tilde_width_m1] = '\0';
+
+			fy_diag_printf(diag, "\n%*s%s%c%.*s%s\n",
+				       tilde_start, "",
+				       color_start, first_mark, tilde_width_m1, rowbuf, color_end);
+
+		}
+		fy_atom_raw_line_iter_finish(&iter);
+	}
+}
+
+void fy_diag_error_token_display(struct fy_diag *diag, enum fy_error_type type, struct fy_token *fyt)
+{
+	if (!diag || !fyt)
+		return;
+
+	fy_diag_error_atom_display(diag, type, fy_token_atom(fyt));
+}
+
+void fy_diag_vreport(struct fy_diag *diag,
+		     const struct fy_diag_report_ctx *fydrc,
+		     const char *fmt, va_list ap)
+{
+	const char *name, *color_start = NULL, *color_end = NULL, *white = NULL;
+	char *msg_str = NULL, *name_str = NULL;
+	const struct fy_mark *start_mark;
+	int line, column;
+	struct fy_diag_errorp *errp;
+	struct fy_diag_error *err;
+	size_t spacesz, msgsz, filesz;
+	char *s;
+
+	if (!diag || !fydrc || !fmt || !fydrc->fyt)
+		return;
+
+	start_mark = fy_token_start_mark(fydrc->fyt);
+
+	if (fydrc->has_override) {
+		name = fydrc->override_file;
+		line = fydrc->override_line;
+		column = fydrc->override_column;
+	} else {
+		name = fy_input_get_filename(fy_token_get_input(fydrc->fyt));
+		line = start_mark->line + 1;
+		column = start_mark->column + 1;
+	}
+
+	/* it will strip trailing newlines */
+	alloca_vsprintf(&msg_str, fmt, ap);
+
+	/* get the colors */
+	fy_diag_get_error_colors(diag, fydrc->type, &color_start, &color_end, &white);
+
+	if (name || (line > 0 && column > 0)) {
+		if (line > 0 && column > 0)
+			alloca_sprintf(&name_str, "%s%s:%d:%d: ", white, name, line, column);
+		else
+			alloca_sprintf(&name_str, "%s%s: ", white, name);
+	}
+
+	if (!diag->collect_errors) {
+		fy_diag_printf(diag, "%s" "%s%s: %s" "%s\n",
+			name_str ? name_str : "",
+			color_start, fy_error_type_to_string(fydrc->type), color_end,
+			msg_str);
+
+		fy_diag_error_token_display(diag, fydrc->type, fydrc->fyt);
+
+		fy_token_unref(fydrc->fyt);
+
+	} else if ((errp = malloc(sizeof(*errp))) != NULL) {
+
+		msgsz = strlen(msg_str) + 1;
+		filesz = strlen(name) + 1;
+		spacesz = msgsz + filesz;
+
+		errp->space = malloc(spacesz);
+		if (!errp->space) {
+			free(errp);
+			goto out;
+		}
+		s = errp->space;
+
+		err = &errp->e;
+		memset(err, 0, sizeof(*err));
+		err->type = fydrc->type;
+		err->module = fydrc->module;
+		err->fyt = fydrc->fyt;
+		err->msg = s;
+		memcpy(s, msg_str, msgsz);
+		s += msgsz;
+		err->file = s;
+		memcpy(s, name, filesz);
+		s += filesz;
+		err->line = line;
+		err->column = column;
+
+		fy_diag_errorp_list_add_tail(&diag->errors, errp);
+	}
+out:
+	if (!diag->on_error && fydrc->type == FYET_ERROR)
+		diag->on_error = true;
+}
+
+void fy_diag_report(struct fy_diag *diag,
+		    const struct fy_diag_report_ctx *fydrc,
+		    const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_diag_vreport(diag, fydrc, fmt, ap);
+	va_end(ap);
+}
+
+/* parser */
+
+int fy_parser_vdiag(struct fy_parser *fyp, unsigned int flags,
+		    const char *file, int line, const char *func,
+		    const char *fmt, va_list ap)
+{
+	struct fy_diag_ctx fydc;
+	int rc;
+
+	if (!fyp || !fyp->diag || !fmt)
+		return -1;
+
+	/* perform the enable tests early to avoid the overhead */
+	if (((flags & FYDF_LEVEL_MASK) >> FYDF_LEVEL_SHIFT) < fyp->diag->cfg.level)
+		return 0;
+
+	/* fill in fy_diag_ctx */
+	memset(&fydc, 0, sizeof(fydc));
+
+	fydc.level = (flags & FYDF_LEVEL_MASK) >> FYDF_LEVEL_SHIFT;
+	fydc.module = (flags & FYDF_MODULE_MASK) >> FYDF_MODULE_SHIFT;
+	fydc.source_file = file;
+	fydc.source_line = line;
+	fydc.source_func = func;
+	fydc.line = fyp_line(fyp);
+	fydc.column = fyp_column(fyp);
+
+	rc = fy_vdiag(fyp->diag, &fydc, fmt, ap);
+
+	if (fyp && !fyp->stream_error && fyp->diag->on_error)
+		fyp->stream_error = true;
+
+	return rc;
+}
+
+int fy_parser_diag(struct fy_parser *fyp, unsigned int flags,
+	    const char *file, int line, const char *func,
+	    const char *fmt, ...)
+{
+	va_list ap;
+	int rc;
+
+	va_start(ap, fmt);
+	rc = fy_parser_vdiag(fyp, flags, file, line, func, fmt, ap);
+	va_end(ap);
+
+	return rc;
+}
+
+void fy_parser_diag_vreport(struct fy_parser *fyp,
+		            const struct fy_diag_report_ctx *fydrc,
+			    const char *fmt, va_list ap)
+{
+	struct fy_diag *diag;
+
+	if (!fyp || !fyp->diag || !fydrc || !fmt)
+		return;
+
+	diag = fyp->diag;
+
+	fy_diag_vreport(diag, fydrc, fmt, ap);
+
+	if (fyp && !fyp->stream_error && diag->on_error)
+		fyp->stream_error = true;
+}
+
+void fy_parser_diag_report(struct fy_parser *fyp,
+			   const struct fy_diag_report_ctx *fydrc,
+			   const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_parser_diag_vreport(fyp, fydrc, fmt, ap);
+	va_end(ap);
+}
+
+/* document */
+
+int fy_document_vdiag(struct fy_document *fyd, unsigned int flags,
+		      const char *file, int line, const char *func,
+		      const char *fmt, va_list ap)
+{
+	struct fy_diag_ctx fydc;
+	int rc;
+
+	if (!fyd || !fmt || !fyd->diag)
+		return -1;
+
+	/* perform the enable tests early to avoid the overhead */
+	if (((flags & FYDF_LEVEL_MASK) >> FYDF_LEVEL_SHIFT) < fyd->diag->cfg.level)
+		return 0;
+
+	/* fill in fy_diag_ctx */
+	memset(&fydc, 0, sizeof(fydc));
+
+	fydc.level = (flags & FYDF_LEVEL_MASK) >> FYDF_LEVEL_SHIFT;
+	fydc.module = (flags & FYDF_MODULE_MASK) >> FYDF_MODULE_SHIFT;
+	fydc.source_file = file;
+	fydc.source_line = line;
+	fydc.source_func = func;
+	fydc.line = -1;
+	fydc.column = -1;
+
+	rc = fy_vdiag(fyd->diag, &fydc, fmt, ap);
+
+	return rc;
+}
+
+int fy_document_diag(struct fy_document *fyd, unsigned int flags,
+		     const char *file, int line, const char *func,
+		     const char *fmt, ...)
+{
+	va_list ap;
+	int rc;
+
+	va_start(ap, fmt);
+	rc = fy_document_vdiag(fyd, flags, file, line, func, fmt, ap);
+	va_end(ap);
+
+	return rc;
+}
+
+void fy_document_diag_vreport(struct fy_document *fyd,
+			      const struct fy_diag_report_ctx *fydrc,
+			      const char *fmt, va_list ap)
+{
+	if (!fyd || !fyd->diag || !fydrc || !fmt)
+		return;
+
+	fy_diag_vreport(fyd->diag, fydrc, fmt, ap);
+}
+
+void fy_document_diag_report(struct fy_document *fyd,
+			     const struct fy_diag_report_ctx *fydrc,
+			     const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_document_diag_vreport(fyd, fydrc, fmt, ap);
+	va_end(ap);
+}
+
+/* composer */
+int fy_composer_vdiag(struct fy_composer *fyc, unsigned int flags,
+		      const char *file, int line, const char *func,
+		      const char *fmt, va_list ap)
+{
+	struct fy_diag_ctx fydc;
+	int rc;
+
+	if (!fyc || !fmt || !fyc->cfg.diag)
+		return -1;
+
+	/* perform the enable tests early to avoid the overhead */
+	if (((flags & FYDF_LEVEL_MASK) >> FYDF_LEVEL_SHIFT) < fyc->cfg.diag->cfg.level)
+		return 0;
+
+	/* fill in fy_diag_ctx */
+	memset(&fydc, 0, sizeof(fydc));
+
+	fydc.level = (flags & FYDF_LEVEL_MASK) >> FYDF_LEVEL_SHIFT;
+	fydc.module = (flags & FYDF_MODULE_MASK) >> FYDF_MODULE_SHIFT;
+	fydc.source_file = file;
+	fydc.source_line = line;
+	fydc.source_func = func;
+	fydc.line = -1;
+	fydc.column = -1;
+
+	rc = fy_vdiag(fyc->cfg.diag, &fydc, fmt, ap);
+
+	return rc;
+}
+
+int fy_composer_diag(struct fy_composer *fyc, unsigned int flags,
+		     const char *file, int line, const char *func,
+		     const char *fmt, ...)
+{
+	va_list ap;
+	int rc;
+
+	va_start(ap, fmt);
+	rc = fy_composer_vdiag(fyc, flags, file, line, func, fmt, ap);
+	va_end(ap);
+
+	return rc;
+}
+
+void fy_composer_diag_vreport(struct fy_composer *fyc,
+			      const struct fy_diag_report_ctx *fydrc,
+			      const char *fmt, va_list ap)
+{
+	if (!fyc || !fyc->cfg.diag || !fydrc || !fmt)
+		return;
+
+	fy_diag_vreport(fyc->cfg.diag, fydrc, fmt, ap);
+}
+
+void fy_composer_diag_report(struct fy_composer *fyc,
+			     const struct fy_diag_report_ctx *fydrc,
+			     const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_composer_diag_vreport(fyc, fydrc, fmt, ap);
+	va_end(ap);
+}
+
+/* document_builder */
+int fy_document_builder_vdiag(struct fy_document_builder *fydb, unsigned int flags,
+		      const char *file, int line, const char *func,
+		      const char *fmt, va_list ap)
+{
+	struct fy_diag_ctx fydc;
+	int rc;
+
+	if (!fydb || !fmt || !fydb->cfg.diag)
+		return -1;
+
+	/* perform the enable tests early to avoid the overhead */
+	if (((flags & FYDF_LEVEL_MASK) >> FYDF_LEVEL_SHIFT) < fydb->cfg.diag->cfg.level)
+		return 0;
+
+	/* fill in fy_diag_ctx */
+	memset(&fydc, 0, sizeof(fydc));
+
+	fydc.level = (flags & FYDF_LEVEL_MASK) >> FYDF_LEVEL_SHIFT;
+	fydc.module = (flags & FYDF_MODULE_MASK) >> FYDF_MODULE_SHIFT;
+	fydc.source_file = file;
+	fydc.source_line = line;
+	fydc.source_func = func;
+	fydc.line = -1;
+	fydc.column = -1;
+
+	rc = fy_vdiag(fydb->cfg.diag, &fydc, fmt, ap);
+
+	return rc;
+}
+
+int fy_document_builder_diag(struct fy_document_builder *fydb, unsigned int flags,
+		     const char *file, int line, const char *func,
+		     const char *fmt, ...)
+{
+	va_list ap;
+	int rc;
+
+	va_start(ap, fmt);
+	rc = fy_document_builder_vdiag(fydb, flags, file, line, func, fmt, ap);
+	va_end(ap);
+
+	return rc;
+}
+
+void fy_document_builder_diag_vreport(struct fy_document_builder *fydb,
+			      const struct fy_diag_report_ctx *fydrc,
+			      const char *fmt, va_list ap)
+{
+	if (!fydb || !fydb->cfg.diag || !fydrc || !fmt)
+		return;
+
+	fy_diag_vreport(fydb->cfg.diag, fydrc, fmt, ap);
+}
+
+void fy_document_builder_diag_report(struct fy_document_builder *fydb,
+			     const struct fy_diag_report_ctx *fydrc,
+			     const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_document_builder_diag_vreport(fydb, fydrc, fmt, ap);
+	va_end(ap);
+}
+
+/* reader */
+
+int fy_reader_vdiag(struct fy_reader *fyr, unsigned int flags,
+		    const char *file, int line, const char *func,
+		    const char *fmt, va_list ap)
+{
+	struct fy_diag_ctx fydc;
+	int fydc_level, fyd_level;
+
+	if (!fyr || !fyr->diag || !fmt)
+		return -1;
+
+	/* perform the enable tests early to avoid the overhead */
+	fydc_level = (flags & FYDF_LEVEL_MASK) >> FYDF_LEVEL_SHIFT;
+	fyd_level = fyr->diag->cfg.level;
+
+	if (fydc_level < fyd_level)
+		return 0;
+
+	/* fill in fy_diag_ctx */
+	memset(&fydc, 0, sizeof(fydc));
+
+	fydc.level = fydc_level;
+	fydc.module = FYEM_SCAN;	/* reader is always scanner */
+	fydc.source_file = file;
+	fydc.source_line = line;
+	fydc.source_func = func;
+	fydc.line = fyr->line;
+	fydc.column = fyr->column;
+
+	return fy_vdiag(fyr->diag, &fydc, fmt, ap);
+}
+
+int fy_reader_diag(struct fy_reader *fyr, unsigned int flags,
+		   const char *file, int line, const char *func,
+		   const char *fmt, ...)
+{
+	va_list ap;
+	int rc;
+
+	va_start(ap, fmt);
+	rc = fy_reader_vdiag(fyr, flags, file, line, func, fmt, ap);
+	va_end(ap);
+
+	return rc;
+}
+
+void fy_reader_diag_vreport(struct fy_reader *fyr,
+		            const struct fy_diag_report_ctx *fydrc,
+			    const char *fmt, va_list ap)
+{
+	if (!fyr || !fyr->diag || !fydrc || !fmt)
+		return;
+
+	fy_diag_vreport(fyr->diag, fydrc, fmt, ap);
+}
+
+void fy_reader_diag_report(struct fy_reader *fyr,
+			   const struct fy_diag_report_ctx *fydrc,
+			   const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_reader_diag_vreport(fyr, fydrc, fmt, ap);
+	va_end(ap);
+}
+
+void fy_diag_node_vreport(struct fy_diag *diag, struct fy_node *fyn,
+			  enum fy_error_type type, const char *fmt, va_list ap)
+{
+	struct fy_diag_report_ctx drc;
+	bool save_on_error;
+
+	if (!fyn || !diag)
+		return;
+
+	save_on_error = diag->on_error;
+	diag->on_error = false;
+
+	memset(&drc, 0, sizeof(drc));
+	drc.type = type;
+	drc.module = FYEM_UNKNOWN;
+	drc.fyt = fy_node_token(fyn);
+	fy_diag_vreport(diag, &drc, fmt, ap);
+
+	diag->on_error = save_on_error;
+}
+
+void fy_diag_node_report(struct fy_diag *diag, struct fy_node *fyn,
+			 enum fy_error_type type, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_diag_node_vreport(diag, fyn, type, fmt, ap);
+	va_end(ap);
+}
+
+void fy_diag_node_override_vreport(struct fy_diag *diag, struct fy_node *fyn,
+				   enum fy_error_type type, const char *file,
+				   int line, int column,
+				   const char *fmt, va_list ap)
+{
+	struct fy_diag_report_ctx drc;
+	bool save_on_error;
+
+	if (!fyn || !diag)
+		return;
+
+	save_on_error = diag->on_error;
+	diag->on_error = false;
+
+	memset(&drc, 0, sizeof(drc));
+	drc.type = type;
+	drc.module = FYEM_UNKNOWN;
+	drc.fyt = fy_node_token(fyn);
+	drc.has_override = true;
+	drc.override_file = file;
+	drc.override_line = line;
+	drc.override_column = column;
+	fy_diag_vreport(diag, &drc, fmt, ap);
+
+	diag->on_error = save_on_error;
+}
+
+void fy_diag_node_override_report(struct fy_diag *diag, struct fy_node *fyn,
+				  enum fy_error_type type, const char *file,
+				  int line, int column, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_diag_node_override_vreport(diag, fyn, type, file, line, column, fmt, ap);
+	va_end(ap);
+}
+
+void fy_node_vreport(struct fy_node *fyn, enum fy_error_type type,
+		     const char *fmt, va_list ap)
+{
+	if (!fyn || !fyn->fyd)
+		return;
+
+	fy_diag_node_vreport(fyn->fyd->diag, fyn, type, fmt, ap);
+}
+
+void fy_node_report(struct fy_node *fyn, enum fy_error_type type,
+		    const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_node_vreport(fyn, type, fmt, ap);
+	va_end(ap);
+}
+
+void fy_node_override_vreport(struct fy_node *fyn, enum fy_error_type type,
+			      const char *file, int line, int column,
+			      const char *fmt, va_list ap)
+{
+	if (!fyn || !fyn->fyd)
+		return;
+
+	fy_diag_node_override_vreport(fyn->fyd->diag, fyn, type,
+				      file, line, column, fmt, ap);
+}
+
+void fy_node_override_report(struct fy_node *fyn, enum fy_error_type type,
+			     const char *file, int line, int column,
+			     const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_node_override_vreport(fyn, type, file, line, column, fmt, ap);
+	va_end(ap);
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-diag.h b/contrib/libs/libfyaml/src/lib/fy-diag.h
new file mode 100644
index 0000000000..2834c0a041
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-diag.h
@@ -0,0 +1,730 @@
+/*
+ * fy-diag.h - diagnostics
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_DIAG_H
+#define FY_DIAG_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-list.h"
+#include "fy-token.h"
+
+#if !defined(NDEBUG) && defined(HAVE_DEVMODE) && HAVE_DEVMODE
+#define FY_DEVMODE
+#else
+#undef FY_DEVMODE
+#endif
+
+/* error flags (above 0x100 is library specific) */
+#define FYEF_SOURCE	0x0001
+#define FYEF_POSITION	0x0002
+#define FYEF_TYPE	0x0004
+#define FYEF_USERSTART	0x0100
+
+#define FYDF_LEVEL_SHIFT	0
+#define FYDF_LEVEL_MASK		(0x0f << FYDF_LEVEL_SHIFT)
+#define FYDF_LEVEL(x)		(((unsigned int)(x) << FYDF_LEVEL_SHIFT) & FYDF_LEVEL_MASK)
+#define FYDF_DEBUG		FYDF_LEVEL(FYET_DEBUG)
+#define FYDF_INFO		FYDF_LEVEL(FYET_INFO)
+#define FYDF_NOTICE		FYDF_LEVEL(FYET_NOTICE)
+#define FYDF_WARNING		FYDF_LEVEL(FYET_WARNING)
+#define FYDF_ERROR		FYDF_LEVEL(FYET_ERROR)
+
+#define FYDF_MODULE_SHIFT	4
+#define FYDF_MODULE_MASK	(0x0f << FYDF_MODULE_SHIFT)
+#define FYDF_MODULE(x)		(((unsigned int)(x) << FYDF_MODULE_SHIFT) & FYDF_MODULE_MASK)
+#define FYDF_ATOM		FYDF_MODULE(FYEM_ATOM)
+#define FYDF_SCANNER		FYDF_MODULE(FYEM_SCANNER)
+#define FYDF_PARSER		FYDF_MODULE(FYEM_PARSER)
+#define FYDF_TREE		FYDF_MODULE(FYEM_TREE)
+#define FYDF_BUILDER		FYDF_MODULE(FYEM_BUILDER)
+#define FYDF_INTERNAL		FYDF_MODULE(FYEM_INTERNAL)
+#define FYDF_SYSTEM		FYDF_MODULE(FYEM_SYSTEM)
+#define FYDF_MODULE_USER_MASK	7
+#define FYDF_MODULE_USER(x)	FYDF_MODULE(8 + ((x) & FYDF_MODULE_USER_MASK))
+
+struct fy_diag_term_info {
+	int rows;
+	int columns;
+};
+
+struct fy_diag_report_ctx {
+	enum fy_error_type type;
+	enum fy_error_module module;
+	struct fy_token *fyt;
+	bool has_override;
+	const char *override_file;
+	int override_line;
+	int override_column;
+};
+
+FY_TYPE_FWD_DECL_LIST(diag_errorp);
+struct fy_diag_errorp {
+	struct fy_list_head node;
+	char *space;
+	struct fy_diag_error e;
+};
+FY_TYPE_DECL_LIST(diag_errorp);
+
+struct fy_diag {
+	struct fy_diag_cfg cfg;
+	int refs;
+	bool on_error : 1;
+	bool destroyed : 1;
+	bool collect_errors : 1;
+	bool terminal_probed : 1;
+	struct fy_diag_term_info term_info;
+	struct fy_diag_errorp_list errors;
+};
+
+void fy_diag_free(struct fy_diag *diag);
+
+void fy_diag_vreport(struct fy_diag *diag,
+		     const struct fy_diag_report_ctx *fydrc,
+		     const char *fmt, va_list ap);
+void fy_diag_report(struct fy_diag *diag,
+		    const struct fy_diag_report_ctx *fydrc,
+		    const char *fmt, ...)
+			FY_ATTRIBUTE(format(printf, 3, 4));
+
+#ifdef FY_DEVMODE
+#define __FY_DEBUG_UNUSED__	/* nothing */
+#else
+#define __FY_DEBUG_UNUSED__	FY_ATTRIBUTE(__unused__)
+#endif
+
+/* parser diagnostics */
+
+struct fy_parser;
+
+void fy_diag_cfg_from_parser_flags(struct fy_diag_cfg *cfg, enum fy_parse_cfg_flags pflags);
+
+int fy_parser_vdiag(struct fy_parser *fyp, unsigned int flags,
+		    const char *file, int line, const char *func,
+		    const char *fmt, va_list ap);
+
+int fy_parser_diag(struct fy_parser *fyp, unsigned int flags,
+		   const char *file, int line, const char *func,
+		   const char *fmt, ...)
+			FY_ATTRIBUTE(format(printf, 6, 7));
+
+void fy_diag_error_atom_display(struct fy_diag *diag, enum fy_error_type type,
+				 struct fy_atom *atom);
+void fy_diag_error_token_display(struct fy_diag *diag, enum fy_error_type type,
+				 struct fy_token *fyt);
+
+void fy_parser_diag_vreport(struct fy_parser *fyp,
+			    const struct fy_diag_report_ctx *fydrc,
+			    const char *fmt, va_list ap);
+void fy_parser_diag_report(struct fy_parser *fyp,
+			   const struct fy_diag_report_ctx *fydrc,
+			   const char *fmt, ...)
+		FY_ATTRIBUTE(format(printf, 3, 4));
+
+#ifdef FY_DEVMODE
+
+#define fyp_debug(_fyp, _module, _fmt, ...) \
+	fy_parser_diag((_fyp), FYET_DEBUG | FYDF_MODULE(_module), \
+			__FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#else
+
+#define fyp_debug(_fyp, _module, _fmt, ...) \
+	do { } while(0)
+
+#endif
+
+#define fyp_info(_fyp, _fmt, ...) \
+	fy_parser_diag((_fyp), FYET_INFO, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyp_notice(_fyp, _fmt, ...) \
+	fy_parser_diag((_fyp), FYET_NOTICE, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyp_warning(_fyp, _fmt, ...) \
+	fy_parser_diag((_fyp), FYET_WARNING, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyp_error(_fyp, _fmt, ...) \
+	fy_parser_diag((_fyp), FYET_ERROR, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+
+#define fyp_scan_debug(_fyp, _fmt, ...) \
+	fyp_debug((_fyp), FYEM_SCAN, (_fmt) , ## __VA_ARGS__)
+#define fyp_parse_debug(_fyp, _fmt, ...) \
+	fyp_debug((_fyp), FYEM_PARSE, (_fmt) , ## __VA_ARGS__)
+#define fyp_doc_debug(_fyp, _fmt, ...) \
+	fyp_debug((_fyp), FYEM_DOC, (_fmt) , ## __VA_ARGS__)
+
+#define fyp_error_check(_fyp, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			fyp_error((_fyp), _fmt, ## __VA_ARGS__); \
+			goto _label ; \
+		} \
+	} while(0)
+
+#define _FYP_TOKEN_DIAG(_fyp, _fyt, _type, _module, _fmt, ...) \
+	do { \
+		struct fy_diag_report_ctx _drc; \
+		memset(&_drc, 0, sizeof(_drc)); \
+		_drc.type = (_type); \
+		_drc.module = (_module); \
+		_drc.fyt = (_fyt); \
+		fy_parser_diag_report((_fyp), &_drc, (_fmt) , ## __VA_ARGS__); \
+	} while(0)
+
+#define FYP_TOKEN_DIAG(_fyp, _fyt, _type, _module, _fmt, ...) \
+	_FYP_TOKEN_DIAG(_fyp, fy_token_ref(_fyt), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_PARSE_DIAG(_fyp, _adv, _cnt, _type, _module, _fmt, ...) \
+	_FYP_TOKEN_DIAG(_fyp, \
+		fy_token_create(FYTT_INPUT_MARKER, \
+			fy_fill_atom_at((_fyp), (_adv), (_cnt), \
+			FY_ALLOCA(sizeof(struct fy_atom)))), \
+		_type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_MARK_DIAG(_fyp, _sm, _em, _type, _module, _fmt, ...) \
+	_FYP_TOKEN_DIAG(_fyp, \
+		fy_token_create(FYTT_INPUT_MARKER, \
+			fy_fill_atom_mark(((_fyp)), (_sm), (_em), \
+				FY_ALLOCA(sizeof(struct fy_atom)))), \
+		_type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_NODE_DIAG(_fyp, _fyn, _type, _module, _fmt, ...) \
+	_FYP_TOKEN_DIAG(_fyp, fy_node_token(_fyn), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_TOKEN_ERROR(_fyp, _fyt, _module, _fmt, ...) \
+	FYP_TOKEN_DIAG(_fyp, _fyt, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_PARSE_ERROR(_fyp, _adv, _cnt, _module, _fmt, ...) \
+	FYP_PARSE_DIAG(_fyp, _adv, _cnt, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_MARK_ERROR(_fyp, _sm, _em, _module, _fmt, ...) \
+	FYP_MARK_DIAG(_fyp, _sm, _em, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_NODE_ERROR(_fyp, _fyn, _module, _fmt, ...) \
+	FYP_NODE_DIAG(_fyp, _fyn, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_TOKEN_ERROR_CHECK(_fyp, _fyt, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYP_TOKEN_ERROR(_fyp, _fyt, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYP_PARSE_ERROR_CHECK(_fyp, _adv, _cnt, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYP_PARSE_ERROR(_fyp, _adv, _cnt, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYP_MARK_ERROR_CHECK(_fyp, _sm, _em, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYP_MARK_ERROR(_fyp, _sm, _em, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYP_NODE_ERROR_CHECK(_fyp, _fyn, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYP_NODE_ERROR(_fyp, _fyn, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYP_TOKEN_WARNING(_fyp, _fyt, _module, _fmt, ...) \
+	FYP_TOKEN_DIAG(_fyp, _fyt, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_PARSE_WARNING(_fyp, _adv, _cnt, _module, _fmt, ...) \
+	FYP_PARSE_DIAG(_fyp, _adv, _cnt, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_MARK_WARNING(_fyp, _sm, _em, _module, _fmt, ...) \
+	FYP_MARK_DIAG(_fyp, _sm, _em, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+#define FYP_NODE_WARNING(_fyp, _fyn, _type, _module, _fmt, ...) \
+	FYP_NODE_DIAG(_fyp, _fyn, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+/* reader diagnostics */
+
+struct fy_reader;
+
+int fy_reader_vdiag(struct fy_reader *fyr, unsigned int flags,
+		    const char *file, int line, const char *func,
+		    const char *fmt, va_list ap);
+
+int fy_reader_diag(struct fy_reader *fyr, unsigned int flags,
+		   const char *file, int line, const char *func,
+		   const char *fmt, ...)
+			FY_ATTRIBUTE(format(printf, 6, 7));
+
+void fy_reader_diag_vreport(struct fy_reader *fyr,
+			    const struct fy_diag_report_ctx *fydrc,
+			    const char *fmt, va_list ap);
+void fy_reader_diag_report(struct fy_reader *fyr,
+			   const struct fy_diag_report_ctx *fydrc,
+			   const char *fmt, ...)
+		FY_ATTRIBUTE(format(printf, 3, 4));
+
+#ifdef FY_DEVMODE
+
+#define fyr_debug(_fyr, _fmt, ...) \
+	fy_reader_diag((_fyr), FYET_DEBUG, \
+			__FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#else
+
+#define fyr_debug(_fyr, _fmt, ...) \
+	do { } while(0)
+
+#endif
+
+#define fyr_info(_fyr, _fmt, ...) \
+	fy_reader_diag((_fyr), FYET_INFO, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyr_notice(_fyr, _fmt, ...) \
+	fy_reader_diag((_fyr), FYET_NOTICE, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyr_warning(_fyr, _fmt, ...) \
+	fy_reader_diag((_fyr), FYET_WARNING, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyr_error(_fyr, _fmt, ...) \
+	fy_reader_diag((_fyr), FYET_ERROR, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+
+#define fyr_error_check(_fyr, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			fyr_error((_fyr), _fmt, ## __VA_ARGS__); \
+			goto _label ; \
+		} \
+	} while(0)
+
+#define _FYR_TOKEN_DIAG(_fyr, _fyt, _type, _module, _fmt, ...) \
+	do { \
+		struct fy_diag_report_ctx _drc; \
+		memset(&_drc, 0, sizeof(_drc)); \
+		_drc.type = (_type); \
+		_drc.module = (_module); \
+		_drc.fyt = (_fyt); \
+		fy_reader_diag_report((_fyr), &_drc, (_fmt) , ## __VA_ARGS__); \
+	} while(0)
+
+#define FYR_TOKEN_DIAG(_fyr, _fyt, _type, _module, _fmt, ...) \
+	_FYR_TOKEN_DIAG(_fyr, fy_token_ref(_fyt), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_PARSE_DIAG(_fyr, _adv, _cnt, _type, _module, _fmt, ...) \
+	_FYR_TOKEN_DIAG(_fyr, \
+		fy_token_create(FYTT_INPUT_MARKER, \
+			fy_reader_fill_atom_at((_fyr), (_adv), (_cnt), \
+			FY_ALLOCA(sizeof(struct fy_atom)))), \
+		_type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_MARK_DIAG(_fyr, _sm, _em, _type, _module, _fmt, ...) \
+	_FYR_TOKEN_DIAG(_fyr, \
+		fy_token_create(FYTT_INPUT_MARKER, \
+			fy_reader_fill_atom_mark(((_fyr)), (_sm), (_em), \
+				FY_ALLOCA(sizeof(struct fy_atom)))), \
+		_type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_NODE_DIAG(_fyr, _fyn, _type, _module, _fmt, ...) \
+	_FYR_TOKEN_DIAG(_fyr, fy_node_token(_fyn), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_TOKEN_ERROR(_fyr, _fyt, _module, _fmt, ...) \
+	FYR_TOKEN_DIAG(_fyr, _fyt, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_PARSE_ERROR(_fyr, _adv, _cnt, _module, _fmt, ...) \
+	FYR_PARSE_DIAG(_fyr, _adv, _cnt, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_MARK_ERROR(_fyr, _sm, _em, _module, _fmt, ...) \
+	FYR_MARK_DIAG(_fyr, _sm, _em, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_NODE_ERROR(_fyr, _fyn, _module, _fmt, ...) \
+	FYR_NODE_DIAG(_fyr, _fyn, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_TOKEN_ERROR_CHECK(_fyr, _fyt, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYR_TOKEN_ERROR(_fyr, _fyt, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYR_PARSE_ERROR_CHECK(_fyr, _adv, _cnt, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYR_PARSE_ERROR(_fyr, _adv, _cnt, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYR_MARK_ERROR_CHECK(_fyr, _sm, _em, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYR_MARK_ERROR(_fyr, _sm, _em, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYR_NODE_ERROR_CHECK(_fyr, _fyn, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYR_NODE_ERROR(_fyr, _fyn, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYR_TOKEN_WARNING(_fyr, _fyt, _module, _fmt, ...) \
+	FYR_TOKEN_DIAG(_fyr, _fyt, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_PARSE_WARNING(_fyr, _adv, _cnt, _module, _fmt, ...) \
+	FYR_PARSE_DIAG(_fyr, _adv, _cnt, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_MARK_WARNING(_fyr, _sm, _em, _module, _fmt, ...) \
+	FYR_MARK_DIAG(_fyr, _sm, _em, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+#define FYR_NODE_WARNING(_fyr, _fyn, _type, _module, _fmt, ...) \
+	FYR_NODE_DIAG(_fyr, _fyn, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+/* doc */
+struct fy_document;
+
+int fy_document_vdiag(struct fy_document *fyd, unsigned int flags,
+		      const char *file, int line, const char *func,
+		      const char *fmt, va_list ap);
+
+int fy_document_diag(struct fy_document *fyd, unsigned int flags,
+		     const char *file, int line, const char *func,
+		     const char *fmt, ...)
+			FY_ATTRIBUTE(format(printf, 6, 7));
+
+void fy_document_diag_vreport(struct fy_document *fyd,
+			      const struct fy_diag_report_ctx *fydrc,
+			      const char *fmt, va_list ap);
+void fy_document_diag_report(struct fy_document *fyd,
+			     const struct fy_diag_report_ctx *fydrc,
+			     const char *fmt, ...)
+			FY_ATTRIBUTE(format(printf, 3, 4));
+
+#ifdef FY_DEVMODE
+
+#define fyd_debug(_fyd, _module, _fmt, ...) \
+	fy_document_diag((_fyd), FYET_DEBUG | FYDF_MODULE(_module), \
+			__FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+
+#else
+
+#define fyd_debug(_fyd, _module, _fmt, ...) \
+	do { } while(0)
+
+#endif
+
+#define fyd_info(_fyd, _fmt, ...) \
+	fy_document_diag((_fyd), FYET_INFO, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyd_notice(_fyd, _fmt, ...) \
+	fy_document_diag((_fyd), FYET_NOTICE, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyd_warning(_fyd, _fmt, ...) \
+	fy_document_diag((_fyd), FYET_WARNING, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyd_error(_fyd, _fmt, ...) \
+	fy_document_diag((_fyd), FYET_ERROR, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+
+#define fyd_doc_debug(_fyd, _fmt, ...) \
+	fyd_debug((_fyd), FYEM_DOC, (_fmt) , ## __VA_ARGS__)
+
+#define fyd_error_check(_fyd, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			fyd_error((_fyd), _fmt, ## __VA_ARGS__); \
+			goto _label ; \
+		} \
+	} while(0)
+
+#define _FYD_TOKEN_DIAG(_fyd, _fyt, _type, _module, _fmt, ...) \
+	do { \
+		struct fy_diag_report_ctx _drc; \
+		memset(&_drc, 0, sizeof(_drc)); \
+		_drc.type = (_type); \
+		_drc.module = (_module); \
+		_drc.fyt = (_fyt); \
+		fy_document_diag_report((_fyd), &_drc, (_fmt) , ## __VA_ARGS__); \
+	} while(0)
+
+#define FYD_TOKEN_DIAG(_fyd, _fyt, _type, _module, _fmt, ...) \
+	_FYD_TOKEN_DIAG(_fyd, fy_token_ref(_fyt), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYD_NODE_DIAG(_fyd, _fyn, _type, _module, _fmt, ...) \
+	_FYD_TOKEN_DIAG(_fyd, fy_node_token(_fyn), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYD_TOKEN_ERROR(_fyd, _fyt, _module, _fmt, ...) \
+	FYD_TOKEN_DIAG(_fyd, _fyt, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYD_NODE_ERROR(_fyd, _fyn, _module, _fmt, ...) \
+	FYD_NODE_DIAG(_fyd, _fyn, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYD_TOKEN_ERROR_CHECK(_fyd, _fyt, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYD_TOKEN_ERROR(_fyd, _fyt, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYD_NODE_ERROR_CHECK(_fyd, _fyn, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYD_NODE_ERROR(_fyd, _fyn, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYD_TOKEN_WARNING(_fyd, _fyt, _module, _fmt, ...) \
+	FYD_TOKEN_DIAG(_fyd, _fyt, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+#define FYD_NODE_WARNING(_fyd, _fyn, _type, _module, _fmt, ...) \
+	FYD_NODE_DIAG(_fyd, _fyn, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+/* composer */
+struct fy_composer;
+
+int fy_composer_vdiag(struct fy_composer *fyc, unsigned int flags,
+		      const char *file, int line, const char *func,
+		      const char *fmt, va_list ap);
+
+int fy_composer_diag(struct fy_composer *fyc, unsigned int flags,
+		     const char *file, int line, const char *func,
+		     const char *fmt, ...)
+			FY_ATTRIBUTE(format(printf, 6, 7));
+
+void fy_composer_diag_vreport(struct fy_composer *fyc,
+			      const struct fy_diag_report_ctx *fydrc,
+			      const char *fmt, va_list ap);
+void fy_composer_diag_report(struct fy_composer *fyc,
+			     const struct fy_diag_report_ctx *fydrc,
+			     const char *fmt, ...)
+			FY_ATTRIBUTE(format(printf, 3, 4));
+
+#ifdef FY_DEVMODE
+
+#define fyc_debug(_fyc, _module, _fmt, ...) \
+	fy_composer_diag((_fyc), FYET_DEBUG | FYDF_MODULE(_module), \
+			__FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+
+#else
+
+#define fyc_debug(_fyc, _module, _fmt, ...) \
+	do { } while(0)
+
+#endif
+
+#define fyc_info(_fyc, _fmt, ...) \
+	fy_composer_diag((_fyc), FYET_INFO, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyc_notice(_fyc, _fmt, ...) \
+	fy_composer_diag((_fyc), FYET_NOTICE, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyc_warning(_fyc, _fmt, ...) \
+	fy_composer_diag((_fyc), FYET_WARNING, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fyc_error(_fyc, _fmt, ...) \
+	fy_composer_diag((_fyc), FYET_ERROR, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+
+#define fyc_error_check(_fyc, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			fyc_error((_fyc), _fmt, ## __VA_ARGS__); \
+			goto _label ; \
+		} \
+	} while(0)
+
+#define _FYC_TOKEN_DIAG(_fyc, _fyt, _type, _module, _fmt, ...) \
+	do { \
+		struct fy_diag_report_ctx _drc; \
+		memset(&_drc, 0, sizeof(_drc)); \
+		_drc.type = (_type); \
+		_drc.module = (_module); \
+		_drc.fyt = (_fyt); \
+		fy_composer_diag_report((_fyc), &_drc, (_fmt) , ## __VA_ARGS__); \
+	} while(0)
+
+#define FYC_TOKEN_DIAG(_fyc, _fyt, _type, _module, _fmt, ...) \
+	_FYC_TOKEN_DIAG(_fyc, fy_token_ref(_fyt), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYC_NODE_DIAG(_fyc, _fyn, _type, _module, _fmt, ...) \
+	_FYC_TOKEN_DIAG(_fyc, fy_node_token(_fyn), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYC_TOKEN_ERROR(_fyc, _fyt, _module, _fmt, ...) \
+	FYC_TOKEN_DIAG(_fyc, _fyt, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYC_TOKEN_ERROR_CHECK(_fyc, _fyt, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYC_TOKEN_ERROR(_fyc, _fyt, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYC_TOKEN_WARNING(_fyc, _fyt, _module, _fmt, ...) \
+	FYC_TOKEN_DIAG(_fyc, _fyt, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+/* document builder */
+struct fy_document_builder;
+
+int fy_document_builder_vdiag(struct fy_document_builder *fydb, unsigned int flags,
+			      const char *file, int line, const char *func,
+			      const char *fmt, va_list ap);
+
+int fy_document_builder_diag(struct fy_document_builder *fydb, unsigned int flags,
+			     const char *file, int line, const char *func,
+			     const char *fmt, ...)
+			FY_ATTRIBUTE(format(printf, 6, 7));
+
+void fy_document_builder_diag_vreport(struct fy_document_builder *fydb,
+				      const struct fy_diag_report_ctx *fydrc,
+				      const char *fmt, va_list ap);
+void fy_document_builder_diag_report(struct fy_document_builder *fydb,
+				     const struct fy_diag_report_ctx *fydrc,
+				     const char *fmt, ...)
+				FY_ATTRIBUTE(format(printf, 3, 4));
+
+#ifdef FY_DEVMODE
+
+#define fydb_debug(_fydb, _module, _fmt, ...) \
+	fy_document_builder_diag((_fydb), FYET_DEBUG | FYDF_MODULE(_module), \
+			__FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+
+#else
+
+#define fydb_debug(_fydb, _module, _fmt, ...) \
+	do { } while(0)
+
+#endif
+
+#define fydb_info(_fydb, _fmt, ...) \
+	fy_document_builder_diag((_fydb), FYET_INFO, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fydb_notice(_fydb, _fmt, ...) \
+	fy_document_builder_diag((_fydb), FYET_NOTICE, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fydb_warning(_fydb, _fmt, ...) \
+	fy_document_builder_diag((_fydb), FYET_WARNING, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+#define fydb_error(_fydb, _fmt, ...) \
+	fy_document_builder_diag((_fydb), FYET_ERROR, __FILE__, __LINE__, __func__, \
+			(_fmt) , ## __VA_ARGS__)
+
+#define fydb_error_check(_fydb, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			fydb_error((_fydb), _fmt, ## __VA_ARGS__); \
+			goto _label ; \
+		} \
+	} while(0)
+
+#define _FYDB_TOKEN_DIAG(_fydb, _fyt, _type, _module, _fmt, ...) \
+	do { \
+		struct fy_diag_report_ctx _drc; \
+		memset(&_drc, 0, sizeof(_drc)); \
+		_drc.type = (_type); \
+		_drc.module = (_module); \
+		_drc.fyt = (_fyt); \
+		fy_document_builder_diag_report((_fydb), &_drc, (_fmt) , ## __VA_ARGS__); \
+	} while(0)
+
+#define FYDB_TOKEN_DIAG(_fydb, _fyt, _type, _module, _fmt, ...) \
+	_FYDB_TOKEN_DIAG(_fydb, fy_token_ref(_fyt), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYDB_NODE_DIAG(_fydb, _fyn, _type, _module, _fmt, ...) \
+	_FYDB_TOKEN_DIAG(_fydb, fy_node_token(_fyn), _type, _module, _fmt, ## __VA_ARGS__)
+
+#define FYDB_TOKEN_ERROR(_fydb, _fyt, _module, _fmt, ...) \
+	FYDB_TOKEN_DIAG(_fydb, _fyt, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYDB_NODE_ERROR(_fydb, _fyn, _module, _fmt, ...) \
+	FYDB_NODE_DIAG(_fydb, _fyn, FYET_ERROR, _module, _fmt, ## __VA_ARGS__)
+
+#define FYDB_TOKEN_ERROR_CHECK(_fydb, _fyt, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYDB_TOKEN_ERROR(_fydb, _fyt, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYDB_NODE_ERROR_CHECK(_fydb, _fyn, _module, _cond, _label, _fmt, ...) \
+	do { \
+		if (!(_cond)) { \
+			FYDB_NODE_ERROR(_fydb, _fyn, _module, _fmt, ## __VA_ARGS__); \
+			goto _label; \
+		} \
+	} while(0)
+
+#define FYDB_TOKEN_WARNING(_fydb, _fyt, _module, _fmt, ...) \
+	FYDB_TOKEN_DIAG(_fydb, _fyt, FYET_WARNING, _module, _fmt, ## __VA_ARGS__)
+
+/* alloca formatted print methods */
+#define alloca_vsprintf(_res, _fmt, _ap) \
+	do { \
+		const char *__fmt = (_fmt); \
+		va_list _ap_orig; \
+		int _size; \
+		int _sizew __FY_DEBUG_UNUSED__; \
+		char *_buf = NULL, *_s; \
+		\
+		va_copy(_ap_orig, (_ap)); \
+		_size = vsnprintf(NULL, 0, __fmt, _ap_orig); \
+		va_end(_ap_orig); \
+		if (_size != -1) { \
+			_buf = FY_ALLOCA(_size + 1); \
+			_sizew = vsnprintf(_buf, _size + 1, __fmt, _ap); \
+			assert(_size == _sizew); \
+			_s = _buf + strlen(_buf); \
+			while (_s > _buf && _s[-1] == '\n') \
+				*--_s = '\0'; \
+		} \
+		*(_res) = _buf; \
+	} while(false)
+
+#define alloca_sprintf(_res, _fmt, ...) \
+	do { \
+		const char *__fmt = (_fmt); \
+		int _size; \
+		int _sizew __FY_DEBUG_UNUSED__; \
+		char *_buf = NULL, *_s; \
+		\
+		_size = snprintf(NULL, 0, __fmt, ## __VA_ARGS__); \
+		if (_size != -1) { \
+			_buf = FY_ALLOCA(_size + 1); \
+			_sizew = snprintf(_buf, _size + 1, __fmt, __VA_ARGS__); \
+			assert(_size == _sizew); \
+			_s = _buf + strlen(_buf); \
+			while (_s > _buf && _s[-1] == '\n') \
+				*--_s = '\0'; \
+		} \
+		*(_res) = _buf; \
+	} while(false)
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-doc.c b/contrib/libs/libfyaml/src/lib/fy-doc.c
new file mode 100644
index 0000000000..8cb6a39b86
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-doc.c
@@ -0,0 +1,7340 @@
+/*
+ * fy-doc.c - YAML document methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <unistd.h>
+#endif
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-doc.h"
+
+#include "fy-utils.h"
+
+#define XXH_STATIC_LINKING_ONLY
+#include "xxhash.h"
+
+static const struct fy_hash_desc hd_anchor;
+static const struct fy_hash_desc hd_nanchor;
+static const struct fy_hash_desc hd_mapping;
+
+int fy_node_hash_uint(struct fy_node *fyn, unsigned int *hashp);
+
+static struct fy_node *
+fy_node_by_path_internal(struct fy_node *fyn,
+			 const char *path, size_t pathlen,
+		         enum fy_node_walk_flags flags);
+
+#define FY_NODE_PATH_WALK_DEPTH_DEFAULT	16
+
+static inline unsigned int
+fy_node_walk_max_depth_from_flags(enum fy_node_walk_flags flags)
+{
+	unsigned int max_depth;
+
+	max_depth = ((unsigned int)flags >> FYNWF_MAXDEPTH_SHIFT) & FYNWF_MAXDEPTH_MASK;
+	if (max_depth == 0)
+		max_depth = FY_NODE_PATH_WALK_DEPTH_DEFAULT;
+
+	return max_depth;
+}
+
+static inline unsigned int
+fy_node_walk_marker_from_flags(enum fy_node_walk_flags flags)
+{
+	return ((unsigned int)flags >> FYNWF_MARKER_SHIFT) & FYNWF_MARKER_MASK;
+}
+
+/* internal simple key to optimize string lookups */
+static inline bool is_simple_key(const char *str, size_t len)
+{
+	const char *s, *e;
+	char c;
+
+	if (!str)
+		return false;
+
+	if (len == (size_t)-1)
+		len = strlen(str);
+
+	for (s = str, e = s + len; s < e; s++) {
+
+		c = *s;
+
+		/* note no isalpha() it's locale specific */
+		if (!((c >= 'A' && c <= 'Z') ||
+		      (c >= 'a' && c <= 'z') ||
+		      (c >= '0' && c <= '9') ||
+		      (c == '_')))
+			break;
+	}
+
+	return s == e;
+}
+
+static void fy_resolve_parent_node(struct fy_document *fyd, struct fy_node *fyn, struct fy_node *fyn_parent);
+
+void fy_anchor_destroy(struct fy_anchor *fya)
+{
+	if (!fya)
+		return;
+	fy_token_unref(fya->anchor);
+	free(fya);
+}
+
+struct fy_anchor *fy_anchor_create(struct fy_document *fyd,
+		struct fy_node *fyn, struct fy_token *anchor)
+{
+	struct fy_anchor *fya = NULL;
+
+	fya = malloc(sizeof(*fya));
+	if (!fya)
+		return NULL;
+
+	fya->fyn = fyn;
+	fya->anchor = anchor;
+	fya->multiple = false;
+
+	return fya;
+}
+
+struct fy_anchor *fy_document_anchor_iterate(struct fy_document *fyd, void **prevp)
+{
+	struct fy_anchor_list *fyal;
+
+	if (!fyd || !prevp)
+		return NULL;
+
+	fyal = &fyd->anchors;
+
+	return *prevp = *prevp ? fy_anchor_next(fyal, *prevp) : fy_anchor_list_head(fyal);
+}
+
+#define FYDSAF_COPY		FY_BIT(0)
+#define FYDSAF_MALLOCED		FY_BIT(1)
+
+static int fy_document_set_anchor_internal(struct fy_document *fyd, struct fy_node *fyn, const char *text, size_t len,
+					   unsigned int flags)
+{
+	const bool copy = !!(flags & FYDSAF_COPY);
+	const bool malloced = !!(flags & FYDSAF_MALLOCED);
+	struct fy_anchor *fya = NULL, *fyam = NULL;
+	struct fy_input *fyi = NULL;
+	struct fy_token *fyt = NULL;
+	struct fy_accel_entry *xle;
+	struct fy_atom handle;
+	char *data_copy = NULL;
+	const char *origtext;
+	size_t origlen;
+	int rc;
+
+	if (!fyd || !fyn || fyn->fyd != fyd)
+		return -1;
+
+	if (text && len == (size_t)-1)
+		len = strlen(text);
+
+	fya = fy_document_lookup_anchor_by_node(fyd, fyn);
+
+	if (!text) {
+		/* no anchor, and trying to delete? OK */
+		if (fya)
+			return 0;
+		/* remove the anchor */
+		fy_anchor_list_del(&fyd->anchors, fya);
+
+		if (fy_document_is_accelerated(fyd)) {
+			xle = fy_accel_entry_lookup_key_value(fyd->axl, fya->anchor, fya);
+			fy_accel_entry_remove(fyd->axl, xle);
+
+			xle = fy_accel_entry_lookup_key_value(fyd->naxl, fya->fyn, fya);
+			fy_accel_entry_remove(fyd->naxl, xle);
+		}
+
+		fy_anchor_destroy(fya);
+		return 0;
+	}
+
+	/* trying to add duplicate anchor */
+	if (fya) {
+		origtext = fy_token_get_text(fya->anchor, &origlen);
+		fyd_error_check(fyd, origtext, err_out,
+				"fy_token_get_text() failed");
+
+		FYD_NODE_ERROR(fyd, fyn, FYEM_DOC,
+				"cannot set anchor %.*s (anchor %.*s already exists)",
+				(int)len, text, (int)origlen, origtext);
+		if (malloced && text)
+			free((void *)text);
+		fya = NULL;
+		goto err_out;
+	}
+
+	if (copy) {
+		data_copy = malloc(len);
+		fyd_error_check(fyd, data_copy, err_out,
+				"malloc() failed");
+		memcpy(data_copy, text, len);
+		fyi = fy_input_from_malloc_data(data_copy, len, &handle, true);
+	} else if (malloced)
+		data_copy = (char *)text;
+	else
+		data_copy = NULL;
+
+	if (data_copy)
+		fyi = fy_input_from_malloc_data((void *)text, len, &handle, true);
+	else
+		fyi = fy_input_from_data(text, len, &handle, true);
+	fyd_error_check(fyd, fyi, err_out,
+			"fy_input_from_data() failed");
+	data_copy = NULL;
+
+	/* it must not be something funky */
+	if (!handle.valid_anchor)
+		goto err_out;
+
+	fyt = fy_token_create(FYTT_ANCHOR, &handle);
+	if (!fyt)
+		goto err_out;
+
+	fya = fy_anchor_create(fyd, fyn, fyt);
+	if (!fya)
+		goto err_out;
+
+	fy_anchor_list_add(&fyd->anchors, fya);
+	if (fy_document_is_accelerated(fyd)) {
+		xle = fy_accel_entry_lookup(fyd->axl, fya->anchor);
+		if (xle) {
+			fyam = (void *)xle->value;
+			/* multiple */
+			if (!fyam->multiple)
+				fyam->multiple = true;
+			fya->multiple = true;
+
+			fyd_notice(fyd, "register anchor %.*s is multiple", (int)len, text);
+		}
+
+		xle = fy_accel_entry_insert(fyd->axl, fya->anchor, fya);
+		fyd_error_check(fyd, xle, err_out,
+				"fy_accel_entry_insert() fyd->axl failed");
+	}
+
+	if (fy_document_is_accelerated(fyd)) {
+		rc = fy_accel_insert(fyd->naxl, fyn, fya);
+		fyd_error_check(fyd, !rc, err_out_rc,
+				"fy_accel_insert() fyd->naxl failed");
+	}
+
+	/* take away the input reference */
+	fy_input_unref(fyi);
+
+	return 0;
+err_out:
+	rc = -1;
+err_out_rc:
+	if (data_copy)
+		free(data_copy);
+	fy_anchor_destroy(fya);
+	fy_token_unref(fyt);
+	fy_input_unref(fyi);
+	fyd->diag->on_error = false;
+	return rc;
+}
+
+int fy_document_set_anchor(struct fy_document *fyd, struct fy_node *fyn, const char *text, size_t len)
+{
+	return fy_document_set_anchor_internal(fyd, fyn, text, len, 0);
+}
+
+int fy_node_set_anchor(struct fy_node *fyn, const char *text, size_t len)
+{
+	if (!fyn)
+		return -1;
+	return fy_document_set_anchor_internal(fyn->fyd, fyn, text, len, 0);
+}
+
+int fy_node_set_anchor_copy(struct fy_node *fyn, const char *text, size_t len)
+{
+	if (!fyn)
+		return -1;
+	return fy_document_set_anchor_internal(fyn->fyd, fyn, text, len, FYDSAF_COPY);
+}
+
+int fy_node_set_vanchorf(struct fy_node *fyn, const char *fmt, va_list ap)
+{
+    char *str;
+
+	if (!fyn || !fmt)
+		return -1;
+
+    alloca_vsprintf(&str, fmt, ap);
+	return fy_document_set_anchor_internal(fyn->fyd, fyn, str, FY_NT, FYDSAF_COPY);
+}
+
+int fy_node_set_anchorf(struct fy_node *fyn, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = fy_node_set_vanchorf(fyn, fmt, ap);
+	va_end(ap);
+
+	return ret;
+}
+
+int fy_node_remove_anchor(struct fy_node *fyn)
+{
+	return fy_node_set_anchor(fyn, NULL, 0);
+}
+
+struct fy_anchor *fy_node_get_anchor(struct fy_node *fyn)
+{
+	if (!fyn)
+		return NULL;
+
+	return fy_document_lookup_anchor_by_node(fyn->fyd, fyn);
+}
+
+struct fy_anchor *fy_node_get_nearest_anchor(struct fy_node *fyn)
+{
+	struct fy_anchor *fya;
+	struct fy_node *fynt;
+
+	while ((fya = fy_node_get_anchor(fyn)) == NULL && (fynt = fy_node_get_parent(fyn)))
+		fyn = fynt;
+
+	return fya;
+}
+
+struct fy_node *fy_node_get_nearest_child_of(struct fy_node *fyn_base,
+					     struct fy_node *fyn)
+{
+        struct fy_node *fynp;
+
+        if (!fyn)
+                return NULL;
+        if (!fyn_base)
+                fyn_base = fy_document_root(fy_node_document(fyn));
+        if (!fyn_base)
+                return NULL;
+
+        /* move up until we hit a node that's a child of fyn_base */
+        fynp = fyn;
+        while (fyn && (fynp = fy_node_get_parent(fyn)) != NULL && fyn_base != fynp)
+                fyn = fynp;
+
+        return fyn;
+}
+
+void fy_parse_document_destroy(struct fy_parser *fyp, struct fy_document *fyd)
+{
+	struct fy_node *fyn;
+	struct fy_anchor *fya;
+	struct fy_anchor *fyan;
+	struct fy_accel_entry *xle;
+
+	if (!fyd)
+		return;
+
+	fy_document_cleanup_path_expr_data(fyd);
+
+	fyn = fyd->root;
+	fyd->root = NULL;
+	fy_node_detach_and_free(fyn);
+
+	/* remove all anchors */
+	for (fya = fy_anchor_list_head(&fyd->anchors); fya; fya = fyan) {
+		fyan = fy_anchor_next(&fyd->anchors, fya);
+		fy_anchor_list_del(&fyd->anchors, fya);
+
+		if (fy_document_is_accelerated(fyd)) {
+			xle = fy_accel_entry_lookup_key_value(fyd->axl, fya->anchor, fya);
+			fy_accel_entry_remove(fyd->axl, xle);
+
+			xle = fy_accel_entry_lookup_key_value(fyd->naxl, fya->fyn, fya);
+			fy_accel_entry_remove(fyd->naxl, xle);
+		}
+
+		fy_anchor_destroy(fya);
+	}
+
+	if (fy_document_is_accelerated(fyd)) {
+		fy_accel_cleanup(fyd->axl);
+		free(fyd->axl);
+
+		fy_accel_cleanup(fyd->naxl);
+		free(fyd->naxl);
+	}
+
+	fy_document_state_unref(fyd->fyds);
+
+	fy_diag_unref(fyd->diag);
+
+	free(fyd);
+}
+
+struct fy_document *fy_parse_document_create(struct fy_parser *fyp, struct fy_eventp *fyep)
+{
+	struct fy_document *fyd = NULL;
+	struct fy_document_state *fyds;
+	struct fy_event *fye = NULL;
+	int rc;
+
+	if (!fyp || !fyep)
+		return NULL;
+
+	fye = &fyep->e;
+
+	FYP_TOKEN_ERROR_CHECK(fyp, fy_event_get_token(fye), FYEM_DOC,
+			fye->type == FYET_DOCUMENT_START, err_out,
+			"invalid start of event stream");
+
+	fyd = malloc(sizeof(*fyd));
+	fyp_error_check(fyp, fyd, err_out,
+		"malloc() failed");
+
+	memset(fyd, 0, sizeof(*fyd));
+
+	fyd->diag = fy_diag_ref(fyp->diag);
+	fyd->parse_cfg = fyp->cfg;
+
+	fy_anchor_list_init(&fyd->anchors);
+	if (fy_document_can_be_accelerated(fyd)) {
+		fyd->axl = malloc(sizeof(*fyd->axl));
+		fyp_error_check(fyp, fyd->axl, err_out,
+				"malloc() failed");
+
+		/* start with a very small bucket list */
+		rc = fy_accel_setup(fyd->axl, &hd_anchor, fyd, 8);
+		fyp_error_check(fyp, !rc, err_out,
+				"fy_accel_setup() failed");
+
+		fyd->naxl = malloc(sizeof(*fyd->naxl));
+		fyp_error_check(fyp, fyd->axl, err_out,
+				"malloc() failed");
+
+		/* start with a very small bucket list */
+		rc = fy_accel_setup(fyd->naxl, &hd_nanchor, fyd, 8);
+		fyp_error_check(fyp, !rc, err_out,
+				"fy_accel_setup() failed");
+	}
+
+	fyd->root = NULL;
+
+	fyds = fye->document_start.document_state;
+	fye->document_start.document_state = NULL;
+
+	/* and we're done with this event */
+	fy_parse_eventp_recycle(fyp, fyep);
+
+	/* drop the old reference */
+	fy_document_state_unref(fyd->fyds);
+
+	/* note that we keep the reference */
+	fyd->fyds = fyds;
+
+	fy_document_list_init(&fyd->children);
+
+	return fyd;
+
+err_out:
+	fy_parse_document_destroy(fyp, fyd);
+	fy_parse_eventp_recycle(fyp, fyep);
+	fyd->diag->on_error = false;
+	return NULL;
+}
+
+const struct fy_parse_cfg *fy_document_get_cfg(struct fy_document *fyd)
+{
+	if (!fyd)
+		return NULL;
+	return &fyd->parse_cfg;
+}
+
+struct fy_diag *fy_document_get_diag(struct fy_document *fyd)
+{
+	if (!fyd || !fyd->diag)
+		return NULL;
+	return fy_diag_ref(fyd->diag);
+}
+
+int fy_document_set_diag(struct fy_document *fyd, struct fy_diag *diag)
+{
+	struct fy_diag_cfg dcfg;
+
+	if (!fyd)
+		return -1;
+
+	/* default? */
+	if (!diag) {
+		fy_diag_cfg_default(&dcfg);
+		diag = fy_diag_create(&dcfg);
+		if (!diag)
+			return -1;
+	}
+
+	fy_diag_unref(fyd->diag);
+	fyd->diag = fy_diag_ref(diag);
+
+	return 0;
+}
+
+struct fy_document *fy_node_document(struct fy_node *fyn)
+{
+	return fyn ? fyn->fyd : NULL;
+}
+
+static inline struct fy_anchor *
+fy_document_accel_lookup_anchor_by_token(struct fy_document *fyd, struct fy_token *fyt)
+{
+	assert(fyd);
+	assert(fyd->axl);
+	return (void *)fy_accel_lookup(fyd->axl, fyt);
+}
+
+static inline struct fy_anchor *
+fy_document_accel_lookup_anchor_by_node(struct fy_document *fyd, struct fy_node *fyn)
+{
+	assert(fyd);
+	assert(fyd->naxl);
+	return (void *)fy_accel_lookup(fyd->naxl, fyn);
+}
+
+static inline struct fy_node_pair *
+fy_node_accel_lookup_by_node(struct fy_node *fyn, struct fy_node *fyn_key)
+{
+	assert(fyn);
+	assert(fyn->xl);
+
+	return (void *)fy_accel_lookup(fyn->xl, (const void *)fyn_key);
+}
+
+struct fy_anchor *
+fy_document_lookup_anchor(struct fy_document *fyd, const char *anchor, size_t len)
+{
+	struct fy_anchor *fya;
+	struct fy_anchor_list *fyal;
+	struct fy_input *fyi;
+	struct fy_atom handle;
+	struct fy_token *fyt;
+	const char *text;
+	size_t text_len;
+
+	if (!fyd || !anchor)
+		return NULL;
+
+	if (len == (size_t)-1)
+		len = strlen(anchor);
+
+	if (fy_document_is_accelerated(fyd)) {
+		fyi = fy_input_from_data(anchor, len, &handle, true);
+		if (!fyi)
+			return NULL;
+
+		fyt = fy_token_create(FYTT_ANCHOR, &handle);
+
+		if (!fyt) {
+			fy_input_unref(fyi);
+			return NULL;
+		}
+
+		fya = fy_document_accel_lookup_anchor_by_token(fyd, fyt);
+
+		fy_input_unref(fyi);
+		fy_token_unref(fyt);
+
+		if (!fya)
+			return NULL;
+
+		/* single anchor? return it */
+		if (!fya->multiple)
+			return fya;
+
+		/* multiple anchors, fall-through */
+	}
+
+	/* note that we're performing the lookup in reverse creation order
+	 * so that we pick the most recent
+	 */
+	fyal = &fyd->anchors;
+	for (fya = fy_anchor_list_tail(fyal); fya; fya = fy_anchor_prev(fyal, fya)) {
+		text = fy_anchor_get_text(fya, &text_len);
+		if (!text)
+			return NULL;
+
+		if (len == text_len && !memcmp(anchor, text, len))
+			return fya;
+	}
+
+	return NULL;
+}
+
+struct fy_anchor *
+fy_document_lookup_anchor_by_token(struct fy_document *fyd,
+				   struct fy_token *anchor)
+{
+	struct fy_anchor *fya, *fya_found, *fya_found2;
+	struct fy_anchor_list *fyal;
+	const char *anchor_text, *text;
+	size_t anchor_len, text_len;
+	int count;
+
+	if (!fyd || !anchor)
+		return NULL;
+
+	/* first try direct match (it's faster and the common case) */
+	if (fy_document_is_accelerated(fyd)) {
+		fya = fy_document_accel_lookup_anchor_by_token(fyd, anchor);
+		if (!fya)
+			return NULL;
+
+		/* single anchor? return it */
+		if (!fya->multiple)
+			return fya;
+
+		/* multiple anchors, fall-through */
+	}
+
+	anchor_text = fy_token_get_text(anchor, &anchor_len);
+	if (!anchor_text)
+		return NULL;
+
+	fyal = &fyd->anchors;
+
+	/* first pass, try with a single match */
+	count = 0;
+	fya_found = NULL;
+	for (fya = fy_anchor_list_head(fyal); fya; fya = fy_anchor_next(fyal, fya)) {
+		text = fy_anchor_get_text(fya, &text_len);
+		if (!text)
+			return NULL;
+
+		if (anchor_len == text_len && !memcmp(anchor_text, text, anchor_len)) {
+			count++;
+			fya_found = fya;
+		}
+	}
+
+	/* not found */
+	if (!count)
+		return NULL;
+
+	/* single one? fine */
+	if (count == 1)
+		return fya_found;
+
+	/* multiple ones, must pick the one that's the last one before
+	 * the requesting token */
+	/* fyd_notice(fyd, "multiple anchors for %.*s", (int)anchor_len, anchor_text); */
+
+	/* only try the ones on the same input
+	 * we don't try to cover the case where the label is referenced
+	 * by other constructed documents
+	 */
+	fya_found2 = NULL;
+	for (fya = fy_anchor_list_head(fyal); fya; fya = fy_anchor_next(fyal, fya)) {
+
+		/* only on the same input */
+		if (fy_token_get_input(fya->anchor) != fy_token_get_input(anchor))
+			continue;
+
+		text = fy_anchor_get_text(fya, &text_len);
+		if (!text)
+			return NULL;
+
+		if (anchor_len == text_len && !memcmp(anchor_text, text, anchor_len) &&
+		    fy_token_start_pos(fya->anchor) < fy_token_start_pos(anchor)) {
+			fya_found2 = fya;
+		}
+	}
+
+	/* just return the one find earlier */
+	if (!fya_found2)
+		return fya_found;
+
+	/* return the one that was the latest */
+	return fya_found2;
+}
+
+struct fy_anchor *fy_document_lookup_anchor_by_node(struct fy_document *fyd, struct fy_node *fyn)
+{
+	struct fy_anchor *fya;
+	struct fy_anchor_list *fyal;
+
+	if (!fyd || !fyn)
+		return NULL;
+
+	if (fy_document_is_accelerated(fyd)) {
+		fya = fy_document_accel_lookup_anchor_by_node(fyd, fyn);
+	} else {
+		fyal = &fyd->anchors;
+		for (fya = fy_anchor_list_head(fyal); fya; fya = fy_anchor_next(fyal, fya)) {
+			if (fya->fyn == fyn)
+				break;
+		}
+	}
+
+	return fya;
+}
+
+const char *fy_anchor_get_text(struct fy_anchor *fya, size_t *lenp)
+{
+	if (!fya || !lenp)
+		return NULL;
+	return fy_token_get_text(fya->anchor, lenp);
+}
+
+struct fy_node *fy_anchor_node(struct fy_anchor *fya)
+{
+	if (!fya)
+		return NULL;
+	return fya->fyn;
+}
+
+int fy_node_pair_free(struct fy_node_pair *fynp)
+{
+	int rc, rc_ret = 0;
+
+	if (!fynp)
+		return 0;
+
+	rc = fy_node_free(fynp->key);
+	if (rc)
+		rc_ret = -1;
+	rc = fy_node_free(fynp->value);
+	if (rc)
+		rc_ret = -1;
+
+	free(fynp);
+
+	return rc_ret;
+}
+
+void fy_node_pair_detach_and_free(struct fy_node_pair *fynp)
+{
+	if (!fynp)
+		return;
+
+	fy_node_detach_and_free(fynp->key);
+	fy_node_detach_and_free(fynp->value);
+	free(fynp);
+}
+
+struct fy_node_pair *fy_node_pair_alloc(struct fy_document *fyd)
+{
+	struct fy_node_pair *fynp = NULL;
+
+	fynp = malloc(sizeof(*fynp));
+	if (!fynp)
+		return NULL;
+
+	fynp->key = NULL;
+	fynp->value = NULL;
+	fynp->fyd = fyd;
+	fynp->parent = NULL;
+	return fynp;
+}
+
+int fy_node_free(struct fy_node *fyn)
+{
+	struct fy_document *fyd;
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp;
+	struct fy_anchor *fya, *fyan;
+		struct fy_accel_entry_iter xli;
+	struct fy_accel_entry *xle, *xlen;
+
+	if (!fyn)
+		return 0;
+
+	/* a document must exist */
+	fyd = fyn->fyd;
+	if (!fyd)
+		return -1;
+
+	if (fyn->attached)
+		return -1;
+
+	if (fy_document_is_accelerated(fyd)) {
+		for (xle = fy_accel_entry_iter_start(&xli, fyd->naxl, fyn);
+		     xle; xle = xlen) {
+			xlen = fy_accel_entry_iter_next(&xli);
+
+			fya = (void *)xle->value;
+
+			fy_anchor_list_del(&fyd->anchors, fya);
+
+			xle = fy_accel_entry_lookup_key_value(fyd->axl, fya->anchor, fya);
+			fy_accel_entry_remove(fyd->axl, xle);
+
+			xle = fy_accel_entry_lookup_key_value(fyd->naxl, fya->fyn, fya);
+			fy_accel_entry_remove(fyd->naxl, xle);
+
+			fy_anchor_destroy(fya);
+		}
+		fy_accel_entry_iter_finish(&xli);
+	} else {
+		/* remove anchors that are located on this node */
+		for (fya = fy_anchor_list_head(&fyd->anchors); fya; fya = fyan) {
+			fyan = fy_anchor_next(&fyd->anchors, fya);
+			if (fya->fyn == fyn) {
+				fy_anchor_list_del(&fyd->anchors, fya);
+				fy_anchor_destroy(fya);
+			}
+		}
+	}
+
+	/* clear the meta data of this node */
+	fy_node_clear_meta(fyn);
+
+	fy_token_unref(fyn->tag);
+	fyn->tag = NULL;
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		fy_token_unref(fyn->scalar);
+		fyn->scalar = NULL;
+		break;
+	case FYNT_SEQUENCE:
+		while ((fyni = fy_node_list_pop(&fyn->sequence)) != NULL)
+			fy_node_detach_and_free(fyni);
+		fy_token_unref(fyn->sequence_start);
+		fy_token_unref(fyn->sequence_end);
+		fyn->sequence_start = NULL;
+		fyn->sequence_end = NULL;
+		break;
+	case FYNT_MAPPING:
+		while ((fynp = fy_node_pair_list_pop(&fyn->mapping)) != NULL) {
+			if (fyn->xl)
+				fy_accel_remove(fyn->xl, fynp->key);
+			fy_node_pair_detach_and_free(fynp);
+		}
+		fy_token_unref(fyn->mapping_start);
+		fy_token_unref(fyn->mapping_end);
+		fyn->mapping_start = NULL;
+		fyn->mapping_end = NULL;
+		break;
+	}
+
+	if (fyn->xl) {
+		fy_accel_cleanup(fyn->xl);
+		free(fyn->xl);
+	}
+
+	fy_node_cleanup_path_expr_data(fyn);
+
+	free(fyn);
+
+	return 0;
+}
+
+void fy_node_detach_and_free(struct fy_node *fyn)
+{
+	int rc __FY_DEBUG_UNUSED__;
+
+	if (!fyn || !fyn->fyd)
+		return;
+
+	fyn->attached = false;
+
+	/* it must always succeed */
+	rc = fy_node_free(fyn);
+	assert(!rc);
+}
+
+struct fy_node *fy_node_alloc(struct fy_document *fyd, enum fy_node_type type)
+{
+	struct fy_node *fyn = NULL;
+	int rc;
+
+	fyn = malloc(sizeof(*fyn));
+	if (!fyn)
+		return NULL;
+
+	memset(fyn, 0, sizeof(*fyn));
+
+	fyn->style = FYNS_ANY;
+	fyn->fyd = fyd;
+	fyn->type = type;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		break;
+
+	case FYNT_SEQUENCE:
+		fy_node_list_init(&fyn->sequence);
+		break;
+	case FYNT_MAPPING:
+		fy_node_pair_list_init(&fyn->mapping);
+
+		if (fy_document_is_accelerated(fyd)) {
+			fyn->xl = malloc(sizeof(*fyn->xl));
+			fyd_error_check(fyd, fyn->xl, err_out,
+					"malloc() failed");
+
+			/* start with a very small bucket list */
+			rc = fy_accel_setup(fyn->xl, &hd_mapping, fyd, 8);
+			fyd_error_check(fyd, !rc, err_out,
+					"fy_accel_setup() failed");
+		}
+		break;
+	}
+	return fyn;
+
+err_out:
+	if (fyn) {
+		if (fyn->xl) {
+			fy_accel_cleanup(fyn->xl);
+			free(fyn->xl);
+		}
+		free(fyn);
+	}
+	return NULL;
+}
+
+struct fy_token *fy_node_non_synthesized_token(struct fy_node *fyn)
+{
+	struct fy_token *fyt_start = NULL, *fyt_end = NULL;
+	struct fy_token *fyt;
+	struct fy_input *fyi;
+	struct fy_atom handle;
+	unsigned int aflags;
+	const char *s, *e;
+	size_t size;
+
+	if (!fyn)
+		return NULL;
+
+	fyi = fy_node_get_input(fyn);
+	if (!fyi)
+		return NULL;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		return fy_token_ref(fyn->scalar);
+
+	case FYNT_SEQUENCE:
+		fyt_start = fyn->sequence_start;
+		fyt_end = fyn->sequence_end;
+		break;
+
+	case FYNT_MAPPING:
+		fyt_start = fyn->mapping_start;
+		fyt_end = fyn->mapping_end;
+		break;
+
+	}
+
+	if (!fyt_start || !fyt_end)
+		return NULL;
+
+	s = (char *)fy_input_start(fyi) + fyt_start->handle.start_mark.input_pos;
+	e = (char *)fy_input_start(fyi) + fyt_end->handle.end_mark.input_pos;
+	size = (size_t)(e - s);
+
+	if (size > 0)
+		aflags = fy_analyze_scalar_content(s, size,
+				fy_token_atom_json_mode(fyt_start),
+				fy_token_atom_lb_mode(fyt_start),
+				fy_token_atom_flow_ws_mode(fyt_start));
+	else
+		aflags = FYACF_EMPTY | FYACF_FLOW_PLAIN | FYACF_BLOCK_PLAIN;
+
+	memset(&handle, 0, sizeof(handle));
+	handle.start_mark = fyt_start->handle.start_mark;
+	handle.end_mark = fyt_end->handle.end_mark;
+
+	/* if it's plain, all is good */
+	if (aflags & FYACF_FLOW_PLAIN) {
+		handle.storage_hint = size;	/* maximum */
+		handle.storage_hint_valid = false;
+		handle.direct_output = !!(aflags & FYACF_JSON_ESCAPE);	/* direct only when no json escape */
+		handle.style = FYAS_PLAIN;
+	} else {
+		handle.storage_hint = 0;	/* just calculate */
+		handle.storage_hint_valid = false;
+		handle.direct_output = false;
+		handle.style = FYAS_DOUBLE_QUOTED_MANUAL;
+	}
+	handle.empty = !!(aflags & FYACF_EMPTY);
+	handle.has_lb = !!(aflags & FYACF_LB);
+	handle.has_ws = !!(aflags & FYACF_WS);
+	handle.starts_with_ws = !!(aflags & FYACF_STARTS_WITH_WS);
+	handle.starts_with_lb = !!(aflags & FYACF_STARTS_WITH_LB);
+	handle.ends_with_ws = !!(aflags & FYACF_ENDS_WITH_WS);
+	handle.ends_with_lb = !!(aflags & FYACF_ENDS_WITH_LB);
+	handle.trailing_lb = !!(aflags & FYACF_TRAILING_LB);
+	handle.size0 = !!(aflags & FYACF_SIZE0);
+	handle.valid_anchor = !!(aflags & FYACF_VALID_ANCHOR);
+	handle.json_mode = false;		/* always false */
+	handle.lb_mode = fylb_cr_nl;		/* always \r\n */
+	handle.fws_mode = fyfws_space_tab;	/* always space + tab */
+
+	handle.chomp = FYAC_STRIP;
+	handle.increment = 0;
+	handle.fyi = fyi;
+	handle.tabsize = 0;
+
+	fyt = fy_token_create(FYTT_INPUT_MARKER, &handle);
+	if (!fyt)
+		return NULL;
+
+	return fyt;
+}
+
+struct fy_token *fy_node_token(struct fy_node *fyn)
+{
+	struct fy_atom atom;
+	struct fy_input *fyi = NULL;
+	struct fy_token *fyt = NULL;
+	char *buf = NULL;
+
+	if (!fyn)
+		return NULL;
+
+	/* if it's non synthetic we can use the node extends */
+	if (!fy_node_is_synthetic(fyn))
+		return fy_node_non_synthesized_token(fyn);
+
+	/* emit to a string and create the token there */
+	buf = fy_emit_node_to_string(fyn, FYECF_MODE_FLOW_ONELINE | FYECF_WIDTH_INF);
+	if (!buf)
+		goto err_out;
+
+	fyi = fy_input_from_malloc_data(buf, FY_NT, &atom, true);
+	if (!fyi)
+		goto err_out;
+
+	fyt = fy_token_create(FYTT_INPUT_MARKER, &atom);
+	if (!fyt)
+		goto err_out;
+
+	/* take away the input reference */
+	fy_input_unref(fyi);
+
+	return fyt;
+
+err_out:
+	fy_input_unref(fyi);
+	if (buf)
+		free(buf);
+	return NULL;
+}
+
+bool fy_node_uses_single_input_only(struct fy_node *fyn, struct fy_input *fyi)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp;
+
+	if (!fyn || !fyi)
+		return false;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		return fy_token_get_input(fyn->scalar) == fyi;
+
+	case FYNT_SEQUENCE:
+		if (fy_token_get_input(fyn->sequence_start) != fyi)
+			return false;
+
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+		     fyni = fy_node_next(&fyn->sequence, fyni)) {
+
+			if (!fy_node_uses_single_input_only(fyni, fyi))
+				return false;
+		}
+
+		if (fy_token_get_input(fyn->sequence_end) != fyi)
+			return false;
+		break;
+
+	case FYNT_MAPPING:
+		if (fy_token_get_input(fyn->mapping_start) != fyi)
+			return false;
+
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp;
+		     fynp = fy_node_pair_next(&fyn->mapping, fynp)) {
+
+			if (fynp->key && !fy_node_uses_single_input_only(fynp->key, fyi))
+				return false;
+
+			if (fynp->value && !fy_node_uses_single_input_only(fynp->value, fyi))
+				return false;
+		}
+
+		if (fy_token_get_input(fyn->mapping_end) != fyi)
+			return false;
+
+		break;
+	}
+
+	return true;
+}
+
+struct fy_input *fy_node_get_first_input(struct fy_node *fyn)
+{
+	if (!fyn)
+		return NULL;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		return fy_token_get_input(fyn->scalar);
+
+	case FYNT_SEQUENCE:
+		return fy_token_get_input(fyn->sequence_start);
+
+	case FYNT_MAPPING:
+		return fy_token_get_input(fyn->mapping_start);
+	}
+
+	/* should never happen */
+	return NULL;
+}
+
+/* a node is synthetic if any of it's tokens reside in
+ * different inputs, or any sequence/mapping has been
+ * created via the manual sequence/mapping creation methods
+ */
+bool fy_node_is_synthetic(struct fy_node *fyn)
+{
+	return fyn && fyn->synthetic;
+}
+
+/* map this node and all of it's parents synthetic */
+void fy_node_mark_synthetic(struct fy_node *fyn)
+{
+	if (!fyn)
+		return;
+	fyn->synthetic = true;
+	while ((fyn = fy_node_get_document_parent(fyn)) != NULL)
+		fyn->synthetic = true;
+}
+
+struct fy_input *fy_node_get_input(struct fy_node *fyn)
+{
+	struct fy_input *fyi = NULL;
+
+	fyi = fy_node_get_first_input(fyn);
+	if (!fyi)
+		return NULL;
+
+	return fy_node_uses_single_input_only(fyn, fyi) ? fyi : NULL;
+}
+
+int fy_document_register_anchor(struct fy_document *fyd,
+				struct fy_node *fyn, struct fy_token *anchor)
+{
+	struct fy_anchor *fya, *fyam;
+	struct fy_accel_entry *xle;
+	const char *text;
+	size_t text_len;
+	int rc;
+
+	fya = fy_anchor_create(fyd, fyn, anchor);
+	fyd_error_check(fyd, fya, err_out,
+			"fy_anchor_create() failed");
+
+	fy_anchor_list_add_tail(&fyd->anchors, fya);
+	if (fy_document_is_accelerated(fyd)) {
+		xle = fy_accel_entry_lookup(fyd->axl, fya->anchor);
+		if (xle) {
+			fyam = (void *)xle->value;
+			/* multiple */
+			if (!fyam->multiple)
+				fyam->multiple = true;
+			fya->multiple = true;
+
+			text = fy_anchor_get_text(fya, &text_len);
+			fyd_notice(fyd, "register anchor %.*s is multiple", (int)text_len, text);
+		}
+
+		xle = fy_accel_entry_insert(fyd->axl, fya->anchor, fya);
+		fyd_error_check(fyd, xle, err_out,
+				"fy_accel_entry_insert() fyd->axl failed");
+	}
+
+	if (fy_document_is_accelerated(fyd)) {
+		rc = fy_accel_insert(fyd->naxl, fyn, fya);
+		fyd_error_check(fyd, !rc, err_out_rc,
+				"fy_accel_insert() fyd->naxl failed");
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	fyd->diag->on_error = false;
+	return rc;
+}
+
+struct fy_node_cmp_arg {
+	fy_node_scalar_compare_fn cmp_fn;
+	void *arg;
+};
+
+static int fy_node_scalar_cmp_default(struct fy_node *fyn_a,
+				      struct fy_node *fyn_b,
+				      void *arg);
+
+static int fy_node_mapping_sort_cmp_default(const struct fy_node_pair *fynp_a,
+					    const struct fy_node_pair *fynp_b,
+					    void *arg);
+
+bool fy_node_compare_user(struct fy_node *fyn1, struct fy_node *fyn2,
+			 fy_node_mapping_sort_fn sort_fn, void *sort_fn_arg,
+			 fy_node_scalar_compare_fn cmp_fn, void *cmp_fn_arg)
+{
+	struct fy_node *fyni1, *fyni2;
+	struct fy_node_pair *fynp1, *fynp2;
+	bool ret, null1, null2;
+	struct fy_node_pair **fynpp1, **fynpp2;
+	int i, count1, count2;
+	bool alias1, alias2;
+	struct fy_node_cmp_arg def_arg;
+
+	if (!cmp_fn) {
+		cmp_fn = fy_node_scalar_cmp_default;
+		cmp_fn_arg = NULL;
+	}
+	if (!sort_fn) {
+		sort_fn = fy_node_mapping_sort_cmp_default;
+		def_arg.cmp_fn = cmp_fn;
+		def_arg.arg = cmp_fn_arg;
+		sort_fn_arg = &def_arg;
+	} else {
+		def_arg.cmp_fn = NULL;
+		def_arg.arg = NULL;
+	}
+	/* equal pointers? */
+	if (fyn1 == fyn2)
+		return true;
+
+	null1 = !fyn1 || (fyn1->type == FYNT_SCALAR && fy_token_get_text_length(fyn1->scalar) == 0);
+	null2 = !fyn2 || (fyn2->type == FYNT_SCALAR && fy_token_get_text_length(fyn2->scalar) == 0);
+
+	/* both null */
+	if (null1 && null2)
+		return true;
+
+	/* either is NULL, no match */
+	if (null1 || null2)
+		return false;
+
+	/* types must match */
+	if (fyn1->type != fyn2->type)
+		return false;
+
+	ret = true;
+
+	switch (fyn1->type) {
+	case FYNT_SEQUENCE:
+		fyni1 = fy_node_list_head(&fyn1->sequence);
+		fyni2 = fy_node_list_head(&fyn2->sequence);
+		while (fyni1 && fyni2) {
+
+			ret = fy_node_compare(fyni1, fyni2);
+			if (!ret)
+				break;
+
+			fyni1 = fy_node_next(&fyn1->sequence, fyni1);
+			fyni2 = fy_node_next(&fyn2->sequence, fyni2);
+		}
+		if (ret && fyni1 != fyni2 && (!fyni1 || !fyni2))
+			ret = false;
+
+		break;
+
+	case FYNT_MAPPING:
+		count1 = fy_node_mapping_item_count(fyn1);
+		count2 = fy_node_mapping_item_count(fyn2);
+
+		/* mapping counts must match */
+		if (count1 != count2) {
+			ret = false;
+			break;
+		}
+
+		fynpp1 = FY_ALLOCA(sizeof(*fynpp1) * (count1 + 1));
+		fy_node_mapping_fill_array(fyn1, fynpp1, count1);
+		fy_node_mapping_perform_sort(fyn1, sort_fn, sort_fn_arg, fynpp1, count1);
+
+		fynpp2 = FY_ALLOCA(sizeof(*fynpp2) * (count2 + 1));
+		fy_node_mapping_fill_array(fyn2, fynpp2, count2);
+		fy_node_mapping_perform_sort(fyn2, sort_fn, sort_fn_arg, fynpp2, count2);
+
+		for (i = 0; i < count1; i++) {
+			fynp1 = fynpp1[i];
+			fynp2 = fynpp2[i];
+
+			ret = fy_node_compare(fynp1->key, fynp2->key);
+			if (!ret)
+				break;
+
+			ret = fy_node_compare(fynp1->value, fynp2->value);
+			if (!ret)
+				break;
+		}
+		if (i >= count1)
+			ret = true;
+
+		break;
+
+	case FYNT_SCALAR:
+		alias1 = fy_node_is_alias(fyn1);
+		alias2 = fy_node_is_alias(fyn2);
+
+		/* either both must be aliases or both not */
+		if (alias1 != alias2)
+			return false;
+
+		ret = !cmp_fn(fyn1, fyn2, cmp_fn_arg);
+		break;
+	}
+
+	return ret;
+}
+
+bool fy_node_compare(struct fy_node *fyn1, struct fy_node *fyn2)
+{
+	return fy_node_compare_user(fyn1, fyn2, NULL, NULL, NULL, NULL);
+}
+
+bool fy_node_compare_string(struct fy_node *fyn, const char *str, size_t len)
+{
+	struct fy_document *fyd = NULL;
+	bool ret;
+
+	fyd = fy_document_build_from_string(NULL, str, len);
+	if (!fyd)
+		return false;
+
+	ret = fy_node_compare(fyn, fy_document_root(fyd));
+
+	fy_document_destroy(fyd);
+
+	return ret;
+}
+
+bool fy_node_compare_token(struct fy_node *fyn, struct fy_token *fyt)
+{
+	/* check if there's NULL */
+	if (!fyn || !fyt)
+		return false;
+
+	/* only valid for scalars */
+	if (!fy_node_is_scalar(fyn) || fyt->type != FYTT_SCALAR)
+		return false;
+
+	return fy_token_cmp(fyn->scalar, fyt) == 0;
+}
+
+bool fy_node_compare_text(struct fy_node *fyn, const char *text, size_t len)
+{
+	const char *textn;
+	size_t lenn;
+
+	if (!fyn || !text)
+		return false;
+
+	textn = fy_node_get_scalar(fyn, &lenn);
+	if (!textn)
+		return false;
+
+	if (len == FY_NT)
+		len = strlen(text);
+
+	if (len != lenn)
+		return false;
+
+	return memcmp(text, textn, len) == 0;
+}
+
+struct fy_node_pair *fy_node_mapping_lookup_pair(struct fy_node *fyn, struct fy_node *fyn_key)
+{
+	struct fy_node_pair *fynpi, *fynp;
+
+	/* sanity check */
+	if (!fy_node_is_mapping(fyn))
+		return NULL;
+
+	fynp = NULL;
+
+
+	if (fyn->xl) {
+		fynp = fy_node_accel_lookup_by_node(fyn, fyn_key);
+	} else {
+		for (fynpi = fy_node_pair_list_head(&fyn->mapping); fynpi;
+			fynpi = fy_node_pair_next(&fyn->mapping, fynpi)) {
+			if (fy_node_compare(fynpi->key, fyn_key)) {
+				fynp = fynpi;
+				break;
+			}
+		}
+	}
+
+	return fynp;
+}
+
+int fy_node_mapping_get_pair_index(struct fy_node *fyn, const struct fy_node_pair *fynp)
+{
+	struct fy_node_pair *fynpi;
+	int i;
+
+	for (i = 0, fynpi = fy_node_pair_list_head(&fyn->mapping); fynpi;
+		fynpi = fy_node_pair_next(&fyn->mapping, fynpi), i++) {
+
+		if (fynpi == fynp)
+			return i;
+	}
+
+	return -1;
+}
+
+bool fy_node_mapping_key_is_duplicate(struct fy_node *fyn, struct fy_node *fyn_key)
+{
+	return fy_node_mapping_lookup_pair(fyn, fyn_key) != NULL;
+}
+
+static int
+fy_parse_document_load_node(struct fy_parser *fyp, struct fy_document *fyd,
+			    struct fy_eventp *fyep, struct fy_node **fynp,
+			    int *depthp);
+
+int fy_parse_document_load_alias(struct fy_parser *fyp, struct fy_document *fyd, struct fy_eventp *fyep, struct fy_node **fynp)
+{
+	*fynp = NULL;
+
+	fyp_doc_debug(fyp, "in %s", __func__);
+
+	/* TODO verify aliases etc */
+	fy_parse_eventp_recycle(fyp, fyep);
+	return 0;
+}
+
+static int
+fy_parse_document_load_scalar(struct fy_parser *fyp, struct fy_document *fyd,
+			      struct fy_eventp *fyep, struct fy_node **fynp,
+			      int *depthp)
+{
+	struct fy_node *fyn = NULL;
+	struct fy_event *fye;
+	int rc;
+
+	if (!fyd)
+		return -1;
+
+	fyp_error_check(fyp, fyep || !fyp->stream_error, err_out,
+			"no event to process");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 0, FYEM_DOC,
+			fyep, err_out,
+			"premature end of event stream");
+
+	fyp_doc_debug(fyp, "in %s [%s]", __func__, fy_event_type_txt[fyep->e.type]);
+
+	*fynp = NULL;
+
+	fye = &fyep->e;
+
+	/* we don't free nodes that often, so no need for recycling */
+	fyn = fy_node_alloc(fyd, FYNT_SCALAR);
+	fyp_error_check(fyp, fyn, err_out,
+			"fy_node_alloc() failed");
+
+	if (fye->type == FYET_SCALAR) {
+
+		/* move the tags and value to the node */
+		if (fye->scalar.value)
+			fyn->style = fy_node_style_from_scalar_style(fye->scalar.value->scalar.style);
+		else
+			fyn->style = FYNS_PLAIN;
+		fyn->tag = fye->scalar.tag;
+		fye->scalar.tag = NULL;
+
+		fyn->scalar = fye->scalar.value;
+		fye->scalar.value = NULL;
+
+		if (fye->scalar.anchor) {
+			rc = fy_document_register_anchor(fyd, fyn, fye->scalar.anchor);
+			fyp_error_check(fyp, !rc, err_out_rc,
+					"fy_document_register_anchor() failed");
+			fye->scalar.anchor = NULL;
+		}
+
+	} else if (fye->type == FYET_ALIAS) {
+		fyn->style = FYNS_ALIAS;
+		fyn->scalar = fye->alias.anchor;
+		fye->alias.anchor = NULL;
+	} else
+		assert(0);
+
+	*fynp = fyn;
+	fyn = NULL;
+
+	/* everything OK */
+	fy_parse_eventp_recycle(fyp, fyep);
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	fy_parse_eventp_recycle(fyp, fyep);
+	fyd->diag->on_error = false;
+	return rc;
+}
+
+static int
+fy_parse_document_load_sequence(struct fy_parser *fyp, struct fy_document *fyd,
+				struct fy_eventp *fyep, struct fy_node **fynp,
+				int *depthp)
+{
+	struct fy_node *fyn = NULL, *fyn_item = NULL;
+	struct fy_event *fye = NULL;
+	struct fy_token *fyt_ss = NULL;
+	int rc;
+
+	fyp_error_check(fyp, fyep || !fyp->stream_error, err_out,
+			"no event to process");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 0, FYEM_DOC,
+			fyep, err_out,
+			"premature end of event stream");
+
+	fyp_doc_debug(fyp, "in %s [%s]", __func__, fy_event_type_txt[fyep->e.type]);
+
+	*fynp = NULL;
+
+	fye = &fyep->e;
+
+	fyt_ss = fye->sequence_start.sequence_start;
+
+	/* we don't free nodes that often, so no need for recycling */
+	fyn = fy_node_alloc(fyd, FYNT_SEQUENCE);
+	fyp_error_check(fyp, fyn, err_out,
+			"fy_node_alloc() failed");
+
+	fyn->style = fyt_ss && fyt_ss->type == FYTT_FLOW_SEQUENCE_START ? FYNS_FLOW : FYNS_BLOCK;
+
+	fyn->tag = fye->sequence_start.tag;
+	fye->sequence_start.tag = NULL;
+
+	if (fye->sequence_start.anchor) {
+		rc = fy_document_register_anchor(fyd, fyn, fye->sequence_start.anchor);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_document_register_anchor() failed");
+		fye->sequence_start.anchor = NULL;
+	}
+
+	if (fye->sequence_start.sequence_start) {
+		fyn->sequence_start = fye->sequence_start.sequence_start;
+		fye->sequence_start.sequence_start = NULL;
+	} else
+		fyn->sequence_start = NULL;
+
+	assert(fyn->sequence_start);
+
+	/* done with this */
+	fy_parse_eventp_recycle(fyp, fyep);
+	fyep = NULL;
+
+	while ((fyep = fy_parse_private(fyp)) != NULL) {
+		fye = &fyep->e;
+		if (fye->type == FYET_SEQUENCE_END)
+			break;
+
+		rc = fy_parse_document_load_node(fyp, fyd, fyep, &fyn_item, depthp);
+		fyep = NULL;
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_parse_document_load_node() failed");
+
+		fy_node_list_add_tail(&fyn->sequence, fyn_item);
+		fyn_item->attached = true;
+		fyn_item = NULL;
+	}
+
+	if (!fyep)
+		goto err_out;
+
+	if (fye->sequence_end.sequence_end) {
+		fyn->sequence_end = fye->sequence_end.sequence_end;
+		fye->sequence_end.sequence_end = NULL;
+	} else
+		fyn->sequence_end = NULL;
+
+	assert(fyn->sequence_end);
+
+	*fynp = fyn;
+	fyn = NULL;
+
+	fy_parse_eventp_recycle(fyp, fyep);
+	return 0;
+
+	/* fallthrough */
+err_out:
+	rc = -1;
+err_out_rc:
+	fy_parse_eventp_recycle(fyp, fyep);
+	fy_node_detach_and_free(fyn_item);
+	fy_node_detach_and_free(fyn);
+	return rc;
+}
+
+static int
+fy_parse_document_load_mapping(struct fy_parser *fyp, struct fy_document *fyd,
+			       struct fy_eventp *fyep, struct fy_node **fynp,
+			       int *depthp)
+{
+	struct fy_node *fyn = NULL, *fyn_key = NULL, *fyn_value = NULL;
+	struct fy_node_pair *fynp_item = NULL;
+	struct fy_event *fye = NULL;
+	struct fy_token *fyt_ms = NULL;
+	bool duplicate;
+	int rc;
+
+	fyp_error_check(fyp, fyep || !fyp->stream_error, err_out,
+			"no event to process");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 0, FYEM_DOC,
+			fyep, err_out,
+			"premature end of event stream");
+
+	fyp_doc_debug(fyp, "in %s [%s]", __func__, fy_event_type_txt[fyep->e.type]);
+
+	*fynp = NULL;
+
+	fye = &fyep->e;
+
+	fyt_ms = fye->mapping_start.mapping_start;
+
+	/* we don't free nodes that often, so no need for recycling */
+	fyn = fy_node_alloc(fyd, FYNT_MAPPING);
+	fyp_error_check(fyp, fyn, err_out,
+			"fy_node_alloc() failed");
+
+	fyn->style = fyt_ms && fyt_ms->type == FYTT_FLOW_MAPPING_START ? FYNS_FLOW : FYNS_BLOCK;
+
+	fyn->tag = fye->mapping_start.tag;
+	fye->mapping_start.tag = NULL;
+
+	if (fye->mapping_start.anchor) {
+		rc = fy_document_register_anchor(fyd, fyn, fye->mapping_start.anchor);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_document_register_anchor() failed");
+		fye->mapping_start.anchor = NULL;
+	}
+
+	if (fye->mapping_start.mapping_start) {
+		fyn->mapping_start = fye->mapping_start.mapping_start;
+		fye->mapping_start.mapping_start = NULL;
+	}
+
+	assert(fyn->mapping_start);
+
+	/* done with this */
+	fy_parse_eventp_recycle(fyp, fyep);
+	fyep = NULL;
+
+	while ((fyep = fy_parse_private(fyp)) != NULL) {
+		fye = &fyep->e;
+		if (fye->type == FYET_MAPPING_END)
+			break;
+
+		fynp_item = fy_node_pair_alloc(fyd);
+		fyp_error_check(fyp, fynp_item, err_out,
+				"fy_node_pair_alloc() failed");
+
+		fyn_key = NULL;
+		fyn_value = NULL;
+
+		rc = fy_parse_document_load_node(fyp, fyd,
+						 fyep, &fyn_key, depthp);
+		fyep = NULL;
+
+		assert(fyn_key);
+
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_parse_document_load_node() failed");
+
+		/* if we don't allow duplicate keys */
+		if (!(fyd->parse_cfg.flags & FYPCF_ALLOW_DUPLICATE_KEYS)) {
+
+			/* make sure we don't add an already existing key */
+			duplicate = fy_node_mapping_key_is_duplicate(fyn, fyn_key);
+
+			FYP_NODE_ERROR_CHECK(fyp, fyn_key, FYEM_DOC,
+					!duplicate, err_out,
+					"duplicate key");
+		}
+
+		fyep = fy_parse_private(fyp);
+
+		fyp_error_check(fyp, fyep || !fyp->stream_error, err_out,
+				"fy_parse_private() failed");
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 0, FYEM_DOC,
+				fyep, err_out,
+				"missing mapping value");
+
+		fye = &fyep->e;
+
+		rc = fy_parse_document_load_node(fyp, fyd,
+						 fyep, &fyn_value, depthp);
+		fyep = NULL;
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_parse_document_load_node() failed");
+
+		assert(fyn_value);
+
+		fynp_item->key = fyn_key;
+		fynp_item->value = fyn_value;
+		fy_node_pair_list_add_tail(&fyn->mapping, fynp_item);
+		if (fyn->xl) {
+			rc = fy_accel_insert(fyn->xl, fynp_item->key, fynp_item);
+			fyp_error_check(fyp, !rc, err_out_rc,
+					"fy_accel_insert() failed");
+		}
+
+		if (fynp_item->key)
+			fynp_item->key->attached = true;
+		if (fynp_item->value)
+			fynp_item->value->attached = true;
+		fynp_item = NULL;
+		fyn_key = NULL;
+		fyn_value = NULL;
+	}
+
+	if (!fyep)
+		goto err_out;
+
+	if (fye->mapping_end.mapping_end) {
+		fyn->mapping_end = fye->mapping_end.mapping_end;
+		fye->mapping_end.mapping_end = NULL;
+	}
+
+	assert(fyn->mapping_end);
+
+	*fynp = fyn;
+	fyn = NULL;
+
+	fy_parse_eventp_recycle(fyp, fyep);
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	fy_parse_eventp_recycle(fyp, fyep);
+	fy_node_pair_free(fynp_item);
+	fy_node_detach_and_free(fyn_key);
+	fy_node_detach_and_free(fyn_value);
+	fy_node_detach_and_free(fyn);
+	return rc;
+}
+
+static int
+fy_parse_document_load_node(struct fy_parser *fyp, struct fy_document *fyd,
+			    struct fy_eventp *fyep, struct fy_node **fynp,
+			    int *depthp)
+{
+	struct fy_event *fye;
+	enum fy_event_type type;
+	int ret;
+
+	*fynp = NULL;
+
+	fyp_error_check(fyp, fyep || !fyp->stream_error, err_out,
+			"no event to process");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 0, FYEM_DOC,
+			fyep, err_out,
+			"premature end of event stream");
+
+	fyp_doc_debug(fyp, "in %s [%s]", __func__, fy_event_type_txt[fyep->e.type]);
+
+	fye = &fyep->e;
+
+	type = fye->type;
+
+	FYP_TOKEN_ERROR_CHECK(fyp, fy_event_get_token(fye), FYEM_DOC,
+			type == FYET_ALIAS || type == FYET_SCALAR ||
+			type == FYET_SEQUENCE_START || type == FYET_MAPPING_START, err_out,
+			"bad event");
+
+	(*depthp)++;
+
+	FYP_TOKEN_ERROR_CHECK(fyp, fy_event_get_token(fye), FYEM_DOC,
+			((fyp->cfg.flags & FYPCF_DISABLE_DEPTH_LIMIT) ||
+				*depthp <= fy_depth_limit()), err_out,
+			"depth limit exceeded");
+
+	switch (type) {
+
+	case FYET_ALIAS:
+	case FYET_SCALAR:
+		ret = fy_parse_document_load_scalar(fyp, fyd,
+						     fyep, fynp, depthp);
+		break;
+
+	case FYET_SEQUENCE_START:
+		ret = fy_parse_document_load_sequence(fyp, fyd,
+						       fyep, fynp, depthp);
+		break;
+
+	case FYET_MAPPING_START:
+		ret = fy_parse_document_load_mapping(fyp, fyd,
+						      fyep, fynp, depthp);
+		break;
+
+	default:
+		ret = 0;
+		break;
+	}
+
+	--(*depthp);
+	return ret;
+
+err_out:
+	fy_parse_eventp_recycle(fyp, fyep);
+	return -1;
+}
+
+int fy_parse_document_load_end(struct fy_parser *fyp, struct fy_document *fyd, struct fy_eventp *fyep)
+{
+	struct fy_event *fye;
+	int rc;
+
+	fyp_error_check(fyp, fyep || !fyp->stream_error, err_out,
+			"no event to process");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 0, FYEM_DOC,
+			fyep, err_out,
+			"premature end of event stream");
+
+	fyp_doc_debug(fyp, "in %s [%s]", __func__, fy_event_type_txt[fyep->e.type]);
+
+	fye = &fyep->e;
+
+	FYP_TOKEN_ERROR_CHECK(fyp, fy_event_get_token(fye), FYEM_DOC,
+			fye->type == FYET_DOCUMENT_END, err_out,
+			"bad event");
+
+	/* recycle the document end event */
+	fy_parse_eventp_recycle(fyp, fyep);
+
+	return 0;
+err_out:
+	rc = -1;
+	fy_parse_eventp_recycle(fyp, fyep);
+	return rc;
+}
+
+struct fy_document *fy_parse_load_document_recursive(struct fy_parser *fyp)
+{
+	struct fy_document *fyd = NULL;
+	struct fy_eventp *fyep = NULL;
+	struct fy_event *fye = NULL;
+	int rc, depth;
+	bool was_stream_start;
+
+again:
+	was_stream_start = false;
+	do {
+		/* get next event */
+		fyep = fy_parse_private(fyp);
+
+		/* no more */
+		if (!fyep)
+			return NULL;
+
+		was_stream_start = fyep->e.type == FYET_STREAM_START;
+
+		if (was_stream_start) {
+			fy_parse_eventp_recycle(fyp, fyep);
+			fyep = NULL;
+		}
+
+	} while (was_stream_start);
+
+	fye = &fyep->e;
+
+	/* STREAM_END */
+	if (fye->type == FYET_STREAM_END) {
+		fy_parse_eventp_recycle(fyp, fyep);
+
+		/* final STREAM_END? */
+		if (fyp->state == FYPS_END)
+			return NULL;
+
+		/* multi-stream */
+		goto again;
+	}
+
+	FYP_TOKEN_ERROR_CHECK(fyp, fy_event_get_token(fye), FYEM_DOC,
+			fye->type == FYET_DOCUMENT_START, err_out,
+			"bad event");
+
+	fyd = fy_parse_document_create(fyp, fyep);
+	fyep = NULL;
+
+	fyp_error_check(fyp, fyd, err_out,
+			"fy_parse_document_create() failed");
+
+	fyp_doc_debug(fyp, "calling load_node() for root");
+	depth = 0;
+	rc = fy_parse_document_load_node(fyp, fyd, fy_parse_private(fyp),
+					 &fyd->root, &depth);
+	fyp_error_check(fyp, !rc, err_out,
+			"fy_parse_document_load_node() failed");
+
+	rc = fy_parse_document_load_end(fyp, fyd, fy_parse_private(fyp));
+	fyp_error_check(fyp, !rc, err_out,
+			"fy_parse_document_load_node() failed");
+
+	/* always resolve parents */
+	fy_resolve_parent_node(fyd, fyd->root, NULL);
+
+	if (fyp->cfg.flags & FYPCF_RESOLVE_DOCUMENT) {
+		rc = fy_document_resolve(fyd);
+		fyp_error_check(fyp, !rc, err_out,
+				"fy_document_resolve() failed");
+	}
+
+	return fyd;
+
+err_out:
+	fy_parse_eventp_recycle(fyp, fyep);
+	fy_parse_document_destroy(fyp, fyd);
+	return NULL;
+}
+
+struct fy_document *fy_parse_load_document_with_builder(struct fy_parser *fyp)
+{
+	struct fy_document_builder_cfg cfg;
+	struct fy_document *fyd;
+	int rc;
+
+	if (!fyp)
+		return NULL;
+
+	if (!fyp->fydb) {
+		memset(&cfg, 0, sizeof(cfg));
+		cfg.parse_cfg = fyp->cfg;
+		cfg.userdata = fyp;
+		cfg.diag = fy_diag_ref(fyp->diag);
+
+		fyp->fydb = fy_document_builder_create(&cfg);
+		if (!fyp->fydb)
+			return NULL;
+	}
+
+	fyd = fy_document_builder_load_document(fyp->fydb, fyp);
+	if (!fyd)
+		return NULL;
+
+	if (fyp->cfg.flags & FYPCF_RESOLVE_DOCUMENT) {
+		rc = fy_document_resolve(fyd);
+		if (rc) {
+			fy_document_destroy(fyd);
+			fyp->stream_error = true;
+			return NULL;
+		}
+	}
+
+	return fyd;
+}
+
+struct fy_document *fy_parse_load_document(struct fy_parser *fyp)
+{
+	if (!fyp)
+		return NULL;
+
+	return !(fyp->cfg.flags & FYPCF_PREFER_RECURSIVE) ?
+		fy_parse_load_document_with_builder(fyp) :
+		fy_parse_load_document_recursive(fyp);
+}
+
+struct fy_node *fy_node_copy_internal(struct fy_document *fyd, struct fy_node *fyn_from,
+				      struct fy_node *fyn_parent)
+{
+	struct fy_document *fyd_from;
+	struct fy_node *fyn, *fyni, *fynit;
+	struct fy_node_pair *fynp, *fynpt;
+	struct fy_anchor *fya, *fya_from;
+	const char *anchor;
+	size_t anchor_len;
+	int rc;
+
+	if (!fyd || !fyn_from || !fyn_from->fyd)
+		return NULL;
+
+	fyd_from = fyn_from->fyd;
+
+	fyn = fy_node_alloc(fyd, fyn_from->type);
+	fyd_error_check(fyd, fyn, err_out,
+			"fy_node_alloc() failed");
+
+	fyn->tag = fy_token_ref(fyn_from->tag);
+	fyn->style = fyn_from->style;
+	fyn->parent = fyn_parent;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		fyn->scalar = fy_token_ref(fyn_from->scalar);
+		break;
+
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn_from->sequence); fyni;
+				fyni = fy_node_next(&fyn_from->sequence, fyni)) {
+
+			fynit = fy_node_copy_internal(fyd, fyni, fyn);
+			fyd_error_check(fyd, fynit, err_out,
+					"fy_node_copy_internal() failed");
+
+			fy_node_list_add_tail(&fyn->sequence, fynit);
+			fynit->attached = true;
+		}
+
+		break;
+	case FYNT_MAPPING:
+		for (fynp = fy_node_pair_list_head(&fyn_from->mapping); fynp;
+				fynp = fy_node_pair_next(&fyn_from->mapping, fynp)) {
+
+			fynpt = fy_node_pair_alloc(fyd);
+			fyd_error_check(fyd, fynpt, err_out,
+					"fy_node_pair_alloc() failed");
+
+			fynpt->key = fy_node_copy_internal(fyd, fynp->key, fyn);
+			fynpt->value = fy_node_copy_internal(fyd, fynp->value, fyn);
+			fynp->parent = fyn;
+
+			fy_node_pair_list_add_tail(&fyn->mapping, fynpt);
+			if (fyn->xl) {
+				rc = fy_accel_insert(fyn->xl, fynpt->key, fynpt);
+				fyd_error_check(fyd, !rc, err_out,
+						"fy_accel_insert() failed");
+			}
+			if (fynpt->key) {
+				fynpt->key->attached = true;
+				fynpt->key->key_root = true;
+			}
+			if (fynpt->value)
+				fynpt->value->attached = true;
+		}
+		break;
+	}
+
+	/* drop an anchor to the copy */
+	for (fya_from = fy_anchor_list_head(&fyd_from->anchors); fya_from;
+			fya_from = fy_anchor_next(&fyd_from->anchors, fya_from)) {
+		if (fyn_from == fya_from->fyn)
+			break;
+	}
+
+	/* source node has an anchor */
+	if (fya_from) {
+		fya = fy_document_lookup_anchor_by_token(fyd, fya_from->anchor);
+		if (!fya) {
+			fyd_doc_debug(fyd, "new anchor");
+			/* update the new anchor position */
+			rc = fy_document_register_anchor(fyd, fyn, fya_from->anchor);
+			fyd_error_check(fyd, !rc, err_out,
+					"fy_document_register_anchor() failed");
+
+			fy_token_ref(fya_from->anchor);
+		} else {
+			anchor = fy_anchor_get_text(fya, &anchor_len);
+			fyd_error_check(fyd, anchor, err_out,
+					"fy_anchor_get_text() failed");
+			fyd_doc_debug(fyd, "not overwritting anchor %.*s", (int)anchor_len, anchor);
+		}
+	}
+
+	return fyn;
+
+err_out:
+	return NULL;
+}
+
+struct fy_node *fy_node_copy(struct fy_document *fyd, struct fy_node *fyn_from)
+{
+	struct fy_node *fyn;
+
+	if (!fyd)
+		return NULL;
+
+	fyn = fy_node_copy_internal(fyd, fyn_from, NULL);
+	if (!fyn) {
+		fyd->diag->on_error = false;
+		return NULL;
+	}
+
+	return fyn;
+}
+
+struct fy_document *fy_document_clone(struct fy_document *fydsrc)
+{
+	struct fy_document *fyd = NULL;
+
+	if (!fydsrc)
+		return NULL;
+
+	fyd = fy_document_create(&fydsrc->parse_cfg);
+	if (!fyd)
+		return NULL;
+
+	/* drop the default document state */
+	fy_document_state_unref(fyd->fyds);
+	/* and use the source document state (and ref it) */
+	fyd->fyds = fy_document_state_ref(fydsrc->fyds);
+	assert(fyd->fyds);
+
+	if (fydsrc->root) {
+		fyd->root = fy_node_copy(fyd, fydsrc->root);
+		if (!fyd->root)
+			goto err_out;
+	}
+
+	return fyd;
+err_out:
+	fy_document_destroy(fyd);
+	return NULL;
+}
+
+int fy_node_copy_to_scalar(struct fy_document *fyd, struct fy_node *fyn_to, struct fy_node *fyn_from)
+{
+	struct fy_node *fyn, *fyni;
+	struct fy_node_pair *fynp;
+
+	fyn = fy_node_copy(fyd, fyn_from);
+	if (!fyn)
+		return -1;
+
+	/* the node is guaranteed to be a scalar */
+	fy_token_unref(fyn_to->tag);
+	fyn_to->tag = NULL;
+	fy_token_unref(fyn_to->scalar);
+	fyn_to->scalar = NULL;
+
+	fyn_to->type = fyn->type;
+	fyn_to->tag = fy_token_ref(fyn->tag);
+	fyn_to->style = fyn->style;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		fyn_to->scalar = fyn->scalar;
+		fyn->scalar = NULL;
+		break;
+	case FYNT_SEQUENCE:
+		fy_node_list_init(&fyn_to->sequence);
+		while ((fyni = fy_node_list_pop(&fyn->sequence)) != NULL)
+			fy_node_list_add_tail(&fyn_to->sequence, fyni);
+		break;
+	case FYNT_MAPPING:
+		fy_node_pair_list_init(&fyn_to->mapping);
+		while ((fynp = fy_node_pair_list_pop(&fyn->mapping)) != NULL) {
+			if (fyn->xl)
+				fy_accel_remove(fyn->xl, fynp->key);
+			fy_node_pair_list_add_tail(&fyn_to->mapping, fynp);
+			if (fyn_to->xl)
+				fy_accel_insert(fyn_to->xl, fynp->key, fynp);
+		}
+		break;
+	}
+
+	/* and free */
+	fy_node_free(fyn);
+
+	return 0;
+}
+
+static int fy_document_node_update_tags(struct fy_document *fyd, struct fy_node *fyn)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp, *fynpi;
+	struct fy_token *fyt_td;
+	const char *handle;
+	size_t handle_size;
+	int rc;
+
+	if (!fyd || !fyn)
+		return 0;
+
+	/* replace tag reference with the one that the document contains */
+	if (fyn->tag) {
+		fyd_error_check(fyd, fyn->tag->type == FYTT_TAG, err_out,
+				"bad node tag");
+
+		handle = fy_tag_directive_token_handle(fyn->tag->tag.fyt_td, &handle_size);
+		fyd_error_check(fyd, handle, err_out,
+				"bad tag directive token");
+
+		fyt_td = fy_document_state_lookup_tag_directive(fyd->fyds, handle, handle_size);
+		fyd_error_check(fyd, fyt_td, err_out,
+				"Missing tag directive with handle=%.*s", (int)handle_size, handle);
+
+		/* need to replace this */
+		if (fyt_td != fyn->tag->tag.fyt_td) {
+			fy_token_unref(fyn->tag->tag.fyt_td);
+			fyn->tag->tag.fyt_td = fy_token_ref(fyt_td);
+
+		}
+	}
+
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		break;
+
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+				fyni = fy_node_next(&fyn->sequence, fyni)) {
+
+			rc = fy_document_node_update_tags(fyd, fyni);
+			if (rc)
+				goto err_out_rc;
+		}
+		break;
+
+	case FYNT_MAPPING:
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp; fynp = fynpi) {
+
+			fynpi = fy_node_pair_next(&fyn->mapping, fynp);
+
+			/* the parent of the key is always NULL */
+			rc = fy_document_node_update_tags(fyd, fynp->key);
+			if (rc)
+				goto err_out_rc;
+
+			rc = fy_document_node_update_tags(fyd, fynp->value);
+			if (rc)
+				goto err_out_rc;
+		}
+		break;
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_node_insert(struct fy_node *fyn_to, struct fy_node *fyn_from)
+{
+	struct fy_document *fyd;
+	struct fy_node *fyn_parent, *fyn_cpy, *fyni, *fyn_prev;
+	struct fy_node_pair *fynp, *fynpi, *fynpj;
+	int rc;
+
+	if (!fyn_to || !fyn_to->fyd)
+		return -1;
+
+	fyd = fyn_to->fyd;
+	assert(fyd);
+
+	fyn_parent = fy_node_get_document_parent(fyn_to);
+	fynp = NULL;
+	if (fyn_parent) {
+		fyd_error_check(fyd, fyn_parent->type != FYNT_SCALAR, err_out,
+				    "Illegal scalar parent node type");
+
+		fyd_error_check(fyd, fyn_from, err_out,
+				"Illegal NULL source node");
+
+		if (fyn_parent->type == FYNT_MAPPING) {
+			/* find mapping pair that contains the `to` node */
+			for (fynp = fy_node_pair_list_head(&fyn_parent->mapping); fynp;
+					fynp = fy_node_pair_next(&fyn_parent->mapping, fynp)) {
+				if (fynp->value == fyn_to)
+					break;
+			}
+		}
+	}
+
+	/* verify no funkiness on root */
+	assert(fyn_parent || fyn_to == fyd->root);
+
+	/* deleting target */
+	if (!fyn_from) {
+		fyn_to->parent = NULL;
+
+		if (!fyn_parent) {
+			fyd_doc_debug(fyd, "Deleting root node");
+			fy_node_detach_and_free(fyn_to);
+			fyd->root = NULL;
+		} else if (fyn_parent->type == FYNT_SEQUENCE) {
+			fyd_doc_debug(fyd, "Deleting sequence node");
+			fy_node_list_del(&fyn_parent->sequence, fyn_to);
+			fy_node_detach_and_free(fyn_to);
+		} else {
+			fyd_doc_debug(fyd, "Deleting mapping node");
+			/* should never happen, it's checked right above, but play safe */
+			assert(fyn_parent->type == FYNT_MAPPING);
+
+			fyd_error_check(fyd, fynp, err_out,
+					"Illegal mapping node found");
+
+			fy_node_pair_list_del(&fyn_parent->mapping, fynp);
+			if (fyn_parent->xl)
+				fy_accel_remove(fyn_parent->xl, fynp->key);
+			/* this will also delete fyn_to */
+			fy_node_pair_detach_and_free(fynp);
+		}
+		return 0;
+	}
+
+	/*
+	 * from: scalar
+	 *
+	 * to: another-scalar -> scalar
+	 * to: { key: value } -> scalar
+	 * to: [ seq0, seq1 ] -> scalar
+	 *
+	 * from: [ seq2 ]
+	 * to: scalar -> [ seq2 ]
+	 * to: { key: value } -> [ seq2 ]
+	 * to: [ seq0, seq1 ] -> [ seq0, seq1, sec2 ]
+	 *
+	 * from: { another-key: another-value }
+	 * to: scalar -> { another-key: another-value }
+	 * to: { key: value } -> { key: value, another-key: another-value }
+	 * to: [ seq0, seq1 ] -> { another-key: another-value }
+	 *
+	 * from: { key: another-value }
+	 * to: scalar -> { key: another-value }
+	 * to: { key: value } -> { key: another-value }
+	 * to: [ seq0, seq1 ] -> { key: another-value }
+	 *
+	 */
+
+	/* if types of `from` and `to` differ (or it's a scalar), it's a replace */
+	if (fyn_from->type != fyn_to->type || fyn_from->type == FYNT_SCALAR) {
+
+		fyn_cpy = fy_node_copy(fyd, fyn_from);
+		fyd_error_check(fyd, fyn_cpy, err_out,
+				"fy_node_copy() failed");
+
+		if (!fyn_parent) {
+			fyd_doc_debug(fyd, "Replacing root node");
+			fy_node_detach_and_free(fyd->root);
+			fyd->root = fyn_cpy;
+		} else if (fyn_parent->type == FYNT_SEQUENCE) {
+			fyd_doc_debug(fyd, "Replacing sequence node");
+
+			/* get previous */
+			fyn_prev = fy_node_prev(&fyn_parent->sequence, fyn_to);
+
+			/* delete */
+			fy_node_list_del(&fyn_parent->sequence, fyn_to);
+			fy_node_detach_and_free(fyn_to);
+
+			/* if there's no previous insert to head */
+			if (!fyn_prev)
+				fy_node_list_add(&fyn_parent->sequence, fyn_cpy);
+			else
+				fy_node_list_insert_after(&fyn_parent->sequence, fyn_prev, fyn_cpy);
+		} else {
+			fyd_doc_debug(fyd, "Replacing mapping node value");
+			/* should never happen, it's checked right above, but play safe */
+			assert(fyn_parent->type == FYNT_MAPPING);
+			fyd_error_check(fyd, fynp, err_out,
+					"Illegal mapping node found");
+
+			fy_node_detach_and_free(fynp->value);
+			fynp->value = fyn_cpy;
+		}
+
+		return 0;
+	}
+
+	/* types match, if it's a sequence append */
+	if (fyn_to->type == FYNT_SEQUENCE) {
+
+		fyd_doc_debug(fyd, "Appending to sequence node");
+
+		for (fyni = fy_node_list_head(&fyn_from->sequence); fyni;
+				fyni = fy_node_next(&fyn_from->sequence, fyni)) {
+
+			fyn_cpy = fy_node_copy(fyd, fyni);
+			fyd_error_check(fyd, fyn_cpy, err_out,
+					"fy_node_copy() failed");
+
+			fy_node_list_add_tail(&fyn_to->sequence, fyn_cpy);
+			fyn_cpy->attached = true;
+		}
+	} else {
+		/* only mapping is possible here */
+
+		/* iterate over all the keys in the `from` */
+		for (fynpi = fy_node_pair_list_head(&fyn_from->mapping); fynpi;
+			fynpi = fy_node_pair_next(&fyn_from->mapping, fynpi)) {
+
+			if (fyn_to->xl) {
+				fynpj = fy_node_accel_lookup_by_node(fyn_to, fynpi->key);
+			} else {
+				/* find whether the key already exists */
+				for (fynpj = fy_node_pair_list_head(&fyn_to->mapping); fynpj;
+					fynpj = fy_node_pair_next(&fyn_to->mapping, fynpj)) {
+
+					if (fy_node_compare(fynpi->key, fynpj->key))
+						break;
+				}
+			}
+
+			if (!fynpj) {
+				fyd_doc_debug(fyd, "Appending to mapping node");
+
+				/* not found? append it */
+				fynpj = fy_node_pair_alloc(fyd);
+				fyd_error_check(fyd, fynpj, err_out,
+						"fy_node_pair_alloc() failed");
+
+				fynpj->key = fy_node_copy(fyd, fynpi->key);
+				fyd_error_check(fyd, !fynpi->key || fynpj->key, err_out,
+						"fy_node_copy() failed");
+				fynpj->value = fy_node_copy(fyd, fynpi->value);
+				fyd_error_check(fyd, !fynpi->value || fynpj->value, err_out,
+						"fy_node_copy() failed");
+
+				fy_node_pair_list_add_tail(&fyn_to->mapping, fynpj);
+				if (fyn_to->xl)
+					fy_accel_insert(fyn_to->xl, fynpj->key, fynpj);
+
+				if (fynpj->key)
+					fynpj->key->attached = true;
+				if (fynpj->value)
+					fynpj->value->attached = true;
+
+			} else {
+				fyd_doc_debug(fyd, "Updating mapping node value (deep merge)");
+
+				rc = fy_node_insert(fynpj->value, fynpi->value);
+				fyd_error_check(fyd, !rc, err_out_rc,
+						"fy_node_insert() failed");
+			}
+		}
+	}
+
+	/* adjust parents */
+	switch (fyn_to->type) {
+	case FYNT_SCALAR:
+		break;
+
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn_to->sequence); fyni;
+				fyni = fy_node_next(&fyn_to->sequence, fyni)) {
+
+			fyni->parent = fyn_to;
+		}
+		break;
+
+	case FYNT_MAPPING:
+		for (fynp = fy_node_pair_list_head(&fyn_to->mapping); fynp; fynp = fynpi) {
+
+			fynpi = fy_node_pair_next(&fyn_to->mapping, fynp);
+
+			if (fynp->key) {
+				fynp->key->parent = fyn_to;
+				fynp->key->key_root = true;
+			}
+			if (fynp->value)
+				fynp->value->parent = fyn_to;
+			fynp->parent = fyn_to;
+		}
+		break;
+	}
+
+	/* if the documents differ, merge their states */
+	if (fyn_to->fyd != fyn_from->fyd) {
+		rc = fy_document_state_merge(fyn_to->fyd->fyds, fyn_from->fyd->fyds);
+		fyd_error_check(fyd, !rc, err_out_rc,
+				"fy_document_state_merge() failed");
+
+		rc = fy_document_node_update_tags(fyd, fy_document_root(fyd));
+		fyd_error_check(fyd, !rc, err_out_rc,
+				"fy_document_node_update_tags() failed");
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_document_insert_at(struct fy_document *fyd,
+			  const char *path, size_t pathlen,
+			  struct fy_node *fyn)
+{
+	int rc;
+	struct fy_node *fyn2;
+
+	fyn2 = fy_node_by_path(fy_document_root(fyd), path, pathlen, FYNWF_DONT_FOLLOW);
+	rc = fy_node_insert(fyn2, fyn);
+
+	fy_node_free(fyn);
+
+	return rc;
+}
+
+struct fy_token *fy_document_tag_directive_iterate(struct fy_document *fyd, void **prevp)
+{
+	struct fy_token_list *fytl;
+
+	if (!fyd || !fyd->fyds || !prevp)
+		return NULL;
+
+	fytl = &fyd->fyds->fyt_td;
+
+	return *prevp = *prevp ? fy_token_next(fytl, *prevp) : fy_token_list_head(fytl);
+}
+
+struct fy_token *fy_document_tag_directive_lookup(struct fy_document *fyd, const char *handle)
+{
+	struct fy_token *fyt;
+	void *iter;
+	const char *h;
+	size_t h_size, len;
+
+	if (!fyd || !handle)
+		return NULL;
+	len = strlen(handle);
+
+	iter = NULL;
+	while ((fyt = fy_document_tag_directive_iterate(fyd, &iter)) != NULL) {
+		h = fy_tag_directive_token_handle(fyt, &h_size);
+		if (!h)
+			continue;
+		if (h_size == len && !memcmp(h, handle, len))
+			return fyt;
+	}
+	return NULL;
+}
+
+int fy_document_tag_directive_add(struct fy_document *fyd, const char *handle, const char *prefix)
+{
+	struct fy_token *fyt;
+
+	if (!fyd || !fyd->fyds || !handle || !prefix)
+		return -1;
+
+	/* it must not exist */
+	fyt = fy_document_tag_directive_lookup(fyd, handle);
+	if (fyt)
+		return -1;
+
+	return fy_document_state_append_tag(fyd->fyds, handle, prefix, false);
+}
+
+int fy_document_tag_directive_remove(struct fy_document *fyd, const char *handle)
+{
+	struct fy_token *fyt;
+
+	if (!fyd || !fyd->fyds || !handle)
+		return -1;
+
+	/* it must not exist */
+	fyt = fy_document_tag_directive_lookup(fyd, handle);
+	if (!fyt || fyt->refs != 1)
+		return -1;
+
+	fy_token_list_del(&fyd->fyds->fyt_td, fyt);
+	fy_token_unref(fyt);
+
+	return 0;
+}
+
+static int fy_resolve_alias(struct fy_document *fyd, struct fy_node *fyn)
+{
+	struct fy_node *fyn_copy = NULL;
+	int rc;
+
+	fyn_copy = fy_node_resolve_alias(fyn);
+	FYD_NODE_ERROR_CHECK(fyd, fyn, FYEM_DOC,
+			fyn_copy, err_out,
+			"invalid alias");
+
+	rc = fy_node_copy_to_scalar(fyd, fyn, fyn_copy);
+	fyd_error_check(fyd, !rc, err_out,
+			"fy_node_copy_to_scalar() failed");
+
+	return 0;
+
+err_out:
+	fyd->diag->on_error = false;
+	return -1;
+}
+
+static struct fy_node *
+fy_node_follow_alias(struct fy_node *fyn, enum fy_node_walk_flags flags)
+{
+	enum fy_node_walk_flags ptr_flags;
+	struct fy_anchor *fya;
+	const char *anchor_text, *s, *e, *p, *path;
+	size_t anchor_len, path_len;
+	struct fy_node *fyn_path_root;
+	unsigned int marker;
+
+	if (!fyn || !fy_node_is_alias(fyn))
+		return NULL;
+
+	ptr_flags = flags & FYNWF_PTR(FYNWF_PTR_MASK);
+	if (ptr_flags == FYNWF_PTR_YPATH)
+		return fy_node_alias_resolve_by_ypath(fyn);
+
+	/* try regular label target */
+	fya = fy_document_lookup_anchor_by_token(fyn->fyd, fyn->scalar);
+	if (fya)
+		return fya->fyn;
+
+	anchor_text = fy_token_get_text(fyn->scalar, &anchor_len);
+	if (!anchor_text)
+		return NULL;
+
+	s = anchor_text;
+	e = s + anchor_len;
+
+	fyn_path_root = NULL;
+
+	if (ptr_flags == FYNWF_PTR_YAML && (p = memchr(s, '/', e - s)) != NULL) {
+		/* fyd_notice(fyn->fyd, "%s: alias contains a path component %.*s",
+				__func__, (int)(e - p - 1), p + 1); */
+
+		if (p > s) {
+
+			fya = fy_document_lookup_anchor(fyn->fyd, s, p - s);
+			if (!fya) {
+				/* fyd_notice(fyn->fyd, "%s: unable to resolve alias %.*s @%s",
+						__func__, (int)(p - s), s, fy_node_get_path(fya->fyn)); */
+				return NULL;
+			}
+
+			/* fyd_notice(fyn->fyd, "%s: alias base %.*s @%s",
+					__func__, (int)(p - s), s, fy_node_get_path(fya->fyn)); */
+			path = ++p;
+			path_len = e - p;
+
+			fyn_path_root = fya->fyn;
+
+		} else {
+			/* fyd_notice(fyn->fyd, "%s: absolute %.*s @%s",
+					__func__, (int)(p - s), s, fy_node_get_path(fya->fyn)); */
+			path = s;
+			path_len = e - s;
+
+			fyn_path_root = fyn->fyd->root;
+		}
+	}
+
+	if (!fyn_path_root)
+		return NULL;
+
+	marker = fy_node_walk_marker_from_flags(flags);
+	if (marker >= FYNWF_MAX_USER_MARKER)
+		return NULL;
+
+	/* use the next marker */
+	flags &= ~FYNWF_MARKER(FYNWF_MARKER_MASK);
+	flags |= FYNWF_MARKER(marker + 1);
+
+	return fy_node_by_path_internal(fyn_path_root, path, path_len, flags);
+}
+
+static bool fy_node_pair_is_merge_key(struct fy_node_pair *fynp)
+{
+	struct fy_node *fyn = fynp->key;
+
+	return fyn && fyn->type == FYNT_SCALAR && fyn->style == FYNS_PLAIN &&
+	       fy_plain_atom_streq(fy_token_atom(fyn->scalar), "<<");
+}
+
+static struct fy_node *fy_alias_get_merge_mapping(struct fy_document *fyd, struct fy_node *fyn)
+{
+	struct fy_anchor *fya;
+
+	/* must be an alias */
+	if (!fy_node_is_alias(fyn))
+		return NULL;
+
+	/* anchor must exist */
+	fya = fy_document_lookup_anchor_by_token(fyd, fyn->scalar);
+	if (!fya)
+		return NULL;
+
+	/* and it must be a mapping */
+	if (fya->fyn->type != FYNT_MAPPING)
+		return NULL;
+
+	return fya->fyn;
+}
+
+static bool fy_node_pair_is_valid_merge_key(struct fy_document *fyd, struct fy_node_pair *fynp)
+{
+	struct fy_node *fyn, *fyni, *fynm;
+
+	fyn = fynp->value;
+
+	/* value must exist */
+	if (!fyn)
+		return false;
+
+	/* scalar alias */
+	fynm = fy_alias_get_merge_mapping(fyd, fyn);
+	if (fynm)
+		return true;
+
+	/* it must be a sequence then */
+	if (fyn->type != FYNT_SEQUENCE)
+		return false;
+
+	/* the sequence must only contain valid aliases for mapping */
+	for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+			fyni = fy_node_next(&fyn->sequence, fyni)) {
+
+		/* sequence of aliases only! */
+		fynm = fy_alias_get_merge_mapping(fyd, fyni);
+		if (!fynm)
+			return false;
+
+	}
+
+	return true;
+}
+
+static int fy_resolve_merge_key_populate(struct fy_document *fyd, struct fy_node *fyn,
+					  struct fy_node_pair *fynp, struct fy_node *fynm)
+{
+	struct fy_node_pair *fynpi, *fynpn;
+
+	if (!fyd)
+		return -1;
+
+	fyd_error_check(fyd,
+			fyn && fynp && fynm && fyn->type == FYNT_MAPPING && fynm->type == FYNT_MAPPING,
+			err_out, "bad inputs to %s", __func__);
+
+	for (fynpi = fy_node_pair_list_head(&fynm->mapping); fynpi;
+		fynpi = fy_node_pair_next(&fynm->mapping, fynpi)) {
+
+		/* if we don't allow duplicate keys */
+		if (!(fyd->parse_cfg.flags & FYPCF_ALLOW_DUPLICATE_KEYS)) {
+
+			/* make sure we don't override an already existing key */
+			if (fy_node_mapping_key_is_duplicate(fyn, fynpi->key))
+				continue;
+		}
+
+		fynpn = fy_node_pair_alloc(fyd);
+		fyd_error_check(fyd, fynpn, err_out,
+				"fy_node_pair_alloc() failed");
+
+		fynpn->key = fy_node_copy(fyd, fynpi->key);
+		fynpn->value = fy_node_copy(fyd, fynpi->value);
+
+		fy_node_pair_list_insert_after(&fyn->mapping, fynp, fynpn);
+		if (fyn->xl)
+			fy_accel_insert(fyn->xl, fynpn->key, fynpn);
+	}
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+static int fy_resolve_merge_key(struct fy_document *fyd, struct fy_node *fyn, struct fy_node_pair *fynp)
+{
+	struct fy_node *fynv, *fyni, *fynm;
+	int rc;
+
+	/* it must be a valid merge key value */
+	FYD_NODE_ERROR_CHECK(fyd, fynp->value, FYEM_DOC,
+			fy_node_pair_is_valid_merge_key(fyd, fynp), err_out,
+			"invalid merge key value");
+
+	fynv = fynp->value;
+	fynm = fy_alias_get_merge_mapping(fyd, fynv);
+	if (fynm) {
+		rc = fy_resolve_merge_key_populate(fyd, fyn, fynp, fynm);
+		fyd_error_check(fyd, !rc, err_out_rc,
+				"fy_resolve_merge_key_populate() failed");
+
+		return 0;
+	}
+
+	/* it must be a sequence then */
+	fyd_error_check(fyd, fynv->type == FYNT_SEQUENCE, err_out,
+			"invalid node type to use for merge key");
+
+	/* the sequence must only contain valid aliases for mapping */
+	for (fyni = fy_node_list_head(&fynv->sequence); fyni;
+			fyni = fy_node_next(&fynv->sequence, fyni)) {
+
+		fynm = fy_alias_get_merge_mapping(fyd, fyni);
+		fyd_error_check(fyd, fynm, err_out,
+				"invalid merge key sequence item (not an alias)");
+
+		rc = fy_resolve_merge_key_populate(fyd, fyn, fynp, fynm);
+		fyd_error_check(fyd, !rc, err_out_rc,
+				"fy_resolve_merge_key_populate() failed");
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+/* the anchors are scalars that have the FYNS_ALIAS style */
+static int fy_resolve_anchor_node(struct fy_document *fyd, struct fy_node *fyn)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp, *fynpi, *fynpit;
+	int rc, ret_rc = 0;
+	struct fy_token *fyt;
+
+	if (!fyn)
+		return 0;
+
+	if (fy_node_is_alias(fyn))
+		return fy_resolve_alias(fyd, fyn);
+
+	if (fyn->type == FYNT_SEQUENCE) {
+
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+				fyni = fy_node_next(&fyn->sequence, fyni)) {
+
+			rc = fy_resolve_anchor_node(fyd, fyni);
+			if (rc && !ret_rc)
+				ret_rc = rc;
+		}
+
+	} else if (fyn->type == FYNT_MAPPING) {
+
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp; fynp = fynpi) {
+
+			fynpi = fy_node_pair_next(&fyn->mapping, fynp);
+
+			if (fy_node_pair_is_merge_key(fynp)) {
+				rc = fy_resolve_merge_key(fyd, fyn, fynp);
+				if (rc && !ret_rc)
+					ret_rc = rc;
+
+				/* remove this node pair */
+				if (!rc) {
+					fy_node_pair_list_del(&fyn->mapping, fynp);
+					if (fyn->xl)
+						fy_accel_remove(fyn->xl, fynp->key);
+					fy_node_pair_detach_and_free(fynp);
+				}
+
+			} else {
+
+				rc = fy_resolve_anchor_node(fyd, fynp->key);
+
+				if (!rc) {
+
+					/* check whether the keys are duplicate */
+					for (fynpit = fy_node_pair_list_head(&fyn->mapping); fynpit;
+						fynpit = fy_node_pair_next(&fyn->mapping, fynpit)) {
+
+						/* skip this node pair */
+						if (fynpit == fynp)
+							continue;
+
+						if (!fy_node_compare(fynpit->key, fynp->key))
+							continue;
+
+						/* whoops, duplicate key after resolution */
+						fyt = NULL;
+						switch (fyn->type) {
+						case FYNT_SCALAR:
+							fyt = fyn->scalar;
+							break;
+						case FYNT_SEQUENCE:
+							fyt = fyn->sequence_start;
+							break;
+						case FYNT_MAPPING:
+							fyt = fyn->mapping_start;
+							break;
+						}
+
+						FYD_TOKEN_ERROR_CHECK(fyd, fyt, FYEM_DOC,
+								false, err_out,
+								"duplicate key after resolving");
+
+					}
+
+				}
+
+				if (rc && !ret_rc)
+					ret_rc = rc;
+
+				rc = fy_resolve_anchor_node(fyd, fynp->value);
+				if (rc && !ret_rc)
+					ret_rc = rc;
+
+			}
+		}
+	}
+
+	return ret_rc;
+
+err_out:
+	return -1;
+}
+
+static void fy_resolve_parent_node(struct fy_document *fyd, struct fy_node *fyn, struct fy_node *fyn_parent)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp, *fynpi;
+
+	if (!fyn)
+		return;
+
+	fyn->parent = fyn_parent;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		break;
+
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+				fyni = fy_node_next(&fyn->sequence, fyni)) {
+
+			fy_resolve_parent_node(fyd, fyni, fyn);
+		}
+		break;
+
+	case FYNT_MAPPING:
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp; fynp = fynpi) {
+
+			fynpi = fy_node_pair_next(&fyn->mapping, fynp);
+
+			fy_resolve_parent_node(fyd, fynp->key, fyn);
+			fy_resolve_parent_node(fyd, fynp->value, fyn);
+			fynp->parent = fyn;
+		}
+		break;
+	}
+}
+
+typedef void (*fy_node_applyf)(struct fy_node *fyn);
+
+void fy_node_apply(struct fy_node *fyn, fy_node_applyf func)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp;
+
+	if (!fyn || !func)
+		return;
+
+	(*func)(fyn);
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		break;
+
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+				fyni = fy_node_next(&fyn->sequence, fyni))
+			fy_node_apply(fyni, func);
+		break;
+
+	case FYNT_MAPPING:
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp;
+				fynp = fy_node_pair_next(&fyn->mapping, fynp)) {
+
+			fy_node_apply(fynp->key, func);
+			fy_node_apply(fynp->value, func);
+		}
+		break;
+	}
+}
+
+static void clear_system_marks(struct fy_node *fyn)
+{
+	fyn->marks &= ~FYNWF_SYSTEM_MARKS;
+}
+
+/* clear all the system markers */
+void fy_node_clear_system_marks(struct fy_node *fyn)
+{
+	fy_node_apply(fyn, clear_system_marks);
+}
+
+int fy_document_resolve(struct fy_document *fyd)
+{
+	int rc;
+	bool ret;
+
+	if (!fyd)
+		return 0;
+
+	fy_node_clear_system_marks(fyd->root);
+
+	/* for resolution to work, no reference loops should exist */
+	ret = fy_check_ref_loop(fyd, fyd->root,
+			FYNWF_MAXDEPTH_DEFAULT | FYNWF_FOLLOW, NULL);
+
+	fy_node_clear_system_marks(fyd->root);
+
+	if (ret)
+		goto err_out;
+
+
+	/* now resolve any anchor nodes */
+	rc = fy_resolve_anchor_node(fyd, fyd->root);
+	if (rc)
+		goto err_out_rc;
+
+	/* redo parent resolution */
+	fy_resolve_parent_node(fyd, fyd->root, NULL);
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	fyd->diag->on_error = false;
+	return rc;
+}
+
+void fy_document_free_nodes(struct fy_document *fyd)
+{
+	struct fy_document *fyd_child;
+
+	for (fyd_child = fy_document_list_first(&fyd->children); fyd_child;
+	     fyd_child = fy_document_next(&fyd->children, fyd_child))
+		fy_document_free_nodes(fyd_child);
+
+	fy_node_detach_and_free(fyd->root);
+	fyd->root = NULL;
+}
+
+void fy_document_destroy(struct fy_document *fyd)
+{
+	struct fy_document *fyd_child;
+
+	/* both the document and the parser object must exist */
+	if (!fyd)
+		return;
+
+	/* we have to free the nodes first */
+	fy_document_free_nodes(fyd);
+
+	/* recursively delete children */
+	while ((fyd_child = fy_document_list_pop(&fyd->children)) != NULL) {
+		fyd_child->parent = NULL;
+		fy_document_destroy(fyd_child);
+	}
+
+	fy_parse_document_destroy(NULL, fyd);
+}
+
+int fy_document_set_parent(struct fy_document *fyd, struct fy_document *fyd_child)
+{
+
+	if (!fyd || !fyd_child || fyd_child->parent)
+		return -1;
+
+	fyd_child->parent = fyd;
+	fy_document_list_add_tail(&fyd->children, fyd_child);
+
+	return 0;
+}
+
+static const struct fy_parse_cfg doc_parse_default_cfg = {
+	.flags = FYPCF_DEFAULT_DOC,
+};
+
+struct fy_document *fy_document_create(const struct fy_parse_cfg *cfg)
+{
+	struct fy_document *fyd = NULL;
+	struct fy_diag *diag;
+	int rc;
+
+	if (!cfg)
+		cfg = &doc_parse_default_cfg;
+
+	fyd = malloc(sizeof(*fyd));
+	if (!fyd)
+		goto err_out;
+
+	memset(fyd, 0, sizeof(*fyd));
+	fyd->parse_cfg = *cfg;
+
+	diag = cfg->diag;
+	if (!diag) {
+		diag = fy_diag_create(NULL);
+		if (!diag)
+			goto err_out;
+	} else
+		fy_diag_ref(diag);
+
+	fyd->diag = diag;
+
+	fy_anchor_list_init(&fyd->anchors);
+	if (fy_document_is_accelerated(fyd)) {
+		fyd->axl = malloc(sizeof(*fyd->axl));
+		fyd_error_check(fyd, fyd->axl, err_out,
+				"malloc() failed");
+
+		/* start with a very small bucket list */
+		rc = fy_accel_setup(fyd->axl, &hd_anchor, fyd, 8);
+		fyd_error_check(fyd, !rc, err_out,
+				"fy_accel_setup() failed");
+
+		fyd->naxl = malloc(sizeof(*fyd->naxl));
+		fyd_error_check(fyd, fyd->axl, err_out,
+				"malloc() failed");
+
+		/* start with a very small bucket list */
+		rc = fy_accel_setup(fyd->naxl, &hd_nanchor, fyd, 8);
+		fyd_error_check(fyd, !rc, err_out,
+				"fy_accel_setup() failed");
+	}
+	fyd->root = NULL;
+
+	/* we don't do document create version setting,
+	 * perhaps we should in the future
+	 */
+	fyd->fyds = fy_document_state_default(NULL, NULL);
+	fyd_error_check(fyd, fyd->fyds, err_out,
+			"fy_document_state_default() failed");
+
+	/* turn on JSON mode if it's forced */
+	fyd->fyds->json_mode = (cfg->flags &
+			(FYPCF_JSON_MASK << FYPCF_JSON_SHIFT)) == FYPCF_JSON_FORCE;
+
+	fy_document_list_init(&fyd->children);
+
+	return fyd;
+
+err_out:
+	fy_parse_document_destroy(NULL, fyd);
+	return NULL;
+}
+
+struct fy_document_build_string_ctx {
+	const char *str;
+	size_t len;
+};
+
+static int parser_setup_from_string(struct fy_parser *fyp, void *user)
+{
+	struct fy_document_build_string_ctx *ctx = user;
+
+	return fy_parser_set_string(fyp, ctx->str, ctx->len);
+}
+
+struct fy_document_build_malloc_string_ctx {
+	char *str;
+	size_t len;
+};
+
+static int parser_setup_from_malloc_string(struct fy_parser *fyp, void *user)
+{
+	struct fy_document_build_malloc_string_ctx *ctx = user;
+
+	return fy_parser_set_malloc_string(fyp, ctx->str, ctx->len);
+}
+
+struct fy_document_build_file_ctx {
+	const char *file;
+};
+
+static int parser_setup_from_file(struct fy_parser *fyp, void *user)
+{
+	struct fy_document_build_file_ctx *ctx = user;
+
+	return fy_parser_set_input_file(fyp, ctx->file);
+}
+
+struct fy_document_build_fp_ctx {
+	const char *name;
+	FILE *fp;
+};
+
+static int parser_setup_from_fp(struct fy_parser *fyp, void *user)
+{
+	struct fy_document_build_fp_ctx *ctx = user;
+
+	return fy_parser_set_input_fp(fyp, ctx->name, ctx->fp);
+}
+
+struct fy_document_vbuildf_ctx {
+	const char *fmt;
+	va_list ap;
+};
+
+static int parser_setup_from_fmt_ap(struct fy_parser *fyp, void *user)
+{
+	struct fy_document_vbuildf_ctx *vctx = user;
+	va_list ap, ap_orig;
+	int size, sizew;
+	char *buf;
+
+	/* first try without allocating */
+	va_copy(ap_orig, vctx->ap);
+	size = vsnprintf(NULL, 0, vctx->fmt, ap_orig);
+	va_end(ap_orig);
+
+	fyp_error_check(fyp, size >= 0, err_out,
+			"vsnprintf() failed");
+
+	buf = malloc(size + 1);
+	fyp_error_check(fyp, buf, err_out,
+			"malloc() failed");
+
+	va_copy(ap, vctx->ap);
+	sizew = vsnprintf(buf, size + 1, vctx->fmt, ap);
+	fyp_error_check(fyp, sizew == size, err_out,
+			"vsnprintf() failed");
+	va_end(ap);
+
+	buf[size] = '\0';
+
+	return fy_parser_set_malloc_string(fyp, buf, size);
+
+err_out:
+	return -1;
+}
+
+static struct fy_document *fy_document_build_internal(const struct fy_parse_cfg *cfg,
+		int (*parser_setup)(struct fy_parser *fyp, void *user),
+		void *user)
+{
+	struct fy_parser fyp_data, *fyp = &fyp_data;
+	struct fy_document *fyd = NULL;
+	struct fy_eventp *fyep;
+	bool got_stream_end;
+	int rc;
+
+	if (!parser_setup)
+		return NULL;
+
+	if (!cfg)
+		cfg = &doc_parse_default_cfg;
+
+	rc = fy_parse_setup(fyp, cfg);
+	if (rc)
+		return NULL;
+
+	rc = (*parser_setup)(fyp, user);
+	fyp_error_check(fyp, !rc, err_out,
+			"parser_setup() failed");
+
+	fyd = fy_parse_load_document(fyp);
+
+	/* we're going to handle stream errors from now */
+	if (!fyd)
+		fyp->stream_error = false;
+
+	/* if we collect diagnostics, we can continue */
+	fyp_error_check(fyp, fyd || (fyp->cfg.flags & FYPCF_COLLECT_DIAG), err_out,
+			"fy_parse_load_document() failed");
+
+	/* no document, but we're collecting diagnostics */
+	if (!fyd) {
+
+		fyp_error(fyp, "fy_parse_load_document() failed");
+
+		fyp->stream_error = false;
+		fyd = fy_parse_document_create(fyp, NULL);
+		fyp_error_check(fyp, fyd, err_out,
+				"fy_parse_document_create() failed");
+		fyd->parse_error = true;
+
+		/* XXX */
+		goto out;
+	}
+
+	got_stream_end = false;
+	while (!got_stream_end && (fyep = fy_parse_private(fyp)) != NULL) {
+		if (fyep->e.type == FYET_STREAM_END)
+			got_stream_end = true;
+		fy_parse_eventp_recycle(fyp, fyep);
+	}
+
+	if (got_stream_end) {
+		fyep = fy_parse_private(fyp);
+		fyp_error_check(fyp, !fyep, err_out,
+				"more events after stream end");
+		fy_parse_eventp_recycle(fyp, fyep);
+	}
+
+out:
+	fy_parse_cleanup(fyp);
+	return fyd;
+
+err_out:
+	fy_document_destroy(fyd);
+	fy_parse_cleanup(fyp);
+	return NULL;
+}
+
+struct fy_document *fy_document_build_from_string(const struct fy_parse_cfg *cfg,
+						  const char *str, size_t len)
+{
+	struct fy_document_build_string_ctx ctx = {
+		.str = str,
+		.len = len,
+	};
+
+	return fy_document_build_internal(cfg, parser_setup_from_string, &ctx);
+}
+
+struct fy_document *fy_document_build_from_malloc_string(const struct fy_parse_cfg *cfg,
+							 char *str, size_t len)
+{
+	struct fy_document_build_malloc_string_ctx ctx = {
+		.str = str,
+		.len = len,
+	};
+
+	return fy_document_build_internal(cfg, parser_setup_from_malloc_string, &ctx);
+}
+
+struct fy_document *fy_document_build_from_file(const struct fy_parse_cfg *cfg,
+						const char *file)
+{
+	struct fy_document_build_file_ctx ctx = {
+		.file = file,
+	};
+
+	return fy_document_build_internal(cfg, parser_setup_from_file, &ctx);
+}
+
+struct fy_document *fy_document_build_from_fp(const struct fy_parse_cfg *cfg,
+					      FILE *fp)
+{
+	struct fy_document_build_fp_ctx ctx = {
+		.name = NULL,
+		.fp = fp,
+	};
+
+	return fy_document_build_internal(cfg, parser_setup_from_fp, &ctx);
+}
+
+enum fy_node_type fy_node_get_type(struct fy_node *fyn)
+{
+	/* a NULL is a plain scalar node */
+	return fyn ? fyn->type : FYNT_SCALAR;
+}
+
+enum fy_node_style fy_node_get_style(struct fy_node *fyn)
+{
+	/* a NULL is a plain scalar node */
+	return fyn ? fyn->style : FYNS_PLAIN;
+}
+
+bool fy_node_is_null(struct fy_node *fyn)
+{
+	if (!fyn)
+		return true;
+
+	if (fyn->type != FYNT_SCALAR)
+		return false;
+
+	return fyn->scalar == NULL;
+}
+
+bool fy_node_is_attached(struct fy_node *fyn)
+{
+	return fyn ? fyn->attached : false;
+}
+
+struct fy_node *fy_node_get_parent(struct fy_node *fyn)
+{
+	return fyn && !fyn->key_root ? fyn->parent : NULL;
+}
+
+struct fy_node *fy_node_get_document_parent(struct fy_node *fyn)
+{
+	return fyn ? fyn->parent : NULL;
+}
+
+struct fy_token *fy_node_get_tag_token(struct fy_node *fyn)
+{
+	return fyn ? fyn->tag : NULL;
+}
+
+struct fy_token *fy_node_get_scalar_token(struct fy_node *fyn)
+{
+	return fyn && fyn->type == FYNT_SCALAR ? fyn->scalar : NULL;
+}
+
+struct fy_node *fy_node_pair_key(struct fy_node_pair *fynp)
+{
+	return fynp ? fynp->key : NULL;
+}
+
+struct fy_node *fy_node_pair_value(struct fy_node_pair *fynp)
+{
+	return fynp ? fynp->value : NULL;
+}
+
+int fy_node_pair_set_key(struct fy_node_pair *fynp, struct fy_node *fyn)
+{
+	struct fy_node *fyn_map;
+	struct fy_node_pair *fynpi;
+
+	if (!fynp)
+		return -1;
+
+	/* the node must not be attached */
+	if (fyn && fyn->attached)
+		return -1;
+
+	/* sanity check and duplication check */
+	fyn_map = fynp->parent;
+	if (fyn_map) {
+
+		/* (in)sanity check */
+		if (!fy_node_is_mapping(fyn_map))
+			return -1;
+
+		if (fyn_map->xl) {
+			/* either we're already on the parent list (and it's OK) */
+			/* or we're not and we have a duplicate key */
+			fynpi = fy_node_accel_lookup_by_node(fyn_map, fyn);
+			if (fynpi && fynpi != fynp)
+				return -1;
+			/* remove that key */
+			fy_accel_remove(fyn_map->xl, fynp->key);
+		} else {
+			/* check whether the key is a duplicate
+			* skipping ourselves since our key gets replaced
+			*/
+			for (fynpi = fy_node_pair_list_head(&fyn_map->mapping); fynpi;
+				fynpi = fy_node_pair_next(&fyn_map->mapping, fynpi)) {
+
+				if (fynpi != fynp && fy_node_compare(fynpi->key, fyn))
+					return -1;
+			}
+		}
+
+		fy_node_mark_synthetic(fyn_map);
+	}
+
+	fy_node_detach_and_free(fynp->key);
+	fynp->key = fyn;
+
+	if (fyn_map && fyn_map->xl)
+		fy_accel_insert(fyn_map->xl, fynp->key, fynp);
+
+	fyn->attached = true;
+
+	return 0;
+}
+
+int fy_node_pair_set_value(struct fy_node_pair *fynp, struct fy_node *fyn)
+{
+	if (!fynp)
+		return -1;
+	/* the node must not be attached */
+	if (fyn && fyn->attached)
+		return -1;
+	fy_node_detach_and_free(fynp->value);
+	fynp->value = fyn;
+	fyn->attached = true;
+
+	if (fynp->parent)
+		fy_node_mark_synthetic(fynp->parent);
+
+	return 0;
+}
+
+struct fy_node *fy_document_root(struct fy_document *fyd)
+{
+	return fyd->root;
+}
+
+const char *fy_node_get_tag(struct fy_node *fyn, size_t *lenp)
+{
+	size_t tmplen;
+
+	if (!lenp)
+		lenp = &tmplen;
+
+	if (!fyn || !fyn->tag) {
+		*lenp = 0;
+		return NULL;
+	}
+
+	return fy_token_get_text(fyn->tag, lenp);
+}
+
+const char *fy_node_get_scalar(struct fy_node *fyn, size_t *lenp)
+{
+	size_t tmplen;
+
+	if (!lenp)
+		lenp = &tmplen;
+
+	if (!fyn || fyn->type != FYNT_SCALAR) {
+		*lenp = 0;
+		return NULL;
+	}
+
+	return fy_token_get_text(fyn->scalar, lenp);
+}
+
+const char *fy_node_get_scalar0(struct fy_node *fyn)
+{
+	if (!fyn || fyn->type != FYNT_SCALAR)
+		return NULL;
+
+	return fy_token_get_text0(fyn->scalar);
+}
+
+size_t fy_node_get_scalar_length(struct fy_node *fyn)
+{
+
+	if (!fyn || fyn->type != FYNT_SCALAR)
+		return 0;
+
+	return fy_token_get_text_length(fyn->scalar);
+}
+
+size_t fy_node_get_scalar_utf8_length(struct fy_node *fyn)
+{
+
+	if (!fyn || fyn->type != FYNT_SCALAR)
+		return 0;
+
+	return fy_token_format_utf8_length(fyn->scalar);
+}
+
+struct fy_node *fy_node_sequence_iterate(struct fy_node *fyn, void **prevp)
+{
+	if (!fyn || fyn->type != FYNT_SEQUENCE || !prevp)
+		return NULL;
+
+	return *prevp = *prevp ? fy_node_next(&fyn->sequence, *prevp) : fy_node_list_head(&fyn->sequence);
+}
+
+struct fy_node *fy_node_sequence_reverse_iterate(struct fy_node *fyn, void **prevp)
+{
+	if (!fyn || fyn->type != FYNT_SEQUENCE || !prevp)
+		return NULL;
+
+	return *prevp = *prevp ? fy_node_prev(&fyn->sequence, *prevp) : fy_node_list_tail(&fyn->sequence);
+}
+
+int fy_node_sequence_item_count(struct fy_node *fyn)
+{
+	struct fy_node *fyni;
+	int count;
+
+	if (!fyn || fyn->type != FYNT_SEQUENCE)
+		return -1;
+
+	count = 0;
+	for (fyni = fy_node_list_head(&fyn->sequence); fyni; fyni = fy_node_next(&fyn->sequence, fyni))
+		count++;
+	return count;
+}
+
+bool fy_node_sequence_is_empty(struct fy_node *fyn)
+{
+	return !fyn || fyn->type != FYNT_SEQUENCE || fy_node_list_empty(&fyn->sequence);
+}
+
+struct fy_node *fy_node_sequence_get_by_index(struct fy_node *fyn, int index)
+{
+	struct fy_node *fyni;
+	void *iterp = NULL;
+
+	if (!fyn || fyn->type != FYNT_SEQUENCE)
+		return NULL;
+
+	if (index >= 0) {
+		do {
+			fyni = fy_node_sequence_iterate(fyn, &iterp);
+		} while (fyni && --index >= 0);
+	} else {
+		do {
+			fyni = fy_node_sequence_reverse_iterate(fyn, &iterp);
+		} while (fyni && ++index < 0);
+	}
+
+	return fyni;
+}
+
+struct fy_node_pair *fy_node_mapping_iterate(struct fy_node *fyn, void **prevp)
+{
+	if (!fyn || fyn->type != FYNT_MAPPING || !prevp)
+		return NULL;
+
+	return *prevp = *prevp ? fy_node_pair_next(&fyn->mapping, *prevp) : fy_node_pair_list_head(&fyn->mapping);
+}
+
+struct fy_node_pair *fy_node_mapping_reverse_iterate(struct fy_node *fyn, void **prevp)
+{
+	if (!fyn || fyn->type != FYNT_MAPPING || !prevp)
+		return NULL;
+
+	return *prevp = *prevp ? fy_node_pair_prev(&fyn->mapping, *prevp) : fy_node_pair_list_tail(&fyn->mapping);
+}
+
+struct fy_node *fy_node_collection_iterate(struct fy_node *fyn, void **prevp)
+{
+	struct fy_node_pair *fynp;
+
+	if (!fyn || !prevp)
+		return NULL;
+
+	switch (fyn->type) {
+	case FYNT_SEQUENCE:
+		return fy_node_sequence_iterate(fyn, prevp);
+
+	case FYNT_MAPPING:
+		fynp = fy_node_mapping_iterate(fyn, prevp);
+		if (!fynp)
+			return NULL;
+		return fynp->value;
+
+	case FYNT_SCALAR:
+		fyn = !*prevp ? fyn : NULL;
+		*prevp = fyn;
+		return fyn;
+	}
+
+	return NULL;
+}
+
+
+int fy_node_mapping_item_count(struct fy_node *fyn)
+{
+	struct fy_node_pair *fynpi;
+	int count;
+
+	if (!fyn || fyn->type != FYNT_MAPPING)
+		return -1;
+
+	count = 0;
+	for (fynpi = fy_node_pair_list_head(&fyn->mapping); fynpi; fynpi = fy_node_pair_next(&fyn->mapping, fynpi))
+		count++;
+	return count;
+}
+
+bool fy_node_mapping_is_empty(struct fy_node *fyn)
+{
+	return !fyn || fyn->type != FYNT_MAPPING || fy_node_pair_list_empty(&fyn->mapping);
+}
+
+struct fy_node_pair *fy_node_mapping_get_by_index(struct fy_node *fyn, int index)
+{
+	struct fy_node_pair *fynpi;
+	void *iterp = NULL;
+
+	if (!fyn || fyn->type != FYNT_MAPPING)
+		return NULL;
+
+	if (index >= 0) {
+		do {
+			fynpi = fy_node_mapping_iterate(fyn, &iterp);
+		} while (fynpi && --index >= 0);
+	} else {
+		do {
+			fynpi = fy_node_mapping_reverse_iterate(fyn, &iterp);
+		} while (fynpi && ++index < 0);
+	}
+
+	return fynpi;
+}
+
+struct fy_node_pair *
+fy_node_mapping_lookup_pair_by_simple_key(struct fy_node *fyn,
+					  const char *key, size_t len)
+{
+	struct fy_node_pair *fynpi;
+	struct fy_node *fyn_scalar;
+
+	if (!fyn || fyn->type != FYNT_MAPPING || !key)
+		return NULL;
+
+	if (len == (size_t)-1)
+		len = strlen(key);
+
+	if (fyn->xl) {
+		fyn_scalar = fy_node_create_scalar(fyn->fyd, key, len);
+		if (!fyn_scalar)
+			return NULL;
+
+		fynpi = fy_node_accel_lookup_by_node(fyn, fyn_scalar);
+
+		fy_node_free(fyn_scalar);
+
+		if (fynpi)
+			return fynpi;
+	} else {
+		for (fynpi = fy_node_pair_list_head(&fyn->mapping); fynpi;
+			fynpi = fy_node_pair_next(&fyn->mapping, fynpi)) {
+
+			if (!fy_node_is_scalar(fynpi->key) || fy_node_is_alias(fynpi->key))
+				continue;
+
+			if (!fynpi->key && len == 0)
+				return fynpi;
+
+			if (fynpi->key && !fy_token_memcmp(fynpi->key->scalar, key, len))
+				return fynpi;
+		}
+	}
+
+	return NULL;
+}
+
+struct fy_node *
+fy_node_mapping_lookup_value_by_simple_key(struct fy_node *fyn,
+					   const char *key, size_t len)
+{
+	struct fy_node_pair *fynp;
+
+	fynp = fy_node_mapping_lookup_pair_by_simple_key(fyn, key, len);
+	return fynp ? fy_node_pair_value(fynp) : NULL;
+}
+
+struct fy_node_pair *
+fy_node_mapping_lookup_pair_by_null_key(struct fy_node *fyn)
+{
+	struct fy_node_pair *fynpi;
+
+	if (!fyn || fyn->type != FYNT_MAPPING)
+		return NULL;
+
+	/* no acceleration for NULLs */
+	for (fynpi = fy_node_pair_list_head(&fyn->mapping); fynpi;
+		fynpi = fy_node_pair_next(&fyn->mapping, fynpi)) {
+
+		if (fy_node_is_null(fynpi->key))
+			return fynpi;
+	}
+
+	return NULL;
+}
+
+struct fy_node *
+fy_node_mapping_lookup_value_by_null_key(struct fy_node *fyn)
+{
+	struct fy_node_pair *fynp;
+
+	fynp = fy_node_mapping_lookup_pair_by_null_key(fyn);
+	return fynp ? fy_node_pair_value(fynp) : NULL;
+}
+
+const char *
+fy_node_mapping_lookup_scalar_by_simple_key(struct fy_node *fyn, size_t *lenp,
+					    const char *key, size_t keylen)
+{
+	struct fy_node *fyn_value;
+
+	fyn_value = fy_node_mapping_lookup_value_by_simple_key(fyn, key, keylen);
+	if (!fyn_value || !fy_node_is_scalar(fyn_value))
+		return NULL;
+	return fy_node_get_scalar(fyn_value, lenp);
+}
+
+const char *
+fy_node_mapping_lookup_scalar0_by_simple_key(struct fy_node *fyn,
+					     const char *key, size_t keylen)
+{
+	struct fy_node *fyn_value;
+
+	fyn_value = fy_node_mapping_lookup_value_by_simple_key(fyn, key, keylen);
+	if (!fyn_value || !fy_node_is_scalar(fyn_value))
+		return NULL;
+	return fy_node_get_scalar0(fyn_value);
+}
+
+struct fy_node *fy_node_mapping_lookup_value_by_key(struct fy_node *fyn, struct fy_node *fyn_key)
+{
+	struct fy_node_pair *fynp;
+
+	fynp = fy_node_mapping_lookup_pair(fyn, fyn_key);
+	return fynp ? fynp->value : NULL;
+}
+
+struct fy_node *fy_node_mapping_lookup_key_by_key(struct fy_node *fyn, struct fy_node *fyn_key)
+{
+	struct fy_node_pair *fynp;
+
+	fynp = fy_node_mapping_lookup_pair(fyn, fyn_key);
+	return fynp ? fynp->key : NULL;
+}
+
+struct fy_node_pair *
+fy_node_mapping_lookup_pair_by_string(struct fy_node *fyn, const char *key, size_t len)
+{
+	struct fy_document *fyd;
+	struct fy_node_pair *fynp;
+
+	/* try quick and dirty simple scan */
+	if (is_simple_key(key, len))
+		return fy_node_mapping_lookup_pair_by_simple_key(fyn, key, len);
+
+	fyd = fy_document_build_from_string(NULL, key, len);
+	if (!fyd)
+		return NULL;
+
+	fynp = fy_node_mapping_lookup_pair(fyn, fy_document_root(fyd));
+
+	fy_document_destroy(fyd);
+
+	return fynp;
+}
+
+struct fy_node *
+fy_node_mapping_lookup_by_string(struct fy_node *fyn,
+				 const char *key, size_t len)
+{
+	struct fy_node_pair *fynp;
+
+	fynp = fy_node_mapping_lookup_pair_by_string(fyn, key, len);
+	return fynp ? fynp->value : NULL;
+}
+
+struct fy_node *
+fy_node_mapping_lookup_value_by_string(struct fy_node *fyn,
+				       const char *key, size_t len)
+{
+	return fy_node_mapping_lookup_by_string(fyn, key, len);
+}
+
+struct fy_node *
+fy_node_mapping_lookup_key_by_string(struct fy_node *fyn,
+				     const char *key, size_t len)
+{
+	struct fy_node_pair *fynp;
+
+	fynp = fy_node_mapping_lookup_pair_by_string(fyn, key, len);
+	return fynp ? fynp->key : NULL;
+}
+
+bool fy_node_is_empty(struct fy_node *fyn)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp;
+	struct fy_atom *atom;
+
+	/* skip if no value node or token */
+	if (!fyn)
+		return true;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		atom = fy_token_atom(fyn->scalar);
+		if (atom && !atom->size0 && !atom->empty)
+			return false;
+		break;
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+				fyni = fy_node_next(&fyn->sequence, fyni)) {
+			if (!fy_node_is_empty(fyni))
+				return false;
+		}
+		break;
+	case FYNT_MAPPING:
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp;
+				fynp = fy_node_pair_next(&fyn->mapping, fynp)) {
+			if (!fy_node_is_empty(fynp->value))
+				return false;
+		}
+		break;
+	}
+	return true;
+}
+
+#define fy_node_walk_ctx_create_a(_max_depth, _mark, _res) \
+	do { \
+		unsigned int __max_depth = (_max_depth); \
+		struct fy_node_walk_ctx *_ctx; \
+		\
+		_ctx = FY_ALLOCA(sizeof(*_ctx) + sizeof(struct fy_node *) * __max_depth); \
+		_ctx->max_depth = _max_depth; \
+		_ctx->next_slot = 0; \
+		_ctx->mark = (_mark); \
+		*(_res) = _ctx; \
+	} while(false)
+
+static inline void fy_node_walk_mark_start(struct fy_node_walk_ctx *ctx)
+{
+	ctx->next_slot = 0;
+}
+
+static inline void fy_node_walk_mark_end(struct fy_node_walk_ctx *ctx)
+{
+	struct fy_node *fyn;
+
+	while (ctx->next_slot > 0) {
+		fyn = ctx->marked[--ctx->next_slot];
+		fyn->marks &= ~ctx->mark;
+	}
+}
+
+/* fyn is guaranteed to be non NULL and an alias */
+static inline bool fy_node_walk_mark(struct fy_node_walk_ctx *ctx, struct fy_node *fyn)
+{
+	struct fy_document *fyd = fyn->fyd;
+	struct fy_token *fyt = NULL;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		fyt = fyn->scalar;
+		break;
+	case FYNT_SEQUENCE:
+		fyt = fyn->sequence_start;
+		break;
+	case FYNT_MAPPING:
+		fyt = fyn->mapping_start;
+		break;
+	}
+
+	/* depth error */
+	FYD_TOKEN_ERROR_CHECK(fyd, fyt, FYEM_DOC,
+		ctx->next_slot < ctx->max_depth, err_out,
+		"max recursion depth exceeded (%u)", ctx->max_depth);
+
+	/* mark found, loop */
+	FYD_TOKEN_ERROR_CHECK(fyd, fyt, FYEM_DOC,
+		!(fyn->marks & ctx->mark), err_out,
+		"cyclic reference detected");
+
+	fyn->marks |= ctx->mark;
+	ctx->marked[ctx->next_slot++] = fyn;
+
+	return true;
+
+err_out:
+	return false;
+}
+
+static struct fy_node *
+fy_node_follow_aliases(struct fy_node *fyn, enum fy_node_walk_flags flags, bool single)
+{
+	enum fy_node_walk_flags ptr_flags;
+	struct fy_ptr_node_list nl;
+	struct fy_ptr_node *fypn;
+
+	if (!fyn || !fy_node_is_alias(fyn) || !(flags & FYNWF_FOLLOW))
+		return fyn;
+
+	ptr_flags = flags & FYNWF_PTR(FYNWF_PTR_MASK);
+	if (ptr_flags != FYNWF_PTR_YAML && ptr_flags != FYNWF_PTR_YPATH)
+		return fyn;
+
+	fy_ptr_node_list_init(&nl);
+
+	while (fyn && fy_node_is_alias(fyn)) {
+
+		// fprintf(stderr, "%s: %s\n", __func__, fy_node_get_path_FY_ALLOCA(fyn));
+
+		/* check for loops */
+		if (fy_ptr_node_list_contains(&nl, fyn)) {
+			fyn = NULL;
+			break;
+		}
+
+		/* out of memory? */
+		fypn = fy_ptr_node_create(fyn);
+		if (!fypn) {
+			fyn = NULL;
+			break;
+		}
+		fy_ptr_node_list_add_tail(&nl, fypn);
+
+		fyn = fy_node_follow_alias(fyn, flags);
+
+		if (single)
+			break;
+	}
+
+	/* release */
+	while ((fypn = fy_ptr_node_list_pop(&nl)) != NULL)
+		fy_ptr_node_destroy(fypn);
+
+	return fyn;
+}
+
+struct fy_node *fy_node_resolve_alias(struct fy_node *fyn)
+{
+	enum fy_node_walk_flags flags;
+
+	if (!fyn)
+		return NULL;
+
+	flags = FYNWF_FOLLOW | FYNWF_MAXDEPTH_DEFAULT | FYNWF_MARKER_DEFAULT;
+	if (fyn->fyd->parse_cfg.flags & FYPCF_YPATH_ALIASES)
+		flags |= FYNWF_PTR_YPATH;
+	else
+		flags |= FYNWF_PTR_YAML;
+	return fy_node_follow_aliases(fyn, flags, false);
+}
+
+struct fy_node *fy_node_dereference(struct fy_node *fyn)
+{
+	enum fy_node_walk_flags flags;
+
+	if (!fyn || !fy_node_is_alias(fyn))
+		return NULL;
+
+	flags = FYNWF_FOLLOW | FYNWF_MAXDEPTH_DEFAULT | FYNWF_MARKER_DEFAULT;
+	if (fyn->fyd->parse_cfg.flags & FYPCF_YPATH_ALIASES)
+		flags |= FYNWF_PTR_YPATH;
+	else
+		flags |= FYNWF_PTR_YAML;
+	return fy_node_follow_aliases(fyn, flags, true);
+}
+
+static struct fy_node *
+fy_node_by_path_internal(struct fy_node *fyn,
+			 const char *path, size_t pathlen,
+		         enum fy_node_walk_flags flags)
+{
+	enum fy_node_walk_flags ptr_flags;
+	struct fy_node *fynt, *fyni;
+	const char *s, *e, *ss, *ee;
+	char *end_idx, *json_key, *t, *p, *uri_path;
+	char c;
+	int idx, rlen;
+	size_t len, json_key_len, uri_path_len;
+	bool has_json_key_esc;
+	uint8_t code[4];
+	int code_length;
+	bool trailing_slash;
+
+	if (!fyn || !path)
+		return NULL;
+
+	ptr_flags = flags & FYNWF_PTR(FYNWF_PTR_MASK);
+	if (ptr_flags == FYNWF_PTR_YPATH)
+		return fy_node_by_ypath(fyn, path, pathlen);
+
+	s = path;
+	if (pathlen == (size_t)-1)
+		pathlen = strlen(path);
+	e = s + pathlen;
+
+	/* a trailing slash works just like unix and symbolic links
+	 * if it does not exist no symbolic link lookups are performed
+	 * at the end of the operation.
+	 * if it exists they are followed upon resolution
+	 */
+	trailing_slash = pathlen > 0 && path[pathlen - 1] == '/';
+
+	/* and continue on path lookup with the rest */
+
+	/* skip all prefixed / */
+	switch (ptr_flags) {
+	default:
+	case FYNWF_PTR_YAML:
+		while (s < e && *s == '/')
+			s++;
+		/* for a last component / always match this one */
+		if (s >= e)
+			goto out;
+		break;
+
+	case FYNWF_PTR_JSON:
+		/* "" -> everything here */
+		if (s == e)
+			return fyn;
+		/* it must have a separator here */
+		if (*s != '/')
+			return NULL;
+		s++;
+		break;
+
+	case FYNWF_PTR_RELJSON:
+		break;
+	}
+
+	/* fyd_notice(fyn->fyd, "%s:%d following alias @%s \"%.*s\"",
+			__func__, __LINE__, fy_node_get_path(fyn), (int)(e - s), s); */
+	fyn = fy_node_follow_aliases(fyn, flags, true);
+
+	/* scalar can be only last element in the path (it has no key) */
+	if (fy_node_is_scalar(fyn)) {
+		if (*s)
+			fyn = NULL;	/* not end of the path - fail */
+		goto out;
+	}
+
+	/* for a sequence the only allowed key is [n] where n is the index to follow */
+	if (fy_node_is_sequence(fyn)) {
+
+		c = -1;
+		switch (ptr_flags) {
+		default:
+		case FYNWF_PTR_YAML:
+			while (s < e && isspace(*s))
+				s++;
+
+			c = *s;
+			if (c == '[')
+				s++;
+			else if (!isdigit(c) && c != '-')
+				return NULL;
+
+			idx = (int)strtol(s, &end_idx, 10);
+
+			/* no digits found at all */
+			if (idx == 0 && end_idx == s)
+				return NULL;
+
+			s = end_idx;
+
+			while (s < e && isspace(*s))
+				s++;
+
+			if (c == '[' && *s++ != ']')
+				return NULL;
+
+			while (s < e && isspace(*s))
+				s++;
+
+			break;
+
+		case FYNWF_PTR_JSON:
+		case FYNWF_PTR_RELJSON:
+
+			/* special array end - always fails */
+			if (*s == '-')
+				return NULL;
+
+			idx = (int)strtol(s, &end_idx, 10);
+
+			/* no digits found at all */
+			if (idx == 0 && end_idx == s)
+				return NULL;
+
+			/* no negatives */
+			if (idx < 0)
+				return NULL;
+
+			s = end_idx;
+
+			if (s < e && *s == '/')
+				s++;
+
+			break;
+		}
+
+		len = e - s;
+
+		fyn = fy_node_sequence_get_by_index(fyn, idx);
+		if (trailing_slash)
+			fyn = fy_node_follow_aliases(fyn, flags, false);
+		fyn = fy_node_by_path_internal(fyn, s, len, flags);
+		goto out;
+	}
+
+	/* be a little bit paranoid */
+	assert(fy_node_is_mapping(fyn));
+
+	path = s;
+	pathlen = (size_t)(e - s);
+
+	switch (ptr_flags) {
+	default:
+	case FYNWF_PTR_YAML:
+
+		/* scan ahead for the end of the path component
+		* note that we don't do UTF8 here, because all the
+		* escapes are regular ascii characters, i.e.
+		* '/', '*', '&', '.', '{', '}', '[', ']' and '\\'
+		*/
+
+		while (s < e) {
+			c = *s;
+			/* end of path component? */
+			if (c == '/')
+				break;
+			s++;
+
+			if (c == '\\') {
+				/* it must be a valid escape */
+				if (s >= e || !strchr("/*&.{}[]\\", *s))
+					return NULL;
+				s++;
+			} else if (c == '"') {
+				while (s < e && *s != '"') {
+					c = *s++;
+					if (c == '\\' && (s < e && *s == '"'))
+						s++;
+				}
+				/* not a normal double quote end */
+				if (s >= e || *s != '"')
+					return NULL;
+				s++;
+			} else if (c == '\'') {
+				while (s < e && *s != '\'') {
+					c = *s++;
+					if (c == '\'' && (s < e && *s == '\''))
+						s++;
+				}
+				/* not a normal single quote end */
+				if (s >= e || *s != '\'')
+					return NULL;
+				s++;
+			}
+		}
+		len = s - path;
+
+		fynt = fyn;
+		fyn = fy_node_mapping_lookup_by_string(fyn, path, len);
+
+		/* failed! last ditch attempt, is there a merge key? */
+		if (!fyn && fynt && (flags & FYNWF_FOLLOW) && ptr_flags == FYNWF_PTR_YAML) {
+			fyn = fy_node_mapping_lookup_by_string(fynt, "<<", 2);
+			if (!fyn)
+				goto out;
+
+			if (fy_node_is_alias(fyn)) {
+
+				/* single alias '<<: *foo' */
+				fyn = fy_node_mapping_lookup_by_string(
+						fy_node_follow_aliases(fyn, flags, false), path, len);
+
+			} else if (fy_node_is_sequence(fyn)) {
+
+				/* multi aliases '<<: [ *foo, *bar ]' */
+				fynt = fyn;
+				for (fyni = fy_node_list_head(&fynt->sequence); fyni;
+						fyni = fy_node_next(&fynt->sequence, fyni)) {
+					if (!fy_node_is_alias(fyni))
+						continue;
+					fyn = fy_node_mapping_lookup_by_string(
+							fy_node_follow_aliases(fyni, flags, false),
+							path, len);
+					if (fyn)
+						break;
+				}
+			} else
+				fyn = NULL;
+		}
+		break;
+
+	case FYNWF_PTR_JSON:
+	case FYNWF_PTR_RELJSON:
+
+		has_json_key_esc = false;
+		while (s < e) {
+			c = *s;
+			/* end of path component? */
+			if (c == '/')
+				break;
+			s++;
+			if (c == '~')
+				has_json_key_esc = true;
+		}
+		len = s - path;
+
+		if (has_json_key_esc) {
+			/* note that the escapes reduce the length, so allocating the
+			 * same size is guaranteed safe */
+			json_key = FY_ALLOCA(len + 1);
+
+			ss = path;
+			ee = s;
+			t = json_key;
+			while (ss < ee) {
+				if (*ss != '~') {
+					*t++ = *ss++;
+					continue;
+				}
+				/* unterminated ~ escape, or neither ~0, ~1 */
+				if (ss + 1 >= ee || (ss[1] < '0' && ss[1] > '1'))
+					return NULL;
+				*t++ = ss[1] == '0' ? '~' : '/';
+				ss += 2;
+			}
+			json_key_len = t - json_key;
+
+			path = json_key;
+			len = json_key_len;
+		}
+
+		/* URI encoded escaped */
+		if ((flags & FYNWF_URI_ENCODED) && memchr(path, '%', len)) {
+			/* escapes shrink, so safe to allocate as much */
+			uri_path = FY_ALLOCA(len + 1);
+
+			ss = path;
+			ee = path + len;
+			t = uri_path;
+			while (ss < ee) {
+				/* copy run until '%' or end */
+				p = memchr(ss, '%', ee - ss);
+				rlen = (p ? p : ee) - ss;
+				memcpy(t, ss, rlen);
+				ss += rlen;
+				t += rlen;
+
+				/* if end, break */
+				if (!p)
+					break;
+
+				/* collect a utf8 character sequence */
+				code_length = sizeof(code);
+				ss = fy_uri_esc(ss, ee - ss, code, &code_length);
+				if (!ss) {
+					/* bad % escape sequence */
+					return NULL;
+				}
+				memcpy(t, code, code_length);
+				t += code_length;
+			}
+			uri_path_len = t - uri_path;
+
+			path = uri_path;
+			len = uri_path_len;
+		}
+
+		fynt = fyn;
+		fyn = fy_node_mapping_lookup_value_by_simple_key(fyn, path, len);
+		break;
+	}
+
+	len = e - s;
+
+	if (len > 0 && trailing_slash) {
+		/* fyd_notice(fyn->fyd, "%s:%d following alias @%s \"%.*s\"",
+				__func__, __LINE__, fy_node_get_path(fyn), (int)(e - s), s); */
+		fyn = fy_node_follow_aliases(fyn, flags, true);
+	}
+
+	fyn = fy_node_by_path_internal(fyn, s, len, flags);
+
+out:
+	len = e - s;
+
+	if (len > 0 && trailing_slash) {
+		/* fyd_notice(fyn->fyd, "%s:%d following alias @%s \"%.*s\"",
+				__func__, __LINE__, fy_node_get_path(fyn), (int)(e - s), s); */
+		fyn = fy_node_follow_aliases(fyn, flags, true);
+	}
+
+	return fyn;
+}
+
+struct fy_node *fy_node_by_path(struct fy_node *fyn,
+				const char *path, size_t len,
+				enum fy_node_walk_flags flags)
+{
+	struct fy_document *fyd;
+	struct fy_anchor *fya;
+	const char *s, *e, *t, *anchor;
+	size_t alen;
+	char c;
+	int idx, w;
+	char *end_idx;
+
+	if (!fyn || !path)
+		return NULL;
+
+	if (len == (size_t)-1)
+		len = strlen(path);
+
+	/* verify that the path string is well formed UTF8 */
+	s = path;
+	e = s + len;
+
+	fyd = fyn->fyd;
+	while (s < e) {
+		c = fy_utf8_get(s, e - s, &w);
+		if (c < 0) {
+			fyd_error(fyd, "fy_node_by_path() malformed path string\n");
+			return NULL;
+		}
+		s += w;
+	}
+
+	/* rewind */
+	s = path;
+
+	/* if it's a YPATH, just punt to that method */
+	if ((flags & FYNWF_PTR(FYNWF_PTR_MASK)) == FYNWF_PTR_YPATH)
+		return fy_node_by_ypath(fyn, path, len);
+
+	/* fyd_notice(fyn->fyd, "%s: %.*s", __func__, (int)(len), s); */
+
+	/* first path component may be an alias */
+	if ((flags & FYNWF_FOLLOW) && fyn && path) {
+		while (s < e && isspace(*s))
+			s++;
+
+		if (s >= e || *s != '*')
+			goto regular_path_lookup;
+
+		s++;
+
+		c = -1;
+		for (t = s; t < e; t++) {
+			c = *t;
+			/* it ends on anything non alias */
+			if (c == '[' || c == ']' ||
+				c == '{' || c == '}' ||
+				c == ',' || c == ' ' || c == '\t' ||
+				c == '/')
+				break;
+		}
+
+		/* bad alias form for path */
+		if (c == '[' || c == ']' || c == '{' || c == '}' || c == ',')
+			return NULL;
+
+		anchor = s;
+		alen = t - s;
+
+		if (alen) {
+			/* we must be terminated by '/' or space followed by '/' */
+			/* strip until spaces and '/' end */
+			while (t < e && (*t == ' ' || *t == '\t'))
+				t++;
+
+			while (t < e && *t == '/')
+				t++;
+
+			/* update path */
+			path = t;
+			len = e - t;
+
+			/* fyd_notice(fyn->fyd, "%s: looking up anchor=%.*s", __func__, (int)(alen), anchor); */
+
+			/* lookup anchor */
+			fya = fy_document_lookup_anchor(fyn->fyd, anchor, alen);
+			if (!fya) {
+				/* fyd_notice(fyn->fyd, "%s: failed to lookup anchor=%.*s", __func__, (int)(alen), anchor); */
+				return NULL;
+			}
+
+			/* fyd_notice(fyn->fyd, "%s: found anchor=%.*s at %s",
+					__func__, (int)(alen), anchor, fy_node_get_path(fya->fyn)); */
+
+			/* nothing more? we're done */
+			if (*path == '\0')
+				return fya->fyn;
+
+			/* anchor found... all good */
+
+			fyn = fya->fyn;
+		} else {
+			/* no anchor it must be of the form *\/ */
+
+			path = s;
+			len = e - s;
+		}
+
+		/* fyd_notice(fyn->fyd, "%s: continuing looking for %.*s",
+				__func__, (int)(len), path); */
+
+	}
+
+regular_path_lookup:
+
+	/* if it's a relative json pointer... */
+	if ((flags & FYNWF_PTR(FYNWF_PTR_MASK)) == FYNWF_PTR_RELJSON) {
+
+		/* it must at least be one digit */
+		if (len == 0)
+			return NULL;
+
+		idx = (int)strtol(path, &end_idx, 10);
+
+		/* at least one digit must exist */
+		if (idx == 0 && path == end_idx)
+			return NULL;
+
+		e = path + len;
+		len = e - end_idx;
+		path = end_idx;
+
+		/* we don't do the trailing # here */
+		if (len == 1 && *path == '#')
+			return NULL;
+
+		while (idx-- > 0)
+			fyn = fy_node_get_parent(fyn);
+
+		/* convert to regular json pointer from now on */
+		flags &= ~FYNWF_PTR(FYNWF_PTR_MASK);
+		flags |= FYNWF_PTR_JSON;
+	}
+
+	return fy_node_by_path_internal(fyn, path, len, flags);
+}
+
+static char *
+fy_node_get_reference_internal(struct fy_node *fyn_base, struct fy_node *fyn, bool near)
+{
+	struct fy_anchor *fya;
+	const char *path;
+	char *path2, *path3;
+	const char *text;
+	size_t len;
+
+	if (!fyn)
+		return NULL;
+
+	path2 = NULL;
+
+	/* if the node has an anchor use it (ie return *foo) */
+	if (!fyn_base && (fya = fy_node_get_anchor(fyn)) != NULL) {
+		text = fy_anchor_get_text(fya, &len);
+		if (!text)
+			return NULL;
+		path2 = FY_ALLOCA(1 + len + 1);
+		path2[0] = '*';
+		memcpy(path2 + 1, text, len);
+		path2[len + 1] = '\0';
+
+	} else {
+
+		fya = fyn_base ? fy_node_get_anchor(fyn_base) : NULL;
+		if (!fya && near)
+			fya = fy_node_get_nearest_anchor(fyn);
+		if (!fya) {
+			/* no anchor, direct reference (ie return *\/foo\/bar */
+			fy_node_get_path_alloca(fyn, &path);
+			if (!*path)
+				return NULL;
+			path2 = FY_ALLOCA(1 + strlen(path) + 1);
+			path2[0] = '*';
+			strcpy(path2 + 1, path);
+		} else {
+			text = fy_anchor_get_text(fya, &len);
+			if (!text)
+				return NULL;
+			if (fy_anchor_node(fya) != fyn) {
+				fy_node_get_path_relative_to_alloca(fy_anchor_node(fya), fyn, &path);
+				if (*path) {
+					/* we have a relative path */
+					path2 = FY_ALLOCA(1 + len + 1 + strlen(path) + 1);
+					path2[0] = '*';
+					memcpy(path2 + 1, text, len);
+					path2[len + 1] = '/';
+					memcpy(1 + path2 + len + 1, path, strlen(path) + 1);
+				} else {
+					/* absolute path */
+					fy_node_get_path_alloca(fyn, &path);
+					if (!*path)
+						return NULL;
+					path2 = FY_ALLOCA(1 + strlen(path) + 1);
+					path2[0] = '*';
+					strcpy(path2 + 1, path);
+				}
+			} else {
+				path2 = FY_ALLOCA(1 + len + 1);
+				path2[0] = '*';
+				memcpy(path2 + 1, text, len);
+				path2[len + 1] = '\0';
+			}
+		}
+	}
+
+	if (!path2)
+		return NULL;
+
+	path3 = strdup(path2);
+	if (!path3)
+		return NULL;
+
+	return path3;
+}
+
+char *fy_node_get_reference(struct fy_node *fyn)
+{
+	return fy_node_get_reference_internal(NULL, fyn, false);
+}
+
+struct fy_node *fy_node_create_reference(struct fy_node *fyn)
+{
+	struct fy_node *fyn_ref;
+	char *path, *alias;
+
+	path = fy_node_get_reference(fyn);
+	if (!path)
+		return NULL;
+
+	alias = path;
+	if (*alias == '*')
+		alias++;
+
+	fyn_ref = fy_node_create_alias_copy(fy_node_document(fyn), alias, FY_NT);
+
+	free(path);
+
+	return fyn_ref;
+}
+
+char *fy_node_get_relative_reference(struct fy_node *fyn_base, struct fy_node *fyn)
+{
+	return fy_node_get_reference_internal(fyn_base, fyn, false);
+}
+
+struct fy_node *fy_node_create_relative_reference(struct fy_node *fyn_base, struct fy_node *fyn)
+{
+	struct fy_node *fyn_ref;
+	char *path, *alias;
+
+	path = fy_node_get_relative_reference(fyn_base, fyn);
+	if (!path)
+		return NULL;
+
+	alias = path;
+	if (*alias == '*')
+		alias++;
+
+	fyn_ref = fy_node_create_alias_copy(fy_node_document(fyn), alias, FY_NT);
+
+	free(path);
+
+	return fyn_ref;
+}
+
+bool fy_check_ref_loop(struct fy_document *fyd, struct fy_node *fyn,
+		       enum fy_node_walk_flags flags,
+		       struct fy_node_walk_ctx *ctx)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp, *fynpi;
+	struct fy_node_walk_ctx *ctxn;
+	bool ret;
+
+	if (!fyn)
+		return false;
+
+	/* visited? no need to check */
+	if (fyn->marks & FY_BIT(FYNWF_VISIT_MARKER))
+		return false;
+
+	/* marked node, it's a loop */
+	if (ctx && !fy_node_walk_mark(ctx, fyn))
+		return true;
+
+	ret = false;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+
+		/* if it's not an alias, we're done */
+		if (!fy_node_is_alias(fyn))
+			break;
+
+		ctxn = ctx;
+		if (!ctxn) 
+			fy_node_walk_ctx_create_a(
+				fy_node_walk_max_depth_from_flags(flags), FYNWF_REF_MARKER, &ctxn);
+
+
+		if (!ctx) {
+			fy_node_walk_mark_start(ctxn);
+
+			/* mark this node */
+			fy_node_walk_mark(ctxn, fyn);
+		}
+
+		fyni = fy_node_follow_alias(fyn, flags);
+
+		ret = fy_check_ref_loop(fyd, fyni, flags, ctxn);
+
+		if (!ctx)
+			fy_node_walk_mark_end(ctxn);
+
+		if (ret)
+			break;
+
+		break;
+
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+				fyni = fy_node_next(&fyn->sequence, fyni)) {
+
+			ret = fy_check_ref_loop(fyd, fyni, flags, ctx);
+			if (ret)
+				break;
+		}
+		break;
+
+	case FYNT_MAPPING:
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp; fynp = fynpi) {
+
+			fynpi = fy_node_pair_next(&fyn->mapping, fynp);
+
+			ret = fy_check_ref_loop(fyd, fynp->key, flags, ctx);
+			if (ret)
+				break;
+
+			ret = fy_check_ref_loop(fyd, fynp->value, flags, ctx);
+			if (ret)
+				break;
+		}
+		break;
+	}
+
+	/* mark as visited */
+	fyn->marks |= FY_BIT(FYNWF_VISIT_MARKER);
+
+	return ret;
+}
+
+char *fy_node_get_parent_address(struct fy_node *fyn)
+{
+	struct fy_node *parent, *fyni;
+	struct fy_node_pair *fynp;
+	struct fy_node *fyna;
+	char *path = NULL;
+	const char *str;
+	size_t len;
+	int idx;
+	bool is_key_root;
+	int ret;
+	const char *fmt;
+	char *new_path, *old_path;
+
+	if (!fyn)
+		return NULL;
+
+	parent = fy_node_get_document_parent(fyn);
+	if (!parent)
+		return NULL;
+
+	if (fy_node_is_sequence(parent)) {
+
+		/* for a sequence, find the index */
+		idx = 0;
+		for (fyni = fy_node_list_head(&parent->sequence); fyni;
+				fyni = fy_node_next(&parent->sequence, fyni)) {
+			if (fyni == fyn)
+				break;
+			idx++;
+		}
+
+		if (!fyni)
+			return NULL;
+
+		ret = asprintf(&path, "%d", idx);
+		if (ret == -1)
+			return NULL;
+	}
+
+	if (fy_node_is_mapping(parent)) {
+
+		is_key_root = fyn->key_root;
+
+		idx = 0;
+		fyna = NULL;
+		for (fynp = fy_node_pair_list_head(&parent->mapping); fynp;
+				fynp = fy_node_pair_next(&parent->mapping, fynp)) {
+
+			if ((!is_key_root && fynp->value == fyn) || (is_key_root && fynp->key == fyn))
+				break;
+			idx++;
+		}
+
+		if (!fynp)
+			return NULL;
+
+		fyna = fynp->key;
+		if (!fyna)
+			return NULL;
+
+		/* if key is a plain scalar try to not use a complex style (even for quoted) */
+		if (fyna && fy_node_is_scalar(fyna) && !fy_node_is_alias(fyna) &&
+				(str = fy_token_get_scalar_path_key(fyna->scalar, &len)) != NULL) {
+
+			fmt = !is_key_root ? "%.*s" : ".key(%.*s)";
+			ret = asprintf(&path, fmt, (int)len, str);
+			if (ret == -1)
+				return NULL;
+
+		} else {
+
+			/* something complex, emit it */
+			path = fy_emit_node_to_string(fyna,
+				FYECF_MODE_FLOW_ONELINE | FYECF_WIDTH_INF |
+				FYECF_STRIP_LABELS	| FYECF_STRIP_TAGS |
+				FYECF_NO_ENDING_NEWLINE);
+			if (!path)
+				return NULL;
+
+			if (is_key_root) {
+				old_path = path;
+				ret = asprintf(&new_path, ".key(%s)", path);
+				if (ret == -1) {
+					free(path);
+					return NULL;
+				}
+				free(old_path);
+				path = new_path;
+			}
+		}
+	}
+
+	return path;
+}
+
+char *fy_node_get_path(struct fy_node *fyn)
+{
+	struct path_track {
+		struct path_track *prev;
+		char *path;
+	};
+	struct path_track *track, *newtrack;
+	char *path, *s, *path_mem;
+	size_t len;
+	struct fy_node *parent;
+
+	if (!fyn)
+		return NULL;
+
+	/* easy on the root */
+	parent = fy_node_get_document_parent(fyn);
+	if (!parent) {
+		path_mem = strdup("/");
+		return path_mem;
+	}
+
+	track = NULL;
+	len = 0;
+	while ((path = fy_node_get_parent_address(fyn))) {
+		newtrack = FY_ALLOCA(sizeof(*newtrack));
+		newtrack->prev = track;
+		newtrack->path = path;
+
+		track = newtrack;
+
+		len += strlen(path) + 1;
+
+		fyn = fy_node_get_document_parent(fyn);
+	}
+	len += 2;
+
+	path_mem = malloc(len);
+
+	s = path_mem;
+
+	while (track) {
+		len = strlen(track->path);
+		if (s) {
+			*s++ = '/';
+			memcpy(s, track->path, len);
+			s += len;
+		}
+		free(track->path);
+		track = track->prev;
+	}
+
+	if (s)
+		*s = '\0';
+
+	return path_mem;
+}
+
+char *fy_node_get_path_relative_to(struct fy_node *fyn_parent, struct fy_node *fyn)
+{
+	char *path, *ppath, *path2, *path_ret;
+	size_t pathlen, ppathlen;
+	struct fy_node *ni, *nj;
+
+	if (!fyn)
+		return NULL;
+
+	/* must be on the same document */
+	if (fyn_parent && (fyn_parent->fyd != fyn->fyd))
+		return NULL;
+
+	if (!fyn_parent)
+		fyn_parent = fyn->fyd->root;
+
+	/* verify that it's a parent */
+	ni = fyn;
+	while ((nj = fy_node_get_parent(ni)) != NULL && nj != fyn_parent)
+		ni = nj;
+
+	/* not a parent, illegal */
+	if (!nj)
+		return NULL;
+
+	/* here we go... */
+	path = "";
+	pathlen = 0;
+
+	ni = fyn;
+	while ((nj = fy_node_get_parent(ni)) != NULL) {
+		ppath = fy_node_get_parent_address(ni);
+		if (!ppath)
+			return NULL;
+
+		ppathlen = strlen(ppath);
+
+		if (pathlen > 0) {
+			path2 = FY_ALLOCA(pathlen + 1 + ppathlen + 1);
+			memcpy(path2, ppath, ppathlen);
+			path2[ppathlen] = '/';
+			memcpy(path2 + ppathlen + 1, path, pathlen);
+			path2[ppathlen + 1 + pathlen] = '\0';
+		} else {
+			path2 = FY_ALLOCA(ppathlen + 1);
+			memcpy(path2, ppath, ppathlen);
+			path2[ppathlen] = '\0';
+		}
+
+		path = path2;
+		pathlen = strlen(path);
+
+		free(ppath);
+		ni = nj;
+
+		if (ni == fyn_parent)
+			break;
+	}
+
+	path_ret = strdup(path);
+	return path_ret;
+}
+
+char *fy_node_get_short_path(struct fy_node *fyn)
+{
+	struct fy_node *fyn_anchor;
+	struct fy_anchor *fya;
+	const char *text;
+	size_t len;
+	const char *str;
+	char *path;
+
+	if (!fyn)
+		return NULL;
+
+	/* get the nearest anchor traversing upwards */
+	fya = fy_node_get_nearest_anchor(fyn);
+	if (!fya)
+		return fy_node_get_path(fyn);
+
+	fyn_anchor = fy_anchor_node(fya);
+
+	text = fy_anchor_get_text(fya, &len);
+	if (!text)
+		return NULL;
+
+	if (fyn_anchor == fyn) {
+		alloca_sprintf(&str, "*%.*s", (int)len, text);
+    } else {
+        fy_node_get_path_relative_to_alloca(fyn_anchor, fyn, &path);
+		alloca_sprintf(&str, "*%.*s/%s", (int)len, text, path);
+	}
+
+	path = strdup(str);
+	return path;
+}
+
+static struct fy_node *
+fy_document_load_node(struct fy_document *fyd, struct fy_parser *fyp,
+		      struct fy_document_state **fydsp)
+{
+	struct fy_eventp *fyep = NULL;
+	struct fy_event *fye = NULL;
+	struct fy_node *fyn = NULL;
+	int rc, depth;
+	bool was_stream_start;
+
+	if (!fyd || !fyp)
+		return NULL;
+
+	/* only single documents */
+	fy_parser_set_next_single_document(fyp);
+	fy_parser_set_default_document_state(fyp, fyd->fyds);
+
+again:
+	was_stream_start = false;
+	do {
+		/* get next event */
+		fyep = fy_parse_private(fyp);
+
+		/* no more */
+		if (!fyep)
+			return NULL;
+
+		was_stream_start = fyep->e.type == FYET_STREAM_START;
+
+		if (was_stream_start) {
+			fy_parse_eventp_recycle(fyp, fyep);
+			fyep = NULL;
+		}
+
+	} while (was_stream_start);
+
+	fye = &fyep->e;
+
+	/* STREAM_END */
+	if (fye->type == FYET_STREAM_END) {
+		fy_parse_eventp_recycle(fyp, fyep);
+
+		/* final STREAM_END? */
+		if (fyp->state == FYPS_END)
+			return NULL;
+
+		/* multi-stream */
+		goto again;
+	}
+
+	FYD_TOKEN_ERROR_CHECK(fyd, fy_event_get_token(fye), FYEM_DOC,
+			fye->type == FYET_DOCUMENT_START, err_out,
+			"bad event");
+
+	fy_parse_eventp_recycle(fyp, fyep);
+	fyep = NULL;
+	fye = NULL;
+
+	fyd_doc_debug(fyd, "calling load_node() for root");
+	depth = 0;
+	rc = fy_parse_document_load_node(fyp, fyd, fy_parse_private(fyp), &fyn, &depth);
+	fyd_error_check(fyd, !rc, err_out,
+			"fy_parse_document_load_node() failed");
+
+	rc = fy_parse_document_load_end(fyp, fyd, fy_parse_private(fyp));
+	fyd_error_check(fyd, !rc, err_out,
+			"fy_parse_document_load_node() failed");
+
+	/* always resolve parents */
+	fy_resolve_parent_node(fyd, fyn, NULL);
+
+	if (fydsp)
+		*fydsp = fy_document_state_ref(fyp->current_document_state);
+
+	return fyn;
+
+err_out:
+	fy_parse_eventp_recycle(fyp, fyep);
+	fyd->diag->on_error = false;
+	return NULL;
+}
+
+static struct fy_node *
+fy_node_build_internal(struct fy_document *fyd,
+		int (*parser_setup)(struct fy_parser *fyp, void *user),
+		void *user)
+{
+	struct fy_document_state *fyds = NULL;
+	struct fy_node *fyn = NULL;
+	struct fy_parser fyp_data, *fyp = &fyp_data;
+	struct fy_parse_cfg cfg;
+	struct fy_eventp *fyep;
+	int rc;
+	bool got_stream_end;
+
+	if (!fyd || !parser_setup)
+		return NULL;
+
+	cfg = fyd->parse_cfg;
+	cfg.diag = fyd->diag;
+	rc = fy_parse_setup(fyp, &cfg);
+	if (rc) {
+		fyd->diag->on_error = false;
+		return NULL;
+	}
+
+	rc = (*parser_setup)(fyp, user);
+	fyd_error_check(fyd, !rc, err_out,
+			"parser_setup() failed");
+
+	fyn = fy_document_load_node(fyd, fyp, &fyds);
+	fyd_error_check(fyd, fyn, err_out,
+			"fy_document_load_node() failed");
+
+	got_stream_end = false;
+	while (!got_stream_end && (fyep = fy_parse_private(fyp)) != NULL) {
+		if (fyep->e.type == FYET_STREAM_END)
+			got_stream_end = true;
+		fy_parse_eventp_recycle(fyp, fyep);
+	}
+
+	if (got_stream_end) {
+		fyep = fy_parse_private(fyp);
+
+		FYD_TOKEN_ERROR_CHECK(fyd, fy_event_get_token(&fyep->e), FYEM_DOC,
+				!fyep, err_out,
+				"trailing events after the last");
+
+		fy_parse_eventp_recycle(fyp, fyep);
+	}
+
+	rc = fy_document_state_merge(fyd->fyds, fyds);
+	fyd_error_check(fyd, !rc, err_out,
+			"fy_document_state_merge() failed");
+
+	fy_document_state_unref(fyds);
+
+	fy_parse_cleanup(fyp);
+
+	return fyn;
+
+err_out:
+	fy_node_detach_and_free(fyn);
+	fy_document_state_unref(fyds);
+	fy_parse_cleanup(fyp);
+	fyd->diag->on_error = false;
+	return NULL;
+}
+
+struct fy_node *fy_node_build_from_string(struct fy_document *fyd, const char *str, size_t len)
+{
+	struct fy_document_build_string_ctx ctx = {
+		.str = str,
+		.len = len,
+	};
+
+	return fy_node_build_internal(fyd, parser_setup_from_string, &ctx);
+}
+
+struct fy_node *fy_node_build_from_malloc_string(struct fy_document *fyd, char *str, size_t len)
+{
+	struct fy_document_build_malloc_string_ctx ctx = {
+		.str = str,
+		.len = len,
+	};
+
+	return fy_node_build_internal(fyd, parser_setup_from_malloc_string, &ctx);
+}
+
+struct fy_node *fy_node_build_from_file(struct fy_document *fyd, const char *file)
+{
+	struct fy_document_build_file_ctx ctx = {
+		.file = file,
+	};
+
+	return fy_node_build_internal(fyd, parser_setup_from_file, &ctx);
+}
+
+struct fy_node *fy_node_build_from_fp(struct fy_document *fyd, FILE *fp)
+{
+	struct fy_document_build_fp_ctx ctx = {
+		.name = NULL,
+		.fp = fp,
+	};
+
+	return fy_node_build_internal(fyd, parser_setup_from_fp, &ctx);
+}
+
+int fy_document_set_root(struct fy_document *fyd, struct fy_node *fyn)
+{
+	if (!fyd)
+		return -1;
+
+	if (fyn && fyn->attached)
+		return -1;
+
+	fy_node_detach_and_free(fyd->root);
+	fyd->root = NULL;
+
+	fyn->parent = NULL;
+	fyd->root = fyn;
+
+	if (fyn)
+		fyn->attached = true;
+
+	return 0;
+}
+
+#define FYNCSIF_ALIAS		FY_BIT(0)
+#define FYNCSIF_SIMPLE		FY_BIT(1)
+#define FYNCSIF_COPY		FY_BIT(2)
+#define FYNCSIF_MALLOCED	FY_BIT(3)
+
+static struct fy_node *
+fy_node_create_scalar_internal(struct fy_document *fyd, const char *data, size_t size,
+			       unsigned int flags)
+{
+	const bool alias = !!(flags & FYNCSIF_ALIAS);
+	const bool simple = !!(flags & FYNCSIF_SIMPLE);
+	const bool copy = !!(flags & FYNCSIF_COPY);
+	const bool malloced = !!(flags & FYNCSIF_MALLOCED);
+	struct fy_node *fyn = NULL;
+	struct fy_input *fyi;
+	struct fy_atom handle;
+	enum fy_scalar_style style;
+	char *data_copy = NULL;
+
+	if (!fyd)
+		return NULL;
+
+	if (data && size == (size_t)-1)
+		size = strlen(data);
+
+	fyn = fy_node_alloc(fyd, FYNT_SCALAR);
+	fyd_error_check(fyd, fyn, err_out,
+			"fy_node_alloc() failed");
+
+	if (copy) {
+		data_copy = malloc(size);
+		fyd_error_check(fyd, data_copy, err_out,
+				"malloc() failed");
+		memcpy(data_copy, data, size);
+		fyi = fy_input_from_malloc_data(data_copy, size, &handle, simple);
+	} else if (malloced)
+		fyi = fy_input_from_malloc_data((void *)data, size, &handle, simple);
+	else
+		fyi = fy_input_from_data(data, size, &handle, simple);
+	fyd_error_check(fyd, fyi, err_out,
+			"fy_input_from_data() failed");
+	data_copy = NULL;
+
+	if (!alias) {
+		style = handle.style == FYAS_PLAIN ? FYSS_PLAIN : FYSS_DOUBLE_QUOTED;
+		fyn->scalar = fy_token_create(FYTT_SCALAR, &handle, style);
+	} else
+		fyn->scalar = fy_token_create(FYTT_ALIAS, &handle, NULL);
+
+	fyd_error_check(fyd, fyn->scalar, err_out,
+			"fy_token_create() failed");
+
+	fyn->style = !alias ? (style == FYSS_PLAIN ? FYNS_PLAIN : FYNS_DOUBLE_QUOTED) : FYNS_ALIAS;
+
+	/* take away the input reference */
+	fy_input_unref(fyi);
+
+	return fyn;
+
+err_out:
+	if (data_copy)
+		free(data_copy);
+	fy_node_detach_and_free(fyn);
+	fyd->diag->on_error = false;
+	return NULL;
+}
+
+struct fy_node *fy_node_create_scalar(struct fy_document *fyd, const char *data, size_t size)
+{
+	return fy_node_create_scalar_internal(fyd, data, size, 0);
+}
+
+struct fy_node *fy_node_create_alias(struct fy_document *fyd, const char *data, size_t size)
+{
+	return fy_node_create_scalar_internal(fyd, data, size, FYNCSIF_ALIAS);
+}
+
+struct fy_node *fy_node_create_scalar_copy(struct fy_document *fyd, const char *data, size_t size)
+{
+	return fy_node_create_scalar_internal(fyd, data, size, FYNCSIF_COPY);
+}
+
+struct fy_node *fy_node_create_alias_copy(struct fy_document *fyd, const char *data, size_t size)
+{
+	return fy_node_create_scalar_internal(fyd, data, size, FYNCSIF_ALIAS | FYNCSIF_COPY);
+}
+
+struct fy_node *fy_node_create_vscalarf(struct fy_document *fyd, const char *fmt, va_list ap)
+{
+    char *str;
+
+	if (!fyd || !fmt)
+		return NULL;
+
+    alloca_vsprintf(&str, fmt, ap);
+	return fy_node_create_scalar_internal(fyd, str, FY_NT, FYNCSIF_COPY);
+}
+
+struct fy_node *fy_node_create_scalarf(struct fy_document *fyd, const char *fmt, ...)
+{
+	va_list ap;
+	struct fy_node *fyn;
+
+	va_start(ap, fmt);
+	fyn = fy_node_create_vscalarf(fyd, fmt, ap);
+	va_end(ap);
+
+	return fyn;
+}
+
+int fy_node_set_tag(struct fy_node *fyn, const char *data, size_t len)
+{
+	struct fy_document *fyd;
+	struct fy_tag_scan_info info;
+	int handle_length, uri_length, prefix_length;
+	const char *handle_start;
+	int rc;
+	struct fy_atom handle;
+	struct fy_input *fyi = NULL;
+	struct fy_token *fyt = NULL, *fyt_td = NULL;
+
+	if (!fyn || !data || !len || !fyn->fyd)
+		return -1;
+
+	fyd = fyn->fyd;
+
+	if (len == (size_t)-1)
+		len = strlen(data);
+
+	memset(&info, 0, sizeof(info));
+
+	rc = fy_tag_scan(data, len, &info);
+	if (rc)
+		goto err_out;
+
+	handle_length = info.handle_length;
+	uri_length = info.uri_length;
+	prefix_length = info.prefix_length;
+
+	handle_start = data + prefix_length;
+
+	fyt_td = fy_document_state_lookup_tag_directive(fyd->fyds,
+			handle_start, handle_length);
+	if (!fyt_td)
+		goto err_out;
+
+	fyi = fy_input_from_data(data, len, &handle, true);
+	if (!fyi)
+		goto err_out;
+
+	handle.style = FYAS_URI;
+	handle.direct_output = false;
+	handle.storage_hint = 0;
+	handle.storage_hint_valid = false;
+
+	fyt = fy_token_create(FYTT_TAG, &handle, prefix_length,
+				handle_length, uri_length, fyt_td);
+	if (!fyt)
+		goto err_out;
+
+	fy_token_unref(fyn->tag);
+	fyn->tag = fyt;
+
+	/* take away the input reference */
+	fy_input_unref(fyi);
+
+	return 0;
+err_out:
+	fyd->diag->on_error = false;
+	return -1;
+}
+
+int fy_node_remove_tag(struct fy_node *fyn)
+{
+	if (!fyn || !fyn->tag)
+		return -1;
+
+	fy_token_unref(fyn->tag);
+	fyn->tag = NULL;
+
+	return 0;
+}
+
+struct fy_node *fy_node_create_sequence(struct fy_document *fyd)
+{
+	struct fy_node *fyn;
+
+	fyn = fy_node_alloc(fyd, FYNT_SEQUENCE);
+	if (!fyn)
+		return NULL;
+
+	return fyn;
+}
+
+struct fy_node *fy_node_create_mapping(struct fy_document *fyd)
+{
+	struct fy_node *fyn;
+
+	fyn = fy_node_alloc(fyd, FYNT_MAPPING);
+	if (!fyn)
+		return NULL;
+
+	return fyn;
+}
+
+static int fy_node_sequence_insert_prepare(struct fy_node *fyn_seq, struct fy_node *fyn)
+{
+	struct fy_document *fyd;
+
+	if (!fyn_seq || !fyn || fyn_seq->type != FYNT_SEQUENCE)
+		return -1;
+
+	/* can't insert a node that's attached already */
+	if (fyn->attached)
+		return -1;
+
+	/* a document must be associated with the sequence */
+	fyd = fyn_seq->fyd;
+	if (!fyd)
+		return -1;
+
+	/* the documents of the nodes must match */
+	if (fyn->fyd != fyd)
+		return -1;
+
+	fyn->parent = fyn_seq;
+
+	return 0;
+}
+
+int fy_node_sequence_append(struct fy_node *fyn_seq, struct fy_node *fyn)
+{
+	int ret;
+
+	ret = fy_node_sequence_insert_prepare(fyn_seq, fyn);
+	if (ret)
+		return ret;
+
+	fy_node_mark_synthetic(fyn_seq);
+	fy_node_list_add_tail(&fyn_seq->sequence, fyn);
+	fyn->attached = true;
+	return 0;
+}
+
+int fy_node_sequence_prepend(struct fy_node *fyn_seq, struct fy_node *fyn)
+{
+	int ret;
+
+	ret = fy_node_sequence_insert_prepare(fyn_seq, fyn);
+	if (ret)
+		return ret;
+
+	fy_node_mark_synthetic(fyn_seq);
+	fy_node_list_add(&fyn_seq->sequence, fyn);
+	fyn->attached = true;
+	return 0;
+}
+
+static bool fy_node_sequence_contains_node(struct fy_node *fyn_seq, struct fy_node *fyn)
+{
+	struct fy_node *fyni;
+
+	if (!fyn_seq || !fyn || fyn_seq->type != FYNT_SEQUENCE)
+		return false;
+
+	for (fyni = fy_node_list_head(&fyn_seq->sequence); fyni; fyni = fy_node_next(&fyn_seq->sequence, fyni))
+		if (fyni == fyn)
+			return true;
+
+	return false;
+}
+
+int fy_node_sequence_insert_before(struct fy_node *fyn_seq,
+				   struct fy_node *fyn_mark, struct fy_node *fyn)
+{
+	int ret;
+
+	if (!fy_node_sequence_contains_node(fyn_seq, fyn_mark))
+		return -1;
+
+	ret = fy_node_sequence_insert_prepare(fyn_seq, fyn);
+	if (ret)
+		return ret;
+
+	fy_node_mark_synthetic(fyn_seq);
+	fy_node_list_insert_before(&fyn_seq->sequence, fyn_mark, fyn);
+	fyn->attached = true;
+
+	return 0;
+}
+
+int fy_node_sequence_insert_after(struct fy_node *fyn_seq,
+				   struct fy_node *fyn_mark, struct fy_node *fyn)
+{
+	int ret;
+
+	if (!fy_node_sequence_contains_node(fyn_seq, fyn_mark))
+		return -1;
+
+	ret = fy_node_sequence_insert_prepare(fyn_seq, fyn);
+	if (ret)
+		return ret;
+
+	fy_node_mark_synthetic(fyn_seq);
+	fy_node_list_insert_after(&fyn_seq->sequence, fyn_mark, fyn);
+	fyn->attached = true;
+
+	return 0;
+}
+
+struct fy_node *fy_node_sequence_remove(struct fy_node *fyn_seq, struct fy_node *fyn)
+{
+	if (!fy_node_sequence_contains_node(fyn_seq, fyn))
+		return NULL;
+
+	fy_node_list_del(&fyn_seq->sequence, fyn);
+	fyn->parent = NULL;
+	fyn->attached = false;
+
+	fy_node_mark_synthetic(fyn_seq);
+
+	return fyn;
+}
+
+static struct fy_node_pair *
+fy_node_mapping_pair_insert_prepare(struct fy_node *fyn_map,
+				    struct fy_node *fyn_key, struct fy_node *fyn_value)
+{
+	struct fy_document *fyd;
+	struct fy_node_pair *fynp;
+
+	if (!fyn_map || fyn_map->type != FYNT_MAPPING)
+		return NULL;
+
+	/* a document must be associated with the mapping */
+	fyd = fyn_map->fyd;
+	if (!fyd)
+		return NULL;
+
+	/* if not NULL, the documents of the nodes must match */
+	if ((fyn_key && fyn_key->fyd != fyd) ||
+	    (fyn_value && fyn_value->fyd != fyd))
+		return NULL;
+
+	/* if not NULL neither the key nor the value must be attached */
+	if ((fyn_key && fyn_key->attached) ||
+	    (fyn_value && fyn_value->attached))
+		return NULL;
+
+	/* if we don't allow duplicate keys */
+	if (!(fyd->parse_cfg.flags & FYPCF_ALLOW_DUPLICATE_KEYS)) {
+
+		 if (fy_node_mapping_key_is_duplicate(fyn_map, fyn_key))
+			return NULL;
+	}
+
+	fynp = fy_node_pair_alloc(fyd);
+	if (!fynp)
+		return NULL;
+
+	if (fyn_key) {
+		fyn_key->parent = fyn_map;
+		fyn_key->key_root = true;
+	}
+	if (fyn_value)
+		fyn_value->parent = fyn_map;
+
+	fynp->key = fyn_key;
+	fynp->value = fyn_value;
+	fynp->parent = fyn_map;
+
+	return fynp;
+}
+
+int fy_node_mapping_append(struct fy_node *fyn_map,
+			   struct fy_node *fyn_key, struct fy_node *fyn_value)
+{
+	struct fy_node_pair *fynp;
+
+	fynp = fy_node_mapping_pair_insert_prepare(fyn_map, fyn_key, fyn_value);
+	if (!fynp)
+		return -1;
+
+	fy_node_pair_list_add_tail(&fyn_map->mapping, fynp);
+	if (fyn_map->xl)
+		fy_accel_insert(fyn_map->xl , fyn_key, fynp);
+
+	if (fyn_key)
+		fyn_key->attached = true;
+	if (fyn_value)
+		fyn_value->attached = true;
+
+	fy_node_mark_synthetic(fyn_map);
+
+	return 0;
+}
+
+int fy_node_mapping_prepend(struct fy_node *fyn_map,
+			    struct fy_node *fyn_key, struct fy_node *fyn_value)
+{
+	struct fy_node_pair *fynp;
+
+	fynp = fy_node_mapping_pair_insert_prepare(fyn_map, fyn_key, fyn_value);
+	if (!fynp)
+		return -1;
+
+	if (fyn_key)
+		fyn_key->attached = true;
+	if (fyn_value)
+		fyn_value->attached = true;
+	fy_node_pair_list_add(&fyn_map->mapping, fynp);
+	if (fyn_map->xl)
+		fy_accel_insert(fyn_map->xl, fyn_key, fynp);
+
+	fy_node_mark_synthetic(fyn_map);
+
+	return 0;
+}
+
+bool fy_node_mapping_contains_pair(struct fy_node *fyn_map, struct fy_node_pair *fynp)
+{
+	struct fy_node_pair *fynpi;
+
+	if (!fyn_map || !fynp || fyn_map->type != FYNT_MAPPING)
+		return false;
+
+	if (fyn_map->xl) {
+		fynpi = fy_node_accel_lookup_by_node(fyn_map, fynp->key);
+		if (fynpi == fynp)
+			return true;
+	} else {
+		for (fynpi = fy_node_pair_list_head(&fyn_map->mapping); fynpi; fynpi = fy_node_pair_next(&fyn_map->mapping, fynpi))
+			if (fynpi == fynp)
+				return true;
+	}
+
+	return false;
+}
+
+int fy_node_mapping_remove(struct fy_node *fyn_map, struct fy_node_pair *fynp)
+{
+	if (!fy_node_mapping_contains_pair(fyn_map, fynp))
+		return -1;
+
+	fy_node_pair_list_del(&fyn_map->mapping, fynp);
+	if (fyn_map->xl)
+		fy_accel_remove(fyn_map->xl, fynp->key);
+
+	if (fynp->key) {
+		fynp->key->parent = NULL;
+		fynp->key->attached = false;
+	}
+
+	if (fynp->value) {
+		fynp->value->parent = NULL;
+		fynp->value->attached = false;
+	}
+
+	fynp->parent = NULL;
+
+	return 0;
+}
+
+/* returns value */
+struct fy_node *fy_node_mapping_remove_by_key(struct fy_node *fyn_map, struct fy_node *fyn_key)
+{
+	struct fy_node_pair *fynp;
+	struct fy_node *fyn_value;
+
+	fynp = fy_node_mapping_lookup_pair(fyn_map, fyn_key);
+	if (!fynp)
+		return NULL;
+
+	fyn_value = fynp->value;
+	if (fyn_value) {
+		fyn_value->parent = NULL;
+		fyn_value->attached = false;
+	}
+
+	/* do not free the key if it's the same pointer */
+	if (fyn_key != fynp->key)
+		fy_node_detach_and_free(fyn_key);
+	fynp->value = NULL;
+
+	fy_node_pair_list_del(&fyn_map->mapping, fynp);
+	if (fyn_map->xl)
+		fy_accel_remove(fyn_map->xl, fynp->key);
+
+	fy_node_pair_detach_and_free(fynp);
+
+	fy_node_mark_synthetic(fyn_map);
+
+	return fyn_value;
+}
+
+void *fy_node_mapping_sort_ctx_arg(struct fy_node_mapping_sort_ctx *ctx)
+{
+	return ctx->arg;
+}
+
+static int fy_node_mapping_sort_cmp(
+#ifdef __APPLE__
+void *arg, const void *a, const void *b
+#else
+const void *a, const void *b, void *arg
+#endif
+)
+{
+	struct fy_node_mapping_sort_ctx *ctx = arg;
+	struct fy_node_pair * const *fynppa = a, * const *fynppb = b;
+
+	assert(fynppa >= ctx->fynpp && fynppa < ctx->fynpp + ctx->count);
+	assert(fynppb >= ctx->fynpp && fynppb < ctx->fynpp + ctx->count);
+
+	return ctx->key_cmp(*fynppa, *fynppb, ctx->arg);
+}
+
+/* not! thread safe! */
+#if !defined(HAVE_QSORT_R) || !HAVE_QSORT_R || defined(__EMSCRIPTEN__) || defined(_MSC_VER)
+static struct fy_node_mapping_sort_ctx *fy_node_mapping_sort_ctx_no_qsort_r;
+
+static int fy_node_mapping_sort_cmp_no_qsort_r(const void *a, const void *b)
+{
+#ifdef __APPLE__
+	return fy_node_mapping_sort_cmp(
+			fy_node_mapping_sort_ctx_no_qsort_r,
+			a, b);
+#else
+	return fy_node_mapping_sort_cmp( a, b,
+			fy_node_mapping_sort_ctx_no_qsort_r);
+#endif
+}
+
+#endif
+
+static int fy_node_scalar_cmp_default(struct fy_node *fyn_a,
+				      struct fy_node *fyn_b,
+				      void *arg)
+{
+	/* handles NULL cases */
+	if (fyn_a == fyn_b)
+		return 0;
+	if (!fyn_a)
+		return 1;
+	if (!fyn_b)
+		return -1;
+	return fy_token_cmp(fyn_a->scalar, fyn_b->scalar);
+}
+
+/* the default sort method */
+static int fy_node_mapping_sort_cmp_default(const struct fy_node_pair *fynp_a,
+					    const struct fy_node_pair *fynp_b,
+					    void *arg)
+{
+	int idx_a, idx_b;
+	bool alias_a, alias_b, scalar_a, scalar_b;
+	struct fy_node_cmp_arg *cmp_arg;
+	fy_node_scalar_compare_fn cmp_fn;
+	void *cmp_fn_arg;
+
+	cmp_arg = arg;
+	cmp_fn = cmp_arg ? cmp_arg->cmp_fn : fy_node_scalar_cmp_default;
+	cmp_fn_arg = cmp_arg ? cmp_arg->arg : NULL;
+
+	/* order is: maps first, followed by sequences, and last scalars sorted */
+	scalar_a = !fynp_a->key || fy_node_is_scalar(fynp_a->key);
+	scalar_b = !fynp_b->key || fy_node_is_scalar(fynp_b->key);
+
+	/* scalar? perform comparison */
+	if (scalar_a && scalar_b) {
+
+		/* if both are aliases, sort skipping the '*' */
+		alias_a = fy_node_is_alias(fynp_a->key);
+		alias_b = fy_node_is_alias(fynp_b->key);
+
+		/* aliases win */
+		if (alias_a && !alias_b)
+			return -1;
+
+		if (!alias_a && alias_b)
+			return 1;
+
+		return cmp_fn(fynp_a->key, fynp_b->key, cmp_fn_arg);
+	}
+
+	/* b is scalar, a is not */
+	if (!scalar_a && scalar_b)
+		return -1;
+
+	/* a is scalar, b is not */
+	if (scalar_a && !scalar_b)
+		return 1;
+
+	/* different types, mappings win */
+	if (fynp_a->key->type != fynp_b->key->type)
+		return fynp_a->key->type == FYNT_MAPPING ? -1 : 1;
+
+	/* ok, need to compare indices now */
+	idx_a = fy_node_mapping_get_pair_index(fynp_a->parent, fynp_a);
+	idx_b = fy_node_mapping_get_pair_index(fynp_b->parent, fynp_b);
+
+	return idx_a > idx_b ? 1 : (idx_a < idx_b ? -1 : 0);
+}
+
+void fy_node_mapping_fill_array(struct fy_node *fyn_map,
+		struct fy_node_pair **fynpp, int count)
+{
+	struct fy_node_pair *fynpi;
+	int i;
+
+	for (i = 0, fynpi = fy_node_pair_list_head(&fyn_map->mapping); i < count && fynpi;
+		fynpi = fy_node_pair_next(&fyn_map->mapping, fynpi), i++)
+		fynpp[i] = fynpi;
+
+	/* if there's enough space, put down a NULL at the end */
+	if (i < count)
+		fynpp[i++] = NULL;
+	assert(i == count);
+
+}
+
+void fy_node_mapping_perform_sort(struct fy_node *fyn_map,
+		fy_node_mapping_sort_fn key_cmp, void *arg,
+		struct fy_node_pair **fynpp, int count)
+{
+	struct fy_node_mapping_sort_ctx ctx;
+	struct fy_node_cmp_arg def_arg;
+
+	if (!key_cmp) {
+		def_arg.cmp_fn = fy_node_scalar_cmp_default;
+		def_arg.arg = arg;
+	} else {
+		def_arg.cmp_fn = NULL;
+		def_arg.arg = NULL;
+	}
+	ctx.key_cmp = key_cmp ? key_cmp : fy_node_mapping_sort_cmp_default;
+	ctx.arg = key_cmp ? arg : &def_arg;
+	ctx.fynpp = fynpp;
+	ctx.count = count;
+#if defined(HAVE_QSORT_R) && HAVE_QSORT_R && !defined(__EMSCRIPTEN__) && !defined(_MSC_VER)
+#ifdef __APPLE__
+	qsort_r(fynpp, count, sizeof(*fynpp), &ctx, fy_node_mapping_sort_cmp);
+#else
+	qsort_r(fynpp, count, sizeof(*fynpp), fy_node_mapping_sort_cmp, &ctx);
+#endif
+#else
+	/* caution, not thread safe */
+	fy_node_mapping_sort_ctx_no_qsort_r = &ctx;
+	qsort(fynpp, count, sizeof(*fynpp), fy_node_mapping_sort_cmp_no_qsort_r);
+	fy_node_mapping_sort_ctx_no_qsort_r = NULL;
+#endif
+}
+
+struct fy_node_pair **fy_node_mapping_sort_array(struct fy_node *fyn_map,
+		fy_node_mapping_sort_fn key_cmp, void *arg, int *countp)
+{
+	int count;
+	struct fy_node_pair **fynpp;
+
+	count = fy_node_mapping_item_count(fyn_map);
+	if (count < 0)
+		return NULL;
+
+	fynpp = malloc((count + 1) * sizeof(*fynpp));
+	if (!fynpp)
+		return NULL;
+
+	memset(fynpp, 0, (count + 1) * sizeof(*fynpp));
+
+	fy_node_mapping_fill_array(fyn_map, fynpp, count);
+	fy_node_mapping_perform_sort(fyn_map, key_cmp, arg, fynpp, count);
+
+	if (countp)
+		*countp = count;
+
+	return fynpp;
+}
+
+void fy_node_mapping_release_array(struct fy_node *fyn_map, struct fy_node_pair **fynpp)
+{
+	if (!fyn_map || !fynpp)
+		return;
+
+	free(fynpp);
+}
+
+int fy_node_mapping_sort(struct fy_node *fyn_map,
+		fy_node_mapping_sort_fn key_cmp,
+		void *arg)
+{
+	int count, i;
+	struct fy_node_pair **fynpp, *fynpi;
+
+	fynpp = fy_node_mapping_sort_array(fyn_map, key_cmp, arg, &count);
+	if (!fynpp)
+		return -1;
+
+	fy_node_pair_list_init(&fyn_map->mapping);
+	for (i = 0; i < count; i++) {
+		fynpi = fynpp[i];
+		fy_node_pair_list_add_tail(&fyn_map->mapping, fynpi);
+	}
+
+	fy_node_mapping_release_array(fyn_map, fynpp);
+
+	return 0;
+}
+
+int fy_node_sort(struct fy_node *fyn, fy_node_mapping_sort_fn key_cmp, void *arg)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp, *fynpi;
+	int ret;
+
+	if (!fyn)
+		return 0;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		break;
+
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+				fyni = fy_node_next(&fyn->sequence, fyni)) {
+
+			fy_node_sort(fyni, key_cmp, arg);
+		}
+		break;
+
+	case FYNT_MAPPING:
+		ret = fy_node_mapping_sort(fyn, key_cmp, arg);
+		if (ret)
+			return ret;
+
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp; fynp = fynpi) {
+
+			fynpi = fy_node_pair_next(&fyn->mapping, fynp);
+
+			/* the parent of the key is always NULL */
+			ret = fy_node_sort(fynp->key, key_cmp, arg);
+			if (ret)
+				return ret;
+
+			ret = fy_node_sort(fynp->value, key_cmp, arg);
+			if (ret)
+				return ret;
+
+			fynp->parent = fyn;
+		}
+		break;
+	}
+
+	return 0;
+}
+
+struct fy_node *fy_node_vbuildf(struct fy_document *fyd, const char *fmt, va_list ap)
+{
+	struct fy_document_vbuildf_ctx vctx;
+	struct fy_node *fyn;
+
+	vctx.fmt = fmt;
+	va_copy(vctx.ap, ap);
+	fyn = fy_node_build_internal(fyd, parser_setup_from_fmt_ap, &vctx);
+	va_end(ap);
+
+	return fyn;
+}
+
+struct fy_node *fy_node_buildf(struct fy_document *fyd, const char *fmt, ...)
+{
+	struct fy_node *fyn;
+	va_list ap;
+
+	va_start(ap, fmt);
+	fyn = fy_node_vbuildf(fyd, fmt, ap);
+	va_end(ap);
+
+	return fyn;
+}
+
+struct fy_document *fy_document_vbuildf(const struct fy_parse_cfg *cfg, const char *fmt, va_list ap)
+{
+	struct fy_document *fyd;
+	struct fy_document_vbuildf_ctx vctx;
+
+	vctx.fmt = fmt;
+	va_copy(vctx.ap, ap);
+	fyd = fy_document_build_internal(cfg, parser_setup_from_fmt_ap, &vctx);
+	va_end(ap);
+
+	return fyd;
+}
+
+struct fy_document *fy_document_buildf(const struct fy_parse_cfg *cfg, const char *fmt, ...)
+{
+	struct fy_document *fyd;
+	va_list ap;
+
+	va_start(ap, fmt);
+	fyd = fy_document_vbuildf(cfg, fmt, ap);
+	va_end(ap);
+
+	return fyd;
+}
+
+struct flow_reader_container {
+	struct fy_reader reader;
+	const struct fy_parse_cfg *cfg;
+};
+
+static struct fy_diag *flow_reader_get_diag(struct fy_reader *fyr)
+{
+	struct flow_reader_container *frc = fy_container_of(fyr, struct flow_reader_container, reader);
+	return frc->cfg ? frc->cfg->diag : NULL;
+}
+
+static const struct fy_reader_ops reader_ops = {
+	.get_diag = flow_reader_get_diag,
+};
+
+struct fy_document *
+fy_flow_document_build_from_string(const struct fy_parse_cfg *cfg,
+				   const char *str, size_t len, size_t *consumed)
+{
+	struct flow_reader_container frc;
+	struct fy_reader *fyr = NULL;
+	struct fy_parser fyp_data, *fyp = &fyp_data;
+	struct fy_parse_cfg cfg_data;
+	struct fy_input *fyi;
+	struct fy_document *fyd;
+	struct fy_mark mark;
+	int rc;
+
+	if (!str)
+		return NULL;
+
+	if (consumed)
+		*consumed = 0;
+
+	if (!cfg) {
+		memset(&cfg_data, 0, sizeof(cfg_data));
+		cfg_data.flags = FYPCF_DEFAULT_PARSE;
+		cfg = &cfg_data;
+	}
+
+	memset(&frc, 0, sizeof(frc));
+	fyr = &frc.reader;
+	frc.cfg = cfg;
+
+	fy_reader_setup(fyr, &reader_ops);
+
+	rc = fy_parse_setup(fyp, cfg);
+	if (rc)
+		goto err_no_parse;
+
+	fyi = fy_input_from_data(str, len, NULL, false);
+	if (!fyi)
+		goto err_no_input;
+
+	rc = fy_reader_input_open(fyr, fyi, NULL);
+	if (rc)
+		goto err_no_input_open;
+
+	fy_parser_set_reader(fyp, fyr);
+	fy_parser_set_flow_only_mode(fyp, true);
+
+	fyd = fy_parse_load_document(fyp);
+
+	fy_parse_cleanup(fyp);
+
+	if (fyd && consumed) {
+		fy_reader_get_mark(fyr, &mark);
+		*consumed = mark.input_pos;
+	}
+
+	fy_reader_cleanup(fyr);
+	fy_input_unref(fyi);
+
+	return fyd;
+
+err_no_input_open:
+	fy_input_unref(fyi);
+err_no_input:
+	fy_parse_cleanup(fyp);
+err_no_parse:
+	fy_reader_cleanup(fyr);
+	return NULL;
+}
+
+int fy_node_vscanf(struct fy_node *fyn, const char *fmt, va_list ap)
+{
+	size_t len;
+	char *fmt_cpy, *s, *e, *t, *te, *key, *fmtspec;
+	const char *value;
+	char *value0;
+	size_t value_len, value0_len;
+	int count, ret;
+	struct fy_node *fynv;
+	va_list apt;
+
+	if (!fyn || !fmt)
+		goto err_out;
+
+	len = strlen(fmt);
+	fmt_cpy = FY_ALLOCA(len + 1);
+	memcpy(fmt_cpy, fmt, len + 1);
+	s = fmt_cpy;
+	e = s + len;
+
+	/* the format is of the form 'access key' %fmt[...] */
+	/* so we search for a (non escaped '%) */
+	value0 = NULL;
+	value0_len = 0;
+	count = 0;
+	while (s < e) {
+		/* a '%' format must exist */
+		t = strchr(s, '%');
+		if (!t)
+			goto err_out;
+
+		/* skip escaped % */
+		if (t + 1 < e && t[1] == '%') {
+			s = t + 2;
+			continue;
+		}
+
+		/* trim spaces from key */
+		while (isspace(*s))
+			s++;
+		te = t;
+		while (te > s && isspace(te[-1]))
+			*--te = '\0';
+
+		key = s;
+
+		/* we have to scan until the next space that's not in char set */
+		fmtspec = t;
+		while (t < e) {
+			if (isspace(*t))
+				break;
+			/* character set (may include space) */
+			if (*t == '[') {
+				t++;
+				/* skip caret */
+				if (t < e && *t == '^')
+					t++;
+				/* if first character in the set is ']' accept it */
+				if (t < e && *t == ']')
+					t++;
+				/* now skip until end of character set */
+				while (t < e && *t != ']')
+					t++;
+				continue;
+			}
+			t++;
+		}
+		if (t < e)
+			*t++ = '\0';
+
+		/* find by (relative) path */
+		fynv = fy_node_by_path(fyn, key, t - s, FYNWF_DONT_FOLLOW);
+		if (!fynv || fynv->type != FYNT_SCALAR)
+			break;
+
+		/* there must be a text */
+		value = fy_token_get_text(fynv->scalar, &value_len);
+		if (!value)
+			break;
+
+		/* allocate buffer it's smaller than the one we have already */
+		if (!value0 || value0_len < value_len) {
+			value0 = FY_ALLOCA(value_len + 1);
+			value0_len = value_len;
+		}
+
+		memcpy(value0, value, value_len);
+		value0[value_len] = '\0';
+
+		va_copy(apt, ap);
+		/* scanf, all arguments are pointers */
+		(void)va_arg(ap, void *);	/* advance argument pointer */
+
+		/* pass it to the system's scanf method */
+		ret = vsscanf(value0, fmtspec, apt);
+
+		/* since it's a single specifier, it must be one on success */
+		if (ret != 1)
+			break;
+
+		s = t;
+		count++;
+	}
+
+	return count;
+
+err_out:
+	errno = -EINVAL;
+	return -1;
+}
+
+int fy_node_scanf(struct fy_node *fyn, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = fy_node_vscanf(fyn, fmt, ap);
+	va_end(ap);
+
+	return ret;
+}
+
+int fy_document_vscanf(struct fy_document *fyd, const char *fmt, va_list ap)
+{
+	return fy_node_vscanf(fyd->root, fmt, ap);
+}
+
+int fy_document_scanf(struct fy_document *fyd, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = fy_document_vscanf(fyd, fmt, ap);
+	va_end(ap);
+
+	return ret;
+}
+
+bool fy_document_has_directives(const struct fy_document *fyd)
+{
+	struct fy_document_state *fyds;
+
+	if (!fyd)
+		return false;
+
+	fyds = fyd->fyds;
+	if (!fyds)
+		return false;
+
+	return fyds->fyt_vd || !fy_token_list_empty(&fyds->fyt_td);
+}
+
+bool fy_document_has_explicit_document_start(const struct fy_document *fyd)
+{
+	return fyd ? !fyd->fyds->start_implicit : false;
+}
+
+bool fy_document_has_explicit_document_end(const struct fy_document *fyd)
+{
+	return fyd ? !fyd->fyds->end_implicit : false;
+}
+
+void *fy_node_get_meta(struct fy_node *fyn)
+{
+	return fyn && fyn->has_meta ? fyn->meta : NULL;
+}
+
+int fy_node_set_meta(struct fy_node *fyn, void *meta)
+{
+	struct fy_document *fyd;
+
+	if (!fyn || !fyn->fyd)
+		return -1;
+
+	fyd = fyn->fyd;
+	if (fyn->has_meta && fyd->meta_clear_fn)
+		fyd->meta_clear_fn(fyn, fyn->meta, fyd->meta_user);
+	fyn->meta = meta;
+	fyn->has_meta = true;
+
+	return 0;
+}
+
+void fy_node_clear_meta(struct fy_node *fyn)
+{
+	struct fy_document *fyd;
+
+	if (!fyn || !fyn->has_meta || !fyn->fyd)
+		return;
+
+	fyd = fyn->fyd;
+	if (fyd->meta_clear_fn)
+		fyd->meta_clear_fn(fyn, fyn->meta, fyd->meta_user);
+	fyn->meta = NULL;
+	fyn->has_meta = false;
+}
+
+static void fy_node_clear_meta_internal(struct fy_node *fyn)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp, *fynpi;
+
+	if (!fyn)
+		return;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		break;
+
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+				fyni = fy_node_next(&fyn->sequence, fyni)) {
+
+			fy_node_clear_meta_internal(fyni);
+		}
+		break;
+
+	case FYNT_MAPPING:
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp; fynp = fynpi) {
+
+			fynpi = fy_node_pair_next(&fyn->mapping, fynp);
+
+			fy_node_clear_meta_internal(fynp->key);
+			fy_node_clear_meta_internal(fynp->value);
+		}
+		break;
+	}
+
+	fy_node_clear_meta(fyn);
+}
+
+int fy_document_register_meta(struct fy_document *fyd,
+			      fy_node_meta_clear_fn clear_fn,
+			      void *user)
+{
+	if (!fyd || !clear_fn || fyd->meta_clear_fn)
+		return -1;
+
+	fyd->meta_clear_fn = clear_fn;
+	fyd->meta_user = user;
+
+	return 0;
+}
+
+void fy_document_unregister_meta(struct fy_document *fyd)
+{
+	if (!fyd)
+		return;
+
+	fy_node_clear_meta_internal(fy_document_root(fyd));
+
+	fyd->meta_clear_fn = NULL;
+	fyd->meta_user = NULL;
+}
+
+bool fy_node_set_marker(struct fy_node *fyn, unsigned int marker)
+{
+	unsigned int prev_marks;
+
+	if (!fyn || marker > FYNWF_MAX_USER_MARKER)
+		return false;
+	prev_marks = fyn->marks;
+	fyn->marks |= FY_BIT(marker);
+	return !!(prev_marks & FY_BIT(marker));
+}
+
+bool fy_node_clear_marker(struct fy_node *fyn, unsigned int marker)
+{
+	unsigned int prev_marks;
+
+	if (!fyn || marker > FYNWF_MAX_USER_MARKER)
+		return false;
+	prev_marks = fyn->marks;
+	fyn->marks &= ~FY_BIT(marker);
+	return !!(prev_marks & FY_BIT(marker));
+}
+
+bool fy_node_is_marker_set(struct fy_node *fyn, unsigned int marker)
+{
+	if (!fyn || marker > FYNWF_MAX_USER_MARKER)
+		return false;
+	return !!(fyn->marks & FY_BIT(marker));
+}
+
+FILE *fy_document_get_error_fp(struct fy_document *fyd)
+{
+	/* just this for now */
+	return stderr;
+}
+
+enum fy_parse_cfg_flags fy_document_get_cfg_flags(const struct fy_document *fyd)
+{
+	if (!fyd)
+		return fy_parser_get_cfg_flags(NULL);
+
+	return fyd->parse_cfg.flags;
+}
+
+bool fy_document_can_be_accelerated(struct fy_document *fyd)
+{
+	if (!fyd)
+		return false;
+
+	return !(fyd->parse_cfg.flags & FYPCF_DISABLE_ACCELERATORS);
+}
+
+bool fy_document_is_accelerated(struct fy_document *fyd)
+{
+	if (!fyd)
+		return false;
+
+	return fyd->axl && fyd->naxl;
+}
+
+static int hd_anchor_hash(struct fy_accel *xl, const void *key, void *userdata, void *hash)
+{
+	struct fy_token *fyt = (void *)key;
+	unsigned int *hashp = hash;
+	const char *text;
+	size_t len;
+
+	text = fy_token_get_text(fyt, &len);
+	if (!text)
+		return -1;
+
+	*hashp = XXH32(text, len, 2654435761U);
+	return 0;
+}
+
+static bool hd_anchor_eq(struct fy_accel *xl, const void *hash, const void *key1, const void *key2, void *userdata)
+{
+	struct fy_token *fyt1 = (void *)key1, *fyt2 = (void *)key2;
+	const char *text1, *text2;
+	size_t len1, len2;
+
+	text1 = fy_token_get_text(fyt1, &len1);
+	if (!text1)
+		return false;
+	text2 = fy_token_get_text(fyt2, &len2);
+	if (!text2)
+		return false;
+
+	return len1 == len2 && !memcmp(text1, text2, len1);
+}
+
+static const struct fy_hash_desc hd_anchor = {
+	.size = sizeof(unsigned int),
+	.max_bucket_grow_limit = 6,	/* TODO allow tuning */
+	.hash = hd_anchor_hash,
+	.eq = hd_anchor_eq,
+};
+
+static int hd_nanchor_hash(struct fy_accel *xl, const void *key, void *userdata, void *hash)
+{
+	struct fy_node *fyn = (void *)key;
+	unsigned int *hashp = hash;
+	uintptr_t ptr = (uintptr_t)fyn;
+
+	*hashp = XXH32(&ptr, sizeof(ptr), 2654435761U);
+
+	return 0;
+}
+
+static bool hd_nanchor_eq(struct fy_accel *xl, const void *hash, const void *key1, const void *key2, void *userdata)
+{
+	struct fy_node *fyn1 = (void *)key1, *fyn2 = (void *)key2;
+
+	return fyn1 == fyn2;
+}
+
+static const struct fy_hash_desc hd_nanchor = {
+	.size = sizeof(unsigned int),
+	.max_bucket_grow_limit = 6,	/* TODO allow tuning */
+	.hash = hd_nanchor_hash,
+	.eq = hd_nanchor_eq,
+};
+
+
+static int hd_mapping_hash(struct fy_accel *xl, const void *key, void *userdata, void *hash)
+{
+	return fy_node_hash_uint((struct fy_node *)key, hash);
+}
+
+static bool hd_mapping_eq(struct fy_accel *xl, const void *hash, const void *key1, const void *key2, void *userdata)
+{
+	return fy_node_compare((struct fy_node *)key1, (struct fy_node *)key2);
+}
+
+static const struct fy_hash_desc hd_mapping = {
+	.size = sizeof(unsigned int),
+	.max_bucket_grow_limit = 6,	/* TODO allow tuning */
+	.hash = hd_mapping_hash,
+	.eq = hd_mapping_eq,
+};
+
+typedef void (*fy_hash_update_fn)(void *state, const void *ptr, size_t size);
+
+static int
+fy_node_hash_internal(struct fy_node *fyn, fy_hash_update_fn update_fn, void *state)
+{
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp;
+	struct fy_node_pair **fynpp;
+	struct fy_token_iter iter;
+	int i, count, rc;
+	const struct fy_iter_chunk *ic;
+
+	if (!fyn) {
+		/* NULL */
+		update_fn(state, "s", 1);	/* as zero length scalar */
+		return 0;
+	}
+
+	switch (fyn->type) {
+	case FYNT_SEQUENCE:
+		/* SEQUENCE */
+		update_fn(state, "S", 1);
+
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+		     fyni = fy_node_next(&fyn->sequence, fyni)) {
+
+			rc = fy_node_hash_internal(fyni, update_fn, state);
+			if (rc)
+				return rc;
+		}
+
+		break;
+
+	case FYNT_MAPPING:
+		count = fy_node_mapping_item_count(fyn);
+
+		fynpp = FY_ALLOCA(sizeof(*fynpp) * (count + 1));
+
+		fy_node_mapping_fill_array(fyn, fynpp, count);
+		fy_node_mapping_perform_sort(fyn, NULL, NULL, fynpp, count);
+
+		/* MAPPING */
+		update_fn(state, "M", 1);
+
+		for (i = 0; i < count; i++) {
+			fynp = fynpp[i];
+
+			/* MAPPING KEY */
+			update_fn(state, "K", 1);
+			rc = fy_node_hash_internal(fynp->key, update_fn, state);
+			if (rc)
+				return rc;
+
+			/* MAPPING VALUE */
+			update_fn(state, "V", 1);
+			rc = fy_node_hash_internal(fynp->value, update_fn, state);
+			if (rc)
+				return rc;
+		}
+
+		break;
+
+	case FYNT_SCALAR:
+		update_fn(state, !fy_node_is_alias(fyn) ? "s" : "A", 1);
+
+		fy_token_iter_start(fyn->scalar, &iter);
+		ic = NULL;
+		while ((ic = fy_token_iter_chunk_next(&iter, ic, &rc)) != NULL)
+			update_fn(state, ic->str, ic->len);
+		fy_token_iter_finish(&iter);
+
+		break;
+	}
+
+	return 0;
+}
+
+static void update_xx32(void *state, const void *ptr, size_t size)
+{
+	XXH32_update(state, ptr, size);
+}
+
+int fy_node_hash_uint(struct fy_node *fyn, unsigned int *hashp)
+{
+	XXH32_state_t state;
+	int rc;
+
+	XXH32_reset(&state, 2654435761U);
+
+	rc = fy_node_hash_internal(fyn, update_xx32, &state);
+	if (rc)
+		return rc;
+
+	*hashp = XXH32_digest(&state);
+	return 0;
+}
+
+struct fy_document_state *fy_document_get_document_state(struct fy_document *fyd)
+{
+	return fyd ? fyd->fyds : NULL;
+}
+
+int fy_document_set_document_state(struct fy_document *fyd, struct fy_document_state *fyds)
+{
+	/* document must exist and not have any contents */
+	if (!fyd || fyd->root)
+		return -1;
+
+	if (!fyds)
+		fyds = fy_document_state_default(NULL, NULL);
+	else
+		fyds = fy_document_state_ref(fyds);
+
+	if (!fyds)
+		return -1;
+
+	/* drop the previous document state */
+	fy_document_state_unref(fyd->fyds);
+	/* and use the new document state from now on */
+	fyd->fyds = fyds;
+
+	return 0;
+}
+
+struct fy_ptr_node *fy_ptr_node_create(struct fy_node *fyn)
+{
+	struct fy_ptr_node *fypn;
+
+	if (!fyn)
+		return NULL;
+
+	fypn = malloc(sizeof(*fypn));
+	if (!fypn)
+		return NULL;
+	memset(&fypn->node, 0, sizeof(fypn->node));
+	fypn->fyn = fyn;
+	return fypn;
+}
+
+void fy_ptr_node_destroy(struct fy_ptr_node *fypn)
+{
+	free(fypn);
+}
+
+void fy_ptr_node_list_free_all(struct fy_ptr_node_list *fypnl)
+{
+	struct fy_ptr_node *fypn;
+
+	while ((fypn = fy_ptr_node_list_pop(fypnl)) != NULL)
+		fy_ptr_node_destroy(fypn);
+}
+
+bool fy_ptr_node_list_contains(struct fy_ptr_node_list *fypnl, struct fy_node *fyn)
+{
+	struct fy_ptr_node *fypn;
+
+	if (!fypnl || !fyn)
+		return false;
+	for (fypn = fy_ptr_node_list_head(fypnl); fypn; fypn = fy_ptr_node_next(fypnl, fypn)) {
+		if (fypn->fyn == fyn)
+			return true;
+	}
+	return false;
+}
+
+struct fy_document *
+fy_document_create_from_event(struct fy_parser *fyp, struct fy_event *fye)
+{
+	struct fy_document *fyd;
+	int rc;
+
+	if (!fyp || !fye || fye->type != FYET_DOCUMENT_START)
+		return NULL;
+
+	/* TODO update document end */
+	fyd = fy_document_create(&fyp->cfg);
+	fyp_error_check(fyp, fyd, err_out,
+		"fy_document_create() failed");
+
+	rc = fy_document_set_document_state(fyd, fye->document_start.document_state);
+	fyp_error_check(fyp, !rc, err_out,
+		"fy_document_set_document_state() failed");
+
+	return fyd;
+
+err_out:
+	fy_document_destroy(fyd);
+	return NULL;
+}
+
+int
+fy_document_update_from_event(struct fy_document *fyd, struct fy_parser *fyp, struct fy_event *fye)
+{
+	if (!fyd || !fyp || !fye || fye->type != FYET_DOCUMENT_END)
+		return -1;
+
+	/* nothing besides checks */
+	return 0;
+}
+
+struct fy_node *
+fy_node_create_from_event(struct fy_document *fyd, struct fy_parser *fyp, struct fy_event *fye)
+{
+	struct fy_node *fyn = NULL;
+	struct fy_token *value = NULL, *anchor = NULL;
+	int rc;
+
+	if (!fyd || !fye)
+		return NULL;
+
+	switch (fye->type) {
+	default:
+		break;
+
+	case FYET_SCALAR:
+		fyn = fy_node_alloc(fyd, FYNT_SCALAR);
+		fyp_error_check(fyp, fyn, err_out,
+			"fy_node_alloc() scalar failed");
+
+		value = fye->scalar.value;
+
+		if (value)	/* NULL scalar */
+			fyn->style = fy_node_style_from_scalar_style(value->scalar.style);
+		else
+			fyn->style = FYNS_PLAIN;
+
+		/* NULLs are OK */
+		fyn->tag = fy_token_ref(fye->scalar.tag);
+		fyn->scalar = fy_token_ref(value);
+		anchor = fye->scalar.anchor;
+		break;
+
+	case FYET_ALIAS:
+		fyn = fy_node_alloc(fyd, FYNT_SCALAR);
+		fyp_error_check(fyp, fyn, err_out,
+			"fy_node_alloc() alias failed");
+
+		value = fye->alias.anchor;
+		fyn->style = FYNS_ALIAS;
+		fyn->scalar = fy_token_ref(value);
+		anchor = NULL;
+		break;
+
+	case FYET_MAPPING_START:
+		fyn = fy_node_create_mapping(fyd);
+		fyp_error_check(fyp, fyn, err_out,
+			"fy_node_create_mapping() failed");
+
+		value = fye->mapping_start.mapping_start;
+		fyn->style = value->type == FYTT_FLOW_MAPPING_START ? FYNS_FLOW : FYNS_BLOCK;
+
+		fyn->tag = fy_token_ref(fye->mapping_start.tag);
+		fyn->mapping_start = fy_token_ref(value);
+		fyn->mapping_end = NULL;
+		anchor = fye->mapping_start.anchor;
+		break;
+
+	case FYET_SEQUENCE_START:
+		fyn = fy_node_create_sequence(fyd);
+		fyp_error_check(fyp, fyn, err_out,
+			"fy_node_create_sequence() failed");
+
+		value = fye->sequence_start.sequence_start;
+
+		fyn->style = value->type == FYTT_FLOW_SEQUENCE_START ? FYNS_FLOW : FYNS_BLOCK;
+
+		fyn->tag = fy_token_ref(fye->sequence_start.tag);
+		fyn->sequence_start = fy_token_ref(value);
+		fyn->sequence_end = NULL;
+		anchor = fye->sequence_start.anchor;
+
+		break;
+
+	}
+
+	if (fyn && anchor) {
+		rc = fy_document_register_anchor(fyd, fyn, fy_token_ref(anchor));
+		fyp_error_check(fyp, !rc, err_out,
+			"fy_document_register_anchor() failed");
+	}
+
+	return fyn;
+
+err_out:
+	/* NULL OK */
+	fy_node_free(fyn);
+	return NULL;
+}
+
+int
+fy_node_update_from_event(struct fy_node *fyn, struct fy_parser *fyp, struct fy_event *fye)
+{
+	if (!fyn || !fyp || !fye)
+		return -1;
+
+	switch (fye->type) {
+
+	case FYET_MAPPING_END:
+		if (!fy_node_is_mapping(fyn))
+			return -1;
+		fy_token_unref(fyn->mapping_end);
+		fyn->mapping_end = fy_token_ref(fye->mapping_end.mapping_end);
+
+		break;
+
+	case FYET_SEQUENCE_END:
+		if (!fy_node_is_sequence(fyn))
+			return -1;
+		fy_token_unref(fyn->sequence_end);
+		fyn->sequence_end = fy_token_ref(fye->sequence_end.sequence_end);
+
+		break;
+
+	default:
+		return -1;
+	}
+
+	return 0;
+}
+
+struct fy_node_pair *
+fy_node_pair_create_with_key(struct fy_document *fyd, struct fy_node *fyn_parent, struct fy_node *fyn)
+{
+	struct fy_node_pair *fynp;
+	bool is_duplicate;
+
+	if (!fyd || !fyn_parent || !fy_node_is_mapping(fyn_parent))
+		return NULL;
+
+	/* if we don't allow duplicate keys */
+	if (!(fyd->parse_cfg.flags & FYPCF_ALLOW_DUPLICATE_KEYS)) {
+
+		/* make sure we don't add an already existing key */
+		is_duplicate = fy_node_mapping_key_is_duplicate(fyn_parent, fyn);
+		if (is_duplicate) {
+			FYD_NODE_ERROR(fyd, fyn, FYEM_DOC,
+					"duplicate mapping key");
+			return NULL;
+		}
+	}
+
+	fynp = fy_node_pair_alloc(fyd);
+	fyd_error_check(fyd, fynp, err_out,
+			"fy_node_pair_alloc() failed");
+
+	fynp->parent = fyn_parent;
+
+	fynp->key = fyn;
+	if (fynp->key)
+		fynp->key->attached = true;
+
+	return fynp;
+
+err_out:
+	fy_node_pair_free(fynp);
+	return NULL;
+
+}
+
+int
+fy_node_pair_update_with_value(struct fy_node_pair *fynp, struct fy_node *fyn)
+{
+	struct fy_node *fyn_parent;
+	int rc;
+
+	/* node pair must exist and value must be NULL */
+	if (!fynp || fynp->value || !fynp->parent || !fy_node_is_mapping(fynp->parent) || !fyn->fyd)
+		return -1;
+
+	fynp->value = fyn;
+	if (fynp->value)
+		fynp->value->attached = true;
+
+	fyn_parent = fynp->parent;
+
+	fy_node_pair_list_add_tail(&fyn_parent->mapping, fynp);
+	if (fyn_parent->xl) {
+		rc = fy_accel_insert(fyn_parent->xl, fynp->key, fynp);
+		fyd_error_check(fyn->fyd, !rc, err_out,
+			"fy_accel_insert() failed");
+	}
+
+	return 0;
+
+err_out:
+	fy_node_pair_list_del(&fyn_parent->mapping, fynp);
+	if (fyn)
+		fyn->attached = false;
+	fynp->value = NULL;
+	return -1;
+}
+
+int
+fy_node_sequence_add_item(struct fy_node *fyn_parent, struct fy_node *fyn)
+{
+	/* node pair must exist and value must be NULL */
+	if (!fyn_parent || !fyn || !fy_node_is_sequence(fyn_parent) || !fyn->fyd)
+		return -1;
+
+	fyn->parent = fyn_parent;
+	fy_node_list_add_tail(&fyn_parent->sequence, fyn);
+	fyn->attached = true;
+	return 0;
+}
+
+void fy_document_iterator_setup(struct fy_document_iterator *fydi)
+{
+	memset(fydi, 0, sizeof(*fydi));
+	fydi->state = FYDIS_WAITING_STREAM_START;
+	fydi->fyd = NULL;
+	fydi->iterate_root = NULL;
+
+	/* suppress recycling if we must */
+	fydi->suppress_recycling_force = getenv("FY_VALGRIND") && !getenv("FY_VALGRIND_RECYCLING");
+	fydi->suppress_recycling = fydi->suppress_recycling_force;
+
+	fy_eventp_list_init(&fydi->recycled_eventp);
+	fy_token_list_init(&fydi->recycled_token);
+
+	if (!fydi->suppress_recycling) {
+		fydi->recycled_eventp_list = &fydi->recycled_eventp;
+		fydi->recycled_token_list = &fydi->recycled_token;
+	} else {
+		fydi->recycled_eventp_list = NULL;
+		fydi->recycled_token_list = NULL;
+	}
+
+	/* start with the stack pointing to the in place data */
+	fydi->stack_top = (unsigned int)-1;
+	fydi->stack_alloc = sizeof(fydi->in_place) / sizeof(fydi->in_place[0]);
+	fydi->stack = fydi->in_place;
+}
+
+void fy_document_iterator_cleanup(struct fy_document_iterator *fydi)
+{
+	struct fy_token *fyt;
+	struct fy_eventp *fyep;
+
+	/* free the stack if it's not the inplace one */
+	if (fydi->stack != fydi->in_place)
+		free(fydi->stack);
+	fydi->stack_top = (unsigned int)-1;
+	fydi->stack_alloc = sizeof(fydi->in_place) / sizeof(fydi->in_place[0]);
+	fydi->stack = fydi->in_place;
+
+	while ((fyt = fy_token_list_pop(&fydi->recycled_token)) != NULL)
+		fy_token_free(fyt);
+
+	while ((fyep = fy_eventp_list_pop(&fydi->recycled_eventp)) != NULL)
+		fy_eventp_free(fyep);
+
+	fydi->state = FYDIS_WAITING_STREAM_START;
+	fydi->fyd = NULL;
+	fydi->iterate_root = NULL;
+}
+
+struct fy_document_iterator *fy_document_iterator_create(void)
+{
+	struct fy_document_iterator *fydi;
+
+	fydi = malloc(sizeof(*fydi));
+	if (!fydi)
+		return NULL;
+	fy_document_iterator_setup(fydi);
+	return fydi;
+}
+
+void fy_document_iterator_destroy(struct fy_document_iterator *fydi)
+{
+	if (!fydi)
+		return;
+	fy_document_iterator_cleanup(fydi);
+	free(fydi);
+}
+
+static struct fy_event *
+fydi_event_create(struct fy_document_iterator *fydi, struct fy_node *fyn, bool start)
+{
+	struct fy_eventp *fyep;
+	struct fy_event *fye;
+	struct fy_anchor *fya;
+	struct fy_token *anchor = NULL;
+
+	fyep = fy_document_iterator_eventp_alloc(fydi);
+	if (!fyep) {
+		fydi->state = FYDIS_ERROR;
+		return NULL;
+	}
+	fye = &fyep->e;
+
+	if (start) {
+		fya = fy_node_get_anchor(fyn);
+		anchor = fya ? fya->anchor : NULL;
+	}
+
+	switch (fyn->type) {
+
+	case FYNT_SCALAR:
+		if (fyn->style != FYNS_ALIAS) {
+			fye->type = FYET_SCALAR;
+			fye->scalar.anchor = fy_token_ref(anchor);
+			fye->scalar.tag = fy_token_ref(fyn->tag);
+			fye->scalar.value = fy_token_ref(fyn->scalar);
+		} else {
+			fye->type = FYET_ALIAS;
+			fye->alias.anchor = fy_token_ref(fyn->scalar);
+		}
+		break;
+
+	case FYNT_SEQUENCE:
+		if (start) {
+			fye->type = FYET_SEQUENCE_START;
+			fye->sequence_start.anchor = fy_token_ref(anchor);
+			fye->sequence_start.tag = fy_token_ref(fyn->tag);
+			fye->sequence_start.sequence_start = fy_token_ref(fyn->sequence_start);
+		} else {
+			fye->type = FYET_SEQUENCE_END;
+			fye->sequence_end.sequence_end = fy_token_ref(fyn->sequence_end);
+		}
+		break;
+
+	case FYNT_MAPPING:
+		if (start) {
+			fye->type = FYET_MAPPING_START;
+			fye->mapping_start.anchor = fy_token_ref(anchor);
+			fye->mapping_start.tag = fy_token_ref(fyn->tag);
+			fye->mapping_start.mapping_start = fy_token_ref(fyn->mapping_start);
+		} else {
+			fye->type = FYET_MAPPING_END;
+			fye->mapping_end.mapping_end = fy_token_ref(fyn->mapping_end);
+		}
+		break;
+	}
+
+	return fye;
+}
+
+struct fy_event *
+fy_document_iterator_stream_start(struct fy_document_iterator *fydi)
+{
+	struct fy_event *fye;
+
+	if (!fydi || fydi->state == FYDIS_ERROR)
+		return NULL;
+
+	/* both none and stream start are the same for this */
+	if (fydi->state != FYDIS_WAITING_STREAM_START &&
+	    fydi->state != FYDIS_WAITING_STREAM_END_OR_DOCUMENT_START)
+		goto err_out;
+
+	fye = fy_document_iterator_event_create(fydi, FYET_STREAM_START);
+	if (!fye)
+		goto err_out;
+
+	fydi->state = FYDIS_WAITING_DOCUMENT_START;
+	return fye;
+
+err_out:
+	fydi->state = FYDIS_ERROR;
+	return NULL;
+}
+
+struct fy_event *
+fy_document_iterator_stream_end(struct fy_document_iterator *fydi)
+{
+	struct fy_event *fye;
+
+	if (!fydi || fydi->state == FYDIS_ERROR)
+		return NULL;
+
+	if (fydi->state != FYDIS_WAITING_STREAM_END_OR_DOCUMENT_START &&
+	    fydi->state != FYDIS_WAITING_DOCUMENT_START)
+		goto err_out;
+
+	fye = fy_document_iterator_event_create(fydi, FYET_STREAM_END);
+	if (!fye)
+		goto err_out;
+
+	fydi->state = FYDIS_WAITING_STREAM_START;
+	return fye;
+
+err_out:
+	fydi->state = FYDIS_ERROR;
+	return NULL;
+}
+
+struct fy_event *
+fy_document_iterator_document_start(struct fy_document_iterator *fydi, struct fy_document *fyd)
+{
+	struct fy_event *fye = NULL;
+	struct fy_eventp *fyep;
+
+	if (!fydi || fydi->state == FYDIS_ERROR)
+		return NULL;
+
+	if (!fyd)
+		goto err_out;
+
+	/* we can transition to document start only from document start or stream end */
+	if (fydi->state != FYDIS_WAITING_DOCUMENT_START &&
+	    fydi->state != FYDIS_WAITING_STREAM_END_OR_DOCUMENT_START)
+		goto err_out;
+
+	fyep = fy_document_iterator_eventp_alloc(fydi);
+	if (!fyep)
+		goto err_out;
+	fye = &fyep->e;
+
+	fydi->fyd = fyd;
+
+	/* the iteration root is the document root */
+	fydi->iterate_root = fyd->root;
+
+	/* suppress recycling if we must */
+	fydi->suppress_recycling = (fyd->parse_cfg.flags & FYPCF_DISABLE_RECYCLING) ||
+				   fydi->suppress_recycling_force;
+
+	if (!fydi->suppress_recycling) {
+		fydi->recycled_eventp_list = &fydi->recycled_eventp;
+		fydi->recycled_token_list = &fydi->recycled_token;
+	} else {
+		fydi->recycled_eventp_list = NULL;
+		fydi->recycled_token_list = NULL;
+	}
+
+	fye->type = FYET_DOCUMENT_START;
+	fye->document_start.document_start = NULL;
+	fye->document_start.document_state = fy_document_state_ref(fyd->fyds);
+	fye->document_start.implicit = fyd->fyds->start_implicit;
+
+	/* and go into body */
+	fydi->state = FYDIS_WAITING_BODY_START_OR_DOCUMENT_END;
+
+	return fye;
+
+err_out:
+	fy_document_iterator_event_free(fydi, fye);
+	fydi->state = FYDIS_ERROR;
+	return NULL;
+}
+
+struct fy_event *
+fy_document_iterator_document_end(struct fy_document_iterator *fydi)
+{
+	struct fy_event *fye;
+
+	if (!fydi || fydi->state == FYDIS_ERROR)
+		return NULL;
+
+	if (!fydi->fyd || !fydi->fyd->fyds ||
+	    fydi->state != FYDIS_WAITING_DOCUMENT_END)
+		goto err_out;
+
+	fye = fy_document_iterator_event_create(fydi, FYET_DOCUMENT_END, (int)fydi->fyd->fyds->end_implicit);
+	if (!fye)
+		goto err_out;
+
+	fydi->fyd = NULL;
+	fydi->iterate_root = NULL;
+
+	fydi->state = FYDIS_WAITING_STREAM_END_OR_DOCUMENT_START;
+	return fye;
+
+err_out:
+	fydi->state = FYDIS_ERROR;
+	return NULL;
+}
+
+static bool
+fy_document_iterator_ensure_space(struct fy_document_iterator *fydi, unsigned int space)
+{
+	struct fy_document_iterator_body_state *new_stack;
+	size_t new_size, copy_size;
+	unsigned int new_stack_alloc;
+
+	/* empty stack should always have enough space */
+	if (fydi->stack_top == (unsigned int)-1) {
+		assert(fydi->stack_alloc >= space);
+		return true;
+	}
+
+	if (fydi->stack_top + space < fydi->stack_alloc)
+		return true;
+
+	/* make sure we have enough space */
+	new_stack_alloc = fydi->stack_alloc * 2;
+	while (fydi->stack_top + space >= new_stack_alloc)
+		new_stack_alloc *= 2;
+
+	new_size = new_stack_alloc * sizeof(*new_stack);
+
+	if (fydi->stack == fydi->in_place) {
+		new_stack = malloc(new_size);
+		if (!new_stack)
+			return false;
+		copy_size = (fydi->stack_top + 1) * sizeof(*new_stack);
+		memcpy(new_stack, fydi->stack, copy_size);
+	} else {
+		new_stack = realloc(fydi->stack, new_size);
+		if (!new_stack)
+			return false;
+	}
+	fydi->stack = new_stack;
+	fydi->stack_alloc = new_stack_alloc;
+	return true;
+}
+
+static bool
+fydi_push_collection(struct fy_document_iterator *fydi, struct fy_node *fyn)
+{
+	struct fy_document_iterator_body_state *s;
+
+	/* make sure there's enough space */
+	if (!fy_document_iterator_ensure_space(fydi, 1))
+		return false;
+
+	/* get the next */
+	fydi->stack_top++;
+	s = &fydi->stack[fydi->stack_top];
+	s->fyn = fyn;
+
+	switch (fyn->type) {
+	case FYNT_SEQUENCE:
+		s->fyni = fy_node_list_head(&fyn->sequence);
+		break;
+
+	case FYNT_MAPPING:
+		s->fynp = fy_node_pair_list_head(&fyn->mapping);
+		s->processed_key = false;
+		break;
+
+	default:
+		assert(0);
+		break;
+	}
+
+	return true;
+}
+
+static inline void
+fydi_pop_collection(struct fy_document_iterator *fydi)
+{
+	assert(fydi->stack_top != (unsigned int)-1);
+	fydi->stack_top--;
+}
+
+static inline struct fy_document_iterator_body_state *
+fydi_last_collection(struct fy_document_iterator *fydi)
+{
+	if (fydi->stack_top == (unsigned int)-1)
+		return NULL;
+	return &fydi->stack[fydi->stack_top];
+}
+
+bool
+fy_document_iterator_body_next_internal(struct fy_document_iterator *fydi,
+					struct fy_document_iterator_body_result *res)
+{
+	struct fy_document_iterator_body_state *s;
+	struct fy_node *fyn, *fyn_col;
+	bool end;
+
+	if (!fydi || !res || fydi->state == FYDIS_ERROR)
+		return false;
+
+	if (fydi->state != FYDIS_WAITING_BODY_START_OR_DOCUMENT_END &&
+	    fydi->state != FYDIS_BODY)
+		goto err_out;
+
+	end = false;
+	s = fydi_last_collection(fydi);
+	if (!s) {
+
+		fyn = fydi->iterate_root;
+		/* empty root, or last */
+		if (!fyn || fydi->state == FYDIS_BODY) {
+			fydi->state = FYDIS_WAITING_DOCUMENT_END;
+			return false;
+		}
+
+		/* ok, in body proper */
+		fydi->state = FYDIS_BODY;
+
+	} else {
+
+		fyn_col = s->fyn;
+		assert(fyn_col);
+
+		fyn = NULL;
+		if (fyn_col->type == FYNT_SEQUENCE) {
+			fyn = s->fyni;
+			if (fyn)
+				s->fyni = fy_node_next(&fyn_col->sequence, s->fyni);
+		} else {
+			assert(fyn_col->type == FYNT_MAPPING);
+			if (s->fynp) {
+				if (!s->processed_key) {
+					fyn = s->fynp->key;
+					s->processed_key = true;
+				} else {
+					fyn = s->fynp->value;
+					s->processed_key = false;
+
+					/* next in mapping after value */
+					s->fynp = fy_node_pair_next(&fyn_col->mapping, s->fynp);
+				}
+			}
+		}
+
+		/* if no next node in the collection, it's the end of the collection */
+		if (!fyn) {
+			fyn = fyn_col;
+			end = true;
+		}
+	}
+
+	assert(fyn);
+
+	/* only for collections */
+	if (fyn->type != FYNT_SCALAR) {
+		if (!end) {
+			/* push the new sequence */
+			if (!fydi_push_collection(fydi, fyn))
+				goto err_out;
+		} else
+			fydi_pop_collection(fydi);
+	}
+
+	res->fyn = fyn;
+	res->end = end;
+	return true;
+
+err_out:
+	fydi->state = FYDIS_ERROR;
+	return false;
+}
+
+struct fy_event *fy_document_iterator_body_next(struct fy_document_iterator *fydi)
+{
+	struct fy_document_iterator_body_result res;
+
+	if (!fydi)
+		return NULL;
+
+	if (!fy_document_iterator_body_next_internal(fydi, &res))
+		return NULL;
+
+	return fydi_event_create(fydi, res.fyn, !res.end);
+}
+
+void
+fy_document_iterator_node_start(struct fy_document_iterator *fydi, struct fy_node *fyn)
+{
+	/* do nothing on error */
+	if (!fydi || fydi->state == FYDIS_ERROR)
+		return;
+
+	/* and go into body */
+	fydi->state = FYDIS_WAITING_BODY_START_OR_DOCUMENT_END;
+	fydi->iterate_root = fyn;
+	fydi->fyd = NULL;
+}
+
+struct fy_node *fy_document_iterator_node_next(struct fy_document_iterator *fydi)
+{
+	struct fy_document_iterator_body_result res;
+
+	if (!fydi)
+		return NULL;
+
+	/* do not return ending nodes, are not interested in them */
+	do {
+		if (!fy_document_iterator_body_next_internal(fydi, &res))
+			return NULL;
+
+	} while (res.end);
+
+	return res.fyn;
+}
+
+bool fy_document_iterator_get_error(struct fy_document_iterator *fydi)
+{
+	if (!fydi)
+		return true;
+
+	if (fydi->state != FYDIS_ERROR)
+		return false;
+
+	fy_document_iterator_cleanup(fydi);
+
+	return true;
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-doc.h b/contrib/libs/libfyaml/src/lib/fy-doc.h
new file mode 100644
index 0000000000..d8535c1a1e
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-doc.h
@@ -0,0 +1,262 @@
+/*
+ * fy-doc.h - YAML document internal header file
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_DOC_H
+#define FY_DOC_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-ctype.h"
+#include "fy-utf8.h"
+#include "fy-list.h"
+#include "fy-typelist.h"
+#include "fy-types.h"
+#include "fy-diag.h"
+#include "fy-dump.h"
+#include "fy-docstate.h"
+#include "fy-accel.h"
+#include "fy-walk.h"
+#include "fy-path.h"
+
+struct fy_eventp;
+
+/* TODO vary according to platfom */
+static inline int fy_depth_limit(void)
+{
+	return FYPCF_GUARANTEED_MINIMUM_DEPTH_LIMIT;
+}
+
+FY_TYPE_FWD_DECL_LIST(document);
+
+struct fy_node;
+
+struct fy_node_pair {
+	struct fy_list_head node;
+	struct fy_node *key;
+	struct fy_node *value;
+	struct fy_document *fyd;
+	struct fy_node *parent;
+};
+FY_TYPE_FWD_DECL_LIST(node_pair);
+FY_TYPE_DECL_LIST(node_pair);
+
+FY_TYPE_FWD_DECL_LIST(node);
+struct fy_node {
+	struct fy_list_head node;
+	struct fy_token *tag;
+	enum fy_node_style style;
+	struct fy_node *parent;
+	struct fy_document *fyd;
+	unsigned int marks;
+#if !defined(_MSC_VER)
+	enum fy_node_type type : 2;	/* 2 bits are enough for 3 types */
+#else
+	enum fy_node_type type;	/* it converted incorrectly and can't be used as supposed to be */
+#endif
+	bool has_meta : 1;
+	bool attached : 1;		/* when it's attached somewhere */
+	bool synthetic : 1;		/* node has been modified programmaticaly */
+	bool key_root : 1;		/* node is the root of key fy_node_get_parent() will return NULL */
+	void *meta;
+	struct fy_accel *xl;		/* mapping access accelerator */
+	struct fy_path_expr_node_data *pxnd;
+	union {
+		struct fy_token *scalar;
+		struct fy_node_list sequence;
+		struct fy_node_pair_list mapping;
+	};
+	union {
+		struct fy_token *sequence_start;
+		struct fy_token *mapping_start;
+	};
+	union {
+		struct fy_token *sequence_end;
+		struct fy_token *mapping_end;
+	};
+};
+FY_TYPE_DECL_LIST(node);
+
+struct fy_node *fy_node_alloc(struct fy_document *fyd, enum fy_node_type type);
+struct fy_node_pair *fy_node_pair_alloc(struct fy_document *fyd);
+int fy_node_pair_free(struct fy_node_pair *fynp);
+
+void fy_node_detach_and_free(struct fy_node *fyn);
+void fy_node_pair_detach_and_free(struct fy_node_pair *fynp);
+
+struct fy_anchor {
+	struct fy_list_head node;
+	struct fy_node *fyn;
+	struct fy_token *anchor;
+	bool multiple : 1;
+};
+FY_TYPE_FWD_DECL_LIST(anchor);
+FY_TYPE_DECL_LIST(anchor);
+
+struct fy_document {
+	struct fy_list_head node;
+	struct fy_anchor_list anchors;
+	struct fy_accel *axl;		/* name -> anchor access accelerator */
+	struct fy_accel *naxl;		/* node -> anchor access accelerator */
+	struct fy_document_state *fyds;
+	struct fy_diag *diag;
+	struct fy_parse_cfg parse_cfg;
+	struct fy_node *root;
+	bool parse_error : 1;
+
+	struct fy_document *parent;
+	struct fy_document_list children;
+
+	fy_node_meta_clear_fn meta_clear_fn;
+	void *meta_user;
+
+	struct fy_path_expr_document_data *pxdd;
+};
+/* only the list declaration/methods */
+FY_TYPE_DECL_LIST(document);
+
+struct fy_document *fy_parse_document_create(struct fy_parser *fyp, struct fy_eventp *fyep);
+
+struct fy_node_mapping_sort_ctx {
+	fy_node_mapping_sort_fn key_cmp;
+	void *arg;
+	struct fy_node_pair **fynpp;
+	int count;
+};
+
+void fy_node_mapping_perform_sort(struct fy_node *fyn_map,
+		fy_node_mapping_sort_fn key_cmp, void *arg,
+		struct fy_node_pair **fynpp, int count);
+
+void fy_node_mapping_fill_array(struct fy_node *fyn_map,
+		struct fy_node_pair **fynpp, int count);
+
+struct fy_node_pair **fy_node_mapping_sort_array(struct fy_node *fyn_map,
+		fy_node_mapping_sort_fn key_cmp,
+		void *arg, int *countp);
+
+void fy_node_mapping_release_array(struct fy_node *fyn_map, struct fy_node_pair **fynpp);
+
+struct fy_node_walk_ctx {
+	unsigned int max_depth;
+	unsigned int next_slot;
+	unsigned int mark;
+	struct fy_node *marked[0];
+};
+
+bool fy_node_is_empty(struct fy_node *fyn);
+
+bool fy_check_ref_loop(struct fy_document *fyd, struct fy_node *fyn,
+		       enum fy_node_walk_flags flags,
+		       struct fy_node_walk_ctx *ctx);
+
+#define FYNWF_VISIT_MARKER	(FYNWF_MAX_USER_MARKER + 1)
+#define FYNWF_REF_MARKER	(FYNWF_MAX_USER_MARKER + 2)
+
+#define FYNWF_SYSTEM_MARKS	(FY_BIT(FYNWF_VISIT_MARKER) | \
+				 FY_BIT(FYNWF_REF_MARKER))
+
+bool fy_node_uses_single_input_only(struct fy_node *fyn, struct fy_input *fyi);
+struct fy_input *fy_node_get_first_input(struct fy_node *fyn);
+bool fy_node_is_synthetic(struct fy_node *fyn);
+void fy_node_mark_synthetic(struct fy_node *fyn);
+struct fy_input *fy_node_get_input(struct fy_node *fyn);
+int fy_document_register_anchor(struct fy_document *fyd,
+				struct fy_node *fyn, struct fy_token *anchor);
+bool fy_node_mapping_key_is_duplicate(struct fy_node *fyn, struct fy_node *fyn_key);
+
+struct fy_token *fy_node_non_synthesized_token(struct fy_node *fyn);
+struct fy_token *fy_node_token(struct fy_node *fyn);
+
+FILE *fy_document_get_error_fp(struct fy_document *fyd);
+enum fy_parse_cfg_flags fy_document_get_cfg_flags(const struct fy_document *fyd);
+bool fy_document_is_accelerated(struct fy_document *fyd);
+bool fy_document_can_be_accelerated(struct fy_document *fyd);
+
+/* TODO move to main include */
+struct fy_node *fy_node_collection_iterate(struct fy_node *fyn, void **prevp);
+
+/* indirect node */
+FY_TYPE_FWD_DECL_LIST(ptr_node);
+struct fy_ptr_node {
+	struct fy_list_head node;
+	struct fy_node *fyn;
+};
+FY_TYPE_DECL_LIST(ptr_node);
+
+struct fy_ptr_node *fy_ptr_node_create(struct fy_node *fyn);
+void fy_ptr_node_destroy(struct fy_ptr_node *fypn);
+void fy_ptr_node_list_free_all(struct fy_ptr_node_list *fypnl);
+bool fy_ptr_node_list_contains(struct fy_ptr_node_list *fypnl, struct fy_node *fyn);
+int fy_node_linearize_recursive(struct fy_ptr_node_list *fypnl, struct fy_node *fyn);
+int fy_node_linearize(struct fy_ptr_node_list *fypnl, struct fy_node *fyn);
+void fy_node_iterator_check(struct fy_node *fyn);
+
+
+enum fy_document_iterator_state {
+	FYDIS_WAITING_STREAM_START,
+	FYDIS_WAITING_DOCUMENT_START,
+	FYDIS_WAITING_BODY_START_OR_DOCUMENT_END,
+	FYDIS_BODY,
+	FYDIS_WAITING_DOCUMENT_END,
+	FYDIS_WAITING_STREAM_END_OR_DOCUMENT_START,
+	FYDIS_ERROR,
+};
+
+struct fy_document_iterator_body_state {
+	struct fy_node *fyn;	/* the collection node */
+	bool processed_key : 1;	/* for mapping only */
+	union {
+		struct fy_node *fyni;		/* for sequence */
+		struct fy_node_pair *fynp;	/* for mapping */
+	};
+};
+
+struct fy_document_iterator {
+	enum fy_document_iterator_state state;
+	struct fy_document *fyd;
+	struct fy_node *iterate_root;
+	bool suppress_recycling_force : 1;
+	bool suppress_recycling : 1;
+
+	struct fy_eventp_list recycled_eventp;
+	struct fy_token_list recycled_token;
+
+	struct fy_eventp_list *recycled_eventp_list;	/* NULL when suppressing */
+	struct fy_token_list *recycled_token_list;	/* NULL when suppressing */
+
+	unsigned int stack_top;
+	unsigned int stack_alloc;
+	struct fy_document_iterator_body_state *stack;
+	struct fy_document_iterator_body_state in_place[FYPCF_GUARANTEED_MINIMUM_DEPTH_LIMIT];
+};
+
+void fy_document_iterator_setup(struct fy_document_iterator *fydi);
+void fy_document_iterator_cleanup(struct fy_document_iterator *fydi);
+struct fy_document_iterator *fy_document_iterator_create(void);
+void fy_document_iterator_destroy(struct fy_document_iterator *fydi);
+void fy_document_iterator_start(struct fy_document_iterator *fydi, struct fy_document *fyd);
+void fy_document_iterator_end(struct fy_document_iterator *fydi);
+
+struct fy_document_iterator_body_result {
+	struct fy_node *fyn;
+	bool end;
+};
+
+bool
+fy_document_iterator_body_next_internal(struct fy_document_iterator *fydi,
+					struct fy_document_iterator_body_result *res);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-docbuilder.c b/contrib/libs/libfyaml/src/lib/fy-docbuilder.c
new file mode 100644
index 0000000000..08152f0988
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-docbuilder.c
@@ -0,0 +1,542 @@
+/*
+ * fy-docbuilder.c - YAML document builder methods
+ *
+ * Copyright (c) 2022 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <unistd.h>
+#endif
+
+#include <libfyaml.h>
+
+#include "fy-utils.h"
+
+#include "fy-docbuilder.h"
+
+#include "fy-parse.h"
+#include "fy-doc.h"
+
+const char *fy_document_builder_state_txt[] = {
+	[FYDBS_NODE]	= "node",
+	[FYDBS_MAP_KEY]	= "map-key",
+	[FYDBS_MAP_VAL]	= "map-val",
+	[FYDBS_SEQ]	= "seq",
+};
+
+void
+fy_document_builder_reset(struct fy_document_builder *fydb)
+{
+	struct fy_document_builder_ctx *c;
+	unsigned int i;
+
+	if (!fydb)
+		return;
+
+	for (i = 0, c = fydb->stack; i < fydb->next; i++, c++) {
+		fy_node_free(c->fyn);
+		c->fyn = NULL;
+		fy_node_pair_free(c->fynp);
+		c->fynp = NULL;
+	}
+	fydb->next = 0;
+
+	if (fydb->fyd) {
+		fy_document_destroy(fydb->fyd);
+		fydb->fyd = NULL;
+	}
+	fydb->in_stream = false;
+	fydb->doc_done = false;
+}
+
+static const struct fy_document_builder_cfg docbuilder_default_cfg = {
+	.parse_cfg = {
+		.flags = FYPCF_DEFAULT_DOC,
+	}
+};
+
+struct fy_document_builder *
+fy_document_builder_create(const struct fy_document_builder_cfg *cfg)
+{
+	struct fy_document_builder *fydb = NULL;
+
+	if (!cfg)
+		cfg = &docbuilder_default_cfg;
+
+	fydb = malloc(sizeof(*fydb));
+	if (!fydb)
+		goto err_out;
+
+	memset(fydb, 0, sizeof(*fydb));
+	fydb->cfg = *cfg;
+	fydb->next = 0;
+	fydb->in_stream = false;
+	fydb->doc_done = false;
+	fydb->alloc = fy_depth_limit();	/* always start with this */
+	fydb->max_depth = (cfg->parse_cfg.flags & FYPCF_DISABLE_DEPTH_LIMIT) ? 0 : fy_depth_limit();
+
+	fydb->stack = malloc(fydb->alloc * sizeof(*fydb->stack));
+	if (!fydb->stack)
+		goto err_out;
+
+	return fydb;
+
+err_out:
+	if (fydb) {
+		if (fydb->stack)
+			free(fydb->stack);
+		free(fydb);
+	}
+
+	return NULL;
+}
+
+void
+fy_document_builder_destroy(struct fy_document_builder *fydb)
+{
+	if (!fydb)
+		return;
+
+	fy_document_builder_reset(fydb);
+
+	fy_diag_unref(fydb->cfg.diag);
+	if (fydb->stack)
+		free(fydb->stack);
+	free(fydb);
+}
+
+struct fy_document *
+fy_document_builder_get_document(struct fy_document_builder *fydb)
+{
+	return fydb ? fydb->fyd : NULL;
+}
+
+bool
+fy_document_builder_is_in_stream(struct fy_document_builder *fydb)
+{
+	return fydb && fydb->in_stream;
+}
+
+bool
+fy_document_builder_is_in_document(struct fy_document_builder *fydb)
+{
+	return fydb && fydb->fyd != NULL && !fydb->doc_done;
+}
+
+bool
+fy_document_builder_is_document_complete(struct fy_document_builder *fydb)
+{
+	return fydb && fydb->fyd != NULL && fydb->doc_done;
+}
+
+struct fy_document *
+fy_document_builder_take_document(struct fy_document_builder *fydb)
+{
+	struct fy_document *fyd;
+
+	if (!fy_document_builder_is_document_complete(fydb))
+		return NULL;
+	fyd = fydb->fyd;
+	fydb->fyd = NULL;
+	fydb->doc_done = false;
+	return fyd;
+}
+
+struct fy_document *
+fy_document_builder_peek_document(struct fy_document_builder *fydb)
+{
+	struct fy_document *fyd;
+	struct fy_document_builder_ctx *c;
+
+	if (!fydb)
+		return NULL;
+
+	/* just peek; may be incomplete */
+	fyd = fydb->fyd;
+
+	assert(fydb->next > 0);
+	c = &fydb->stack[0];
+
+	/* wire the root */
+	if (!fyd->root)
+		fyd->root = c->fyn;
+
+	return fyd;
+}
+
+
+void
+fy_document_builder_set_in_stream(struct fy_document_builder *fydb)
+{
+	if (!fydb)
+		return;
+	/* reset */
+	fy_document_builder_reset(fydb);
+
+	fydb->in_stream = true;
+}
+
+int
+fy_document_builder_set_in_document(struct fy_document_builder *fydb, struct fy_document_state *fyds, bool single)
+{
+	struct fy_document_builder_ctx *c;
+	int rc;
+
+	if (!fydb)
+		return -1;
+
+	/* reset */
+	fy_document_builder_reset(fydb);
+
+	fydb->in_stream = true;
+
+	fydb->fyd = fy_document_create(&fydb->cfg.parse_cfg);
+	if (!fydb->fyd)
+		return -1;
+
+	if (fyds) {
+		rc = fy_document_set_document_state(fydb->fyd, fyds);
+		if (rc)
+			return rc;
+	}
+
+	fydb->doc_done = false;
+	fydb->single_mode = single;
+
+	/* be paranoid */
+	assert(fydb->next < fydb->alloc);
+
+	c = &fydb->stack[++fydb->next - 1];
+	memset(c, 0, sizeof(*c));
+	c->s = FYDBS_NODE;
+
+	return 0;
+}
+
+int
+fy_document_builder_process_event(struct fy_document_builder *fydb, struct fy_eventp *fyep)
+{
+	struct fy_event *fye;
+	enum fy_event_type etype;
+	struct fy_document *fyd;
+	struct fy_document_builder_ctx *c, *cp;
+	struct fy_node *fyn, *fyn_parent;
+	struct fy_node_pair *fynp;
+	struct fy_document_builder_ctx *newc;
+	struct fy_token *fyt;
+	int rc;
+
+	fye = fyep ? &fyep->e : NULL;
+	etype = fye ? fye->type : FYET_NONE;
+	fyt = fye ? fy_event_get_token(fye) : NULL;
+
+	/* not in document */
+	if (!fydb->next) {
+		switch (etype) {
+		case FYET_STREAM_START:
+			FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC,
+					!fydb->in_stream, err_out,
+					"STREAM_START while in stream error");
+			fydb->in_stream = true;
+			break;
+
+		case FYET_STREAM_END:
+			FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC,
+					fydb->in_stream, err_out,
+					"STREAM_END while not in stream error");
+			fydb->in_stream = false;
+			return 1;
+
+		case FYET_DOCUMENT_START:
+			FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC,
+					fydb->in_stream, err_out,
+					"DOCUMENT_START while not in stream error");
+
+			/* no-one cares, destroy the document */
+			if (!fydb->fyd)
+				fy_document_destroy(fydb->fyd);
+
+			fydb->fyd = fy_document_create(&fydb->cfg.parse_cfg);
+			fydb_error_check(fydb, fydb->fyd, err_out,
+					"fy_document_create() failed");
+
+			rc = fy_document_set_document_state(fydb->fyd, fyep->e.document_start.document_state);
+			fydb_error_check(fydb, !rc, err_out,
+					"fy_document_set_document_state() failed");
+
+			fydb->doc_done = false;
+			goto push;
+
+		case FYET_DOCUMENT_END:
+			FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC,
+					fydb->in_stream, err_out,
+					"DOCUMENT_END while not in stream error");
+
+			FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC,
+					fydb->fyd, err_out,
+					"DOCUMENT_END without a document");
+
+			fydb->doc_done = true;
+			break;
+
+		default:
+			/* unexpected event */
+			FYDB_TOKEN_ERROR(fydb, fyt, FYEM_DOC,
+					"Unexpected event %s in non-build mode\n",
+						fy_event_type_txt[etype]);
+			goto err_out;
+		}
+
+		return 0;
+	}
+
+	fyd = fydb->fyd;
+
+	c = &fydb->stack[fydb->next - 1];
+	fyn = NULL;
+
+	/* verify that we have a document */
+	assert(fydb->fyd);
+	/* the top state must always be NODE for processing the event */
+	assert(c->s == FYDBS_NODE);
+
+	switch (etype) {
+	case FYET_SCALAR:
+	case FYET_ALIAS:
+		fyn = fy_node_alloc(fyd, FYNT_SCALAR);
+		fydb_error_check(fydb, fyn, err_out,
+				"fy_node_alloc() SCALAR failed");
+
+		if (etype == FYET_SCALAR) {
+			if (fye->scalar.value)
+				fyn->style = fy_node_style_from_scalar_style(fye->scalar.value->scalar.style);
+			else
+				fyn->style = FYNS_PLAIN;
+			fyn->tag = fy_token_ref(fye->scalar.tag);
+			if (fye->scalar.anchor) {
+				rc = fy_document_register_anchor(fyd, fyn, fy_token_ref(fye->scalar.anchor));
+				fydb_error_check(fydb, !rc, err_out,
+						"fy_document_register_anchor() failed");
+			}
+			fyn->scalar = fy_token_ref(fye->scalar.value);
+		} else {
+			fyn->style = FYNS_ALIAS;
+			fyn->scalar = fy_token_ref(fye->alias.anchor);
+		}
+		goto complete;
+
+	case FYET_MAPPING_START:
+		c->s = FYDBS_MAP_KEY;
+
+		fyn = fy_node_alloc(fyd, FYNT_MAPPING);
+		fydb_error_check(fydb, fyn, err_out,
+				"fy_node_alloc() MAPPING failed");
+
+		c->fyn = fyn;
+		fyn->style = fye->mapping_start.mapping_start->type == FYTT_FLOW_MAPPING_START ? FYNS_FLOW : FYNS_BLOCK;
+		fyn->tag = fy_token_ref(fye->mapping_start.tag);
+		if (fye->mapping_start.anchor) {
+			rc = fy_document_register_anchor(fyd, fyn, fy_token_ref(fye->mapping_start.anchor));
+			fydb_error_check(fydb, !rc, err_out,
+					"fy_document_register_anchor() failed");
+		}
+		fyn->mapping_start = fy_token_ref(fye->mapping_start.mapping_start);
+		break;
+
+	case FYET_MAPPING_END:
+
+		FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC, fydb->next > 1, err_out,
+				"Unexpected MAPPING_END (unexpected end of mapping)");
+
+		cp = &fydb->stack[fydb->next - 2];
+
+		FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC, cp->s == FYDBS_MAP_KEY, err_out,
+				"Unexpected MAPPING_END (not in mapping)");
+
+		fyn = cp->fyn;
+		fyn->mapping_end = fy_token_ref(fye->mapping_end.mapping_end);
+		fydb->next--;
+		goto complete;
+
+	case FYET_SEQUENCE_START:
+		c->s = FYDBS_SEQ;
+		fyn = fy_node_alloc(fyd, FYNT_SEQUENCE);
+		fydb_error_check(fydb, fyn, err_out,
+				"fy_node_alloc() SEQUENCE failed");
+
+		c->fyn = fyn;
+		fyn->style = fye->sequence_start.sequence_start->type == FYTT_FLOW_SEQUENCE_START ? FYNS_FLOW : FYNS_BLOCK;
+		fyn->tag = fy_token_ref(fye->sequence_start.tag);
+		if (fye->sequence_start.anchor) {
+			rc = fy_document_register_anchor(fyd, fyn, fy_token_ref(fye->sequence_start.anchor));
+			fydb_error_check(fydb, !rc, err_out,
+					"fy_document_register_anchor() failed");
+		}
+		fyn->sequence_start = fy_token_ref(fye->sequence_start.sequence_start);
+		break;
+
+	case FYET_SEQUENCE_END:
+
+		FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC, fydb->next > 1, err_out,
+				"Unexpected SEQUENCE_END (unexpected end of sequence)");
+
+		cp = &fydb->stack[fydb->next - 2];
+
+		FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC, cp->s == FYDBS_SEQ, err_out,
+				"Unexpected MAPPING_SEQUENCE (not in sequence)");
+
+		fyn = cp->fyn;
+		fyn->sequence_end = fy_token_ref(fye->sequence_end.sequence_end);
+		fydb->next--;
+		goto complete;
+
+	default:
+		/* unexpected event */
+		FYDB_TOKEN_ERROR(fydb, fyt, FYEM_DOC,
+				"Unexpected event %s in build mode\n",
+					fy_event_type_txt[etype]);
+		goto err_out;
+	}
+
+push:
+	FYDB_TOKEN_ERROR_CHECK(fydb, fyt, FYEM_DOC,
+			!fydb->max_depth || fydb->next < fydb->max_depth, err_out,
+			"Max depth (%d) exceeded\n", fydb->next);
+
+	/* grow the stack? */
+	if (fydb->next >= fydb->alloc) {
+		newc = realloc(fydb->stack, fydb->alloc * 2 * sizeof(*fydb->stack));
+		fydb_error_check(fydb, newc, err_out,
+				"Unable to grow the context stack");
+		fydb->alloc *= 2;
+		fydb->stack = newc;
+	}
+	assert(fydb->next < fydb->alloc);
+
+	c = &fydb->stack[++fydb->next - 1];
+	memset(c, 0, sizeof(*c));
+	c->s = FYDBS_NODE;
+	return 0;
+
+err_out:
+	return -1;
+
+complete:
+	assert(fydb->next > 0);
+	c = &fydb->stack[fydb->next - 1];
+	c->fyn = fyn;
+	assert(fydb->next > 0);
+	fydb->next--;
+
+	/* root */
+	if (fydb->next == 0) {
+		fyd->root = fyn;
+		/* if we're in single mode, don't wait for doc end */
+		if (fydb->single_mode)
+			fydb->doc_done = true;
+		return 1;
+	}
+
+	c = &fydb->stack[fydb->next - 1];
+
+	fyn_parent = c->fyn;
+
+	switch (c->s) {
+
+	case FYDBS_MAP_KEY:
+		fynp = fy_node_pair_alloc(fyd);
+		assert(fynp);
+		fynp->key = fyn;
+		c->fynp = fynp;
+
+		/* if we don't allow duplicate keys */
+		if (!(fyd->parse_cfg.flags & FYPCF_ALLOW_DUPLICATE_KEYS)) {
+
+			/* make sure we don't add an already existing key */
+			if (fy_node_mapping_key_is_duplicate(fyn_parent, fyn)) {
+				FYDB_NODE_ERROR(fydb, fyn, FYEM_DOC, "duplicate key");
+				goto err_out;
+			}
+		}
+
+		c->s = FYDBS_MAP_VAL;
+		goto push;
+
+	case FYDBS_MAP_VAL:
+		fynp = c->fynp;
+		assert(fynp);
+		fynp->value = fyn;
+
+		/* set the parent of the node pair and value */
+		fynp->parent = fyn_parent;
+		if (fynp->key) {
+			fynp->key->parent = fyn_parent;
+			fynp->key->key_root = true;
+		}
+		if (fynp->value)
+			fynp->value->parent = fyn_parent;
+
+		fy_node_pair_list_add_tail(&c->fyn->mapping, fynp);
+		if (fyn->xl) {
+			rc = fy_accel_insert(fyn->xl, fynp->key, fynp);
+			assert(!rc);
+		}
+		if (fynp->key)
+			fynp->key->attached = true;
+		if (fynp->value)
+			fynp->value->attached = true;
+
+		c->fynp = NULL;
+		c->s = FYDBS_MAP_KEY;
+		goto push;
+
+	case FYDBS_SEQ:
+		/* append sequence */
+		fyn->parent = fyn_parent;
+		fy_node_list_add_tail(&c->fyn->sequence, fyn);
+		fyn->attached = true;
+		goto push;
+
+	case FYDBS_NODE:
+		/* complete is a scalar */
+		fyn->parent = fyn_parent;
+		return 0;
+	}
+
+	return 0;
+}
+
+struct fy_document *
+fy_document_builder_load_document(struct fy_document_builder *fydb,
+				  struct fy_parser *fyp)
+{
+	struct fy_eventp *fyep = NULL;
+	int rc;
+
+	if (fyp->state == FYPS_END)
+		return NULL;
+
+	while (!fy_document_builder_is_document_complete(fydb) &&
+		(fyep = fy_parse_private(fyp)) != NULL) {
+		rc = fy_document_builder_process_event(fydb, fyep);
+		fy_parse_eventp_recycle(fyp, fyep);
+		if (rc < 0) {
+			fyp->stream_error = true;
+			return NULL;
+		}
+	}
+
+	/* get ownership of the document */
+	return fy_document_builder_take_document(fydb);
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-docbuilder.h b/contrib/libs/libfyaml/src/lib/fy-docbuilder.h
new file mode 100644
index 0000000000..aa506d6845
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-docbuilder.h
@@ -0,0 +1,98 @@
+/*
+ * fy-docbuilder.h - YAML document builder internal header file
+ *
+ * Copyright (c) 2022 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_DOCBUILDER_H
+#define FY_DOCBUILDER_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-doc.h"
+
+enum fy_document_builder_state {
+	FYDBS_NODE,
+	FYDBS_MAP_KEY,
+	FYDBS_MAP_VAL,
+	FYDBS_SEQ,
+};
+
+struct fy_document_builder_ctx {
+	enum fy_document_builder_state s;
+	struct fy_node *fyn;
+	struct fy_node_pair *fynp;	/* for mapping */
+};
+
+struct fy_document_builder_cfg {
+	struct fy_parse_cfg parse_cfg;
+	void *userdata;
+	struct fy_diag *diag;
+};
+
+struct fy_document_builder {
+	struct fy_document_builder_cfg cfg;
+	struct fy_document *fyd;
+	bool single_mode;
+	bool in_stream;
+	bool doc_done;
+	unsigned int next;
+	unsigned int alloc;
+	unsigned int max_depth;
+	struct fy_document_builder_ctx *stack;
+};
+
+struct fy_document_builder *
+fy_document_builder_create(const struct fy_document_builder_cfg *cfg);
+
+void
+fy_document_builder_reset(struct fy_document_builder *fydb);
+
+void
+fy_document_builder_destroy(struct fy_document_builder *fydb);
+
+struct fy_document *
+fy_document_builder_get_document(struct fy_document_builder *fydb);
+
+bool
+fy_document_builder_is_in_stream(struct fy_document_builder *fydb);
+
+bool
+fy_document_builder_is_in_document(struct fy_document_builder *fydb);
+
+bool
+fy_document_builder_is_document_complete(struct fy_document_builder *fydb);
+
+struct fy_document *
+fy_document_builder_take_document(struct fy_document_builder *fydb);
+
+struct fy_document *
+fy_document_builder_peek_document(struct fy_document_builder *fydb);
+
+void
+fy_document_builder_set_in_stream(struct fy_document_builder *fydb);
+
+int
+fy_document_builder_set_in_document(struct fy_document_builder *fydb, struct fy_document_state *fyds, bool single);
+
+int
+fy_document_builder_process_event(struct fy_document_builder *fydb, struct fy_eventp *fyep);
+
+struct fy_document *
+fy_document_builder_load_document(struct fy_document_builder *fydb,
+				  struct fy_parser *fyp);
+
+struct fy_document *
+fy_parse_load_document_with_builder(struct fy_parser *fyp);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-docstate.c b/contrib/libs/libfyaml/src/lib/fy-docstate.c
new file mode 100644
index 0000000000..e7876e4ea6
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-docstate.c
@@ -0,0 +1,394 @@
+/*
+ * fy-docstate.c - YAML document state methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-doc.h"
+
+#include "fy-docstate.h"
+
+struct fy_document_state *fy_document_state_alloc(void)
+{
+	struct fy_document_state *fyds;
+
+	fyds = malloc(sizeof(*fyds));
+	if (!fyds)
+		return NULL;
+	memset(fyds, 0, sizeof(*fyds));
+
+	fyds->fyt_vd = NULL;
+	fy_token_list_init(&fyds->fyt_td);
+
+	fyds->refs = 1;
+
+	return fyds;
+}
+
+void fy_document_state_free(struct fy_document_state *fyds)
+{
+	if (!fyds)
+		return;
+
+	assert(fyds->refs == 1);
+
+	fy_token_unref(fyds->fyt_vd);
+	fy_token_list_unref_all(&fyds->fyt_td);
+
+	free(fyds);
+}
+
+struct fy_document_state *fy_document_state_ref(struct fy_document_state *fyds)
+{
+	if (!fyds)
+		return NULL;
+
+	assert(fyds->refs + 1 > 0);
+
+	fyds->refs++;
+
+	return fyds;
+}
+
+void fy_document_state_unref(struct fy_document_state *fyds)
+{
+	if (!fyds)
+		return;
+
+	assert(fyds->refs > 0);
+
+	if (fyds->refs == 1)
+		fy_document_state_free(fyds);
+	else
+		fyds->refs--;
+}
+
+int fy_document_state_append_tag(struct fy_document_state *fyds,
+				 const char *handle, const char *prefix,
+				 bool is_default)
+{
+	struct fy_token *fyt = NULL;
+	struct fy_input *fyi = NULL;
+	char *data;
+	size_t size, handle_size, prefix_size;
+	struct fy_atom atom;
+
+	size = strlen(handle) + 1 + strlen(prefix);
+	data = malloc(size + 1);
+	if (!data)
+		goto err_out;
+
+	snprintf(data, size + 1, "%s %s", handle, prefix);
+
+	fyi = fy_input_from_malloc_data(data, size, &atom, true);
+	if (!fyi)
+		goto err_out;
+	data = NULL;	/* ownership now at input */
+
+	handle_size = strlen(handle);
+	prefix_size = strlen(prefix);
+
+	fyt = fy_token_create(FYTT_TAG_DIRECTIVE, &atom,
+			     handle_size, prefix_size,
+			     is_default);
+	if (!fyt)
+		goto err_out;
+
+	fy_token_list_add_tail(&fyds->fyt_td, fyt);
+
+	if (!fy_tag_is_default_internal(handle, handle_size, prefix, prefix_size))
+		fyds->tags_explicit = true;
+
+	/* take away the input reference */
+	fy_input_unref(fyi);
+
+	return 0;
+
+err_out:
+	fy_token_unref(fyt);
+	fy_input_unref(fyi);
+	if (data)
+		free(data);
+	return -1;
+}
+
+struct fy_document_state *fy_document_state_default(
+		const struct fy_version *default_version,
+		const struct fy_tag * const *default_tags)
+{
+	struct fy_document_state *fyds = NULL;
+	const struct fy_tag *fytag;
+	int i, rc;
+
+	if (!default_version)
+		default_version = &fy_default_version;
+
+	if (!default_tags)
+		default_tags = fy_default_tags;
+
+	fyds = fy_document_state_alloc();
+	if (!fyds)
+		goto err_out;
+
+	fyds->version = *default_version;
+
+	fyds->version_explicit = false;
+	fyds->tags_explicit = false;
+	fyds->start_implicit = true;
+	fyds->end_implicit = true;
+	fyds->json_mode = false;
+
+	memset(&fyds->start_mark, 0, sizeof(fyds->start_mark));
+	memset(&fyds->end_mark, 0, sizeof(fyds->end_mark));
+
+	fyds->fyt_vd = NULL;
+	fy_token_list_init(&fyds->fyt_td);
+
+	for (i = 0; (fytag = default_tags[i]) != NULL; i++) {
+
+		rc = fy_document_state_append_tag(fyds, fytag->handle, fytag->prefix, true);
+		if (rc)
+			goto err_out;
+	}
+
+	return fyds;
+err_out:
+	fy_document_state_unref(fyds);
+	return NULL;
+}
+
+struct fy_document_state *fy_document_state_copy(struct fy_document_state *fyds)
+{
+	struct fy_document_state *fyds_new = NULL;
+	struct fy_token *fyt_td, *fyt;
+
+	fyds_new = fy_document_state_alloc();
+	if (!fyds_new)
+		goto err_out;
+
+	fyds_new->version = fyds->version;
+	fyds_new->version_explicit = fyds->version_explicit;
+	fyds_new->tags_explicit = fyds->tags_explicit;
+	fyds_new->start_implicit = fyds->start_implicit;
+	fyds_new->end_implicit = fyds->end_implicit;
+	fyds_new->json_mode = fyds->json_mode;
+
+	fyds_new->start_mark = fyds->start_mark;
+	fyds_new->end_mark = fyds->end_mark;
+
+	if (fyds->fyt_vd) {
+		fyt = fy_token_alloc();
+		if (!fyt)
+			goto err_out;
+
+		fyt->type = FYTT_VERSION_DIRECTIVE;
+		fyt->handle = fyds->fyt_vd->handle;
+		fyt->version_directive.vers = fyds->fyt_vd->version_directive.vers;
+
+		/* take reference */
+		fy_input_ref(fyt->handle.fyi);
+
+		fyds_new->fyt_vd = fyt;
+	}
+
+	for (fyt = fy_token_list_first(&fyds->fyt_td); fyt; fyt = fy_token_next(&fyds->fyt_td, fyt)) {
+		fyt_td = fy_token_alloc();
+		if (!fyt_td)
+			goto err_out;
+
+		fyt_td->type = FYTT_TAG_DIRECTIVE;
+		fyt_td->tag_directive.tag_length = fyt->tag_directive.tag_length;
+		fyt_td->tag_directive.uri_length = fyt->tag_directive.uri_length;
+		fyt_td->tag_directive.is_default = fyt->tag_directive.is_default;
+		fyt_td->handle = fyt->handle;
+		fyt_td->tag_directive.prefix0 = NULL;
+		fyt_td->tag_directive.handle0 = NULL;
+
+		/* take reference */
+		fy_input_ref(fyt_td->handle.fyi);
+
+		/* append to the new document state */
+		fy_token_list_add_tail(&fyds_new->fyt_td, fyt_td);
+	}
+
+	return fyds_new;
+
+err_out:
+	fy_document_state_unref(fyds_new);
+	return NULL;
+}
+
+struct fy_token *fy_document_state_lookup_tag_directive(struct fy_document_state *fyds,
+		const char *handle, size_t handle_size)
+{
+	const char *td_handle;
+	size_t td_handle_size;
+	struct fy_token *fyt;
+
+	if (!fyds)
+		return NULL;
+
+	for (fyt = fy_token_list_first(&fyds->fyt_td); fyt; fyt = fy_token_next(&fyds->fyt_td, fyt)) {
+
+		td_handle = fy_tag_directive_token_handle(fyt, &td_handle_size);
+		assert(td_handle);
+
+		if (handle_size == td_handle_size && !memcmp(handle, td_handle, handle_size))
+			return fyt;
+
+	}
+
+	return NULL;
+}
+
+int fy_document_state_merge(struct fy_document_state *fyds,
+			    struct fy_document_state *fydsc)
+{
+	const char *td_prefix, *tdc_handle, *tdc_prefix;
+	size_t td_prefix_size, tdc_handle_size, tdc_prefix_size;
+	struct fy_token *fyt, *fytc_td, *fyt_td;
+
+	if (!fyds || !fydsc)
+		return -1;
+
+	/* check if there's a duplicate handle (which differs */
+	for (fytc_td = fy_token_list_first(&fydsc->fyt_td); fytc_td;
+			fytc_td = fy_token_next(&fydsc->fyt_td, fytc_td)) {
+
+		tdc_handle = fy_tag_directive_token_handle(fytc_td, &tdc_handle_size);
+		if (!tdc_handle)
+			goto err_out;
+		tdc_prefix = fy_tag_directive_token_prefix(fytc_td, &tdc_prefix_size);
+		if (!tdc_prefix)
+			goto err_out;
+
+		fyt_td = fy_document_state_lookup_tag_directive(fyds, tdc_handle, tdc_handle_size);
+		if (fyt_td) {
+			/* exists, must check whether the prefixes match */
+			td_prefix = fy_tag_directive_token_prefix(fyt_td, &td_prefix_size);
+			assert(td_prefix);
+
+			/* match? do nothing */
+			if (tdc_prefix_size == td_prefix_size &&
+			    !memcmp(tdc_prefix, td_prefix, td_prefix_size))
+				continue;
+
+			if (!fy_token_tag_directive_is_overridable(fyt_td))
+				goto err_out;
+
+			/* override tag directive */
+			fy_token_list_del(&fyds->fyt_td, fyt_td);
+			fy_token_unref(fyt_td);
+		}
+
+		fyt = fy_token_create(FYTT_TAG_DIRECTIVE,
+				&fytc_td->handle,
+				fytc_td->tag_directive.tag_length,
+				fytc_td->tag_directive.uri_length,
+				fytc_td->tag_directive.is_default);
+		if (!fyt)
+			goto err_out;
+
+		fy_token_list_add_tail(&fyds->fyt_td, fyt);
+	}
+
+	/* merge other document state */
+	fyds->version_explicit |= fydsc->version_explicit;
+	fyds->tags_explicit |= fydsc->tags_explicit;
+	/* NOTE: json mode is not carried over */
+
+	if (fyds->version.major < fydsc->version.major ||
+	    (fyds->version.major == fydsc->version.major &&
+		fyds->version.minor < fydsc->version.minor))
+		fyds->version = fydsc->version;
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+const struct fy_version *
+fy_document_state_version(struct fy_document_state *fyds)
+{
+	/* return the default if not set */
+	return fyds ? &fyds->version : &fy_default_version;
+}
+
+const struct fy_mark *fy_document_state_start_mark(struct fy_document_state *fyds)
+{
+	return fyds ? &fyds->start_mark : NULL;
+}
+
+const struct fy_mark *fy_document_state_end_mark(struct fy_document_state *fyds)
+{
+	return fyds ? &fyds->end_mark : NULL;
+}
+
+bool fy_document_state_version_explicit(struct fy_document_state *fyds)
+{
+	return fyds ? fyds->version_explicit : false;
+}
+
+bool fy_document_state_tags_explicit(struct fy_document_state *fyds)
+{
+	return fyds ? fyds->tags_explicit : false;
+}
+
+bool fy_document_state_start_implicit(struct fy_document_state *fyds)
+{
+	return fyds ? fyds->start_implicit : true;
+}
+
+bool fy_document_state_end_implicit(struct fy_document_state *fyds)
+{
+	return fyds ? fyds->end_implicit : true;
+}
+
+bool fy_document_state_json_mode(struct fy_document_state *fyds)
+{
+	return fyds ? fyds->json_mode : true;
+}
+
+const struct fy_tag *
+fy_document_state_tag_directive_iterate(struct fy_document_state *fyds, void **iterp)
+{
+	struct fy_token *fyt;
+	const struct fy_tag *tag;
+
+	if (!fyds || !iterp)
+		return NULL;
+
+	fyt = *iterp;
+	fyt = !fyt ? fy_token_list_head(&fyds->fyt_td) : fy_token_next(&fyds->fyt_td, fyt);
+	if (!fyt)
+		return NULL;
+
+	/* sanity check */
+	assert(fyt->type == FYTT_TAG_DIRECTIVE);
+
+	/* always refresh, should be relatively infrequent */
+	fyt->tag_directive.tag.handle = fy_tag_directive_token_handle0(fyt);
+	fyt->tag_directive.tag.prefix = fy_tag_directive_token_prefix0(fyt);
+
+	tag = &fyt->tag_directive.tag;
+
+	*iterp = fyt;
+
+	return tag;
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-docstate.h b/contrib/libs/libfyaml/src/lib/fy-docstate.h
new file mode 100644
index 0000000000..380c5f0d8c
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-docstate.h
@@ -0,0 +1,63 @@
+/*
+ * fy-docstate.h - YAML document state header.
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_DOCSTATE_H
+#define FY_DOCSTATE_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-ctype.h"
+#include "fy-list.h"
+#include "fy-typelist.h"
+#include "fy-token.h"
+
+struct fy_document;
+
+struct fy_document_state {
+	int refs;
+	struct fy_version version;
+	bool version_explicit : 1;
+	bool tags_explicit : 1;
+	bool start_implicit : 1;
+	bool end_implicit : 1;
+	bool json_mode : 1;
+	struct fy_mark start_mark;
+	struct fy_mark end_mark;
+	struct fy_token *fyt_vd;		/* version directive */
+	struct fy_token_list fyt_td;		/* tag directives */
+};
+
+struct fy_document_state *fy_document_state_alloc(void);
+void fy_document_state_free(struct fy_document_state *fyds);
+struct fy_document_state *fy_document_state_ref(struct fy_document_state *fyds);
+void fy_document_state_unref(struct fy_document_state *fyds);
+
+int fy_document_state_append_tag(struct fy_document_state *fyds,
+				 const char *handle, const char *prefix,
+				 bool is_default);
+
+struct fy_document_state *fy_document_state_default(
+		const struct fy_version *default_version,
+		const struct fy_tag * const *default_tags);
+
+struct fy_document_state *fy_document_state_copy(struct fy_document_state *fyds);
+int fy_document_state_merge(struct fy_document_state *fyds,
+			    struct fy_document_state *fydsc);
+
+struct fy_token *fy_document_state_lookup_tag_directive(struct fy_document_state *fyds,
+		const char *handle, size_t handle_size);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-dump.c b/contrib/libs/libfyaml/src/lib/fy-dump.c
new file mode 100644
index 0000000000..ac1980d879
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-dump.c
@@ -0,0 +1,313 @@
+/*
+ * fy-dump.c - various debugging methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#endif
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <limits.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-ctype.h"
+#include "fy-utf8.h"
+
+const char *fy_token_type_txt[FYTT_COUNT] = {
+	[FYTT_NONE]			= "<NONE>",
+	[FYTT_STREAM_START]		= "STRM+",
+	[FYTT_STREAM_END]		= "STRM-",
+	[FYTT_VERSION_DIRECTIVE]	= "VRSD",
+	[FYTT_TAG_DIRECTIVE]		= "TAGD",
+	[FYTT_DOCUMENT_START]		= "DOC+",
+	[FYTT_DOCUMENT_END]		= "DOC-",
+	[FYTT_BLOCK_SEQUENCE_START]	= "BSEQ+",
+	[FYTT_BLOCK_MAPPING_START]	= "BMAP+",
+	[FYTT_BLOCK_END]		= "BEND",
+	[FYTT_FLOW_SEQUENCE_START]	= "FSEQ+",
+	[FYTT_FLOW_SEQUENCE_END]	= "FSEQ-",
+	[FYTT_FLOW_MAPPING_START]	= "FMAP+",
+	[FYTT_FLOW_MAPPING_END]		= "FMAP-",
+	[FYTT_BLOCK_ENTRY]		= "BENTR",
+	[FYTT_FLOW_ENTRY]		= "FENTR",
+	[FYTT_KEY]			= "KEY",
+	[FYTT_SCALAR]			= "SCLR",
+	[FYTT_VALUE]			= "VAL",
+	[FYTT_ALIAS]			= "ALIAS",
+	[FYTT_ANCHOR]			= "ANCHR",
+	[FYTT_TAG]			= "TAG",
+	[FYTT_INPUT_MARKER]		= "INPUT_MARKER",
+
+	[FYTT_PE_SLASH]			= "PE_SLASH",
+	[FYTT_PE_ROOT]			= "PE_ROOT",
+	[FYTT_PE_THIS]			= "PE_THIS",
+	[FYTT_PE_PARENT]		= "PE_PARENT",
+	[FYTT_PE_MAP_KEY]		= "PE_MAP_KEY",
+	[FYTT_PE_SEQ_INDEX]		= "PE_SEQ_INDEX",
+	[FYTT_PE_SEQ_SLICE]		= "PE_SEQ_SLICE",
+	[FYTT_PE_SCALAR_FILTER]		= "PE_SCALAR_FILTER",
+	[FYTT_PE_COLLECTION_FILTER]	= "PE_COLLECTION_FILTER",
+	[FYTT_PE_SEQ_FILTER]		= "PE_SEQ_FILTER",
+	[FYTT_PE_MAP_FILTER]		= "PE_MAP_FILTER",
+	[FYTT_PE_UNIQUE_FILTER]		= "PE_UNIQUE_FILTER",
+	[FYTT_PE_EVERY_CHILD]		= "PE_EVERY_CHILD",
+	[FYTT_PE_EVERY_CHILD_R]		= "PE_EVERY_CHILD_R",
+	[FYTT_PE_ALIAS]			= "PE_ALIAS",
+	[FYTT_PE_SIBLING]		= "PE_SIBLING",
+	[FYTT_PE_COMMA]			= "PE_COMMA",
+	[FYTT_PE_BARBAR]		= "PE_BARBAR",
+	[FYTT_PE_AMPAMP]		= "PE_AMPAMP",
+	[FYTT_PE_LPAREN]		= "PE_LPAREN",
+	[FYTT_PE_RPAREN]		= "PE_RPAREN",
+
+	[FYTT_PE_EQEQ]			= "PE_EQEQ",
+	[FYTT_PE_NOTEQ]			= "PE_NOTEQ",
+	[FYTT_PE_LT]			= "PE_LT",
+	[FYTT_PE_GT]			= "PE_GT",
+	[FYTT_PE_LTE]			= "PE_LTE",
+	[FYTT_PE_GTE]			= "PE_GTE",
+
+	[FYTT_SE_PLUS]			= "SE_PLUS",
+	[FYTT_SE_MINUS]			= "SE_MINUS",
+	[FYTT_SE_MULT]			= "SE_MULT",
+	[FYTT_SE_DIV]			= "SE_DIV",
+
+	[FYTT_PE_METHOD]		= "PE_METHOD",
+	[FYTT_SE_METHOD]		= "SE_METHOD",
+};
+
+char *fy_token_dump_format(struct fy_token *fyt, char *buf, size_t bufsz)
+{
+	const char *typetxt, *text;
+	size_t size;
+	enum fy_token_type type;
+	const char *pfx, *sfx;
+
+	if (fyt && (unsigned int)fyt->type < sizeof(fy_token_type_txt)/
+					     sizeof(fy_token_type_txt[0])) {
+		typetxt = fy_token_type_txt[fyt->type];
+		type = fyt->type;
+	} else {
+		typetxt = "<NULL>";
+		type = FYTT_NONE;
+	}
+
+	size = 0;
+	switch (type) {
+	case FYTT_SCALAR:
+	case FYTT_ALIAS:
+	case FYTT_ANCHOR:
+		text = fy_token_get_text(fyt, &size);
+		break;
+	default:
+		text = NULL;
+		break;
+	}
+
+	if (!text) {
+		snprintf(buf, bufsz, "%s", typetxt);
+		return buf;
+	}
+
+	pfx = typetxt;
+	sfx = "";
+	switch (type) {
+	case FYTT_SCALAR:
+
+		pfx = "\"";
+
+		/* not too large */
+		if (size > 20)
+			size = 20;
+		fy_utf8_format_text_a(text, size, fyue_doublequote, &text);
+		size = strlen(text);
+		if (size > 10) {
+			sfx = "...\"";
+			size = 7;
+		} else {
+			sfx = "\"";
+		}
+		break;
+	case FYTT_ALIAS:
+	case FYTT_ANCHOR:
+		sfx = type == FYTT_ALIAS ? "*" : "&";
+		if (size > 10) {
+			sfx = "...";
+			size = 7;
+		} else
+			sfx = "";
+		break;
+
+	default:
+		break;
+	}
+
+	snprintf(buf, bufsz, "%s%.*s%s", pfx, (int)size, text, sfx);
+
+	return buf;
+}
+
+char *fy_token_list_dump_format(struct fy_token_list *fytl,
+		struct fy_token *fyt_highlight, char *buf, size_t bufsz)
+{
+	char *s, *e;
+	struct fy_token *fyt;
+
+	s = buf;
+	e = buf + bufsz - 1;
+	for (fyt = fy_token_list_first(fytl); fyt; fyt = fy_token_next(fytl, fyt)) {
+
+		if (s >= (e - 1))
+			break;
+
+		s += snprintf(s, e - s, "%s%s",
+				fyt != fy_token_list_first(fytl) ? "," : "",
+				fyt_highlight == fyt ? "*" : "");
+
+		fy_token_dump_format(fyt, s, e - s);
+
+		s += strlen(s);
+	}
+	*s = '\0';
+
+	return buf;
+}
+
+char *fy_simple_key_dump_format(struct fy_parser *fyp, struct fy_simple_key *fysk, char *buf, size_t bufsz)
+{
+	char tbuf[80];
+
+	if (!fysk) {
+		if (bufsz > 0)
+			*buf = '\0';
+		return buf;
+	}
+
+	fy_token_dump_format(fysk->token, tbuf, sizeof(tbuf));
+
+	snprintf(buf, bufsz, "%s/%c%c/%d/<%d-%d,%d-%d>", tbuf,
+			fysk->required ? 'R' : '-',
+			fysk->implicit_complex ? 'C' : '-',
+			fysk->flow_level,
+			fysk->mark.line, fysk->mark.column,
+			fysk->end_mark.line, fysk->end_mark.column);
+	return buf;
+}
+
+char *fy_simple_key_list_dump_format(struct fy_parser *fyp, struct fy_simple_key_list *fyskl,
+		struct fy_simple_key *fysk_highlight, char *buf, size_t bufsz)
+{
+	char *s, *e;
+	struct fy_simple_key *fysk;
+
+	s = buf;
+	e = buf + bufsz - 1;
+	for (fysk = fy_simple_key_list_first(fyskl); fysk; fysk = fy_simple_key_next(fyskl, fysk)) {
+
+		if (s >= (e - 1))
+			break;
+
+		s += snprintf(s, e - s, "%s%s",
+				fysk != fy_simple_key_list_first(fyskl) ? "," : "",
+				fysk_highlight == fysk ? "*" : "");
+
+		fy_simple_key_dump_format(fyp, fysk, s, e - s);
+
+		s += strlen(s);
+	}
+	*s = '\0';
+
+	return buf;
+}
+
+#ifdef FY_DEVMODE
+
+void fyp_debug_dump_token_list(struct fy_parser *fyp, struct fy_token_list *fytl,
+		struct fy_token *fyt_highlight, const char *banner)
+{
+	char buf[4096];
+
+	if (!fyp || !fyp->diag || FYET_DEBUG < fyp->diag->cfg.level)
+		return;
+
+	fyp_scan_debug(fyp, "%s%s\n", banner,
+			fy_token_list_dump_format(fytl, fyt_highlight, buf, sizeof(buf)));
+}
+
+void fyp_debug_dump_token(struct fy_parser *fyp, struct fy_token *fyt, const char *banner)
+{
+	char buf[80];
+
+	if (!fyp || !fyp->diag || FYET_DEBUG < fyp->diag->cfg.level)
+		return;
+
+	fyp_scan_debug(fyp, "%s%s\n", banner,
+			fy_token_dump_format(fyt, buf, sizeof(buf)));
+}
+
+void fyp_debug_dump_simple_key_list(struct fy_parser *fyp, struct fy_simple_key_list *fyskl,
+		struct fy_simple_key *fysk_highlight, const char *banner)
+{
+	char buf[4096];
+
+	if (!fyp || !fyp->diag || FYET_DEBUG < fyp->diag->cfg.level)
+		return;
+
+	fyp_scan_debug(fyp, "%s%s\n", banner,
+			fy_simple_key_list_dump_format(fyp, fyskl, fysk_highlight, buf, sizeof(buf)));
+}
+
+void fyp_debug_dump_simple_key(struct fy_parser *fyp, struct fy_simple_key *fysk, const char *banner)
+{
+	char buf[80];
+
+	if (!fyp || !fyp->diag || FYET_DEBUG < fyp->diag->cfg.level)
+		return;
+
+	fyp_scan_debug(fyp, "%s%s\n", banner,
+			fy_simple_key_dump_format(fyp, fysk, buf, sizeof(buf)));
+}
+
+void fyp_debug_dump_input(struct fy_parser *fyp, const struct fy_input_cfg *fyic,
+		const char *banner)
+{
+	switch (fyic->type) {
+	case fyit_file:
+		fyp_scan_debug(fyp, "%s: filename=\"%s\"\n", banner,
+				fyic->file.filename);
+		break;
+	case fyit_stream:
+		fyp_scan_debug(fyp, "%s: stream=\"%s\" fileno=%d\n", banner,
+				fyic->stream.name, fileno(fyic->stream.fp));
+		break;
+	case fyit_memory:
+		fyp_scan_debug(fyp, "%s: start=%p size=%zu\n", banner,
+				fyic->memory.data, fyic->memory.size);
+		break;
+	case fyit_alloc:
+		fyp_scan_debug(fyp, "%s: start=%p size=%zu\n", banner,
+				fyic->alloc.data, fyic->alloc.size);
+		break;
+	default:
+		break;
+	}
+}
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-dump.h b/contrib/libs/libfyaml/src/lib/fy-dump.h
new file mode 100644
index 0000000000..13b1c9a823
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-dump.h
@@ -0,0 +1,92 @@
+/*
+ * fy-dump.h - dumps for various internal structures
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_DUMP_H
+#define FY_DUMP_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-list.h"
+#include "fy-diag.h"
+
+struct fy_parser;
+struct fy_token;
+struct fy_token_list;
+struct fy_simple_key;
+struct fy_simple_key_list;
+struct fy_input_cfg;
+
+extern const char *fy_token_type_txt[];
+
+char *fy_token_dump_format(struct fy_token *fyt, char *buf, size_t bufsz);
+char *fy_token_list_dump_format(struct fy_token_list *fytl,
+		struct fy_token *fyt_highlight, char *buf, size_t bufsz);
+
+char *fy_simple_key_dump_format(struct fy_parser *fyp, struct fy_simple_key *fysk, char *buf, size_t bufsz);
+char *fy_simple_key_list_dump_format(struct fy_parser *fyp, struct fy_simple_key_list *fyskl,
+		struct fy_simple_key *fysk_highlight, char *buf, size_t bufsz);
+
+#ifdef FY_DEVMODE
+
+void fyp_debug_dump_token_list(struct fy_parser *fyp, struct fy_token_list *fytl,
+			       struct fy_token *fyt_highlight, const char *banner);
+void fyp_debug_dump_token(struct fy_parser *fyp, struct fy_token *fyt, const char *banner);
+
+void fyp_debug_dump_simple_key_list(struct fy_parser *fyp, struct fy_simple_key_list *fyskl,
+				    struct fy_simple_key *fysk_highlight, const char *banner);
+void fyp_debug_dump_simple_key(struct fy_parser *fyp, struct fy_simple_key *fysk, const char *banner);
+
+void fyp_debug_dump_input(struct fy_parser *fyp, const struct fy_input_cfg *fyic,
+			  const char *banner);
+
+#else
+
+static inline void
+fyp_debug_dump_token_list(struct fy_parser *fyp, struct fy_token_list *fytl,
+			  struct fy_token *fyt_highlight, const char *banner)
+{
+	/* nothing */
+}
+
+static inline void
+fyp_debug_dump_token(struct fy_parser *fyp, struct fy_token *fyt, const char *banner)
+{
+	/* nothing */
+}
+
+static inline void
+fyp_debug_dump_simple_key_list(struct fy_parser *fyp, struct fy_simple_key_list *fyskl,
+			       struct fy_simple_key *fysk_highlight, const char *banner)
+{
+	/* nothing */
+}
+
+static inline void
+fyp_debug_dump_simple_key(struct fy_parser *fyp, struct fy_simple_key *fysk, const char *banner)
+{
+	/* nothing */
+}
+
+static inline void
+fy_debug_dump_input(struct fy_parser *fyp, const struct fy_input_cfg *fyic,
+		    const char *banner)
+{
+	/* nothing */
+}
+
+#endif
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-emit-accum.h b/contrib/libs/libfyaml/src/lib/fy-emit-accum.h
new file mode 100644
index 0000000000..acc8ae7491
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-emit-accum.h
@@ -0,0 +1,383 @@
+/*
+ * fy-emit-accum.h - internal YAML emitter accumulator header
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_EMIT_ACCUM_H
+#define FY_EMIT_ACCUM_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include <libfyaml.h>
+
+#include "fy-utf8.h"
+#include "fy-event.h"
+
+struct fy_emit_accum {
+	char *accum;
+	size_t alloc;
+	size_t next;
+	char *inplace;
+	size_t inplacesz;
+	int col, row;
+	int ts;
+	enum fy_lb_mode lb_mode;
+};
+
+static inline void
+fy_emit_accum_init(struct fy_emit_accum *ea,
+		   void *inplace, size_t inplacesz,
+		   int ts, enum fy_lb_mode lb_mode)
+{
+	memset(ea, 0, sizeof(*ea));
+
+	ea->inplace = inplace;
+	ea->inplacesz = inplacesz;
+	ea->accum = ea->inplace;
+	ea->alloc = ea->inplacesz;
+	ea->ts = ts ? ts : 8;
+	ea->lb_mode = lb_mode;
+}
+
+static inline void
+fy_emit_accum_reset(struct fy_emit_accum *ea)
+{
+	ea->next = 0;
+	ea->col = 0;
+	ea->row = 0;
+}
+
+static inline void
+fy_emit_accum_cleanup(struct fy_emit_accum *ea)
+{
+	if (ea->accum && ea->accum != ea->inplace)
+		free(ea->accum);
+	ea->accum = ea->inplace;
+	ea->alloc = ea->inplacesz;
+	fy_emit_accum_reset(ea);
+}
+
+static inline void
+fy_emit_accum_start(struct fy_emit_accum *ea, int col, enum fy_lb_mode lb_mode)
+{
+	fy_emit_accum_reset(ea);
+	ea->col = col;
+	ea->lb_mode = lb_mode;
+}
+
+static inline void
+fy_emit_accum_finish(struct fy_emit_accum *ea)
+{
+	fy_emit_accum_reset(ea);
+}
+
+static inline int
+fy_emit_accum_grow(struct fy_emit_accum *ea, size_t need)
+{
+	size_t atleast, asz;
+	char *new_accum;
+
+	atleast = ea->alloc + need;
+	asz = ea->alloc;
+	/* minimum buffer is 32 */
+	if (asz < 32)
+		asz = 32;
+	do {
+		asz *= 2;
+	} while (asz < atleast);
+	assert(asz > ea->inplacesz);
+	new_accum = realloc(ea->accum == ea->inplace ? NULL : ea->accum, asz);
+	if (!new_accum)	/* out of memory */
+		return -1;
+	if (ea->accum && ea->accum == ea->inplace)
+		memcpy(new_accum, ea->accum, ea->next);
+	ea->alloc = asz;
+	ea->accum = new_accum;
+
+	return 0;
+}
+
+static inline int
+fy_emit_accum_utf8_put_raw(struct fy_emit_accum *ea, int c)
+{
+	size_t w, avail;
+	int ret;
+
+	/* grow if needed */
+	w = fy_utf8_width(c);
+	if (w > (avail = (ea->alloc - ea->next))) {
+		ret = fy_emit_accum_grow(ea, w - avail);
+		if (ret != 0)
+			return ret;
+	}
+	(void)fy_utf8_put_unchecked(ea->accum + ea->next, c);
+	ea->next += w;
+
+	return 0;
+}
+
+static inline int
+fy_emit_accum_put_raw(struct fy_emit_accum *ea, int c)
+{
+	int ret;
+
+	/* only lower ascii please */
+	if (c >= 0x80)
+		return -1;
+
+	/* grow if needed */
+	if (ea->next >= ea->alloc) {
+		ret = fy_emit_accum_grow(ea, 1);
+		if (ret != 0)
+			return ret;
+	}
+	*(ea->accum + ea->next) = (char)c;
+	ea->next++;
+
+	return 0;
+}
+
+static inline int
+fy_emit_accum_utf8_put(struct fy_emit_accum *ea, int c)
+{
+	int ret;
+
+	if (!fy_utf8_is_valid(c))
+		return -1;
+
+	if (fy_is_lb_m(c, ea->lb_mode)) {
+		ret = fy_emit_accum_put_raw(ea, '\n');
+		if (ret)
+			return ret;
+		ea->col = 0;
+		ea->row++;
+	} else if (fy_is_tab(c)) {
+		ret = fy_emit_accum_put_raw(ea, '\t');
+		if (ret)
+			return ret;
+		ea->col += (ea->ts - (ea->col % ea->ts));
+	} else {
+		if (c < 0x80) {
+			ret = fy_emit_accum_put_raw(ea, c);
+			if (ret)
+				return ret;
+		} else {
+			ret = fy_emit_accum_utf8_put_raw(ea, c);
+		}
+		ea->col++;
+	}
+
+	return 0;
+}
+
+static inline int
+fy_emit_accum_utf8_write_raw(struct fy_emit_accum *ea, const void *data, size_t len)
+{
+	size_t avail;
+	int ret;
+
+	/* grow if needed */
+	if (len > (avail = (ea->alloc - ea->next))) {
+		ret = fy_emit_accum_grow(ea, len - avail);
+		if (ret != 0)
+			return ret;
+	}
+	memcpy(ea->accum + ea->next, data, len);
+	ea->next += len;
+
+	return 0;
+}
+
+static inline int
+fy_emit_accum_utf8_write(struct fy_emit_accum *ea, const void *data, size_t len)
+{
+	const char *s, *e;
+	int c, w, ret;
+
+	for (s = data, e = s + len; (c = fy_utf8_get(s, (e - s), &w)) >= 0; s += w) {
+		ret = fy_emit_accum_utf8_put(ea, c);
+		if (ret)
+			break;
+	}
+	return c == FYUG_EOF ? 0 : -1;
+}
+
+static inline int
+fy_emit_accum_utf8_printf_raw(struct fy_emit_accum *ea, const char *fmt, ...)
+		FY_ATTRIBUTE(format(printf, 2, 3));
+
+static inline int
+fy_emit_accum_utf8_printf_raw(struct fy_emit_accum *ea, const char *fmt, ...)
+{
+	va_list ap;
+	size_t avail, len;
+	int ret;
+
+	/* get the size of the string */
+	va_start(ap, fmt);
+	len = vsnprintf(NULL, 0, fmt, ap);
+	va_end(ap);
+
+	/* grow if needed */
+	if ((len + 1) > (avail = (ea->alloc - ea->next))) {
+		ret = fy_emit_accum_grow(ea, (len + 1) - avail);
+		if (ret != 0)
+			return ret;
+	}
+
+	va_start(ap, fmt);
+	(void)vsnprintf(ea->accum + ea->next, len + 1, fmt, ap);
+	va_end(ap);
+
+	ea->next += len;
+
+	return 0;
+}
+
+static inline const char *
+fy_emit_accum_get(struct fy_emit_accum *ea, size_t *lenp)
+{
+	*lenp = ea->next;
+	if (!ea->next) {
+		return "";
+	}
+	return ea->accum;
+}
+
+static inline int
+fy_emit_accum_make_0_terminated(struct fy_emit_accum *ea)
+{
+	int ret;
+
+	/* the empty case is special cased */
+	if (!ea->next)
+		return 0;
+
+	/* grow if needed for the '\0' */
+	if (ea->next >= ea->alloc) {
+		ret = fy_emit_accum_grow(ea, 1);
+		if (ret != 0)
+			return ret;
+	}
+	assert(ea->next < ea->alloc);
+	*(ea->accum + ea->next) = '\0';
+	return 0;
+}
+
+static inline const char *
+fy_emit_accum_get0(struct fy_emit_accum *ea)
+{
+	int ret;
+
+	ret = fy_emit_accum_make_0_terminated(ea);
+	if (ret)
+		return NULL;
+	return ea->accum;
+}
+
+static inline char *
+fy_emit_accum_steal(struct fy_emit_accum *ea, size_t *lenp)
+{
+	int ret;
+	char *buf;
+
+	/* empty, return a malloc'ed buffer to "" */
+	if (!ea->next) {
+		buf = strdup("");
+		if (!buf) {
+			*lenp = 0;
+			return NULL;
+		}
+		*lenp = ea->next;
+	} else if (ea->inplace && ea->accum == ea->inplace) {
+		buf = malloc(ea->next + 1);
+		if (!buf) {
+			*lenp = 0;
+			return NULL;
+		}
+		memcpy(buf, ea->accum, ea->next);
+		buf[ea->next] = '\0';
+		*lenp = ea->next;
+	} else {
+		ret = fy_emit_accum_make_0_terminated(ea);
+		if (ret) {
+			*lenp = 0;
+			return NULL;
+		}
+		assert(ea->accum && ea->accum != ea->inplace);
+		buf = ea->accum;
+		*lenp = ea->next;
+		/* reset to inplace */
+		ea->accum = ea->inplace;
+		ea->alloc = ea->inplacesz;
+	}
+
+	fy_emit_accum_cleanup(ea);
+	return buf;
+}
+
+static inline char *
+fy_emit_accum_steal0(struct fy_emit_accum *ea)
+{
+	size_t len;
+
+	return fy_emit_accum_steal(ea, &len);
+}
+
+static inline bool
+fy_emit_accum_empty(struct fy_emit_accum *ea)
+{
+	return ea->next == 0;
+}
+
+static inline int
+fy_emit_accum_size(struct fy_emit_accum *ea)
+{
+	return ea->next;
+}
+
+static inline int
+fy_emit_accum_column(struct fy_emit_accum *ea)
+{
+	return ea->col;
+}
+
+static inline int
+fy_emit_accum_row(struct fy_emit_accum *ea)
+{
+	return ea->row;
+}
+
+struct fy_emit_accum_state {
+	int col;
+	int row;
+	size_t next;
+};
+
+static inline void
+fy_emit_accum_get_state(struct fy_emit_accum *ea, struct fy_emit_accum_state *s)
+{
+	s->col = ea->col;
+	s->row = ea->row;
+	s->next = ea->next;
+}
+
+static inline void
+fy_emit_accum_rewind_state(struct fy_emit_accum *ea, const struct fy_emit_accum_state *s)
+{
+	/* we can only go back */
+	assert(s->next <= ea->next);
+	ea->col = s->col;
+	ea->row = s->row;
+	ea->next = s->next;
+}
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-emit.c b/contrib/libs/libfyaml/src/lib/fy-emit.c
new file mode 100644
index 0000000000..ad0a18dd57
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-emit.c
@@ -0,0 +1,3554 @@
+/*
+ * fy-emit.c - Internal YAML emitter methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <limits.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <unistd.h>
+#elif defined (_MSC_VER)
+#define STDOUT_FILENO _fileno(stdin)
+#endif
+#include <ctype.h>
+#include <errno.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-emit.h"
+
+/* fwd decl */
+void fy_emit_write(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *str, int len);
+void fy_emit_printf(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *fmt, ...)
+		FY_ATTRIBUTE(format(printf, 3, 4));
+
+static inline bool fy_emit_is_json_mode(const struct fy_emitter *emit)
+{
+	enum fy_emitter_cfg_flags flags;
+
+	if (emit->force_json)
+		return true;
+
+	flags = emit->cfg.flags & FYECF_MODE(FYECF_MODE_MASK);
+	return flags == FYECF_MODE_JSON || flags == FYECF_MODE_JSON_TP || flags == FYECF_MODE_JSON_ONELINE;
+}
+
+static inline bool fy_emit_is_flow_mode(const struct fy_emitter *emit)
+{
+	enum fy_emitter_cfg_flags flags = emit->cfg.flags & FYECF_MODE(FYECF_MODE_MASK);
+
+	return flags == FYECF_MODE_FLOW || flags == FYECF_MODE_FLOW_ONELINE;
+}
+
+static inline bool fy_emit_is_block_mode(const struct fy_emitter *emit)
+{
+	enum fy_emitter_cfg_flags flags = emit->cfg.flags & FYECF_MODE(FYECF_MODE_MASK);
+
+	return flags == FYECF_MODE_BLOCK || flags == FYECF_MODE_DEJSON || flags == FYECF_MODE_PRETTY;
+}
+
+static inline bool fy_emit_is_oneline(const struct fy_emitter *emit)
+{
+	enum fy_emitter_cfg_flags flags = emit->cfg.flags & FYECF_MODE(FYECF_MODE_MASK);
+
+	return flags == FYECF_MODE_FLOW_ONELINE || flags == FYECF_MODE_JSON_ONELINE;
+}
+
+static inline bool fy_emit_is_dejson_mode(const struct fy_emitter *emit)
+{
+	enum fy_emitter_cfg_flags flags = emit->cfg.flags & FYECF_MODE(FYECF_MODE_MASK);
+
+	return flags == FYECF_MODE_DEJSON;
+}
+
+static inline bool fy_emit_is_pretty_mode(const struct fy_emitter *emit)
+{
+	enum fy_emitter_cfg_flags flags = emit->cfg.flags & FYECF_MODE(FYECF_MODE_MASK);
+
+	return flags == FYECF_MODE_PRETTY;
+}
+
+static inline int fy_emit_indent(struct fy_emitter *emit)
+{
+	int indent;
+
+	indent = (emit->cfg.flags & FYECF_INDENT(FYECF_INDENT_MASK)) >> FYECF_INDENT_SHIFT;
+	return indent ? indent : 2;
+}
+
+static inline int fy_emit_width(struct fy_emitter *emit)
+{
+	int width;
+
+	width = (emit->cfg.flags & FYECF_WIDTH(FYECF_WIDTH_MASK)) >> FYECF_WIDTH_SHIFT;
+	if (width == 0)
+		return 80;
+	if (width == FYECF_WIDTH_MASK)
+		return INT_MAX;
+	return width;
+}
+
+static inline bool fy_emit_output_comments(struct fy_emitter *emit)
+{
+	return !!(emit->cfg.flags & FYECF_OUTPUT_COMMENTS);
+}
+
+static int fy_emit_node_check_json(struct fy_emitter *emit, struct fy_node *fyn)
+{
+	struct fy_document *fyd;
+	struct fy_node *fyni;
+	struct fy_node_pair *fynp, *fynpi;
+	int ret;
+
+	if (!fyn)
+		return 0;
+
+	fyd = fyn->fyd;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		FYD_TOKEN_ERROR_CHECK(fyd, fyn->scalar, FYEM_INTERNAL,
+				!fy_node_is_alias(fyn), err_out,
+				"aliases not allowed in JSON emit mode");
+		break;
+
+	case FYNT_SEQUENCE:
+		for (fyni = fy_node_list_head(&fyn->sequence); fyni;
+				fyni = fy_node_next(&fyn->sequence, fyni)) {
+			ret = fy_emit_node_check_json(emit, fyni);
+			if (ret)
+				return ret;
+		}
+		break;
+
+	case FYNT_MAPPING:
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp; fynp = fynpi) {
+
+			fynpi = fy_node_pair_next(&fyn->mapping, fynp);
+
+			ret = fy_emit_node_check_json(emit, fynp->key);
+			if (ret)
+				return ret;
+			ret = fy_emit_node_check_json(emit, fynp->value);
+			if (ret)
+				return ret;
+		}
+		break;
+	}
+	return 0;
+err_out:
+	return -1;
+}
+
+static int fy_emit_node_check(struct fy_emitter *emit, struct fy_node *fyn)
+{
+	int ret;
+
+	if (!fyn)
+		return 0;
+
+	if (fy_emit_is_json_mode(emit) && !emit->source_json) {
+		ret = fy_emit_node_check_json(emit, fyn);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+void fy_emit_node_internal(struct fy_emitter *emit, struct fy_node *fyn, int flags, int indent, bool is_key);
+void fy_emit_scalar(struct fy_emitter *emit, struct fy_node *fyn, int flags, int indent, bool is_key);
+void fy_emit_sequence(struct fy_emitter *emit, struct fy_node *fyn, int flags, int indent);
+void fy_emit_mapping(struct fy_emitter *emit, struct fy_node *fyn, int flags, int indent);
+
+void fy_emit_write(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *str, int len)
+{
+	int c, w;
+	const char *m, *e;
+	int outlen;
+
+	if (!len)
+		return;
+
+	outlen = emit->cfg.output(emit, type, str, len, emit->cfg.userdata);
+	if (outlen != len)
+		emit->output_error = true;
+
+	e = str + len;
+	while ((c = fy_utf8_get(str, (e - str), &w)) >= 0) {
+
+		/* special handling for MSDOS */
+		if (c == '\r' && (e - str) > 1 && str[1] == '\n') {
+			str += 2;
+			emit->column = 0;
+			emit->line++;
+			continue;
+		}
+
+		/* regular line break */
+		if (fy_is_lb_r_n(c)) {
+			emit->column = 0;
+			emit->line++;
+			str += w;
+			continue;
+		}
+
+		/* completely ignore ANSI color escape sequences */
+		if (c == '\x1b' && (e - str) > 2 && str[1] == '[' &&
+		    (m = memchr(str, 'm', e - str)) != NULL) {
+			str = m + 1;
+			continue;
+		}
+
+		emit->column++;
+		str += w;
+	}
+}
+
+void fy_emit_puts(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *str)
+{
+	fy_emit_write(emit, type, str, strlen(str));
+}
+
+void fy_emit_putc(struct fy_emitter *emit, enum fy_emitter_write_type type, int c)
+{
+	char buf[FY_UTF8_FORMAT_BUFMIN];
+
+	fy_utf8_format(c, buf, fyue_none);
+	fy_emit_puts(emit, type, buf);
+}
+
+void fy_emit_vprintf(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *fmt, va_list ap)
+{
+	char *str;
+	int size;
+	va_list ap2;
+
+	va_copy(ap2, ap);
+
+	size = vsnprintf(NULL, 0, fmt, ap);
+	if (size < 0)
+		return;
+
+	str = FY_ALLOCA(size + 1);
+	size = vsnprintf(str, size + 1, fmt, ap2);
+	if (size < 0)
+		return;
+
+	fy_emit_write(emit, type, str, size);
+}
+
+void fy_emit_printf(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_emit_vprintf(emit, type, fmt, ap);
+	va_end(ap);
+}
+
+void fy_emit_write_ws(struct fy_emitter *emit)
+{
+	fy_emit_putc(emit, fyewt_whitespace, ' ');
+	emit->flags |= FYEF_WHITESPACE;
+}
+
+void fy_emit_write_indent(struct fy_emitter *emit, int indent)
+{
+	int len;
+	char *ws;
+
+	indent = indent > 0 ? indent : 0;
+
+	if (!fy_emit_indentation(emit) || emit->column > indent ||
+	    (emit->column == indent && !fy_emit_whitespace(emit)))
+		fy_emit_putc(emit, fyewt_linebreak, '\n');
+
+	if (emit->column < indent) {
+		len = indent - emit->column;
+		ws = FY_ALLOCA(len + 1);
+		memset(ws, ' ', len);
+		ws[len] = '\0';
+		fy_emit_write(emit, fyewt_indent, ws, len);
+	}
+
+	emit->flags |= FYEF_WHITESPACE | FYEF_INDENTATION;
+}
+
+enum document_indicator {
+	di_question_mark,
+	di_colon,
+	di_dash,
+	di_left_bracket,
+	di_right_bracket,
+	di_left_brace,
+	di_right_brace,
+	di_comma,
+	di_bar,
+	di_greater,
+	di_single_quote_start,
+	di_single_quote_end,
+	di_double_quote_start,
+	di_double_quote_end,
+	di_ambersand,
+	di_star,
+};
+
+void fy_emit_write_indicator(struct fy_emitter *emit,
+		enum document_indicator indicator,
+		int flags, int indent,
+		enum fy_emitter_write_type wtype)
+{
+	switch (indicator) {
+
+	case di_question_mark:
+		if (!fy_emit_whitespace(emit))
+			fy_emit_write_ws(emit);
+		fy_emit_putc(emit, wtype, '?');
+		emit->flags &= ~(FYEF_WHITESPACE | FYEF_OPEN_ENDED);
+		break;
+
+	case di_colon:
+		if (!(flags & DDNF_SIMPLE)) {
+			if (!emit->flow_level && !fy_emit_is_oneline(emit))
+				fy_emit_write_indent(emit, indent);
+			if (!fy_emit_whitespace(emit))
+				fy_emit_write_ws(emit);
+		}
+		fy_emit_putc(emit, wtype, ':');
+		emit->flags &= ~(FYEF_WHITESPACE | FYEF_OPEN_ENDED);
+		break;
+
+	case di_dash:
+		if (!fy_emit_whitespace(emit))
+			fy_emit_write_ws(emit);
+		fy_emit_putc(emit, wtype, '-');
+		emit->flags &= ~(FYEF_WHITESPACE | FYEF_OPEN_ENDED);
+		break;
+
+	case di_left_bracket:
+	case di_left_brace:
+		emit->flow_level++;
+		if (!fy_emit_whitespace(emit))
+			fy_emit_write_ws(emit);
+		fy_emit_putc(emit, wtype, indicator == di_left_bracket ? '[' : '{');
+		emit->flags |= FYEF_WHITESPACE;
+		emit->flags &= ~(FYEF_INDENTATION | FYEF_OPEN_ENDED);
+		break;
+
+	case di_right_bracket:
+	case di_right_brace:
+		emit->flow_level--;
+		fy_emit_putc(emit, wtype, indicator == di_right_bracket ? ']' : '}');
+		emit->flags &= ~(FYEF_WHITESPACE | FYEF_INDENTATION | FYEF_OPEN_ENDED);
+		break;
+
+	case di_comma:
+		fy_emit_putc(emit, wtype, ',');
+		emit->flags &= ~(FYEF_WHITESPACE | FYEF_INDENTATION | FYEF_OPEN_ENDED);
+		break;
+
+	case di_bar:
+	case di_greater:
+		if (!fy_emit_whitespace(emit))
+			fy_emit_write_ws(emit);
+		fy_emit_putc(emit, wtype, indicator == di_bar ? '|' : '>');
+		emit->flags &= ~(FYEF_INDENTATION | FYEF_WHITESPACE | FYEF_OPEN_ENDED);
+		break;
+
+	case di_single_quote_start:
+	case di_double_quote_start:
+		if (!fy_emit_whitespace(emit))
+			fy_emit_write_ws(emit);
+		fy_emit_putc(emit, wtype, indicator == di_single_quote_start ? '\'' : '"');
+		emit->flags &= ~(FYEF_WHITESPACE | FYEF_INDENTATION | FYEF_OPEN_ENDED);
+		break;
+
+	case di_single_quote_end:
+	case di_double_quote_end:
+		fy_emit_putc(emit, wtype, indicator == di_single_quote_end ? '\'' : '"');
+		emit->flags &= ~(FYEF_WHITESPACE | FYEF_INDENTATION | FYEF_OPEN_ENDED);
+		break;
+
+	case di_ambersand:
+		if (!fy_emit_whitespace(emit))
+			fy_emit_write_ws(emit);
+		fy_emit_putc(emit, wtype, '&');
+		emit->flags &= ~(FYEF_WHITESPACE | FYEF_INDENTATION);
+		break;
+
+	case di_star:
+		if (!fy_emit_whitespace(emit))
+			fy_emit_write_ws(emit);
+		fy_emit_putc(emit, wtype, '*');
+		emit->flags &= ~(FYEF_WHITESPACE | FYEF_INDENTATION);
+		break;
+	}
+}
+
+int fy_emit_increase_indent(struct fy_emitter *emit, int flags, int indent)
+{
+	if (indent < 0)
+		return (flags & DDNF_FLOW) ? fy_emit_indent(emit) : 0;
+
+	if (!(flags & DDNF_INDENTLESS))
+		return indent + fy_emit_indent(emit);
+
+	return indent;
+}
+
+void fy_emit_write_comment(struct fy_emitter *emit, int flags, int indent, const char *str, size_t len, struct fy_atom *handle)
+{
+	const char *s, *e, *sr;
+	int c, w;
+	bool breaks;
+
+	if (!str || !len)
+		return;
+
+	if (len == (size_t)-1)
+		len = strlen(str);
+
+	if (!fy_emit_whitespace(emit))
+		fy_emit_write_ws(emit);
+	indent = emit->column;
+
+	s = str;
+	e = str + len;
+
+	sr = s;	/* start of normal output run */
+	breaks = false;
+	while (s < e && (c = fy_utf8_get(s, e - s, &w)) > 0) {
+
+		if (fy_is_lb_m(c, fy_atom_lb_mode(handle))) {
+
+			/* output run */
+			fy_emit_write(emit, fyewt_comment, sr, s - sr);
+			sr = s + w;
+			fy_emit_write_indent(emit, indent);
+			emit->flags |= FYEF_INDENTATION;
+			breaks = true;
+		} else {
+
+			if (breaks) {
+				fy_emit_write(emit, fyewt_comment, sr, s - sr);
+				sr = s;
+				fy_emit_write_indent(emit, indent);
+			}
+			emit->flags &= ~FYEF_INDENTATION;
+			breaks = false;
+		}
+
+		s += w;
+	}
+
+	/* dump what's remaining */
+	fy_emit_write(emit, fyewt_comment, sr, s - sr);
+
+	emit->flags |= (FYEF_WHITESPACE | FYEF_INDENTATION);
+}
+
+struct fy_atom *fy_emit_token_comment_handle(struct fy_emitter *emit, struct fy_token *fyt, enum fy_comment_placement placement)
+{
+	struct fy_atom *handle;
+
+	handle = fy_token_comment_handle(fyt, placement, false);
+	return handle && fy_atom_is_set(handle) ? handle : NULL;
+}
+
+void fy_emit_document_start_indicator(struct fy_emitter *emit)
+{
+	/* do not emit twice */
+	if (emit->flags & FYEF_HAD_DOCUMENT_START)
+		return;
+
+	/* do not try to emit if it's json mode */
+	if (fy_emit_is_json_mode(emit))
+		goto no_doc_emit;
+
+	/* output linebreak anyway */
+	if (emit->column)
+		fy_emit_putc(emit, fyewt_linebreak, '\n');
+
+	/* stripping doc indicators, do not emit */
+	if (emit->cfg.flags & FYECF_STRIP_DOC)
+		goto no_doc_emit;
+
+	/* ok, emit document start indicator */
+	fy_emit_puts(emit, fyewt_document_indicator, "---");
+	emit->flags &= ~FYEF_WHITESPACE;
+	emit->flags |= FYEF_HAD_DOCUMENT_START;
+	return;
+
+no_doc_emit:
+	emit->flags &= ~FYEF_HAD_DOCUMENT_START;
+}
+
+struct fy_token *fy_node_value_token(struct fy_node *fyn)
+{
+	struct fy_token *fyt;
+
+	if (!fyn)
+		return NULL;
+
+	switch (fyn->type) {
+	case FYNT_SCALAR:
+		fyt = fyn->scalar;
+		break;
+	case FYNT_SEQUENCE:
+		fyt = fyn->sequence_start;
+		break;
+	case FYNT_MAPPING:
+		fyt = fyn->mapping_start;
+		break;
+	default:
+		fyt = NULL;
+		break;
+	}
+
+	return fyt;
+}
+
+bool fy_emit_token_has_comment(struct fy_emitter *emit, struct fy_token *fyt, enum fy_comment_placement placement)
+{
+	return fy_emit_token_comment_handle(emit, fyt, placement) ? true : false;
+}
+
+bool fy_emit_node_has_comment(struct fy_emitter *emit, struct fy_node *fyn, enum fy_comment_placement placement)
+{
+	return fy_emit_token_has_comment(emit, fy_node_value_token(fyn), placement);
+}
+
+void fy_emit_token_comment(struct fy_emitter *emit, struct fy_token *fyt, int flags, int indent,
+			  enum fy_comment_placement placement)
+{
+	struct fy_atom *handle;
+	char *text;
+	const char *t;
+	int len;
+
+	handle = fy_emit_token_comment_handle(emit, fyt, placement);
+	if (!handle)
+		return;
+
+	len = fy_atom_format_text_length(handle);
+	if (len < 0)
+		return;
+
+	text = FY_ALLOCA(len + 1);
+
+	if (placement == fycp_top || placement == fycp_bottom) {
+		fy_emit_write_indent(emit, indent);
+		emit->flags |= FYEF_WHITESPACE;
+	}
+
+	t = fy_atom_format_text(handle, text, len + 1);
+
+	fy_emit_write_comment(emit, flags, indent, t, len, handle);
+
+	emit->flags &= ~FYEF_INDENTATION;
+
+	if (placement == fycp_top || placement == fycp_bottom) {
+		fy_emit_write_indent(emit, indent);
+		emit->flags |= FYEF_WHITESPACE;
+	}
+}
+
+void fy_emit_node_comment(struct fy_emitter *emit, struct fy_node *fyn, int flags, int indent,
+			  enum fy_comment_placement placement)
+{
+	struct fy_token *fyt;
+
+	if (!fy_emit_output_comments(emit) || (unsigned int)placement >= fycp_max)
+		return;
+
+	fyt = fy_node_value_token(fyn);
+	if (!fyt)
+		return;
+
+	fy_emit_token_comment(emit, fyt, flags, indent, placement);
+}
+
+void fy_emit_common_node_preamble(struct fy_emitter *emit,
+		struct fy_token *fyt_anchor,
+		struct fy_token *fyt_tag,
+		int flags, int indent)
+{
+	const char *anchor = NULL;
+	const char *tag = NULL;
+	const char *td_prefix __FY_DEBUG_UNUSED__;
+	const char *td_handle;
+	size_t td_prefix_size, td_handle_size;
+	size_t tag_len = 0, anchor_len = 0;
+	bool json_mode = false;
+
+	json_mode = fy_emit_is_json_mode(emit);
+
+	if (!json_mode) {
+		if (!(emit->cfg.flags & FYECF_STRIP_LABELS)) {
+			if (fyt_anchor)
+				anchor = fy_token_get_text(fyt_anchor, &anchor_len);
+		}
+
+		if (!(emit->cfg.flags & FYECF_STRIP_TAGS)) {
+			if (fyt_tag)
+				tag = fy_token_get_text(fyt_tag, &tag_len);
+		}
+
+		if (anchor) {
+			fy_emit_write_indicator(emit, di_ambersand, flags, indent, fyewt_anchor);
+			fy_emit_write(emit, fyewt_anchor, anchor, anchor_len);
+		}
+
+		if (tag) {
+			if (!fy_emit_whitespace(emit))
+				fy_emit_write_ws(emit);
+
+			td_handle = fy_tag_token_get_directive_handle(fyt_tag, &td_handle_size);
+			assert(td_handle);
+			td_prefix = fy_tag_token_get_directive_prefix(fyt_tag, &td_prefix_size);
+			assert(td_prefix);
+
+			if (!td_handle_size)
+				fy_emit_printf(emit, fyewt_tag, "!<%.*s>", (int)tag_len, tag);
+			else
+				fy_emit_printf(emit, fyewt_tag, "%.*s%.*s",
+						(int)td_handle_size, td_handle,
+						(int)(tag_len - td_prefix_size), tag + td_prefix_size);
+
+			emit->flags &= ~(FYEF_WHITESPACE | FYEF_INDENTATION);
+		}
+	}
+
+	/* content for root always starts on a new line */
+	if ((flags & DDNF_ROOT) && emit->column != 0 &&
+            !(emit->flags & FYEF_HAD_DOCUMENT_START)) {
+		fy_emit_putc(emit, fyewt_linebreak, '\n');
+		emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+	}
+}
+
+void fy_emit_node_internal(struct fy_emitter *emit, struct fy_node *fyn, int flags, int indent, bool is_key)
+{
+	enum fy_node_type type;
+	struct fy_anchor *fya;
+	struct fy_token *fyt_anchor = NULL;
+
+	if (!(emit->cfg.flags & FYECF_STRIP_LABELS)) {
+		fya = fy_document_lookup_anchor_by_node(emit->fyd, fyn);
+		if (fya)
+			fyt_anchor = fya->anchor;
+	}
+
+	fy_emit_common_node_preamble(emit, fyt_anchor, fyn->tag, flags, indent);
+
+	type = fyn ? fyn->type : FYNT_SCALAR;
+
+	if (type != FYNT_SCALAR && (flags & DDNF_ROOT) && emit->column != 0) {
+		fy_emit_putc(emit, fyewt_linebreak, '\n');
+		emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+	}
+
+	switch (type) {
+	case FYNT_SCALAR:
+		/* if we're pretty and root at column 0 (meaning it's a single scalar document) output --- */
+		if ((flags & DDNF_ROOT) && fy_emit_is_pretty_mode(emit) && !emit->column &&
+				!fy_emit_is_flow_mode(emit) && !(flags & DDNF_FLOW))
+			fy_emit_document_start_indicator(emit);
+		fy_emit_scalar(emit, fyn, flags, indent, is_key);
+		break;
+	case FYNT_SEQUENCE:
+		FYD_TOKEN_ERROR_CHECK(fyn->fyd, fyn->sequence_start, FYEM_INTERNAL,
+				!is_key || !fy_emit_is_json_mode(emit), err_out,
+				"JSON does not allow sequences as keys");
+		fy_emit_sequence(emit, fyn, flags, indent);
+		break;
+	case FYNT_MAPPING:
+		FYD_TOKEN_ERROR_CHECK(fyn->fyd, fyn->mapping_start, FYEM_INTERNAL,
+				!is_key || !fy_emit_is_json_mode(emit), err_out,
+				"JSON does not allow mappings as keys");
+		fy_emit_mapping(emit, fyn, flags, indent);
+		break;
+	}
+err_out:
+	/* nothing */
+	return;
+}
+
+void fy_emit_token_write_plain(struct fy_emitter *emit, struct fy_token *fyt, int flags, int indent)
+{
+	bool allow_breaks, should_indent, spaces, breaks;
+	int c;
+	enum fy_emitter_write_type wtype;
+	const char *str = NULL;
+	size_t len = 0;
+	struct fy_atom *atom;
+	struct fy_atom_iter iter;
+
+	/* null and not json mode */
+	if (!fyt && !fy_emit_is_json_mode(emit))
+		goto out;
+
+	wtype = (flags & DDNF_SIMPLE_SCALAR_KEY) ? fyewt_plain_scalar_key : fyewt_plain_scalar;
+
+	atom = fy_token_atom(fyt);
+
+	/* null and json mode */
+	if (fy_emit_is_json_mode(emit) && (!fyt || !atom || atom->size0)) {
+		fy_emit_puts(emit, wtype, "null");
+		goto out;
+	}
+
+	/* simple case first (90% of cases) */
+	str = fy_token_get_direct_output(fyt, &len);
+	if (str && fy_token_atom_style(fyt) == FYAS_PLAIN) {
+		fy_emit_write(emit, wtype, str, len);
+		goto out;
+	}
+
+	if (!atom)
+		goto out;
+
+	allow_breaks = !(flags & DDNF_SIMPLE) && !fy_emit_is_json_mode(emit) && !fy_emit_is_oneline(emit);
+
+	spaces = false;
+	breaks = false;
+
+	fy_atom_iter_start(atom, &iter);
+	fy_emit_accum_start(&emit->ea, emit->column, fy_token_atom_lb_mode(fyt));
+	while ((c = fy_atom_iter_utf8_get(&iter)) > 0) {
+
+		if (fy_is_ws(c)) {
+
+			should_indent = allow_breaks && !spaces &&
+					fy_emit_accum_column(&emit->ea) > fy_emit_width(emit);
+
+			if (should_indent && !fy_is_ws(fy_atom_iter_utf8_peek(&iter))) {
+				fy_emit_output_accum(emit, wtype, &emit->ea);
+				emit->flags &= ~FYEF_INDENTATION;
+				fy_emit_write_indent(emit, indent);
+			} else
+				fy_emit_accum_utf8_put(&emit->ea, c);
+
+			spaces = true;
+
+		} else if (fy_is_lb_m(c, fy_token_atom_lb_mode(fyt))) {
+
+			/* blergh */
+			if (!allow_breaks)
+				break;
+
+			/* output run */
+			if (!breaks) {
+				fy_emit_output_accum(emit, wtype, &emit->ea);
+				fy_emit_write_indent(emit, indent);
+			}
+
+			emit->flags &= ~FYEF_INDENTATION;
+			fy_emit_write_indent(emit, indent);
+
+			breaks = true;
+
+		} else {
+
+			if (breaks)
+				fy_emit_write_indent(emit, indent);
+
+			fy_emit_accum_utf8_put(&emit->ea, c);
+
+			emit->flags &= ~FYEF_INDENTATION;
+
+			spaces = false;
+			breaks = false;
+		}
+	}
+	fy_emit_output_accum(emit, wtype, &emit->ea);
+	fy_emit_accum_finish(&emit->ea);
+	fy_atom_iter_finish(&iter);
+
+out:
+	emit->flags &= ~(FYEF_WHITESPACE | FYEF_INDENTATION);
+}
+
+void fy_emit_token_write_alias(struct fy_emitter *emit, struct fy_token *fyt, int flags, int indent)
+{
+	const char *str = NULL;
+	size_t len = 0;
+	struct fy_atom_iter iter;
+	int c;
+
+	if (!fyt)
+		return;
+
+	fy_emit_write_indicator(emit, di_star, flags, indent, fyewt_alias);
+
+	/* try direct output first (99% of cases) */
+	str = fy_token_get_direct_output(fyt, &len);
+	if (str) {
+		fy_emit_write(emit, fyewt_alias, str, len);
+		return;
+	}
+
+	/* corner case, use iterator */
+	fy_atom_iter_start(fy_token_atom(fyt), &iter);
+	fy_emit_accum_start(&emit->ea, emit->column, fy_token_atom_lb_mode(fyt));
+	while ((c = fy_atom_iter_utf8_get(&iter)) > 0)
+		fy_emit_accum_utf8_put(&emit->ea, c);
+	fy_emit_output_accum(emit, fyewt_alias, &emit->ea);
+	fy_emit_accum_finish(&emit->ea);
+	fy_atom_iter_finish(&iter);
+}
+
+void fy_emit_token_write_quoted(struct fy_emitter *emit, struct fy_token *fyt, int flags, int indent, char qc)
+{
+	bool allow_breaks, spaces, breaks;
+	int c, i, w, digit;
+	enum fy_emitter_write_type wtype;
+	const char *str = NULL;
+	size_t len = 0;
+	bool should_indent, done_esc;
+	struct fy_atom *atom;
+	struct fy_atom_iter iter;
+	enum fy_atom_style target_style;
+	uint32_t hi_surrogate, lo_surrogate;
+	uint8_t non_utf8[4];
+	size_t non_utf8_len, k;
+
+	wtype = qc == '\'' ?
+		((flags & DDNF_SIMPLE_SCALAR_KEY) ?
+		 	fyewt_single_quoted_scalar_key : fyewt_single_quoted_scalar) :
+		((flags & DDNF_SIMPLE_SCALAR_KEY) ?
+		 	fyewt_double_quoted_scalar_key : fyewt_double_quoted_scalar);
+
+	fy_emit_write_indicator(emit,
+			qc == '\'' ? di_single_quote_start : di_double_quote_start,
+			flags, indent, wtype);
+
+	/* XXX check whether this is ever the case */
+	if (!fyt)
+		goto out;
+
+	/* note that if the original target style and the target differ
+	 * we can note use direct output
+	 */
+	target_style = qc == '"' ? FYAS_DOUBLE_QUOTED : FYAS_SINGLE_QUOTED;
+
+	/* simple case of direct output (large amount of cases) */
+	str = fy_token_get_direct_output(fyt, &len);
+	if (str && fy_token_atom_style(fyt) == target_style) {
+		fy_emit_write(emit, wtype, str, len);
+		goto out;
+	}
+
+	/* no atom? i.e. empty */
+	atom = fy_token_atom(fyt);
+	if (!atom)
+		goto out;
+
+	allow_breaks = !(flags & DDNF_SIMPLE) && !fy_emit_is_json_mode(emit) && !fy_emit_is_oneline(emit);
+
+	spaces = false;
+	breaks = false;
+
+	fy_atom_iter_start(atom, &iter);
+	fy_emit_accum_start(&emit->ea, emit->column, fy_token_atom_lb_mode(fyt));
+	for (;;) {
+		non_utf8_len = sizeof(non_utf8);
+		c = fy_atom_iter_utf8_quoted_get(&iter, &non_utf8_len, non_utf8);
+		if (c < 0)
+			break;
+
+		if (c == 0 && non_utf8_len > 0) {
+			for (k = 0; k < non_utf8_len; k++) {
+				c = (int)non_utf8[k] & 0xff;
+				fy_emit_accum_utf8_put(&emit->ea, '\\');
+				fy_emit_accum_utf8_put(&emit->ea, 'x');
+				digit = ((unsigned int)c >> 4) & 15;
+				fy_emit_accum_utf8_put(&emit->ea,
+						digit <= 9 ? ('0' + digit) : ('A' + digit - 10));
+				digit = (unsigned int)c & 15;
+				fy_emit_accum_utf8_put(&emit->ea,
+						digit <= 9 ? ('0' + digit) : ('A' + digit - 10));
+			}
+			continue;
+		}
+
+		if (fy_is_space(c) || (qc == '\'' && fy_is_ws(c))) {
+			should_indent = allow_breaks && !spaces &&
+					fy_emit_accum_column(&emit->ea) > fy_emit_width(emit);
+
+			if (should_indent &&
+				((qc == '\'' && fy_is_ws(fy_atom_iter_utf8_peek(&iter))) ||
+				  qc == '"')) {
+				fy_emit_output_accum(emit, wtype, &emit->ea);
+
+				if (qc == '"' && fy_is_ws(fy_atom_iter_utf8_peek(&iter)))
+					fy_emit_putc(emit, wtype, '\\');
+
+				emit->flags &= ~FYEF_INDENTATION;
+				fy_emit_write_indent(emit, indent);
+			} else
+				fy_emit_accum_utf8_put(&emit->ea, c);
+
+			spaces = true;
+			breaks = false;
+
+		} else if (qc == '\'' && fy_is_lb_m(c, fy_token_atom_lb_mode(fyt))) {
+
+			/* blergh */
+			if (!allow_breaks)
+				break;
+
+			/* output run */
+			if (!breaks) {
+				fy_emit_output_accum(emit, wtype, &emit->ea);
+				fy_emit_write_indent(emit, indent);
+			}
+
+			emit->flags &= ~FYEF_INDENTATION;
+			fy_emit_write_indent(emit, indent);
+
+			breaks = true;
+		} else {
+			/* output run */
+			if (breaks) {
+				fy_emit_output_accum(emit, wtype, &emit->ea);
+				fy_emit_write_indent(emit, indent);
+			}
+
+			/* escape */
+			if (qc == '\'' && c == '\'') {
+				fy_emit_accum_utf8_put(&emit->ea, '\'');
+				fy_emit_accum_utf8_put(&emit->ea, '\'');
+			} else if (qc == '"' &&
+				   ((!fy_is_printq(c) || c == '"' || c == '\\') ||
+				    (fy_emit_is_json_mode(emit) && !fy_is_json_unescaped(c)))) {
+
+				fy_emit_accum_utf8_put(&emit->ea, '\\');
+
+				/* common YAML and JSON escapes */
+				done_esc = false;
+				switch (c) {
+				case '\b':
+					fy_emit_accum_utf8_put(&emit->ea, 'b');
+					done_esc = true;
+					break;
+				case '\f':
+					fy_emit_accum_utf8_put(&emit->ea, 'f');
+					done_esc = true;
+					break;
+				case '\n':
+					fy_emit_accum_utf8_put(&emit->ea, 'n');
+					done_esc = true;
+					break;
+				case '\r':
+					fy_emit_accum_utf8_put(&emit->ea, 'r');
+					done_esc = true;
+					break;
+				case '\t':
+					fy_emit_accum_utf8_put(&emit->ea, 't');
+					done_esc = true;
+					break;
+				case '"':
+					fy_emit_accum_utf8_put(&emit->ea, '"');
+					done_esc = true;
+					break;
+				case '\\':
+					fy_emit_accum_utf8_put(&emit->ea, '\\');
+					done_esc = true;
+					break;
+				}
+
+				if (done_esc)
+					goto done;
+
+				if (!fy_emit_is_json_mode(emit)) {
+					switch (c) {
+					case '\0':
+						fy_emit_accum_utf8_put(&emit->ea, '0');
+						break;
+					case '\a':
+						fy_emit_accum_utf8_put(&emit->ea, 'a');
+						break;
+					case '\v':
+						fy_emit_accum_utf8_put(&emit->ea, 'v');
+						break;
+					case '\e':
+						fy_emit_accum_utf8_put(&emit->ea, 'e');
+						break;
+					case 0x85:
+						fy_emit_accum_utf8_put(&emit->ea, 'N');
+						break;
+					case 0xa0:
+						fy_emit_accum_utf8_put(&emit->ea, '_');
+						break;
+					case 0x2028:
+						fy_emit_accum_utf8_put(&emit->ea, 'L');
+						break;
+					case 0x2029:
+						fy_emit_accum_utf8_put(&emit->ea, 'P');
+						break;
+					default:
+						if ((unsigned int)c <= 0xff) {
+							fy_emit_accum_utf8_put(&emit->ea, 'x');
+							w = 2;
+						} else if ((unsigned int)c <= 0xffff) {
+							fy_emit_accum_utf8_put(&emit->ea, 'u');
+							w = 4;
+						} else if ((unsigned int)c <= 0xffffffff) {
+							fy_emit_accum_utf8_put(&emit->ea, 'U');
+							w = 8;
+						}
+
+						for (i = w - 1; i >= 0; i--) {
+							digit = ((unsigned int)c >> (i * 4)) & 15;
+							fy_emit_accum_utf8_put(&emit->ea,
+									digit <= 9 ? ('0' + digit) : ('A' + digit - 10));
+						}
+						break;
+					}
+
+				} else {
+					/* JSON escapes all others in \uXXXX and \uXXXX\uXXXX */
+					w = 4;
+					if ((unsigned int)c <= 0xffff) {
+						fy_emit_accum_utf8_put(&emit->ea, 'u');
+						for (i = w - 1; i >= 0; i--) {
+							digit = ((unsigned int)c >> (i * 4)) & 15;
+							fy_emit_accum_utf8_put(&emit->ea,
+									digit <= 9 ? ('0' + digit) : ('A' + digit - 10));
+						}
+					} else {
+						hi_surrogate = 0xd800 | ((((c >> 16) & 0x1f) - 1) << 6) | ((c >> 10) & 0x3f);
+						lo_surrogate = 0xdc00 | (c & 0x3ff);
+
+						fy_emit_accum_utf8_put(&emit->ea, 'u');
+						for (i = w - 1; i >= 0; i--) {
+							digit = ((unsigned int)hi_surrogate >> (i * 4)) & 15;
+							fy_emit_accum_utf8_put(&emit->ea,
+									digit <= 9 ? ('0' + digit) : ('A' + digit - 10));
+						}
+
+						fy_emit_accum_utf8_put(&emit->ea, '\\');
+						fy_emit_accum_utf8_put(&emit->ea, 'u');
+						for (i = w - 1; i >= 0; i--) {
+							digit = ((unsigned int)lo_surrogate >> (i * 4)) & 15;
+							fy_emit_accum_utf8_put(&emit->ea,
+									digit <= 9 ? ('0' + digit) : ('A' + digit - 10));
+						}
+					}
+				}
+			} else
+				fy_emit_accum_utf8_put(&emit->ea, c);
+done:
+			emit->flags &= ~FYEF_INDENTATION;
+			spaces = false;
+			breaks = false;
+		}
+	}
+	fy_emit_output_accum(emit, wtype, &emit->ea);
+	fy_emit_accum_finish(&emit->ea);
+	fy_atom_iter_finish(&iter);
+
+out:
+	fy_emit_write_indicator(emit,
+			qc == '\'' ? di_single_quote_end : di_double_quote_end,
+			flags, indent, wtype);
+}
+
+bool fy_emit_token_write_block_hints(struct fy_emitter *emit, struct fy_token *fyt, int flags, int indent, char *chompp)
+{
+	char chomp = '\0';
+	bool explicit_chomp = false;
+	struct fy_atom *atom;
+
+	atom = fy_token_atom(fyt);
+	if (!atom) {
+		emit->flags &= ~FYEF_OPEN_ENDED;
+		chomp = '-';
+		goto out;
+	}
+
+	if (atom->starts_with_ws || atom->starts_with_lb) {
+		fy_emit_putc(emit, fyewt_indicator, '0' + fy_emit_indent(emit));
+		explicit_chomp = true;
+	}
+
+	if (!atom->ends_with_lb) {
+		emit->flags &= ~FYEF_OPEN_ENDED;
+		chomp = '-';
+		goto out;
+	}
+
+	if (atom->trailing_lb) {
+		emit->flags |= FYEF_OPEN_ENDED;
+		chomp = '+';
+		goto out;
+	}
+	emit->flags &= ~FYEF_OPEN_ENDED;
+
+out:
+	if (chomp)
+		fy_emit_putc(emit, fyewt_indicator, chomp);
+	*chompp = chomp;
+	return explicit_chomp;
+}
+
+void fy_emit_token_write_literal(struct fy_emitter *emit, struct fy_token *fyt, int flags, int indent)
+{
+	bool breaks;
+	int c;
+	char chomp;
+	struct fy_atom *atom;
+	struct fy_atom_iter iter;
+
+	fy_emit_write_indicator(emit, di_bar, flags, indent, fyewt_indicator);
+
+	fy_emit_token_write_block_hints(emit, fyt, flags, indent, &chomp);
+	if (flags & DDNF_ROOT)
+		indent += fy_emit_indent(emit);
+
+	fy_emit_putc(emit, fyewt_linebreak, '\n');
+	emit->flags |= FYEF_WHITESPACE | FYEF_INDENTATION;
+
+	atom = fy_token_atom(fyt);
+	if (!atom)
+		goto out;
+
+	breaks = true;
+
+	fy_atom_iter_start(atom, &iter);
+	fy_emit_accum_start(&emit->ea, emit->column, fy_token_atom_lb_mode(fyt));
+	while ((c = fy_atom_iter_utf8_get(&iter)) > 0) {
+
+		if (breaks) {
+			fy_emit_write_indent(emit, indent);
+			breaks = false;
+		}
+
+		if (fy_is_lb_m(c, fy_token_atom_lb_mode(fyt))) {
+			fy_emit_output_accum(emit, fyewt_literal_scalar, &emit->ea);
+			emit->flags &= ~FYEF_INDENTATION;
+			breaks = true;
+		} else
+			fy_emit_accum_utf8_put(&emit->ea, c);
+	}
+	fy_emit_output_accum(emit, fyewt_literal_scalar, &emit->ea);
+	fy_emit_accum_finish(&emit->ea);
+	fy_atom_iter_finish(&iter);
+
+out:
+	emit->flags &= ~FYEF_INDENTATION;
+}
+
+void fy_emit_token_write_folded(struct fy_emitter *emit, struct fy_token *fyt, int flags, int indent)
+{
+	bool leading_spaces, breaks;
+	int c, nrbreaks, nrbreakslim;
+	char chomp;
+	struct fy_atom *atom;
+	struct fy_atom_iter iter;
+
+	fy_emit_write_indicator(emit, di_greater, flags, indent, fyewt_indicator);
+
+	fy_emit_token_write_block_hints(emit, fyt, flags, indent, &chomp);
+	if (flags & DDNF_ROOT)
+		indent += fy_emit_indent(emit);
+
+	fy_emit_putc(emit, fyewt_linebreak, '\n');
+	emit->flags |= FYEF_WHITESPACE | FYEF_INDENTATION;
+
+	atom = fy_token_atom(fyt);
+	if (!atom)
+		return;
+
+	breaks = true;
+	leading_spaces = true;
+
+	fy_atom_iter_start(atom, &iter);
+	fy_emit_accum_start(&emit->ea, emit->column, fy_token_atom_lb_mode(fyt));
+	while ((c = fy_atom_iter_utf8_get(&iter)) > 0) {
+
+		if (fy_is_lb_m(c, fy_token_atom_lb_mode(fyt))) {
+
+			/* output run */
+			if (!fy_emit_accum_empty(&emit->ea)) {
+				fy_emit_output_accum(emit, fyewt_literal_scalar, &emit->ea);
+				/* do not output a newline (indent) if at the end or
+				 * this is a leading spaces line */
+				if (!fy_is_z(fy_atom_iter_utf8_peek(&iter)) && !leading_spaces)
+					fy_emit_write_indent(emit, indent);
+			}
+
+			/* count the number of consecutive breaks */
+			nrbreaks = 1;
+			while (fy_is_lb_m((c = fy_atom_iter_utf8_peek(&iter)), fy_token_atom_lb_mode(fyt))) {
+				nrbreaks++;
+				(void)fy_atom_iter_utf8_get(&iter);
+			}
+
+			/* NOTE: Because the number of indents is tricky
+			 * if it's a non blank, non end, it's the number of breaks
+			 * if it's a blank, it's the number of breaks minus 1
+			 * if it's the end, it's the number of breaks minus 2
+			 */
+			nrbreakslim = fy_is_z(c) ? 2 : fy_is_blank(c) ? 1 : 0;
+			while (nrbreaks-- > nrbreakslim) {
+				emit->flags &= ~FYEF_INDENTATION;
+				fy_emit_write_indent(emit, indent);
+			}
+
+			breaks = true;
+
+		} else {
+
+			/* if we had a break, output an indent */
+			if (breaks) {
+				fy_emit_write_indent(emit, indent);
+
+				/* if this line starts with whitespace we need to know */
+				leading_spaces = fy_is_ws(c);
+			}
+
+			if (!breaks && fy_is_space(c) &&
+			    !fy_is_space(fy_atom_iter_utf8_peek(&iter)) &&
+			    fy_emit_accum_column(&emit->ea) > fy_emit_width(emit)) {
+				fy_emit_output_accum(emit, fyewt_folded_scalar, &emit->ea);
+				emit->flags &= ~FYEF_INDENTATION;
+				fy_emit_write_indent(emit, indent);
+			} else
+				fy_emit_accum_utf8_put(&emit->ea, c);
+
+			breaks = false;
+		}
+	}
+	fy_emit_output_accum(emit, fyewt_folded_scalar, &emit->ea);
+	fy_emit_accum_finish(&emit->ea);
+	fy_atom_iter_finish(&iter);
+}
+
+static enum fy_node_style
+fy_emit_token_scalar_style(struct fy_emitter *emit, struct fy_token *fyt,
+			   int flags, int indent, enum fy_node_style style,
+			   struct fy_token *fyt_tag)
+{
+	const char *value = NULL;
+	size_t len = 0;
+	bool json, flow, is_json_plain;
+	struct fy_atom *atom;
+	int aflags = -1;
+	const char *tag;
+	size_t tag_len;
+
+	atom = fy_token_atom(fyt);
+
+	flow = fy_emit_is_flow_mode(emit) || (flags & DDNF_FLOW);
+
+	/* check if style is allowed (i.e. no block styles in flow context) */
+	if (flow && (style == FYNS_LITERAL || style == FYNS_FOLDED))
+		style = FYNS_ANY;
+
+	json = fy_emit_is_json_mode(emit);
+
+	/* literal in JSON mode is output as quoted */
+	if (json && (style == FYNS_LITERAL || style == FYNS_FOLDED))
+		return FYNS_DOUBLE_QUOTED;
+
+	/* is this a plain json atom? */
+	is_json_plain = (json || emit->source_json || fy_emit_is_dejson_mode(emit)) &&
+			(!atom || atom->size0 ||
+			!fy_atom_strcmp(atom, "false") ||
+			!fy_atom_strcmp(atom, "true") ||
+			!fy_atom_strcmp(atom, "null") ||
+			fy_atom_is_number(atom));
+
+	if (is_json_plain) {
+		tag = fy_token_get_text(fyt_tag, &tag_len);
+
+		/* XXX hardcoded string tag resultion */
+		if (tag && tag_len &&
+		     ((tag_len == 1 && *tag == '!') ||
+		      (tag_len == 21 && !memcmp(tag, "tag:yaml.org,2002:str", 21))))
+			return FYNS_DOUBLE_QUOTED;
+	}
+
+	/* JSON NULL, but with plain style */
+	if (json && (style == FYNS_PLAIN || style == FYNS_ANY) && (!atom || (is_json_plain && !atom->size0)))
+		return FYNS_PLAIN;
+
+	if (json)
+		return FYNS_DOUBLE_QUOTED;
+
+	aflags = fy_token_text_analyze(fyt);
+
+	if (flow && (style == FYNS_ANY || style == FYNS_LITERAL || style == FYNS_FOLDED)) {
+
+		if (fyt && !value)
+			value = fy_token_get_text(fyt, &len);
+
+		/* if there's a linebreak, use double quoted style */
+		if (fy_find_any_lb(value, len)) {
+			style = FYNS_DOUBLE_QUOTED;
+			goto out;
+		}
+
+		/* check if there's a non printable */
+		if (!fy_find_non_print(value, len)) {
+			style = FYNS_SINGLE_QUOTED;
+			goto out;
+		}
+
+		/* anything not empty is double quoted here */
+		style = !(aflags & FYTTAF_EMPTY) ? FYNS_PLAIN : FYNS_DOUBLE_QUOTED;
+	}
+
+	/* try to pretify */
+	if (!flow && fy_emit_is_pretty_mode(emit) &&
+		(style == FYNS_ANY || style == FYNS_DOUBLE_QUOTED || style == FYNS_SINGLE_QUOTED)) {
+
+		/* any original style can be a plain, but contains linebreaks, do a literal */
+		if ((aflags & (FYTTAF_CAN_BE_PLAIN | FYTTAF_HAS_LB)) == (FYTTAF_CAN_BE_PLAIN | FYTTAF_HAS_LB)) {
+			style = FYNS_LITERAL;
+			goto out;
+		}
+
+		/* any style, can be just a plain, just make it so */
+		if (style == FYNS_ANY && (aflags & (FYTTAF_CAN_BE_PLAIN | FYTTAF_HAS_LB)) == FYTTAF_CAN_BE_PLAIN) {
+			style = FYNS_PLAIN;
+			goto out;
+		}
+
+	}
+
+	if (!flow && emit->source_json && fy_emit_is_dejson_mode(emit)) {
+		if (is_json_plain || (aflags & (FYTTAF_CAN_BE_PLAIN | FYTTAF_HAS_LB)) == FYTTAF_CAN_BE_PLAIN) {
+			style = FYNS_PLAIN;
+			goto out;
+		}
+	}
+
+out:
+	if (style == FYNS_ANY) {
+		if (fyt)
+			value = fy_token_get_text(fyt, &len);
+
+		style = (aflags & FYTTAF_CAN_BE_PLAIN) ?
+				FYNS_PLAIN : FYNS_DOUBLE_QUOTED;
+	}
+
+	/* special handling for plains on start of line */
+	if ((aflags & FYTTAF_QUOTE_AT_0) && indent == 0 && style == FYNS_PLAIN)
+		style = FYNS_DOUBLE_QUOTED;
+
+	return style;
+}
+
+void fy_emit_token_scalar(struct fy_emitter *emit, struct fy_token *fyt, int flags, int indent,
+			  enum fy_node_style style, struct fy_token *fyt_tag)
+{
+	assert(style != FYNS_FLOW && style != FYNS_BLOCK);
+
+	indent = fy_emit_increase_indent(emit, flags, indent);
+
+	if (!fy_emit_whitespace(emit))
+		fy_emit_write_ws(emit);
+
+	style = fy_emit_token_scalar_style(emit, fyt, flags, indent, style, fyt_tag);
+
+	switch (style) {
+	case FYNS_ALIAS:
+		fy_emit_token_write_alias(emit, fyt, flags, indent);
+		break;
+	case FYNS_PLAIN:
+		fy_emit_token_write_plain(emit, fyt, flags, indent);
+		break;
+	case FYNS_DOUBLE_QUOTED:
+		fy_emit_token_write_quoted(emit, fyt, flags, indent, '"');
+		break;
+	case FYNS_SINGLE_QUOTED:
+		fy_emit_token_write_quoted(emit, fyt, flags, indent, '\'');
+		break;
+	case FYNS_LITERAL:
+		fy_emit_token_write_literal(emit, fyt, flags, indent);
+		break;
+	case FYNS_FOLDED:
+		fy_emit_token_write_folded(emit, fyt, flags, indent);
+		break;
+	default:
+		break;
+	}
+}
+
+void fy_emit_scalar(struct fy_emitter *emit, struct fy_node *fyn, int flags, int indent, bool is_key)
+{
+	enum fy_node_style style;
+
+	/* default style */
+	style = fyn ? fyn->style : FYNS_ANY;
+
+	/* all JSON keys are double quoted */
+	if (fy_emit_is_json_mode(emit) && is_key)
+		style = FYNS_DOUBLE_QUOTED;
+
+	fy_emit_token_scalar(emit,
+			fyn ? fyn->scalar : NULL,
+			flags, indent,
+			style, fyn->tag);
+}
+
+static void fy_emit_sequence_prolog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc)
+{
+	bool json = fy_emit_is_json_mode(emit);
+	bool oneline = fy_emit_is_oneline(emit);
+	bool was_flow = sc->flow;
+
+	sc->old_indent = sc->indent;
+	if (!json) {
+		if (fy_emit_is_block_mode(emit))
+			sc->flow = sc->empty;
+		else
+			sc->flow = fy_emit_is_flow_mode(emit) || emit->flow_level || sc->flow_token || sc->empty;
+
+		if (sc->flow) {
+			if (!emit->flow_level) {
+				sc->indent = fy_emit_increase_indent(emit, sc->flags, sc->indent);
+				sc->old_indent = sc->indent;
+			}
+
+			sc->flags = (sc->flags | DDNF_FLOW) | (sc->flags & ~DDNF_INDENTLESS);
+			fy_emit_write_indicator(emit, di_left_bracket, sc->flags, sc->indent, fyewt_indicator);
+		} else {
+			sc->flags = (sc->flags & ~DDNF_FLOW);
+		}
+	} else {
+		sc->flags = (sc->flags | DDNF_FLOW) | (sc->flags & ~DDNF_INDENTLESS);
+		fy_emit_write_indicator(emit, di_left_bracket, sc->flags, sc->indent, fyewt_indicator);
+	}
+
+	if (!oneline) {
+		if (was_flow || (sc->flags & (DDNF_ROOT | DDNF_SEQ)))
+			sc->indent = fy_emit_increase_indent(emit, sc->flags, sc->indent);
+	}
+
+	sc->flags &= ~DDNF_ROOT;
+}
+
+static void fy_emit_sequence_epilog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc)
+{
+	if (sc->flow || fy_emit_is_json_mode(emit)) {
+		if (!fy_emit_is_oneline(emit) && !sc->empty)
+			fy_emit_write_indent(emit, sc->old_indent);
+		fy_emit_write_indicator(emit, di_right_bracket, sc->flags, sc->old_indent, fyewt_indicator);
+	}
+}
+
+static void fy_emit_sequence_item_prolog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc,
+					 struct fy_token *fyt_value)
+{
+	int tmp_indent;
+
+	sc->flags |= DDNF_SEQ;
+
+	if (!fy_emit_is_oneline(emit))
+		fy_emit_write_indent(emit, sc->indent);
+
+	if (!sc->flow && !fy_emit_is_json_mode(emit))
+		fy_emit_write_indicator(emit, di_dash, sc->flags, sc->indent, fyewt_indicator);
+
+	tmp_indent = sc->indent;
+	if (fy_emit_token_has_comment(emit, fyt_value, fycp_top)) {
+		if (!sc->flow && !fy_emit_is_json_mode(emit))
+			tmp_indent = fy_emit_increase_indent(emit, sc->flags, sc->indent);
+		fy_emit_token_comment(emit, fyt_value, sc->flags, tmp_indent, fycp_top);
+	}
+}
+
+static void fy_emit_sequence_item_epilog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc,
+					 bool last, struct fy_token *fyt_value)
+{
+	if ((sc->flow || fy_emit_is_json_mode(emit)) && !last)
+		fy_emit_write_indicator(emit, di_comma, sc->flags, sc->indent, fyewt_indicator);
+
+	fy_emit_token_comment(emit, fyt_value, sc->flags, sc->indent, fycp_right);
+
+	if (last && (sc->flow || fy_emit_is_json_mode(emit)) && !fy_emit_is_oneline(emit) && !sc->empty)
+		fy_emit_write_indent(emit, sc->old_indent);
+
+	sc->flags &= ~DDNF_SEQ;
+}
+
+void fy_emit_sequence(struct fy_emitter *emit, struct fy_node *fyn, int flags, int indent)
+{
+	struct fy_node *fyni, *fynin;
+	struct fy_token *fyt_value;
+	bool last;
+	struct fy_emit_save_ctx sct, *sc = &sct;
+
+	memset(sc, 0, sizeof(*sc));
+
+	sc->flags = flags;
+	sc->indent = indent;
+	sc->empty = fy_node_list_empty(&fyn->sequence);
+	sc->flow_token = fyn->style == FYNS_FLOW;
+	sc->flow = !!(flags & DDNF_FLOW);
+	sc->old_indent = sc->indent;
+
+	fy_emit_sequence_prolog(emit, sc);
+
+	for (fyni = fy_node_list_head(&fyn->sequence); fyni; fyni = fynin) {
+
+		fynin = fy_node_next(&fyn->sequence, fyni);
+		last = !fynin;
+		fyt_value = fy_node_value_token(fyni);
+
+		fy_emit_sequence_item_prolog(emit, sc, fyt_value);
+		fy_emit_node_internal(emit, fyni, (sc->flags & ~DDNF_ROOT), sc->indent, false);
+		fy_emit_sequence_item_epilog(emit, sc, last, fyt_value);
+	}
+
+	fy_emit_sequence_epilog(emit, sc);
+}
+
+static void fy_emit_mapping_prolog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc)
+{
+	bool json = fy_emit_is_json_mode(emit);
+	bool oneline = fy_emit_is_oneline(emit);
+
+	sc->old_indent = sc->indent;
+	if (!json) {
+		if (fy_emit_is_block_mode(emit))
+			sc->flow = sc->empty;
+		else
+			sc->flow = fy_emit_is_flow_mode(emit) || emit->flow_level || sc->flow_token || sc->empty;
+
+		if (sc->flow) {
+			if (!emit->flow_level) {
+				sc->indent = fy_emit_increase_indent(emit, sc->flags, sc->indent);
+				sc->old_indent = sc->indent;
+			}
+
+			sc->flags = (sc->flags | DDNF_FLOW) | (sc->flags & ~DDNF_INDENTLESS);
+			fy_emit_write_indicator(emit, di_left_brace, sc->flags, sc->indent, fyewt_indicator);
+		} else {
+			sc->flags &= ~(DDNF_FLOW | DDNF_INDENTLESS);
+		}
+	} else {
+		sc->flags = (sc->flags | DDNF_FLOW) | (sc->flags & ~DDNF_INDENTLESS);
+		fy_emit_write_indicator(emit, di_left_brace, sc->flags, sc->indent, fyewt_indicator);
+	}
+
+	if (!oneline && !sc->empty)
+		sc->indent = fy_emit_increase_indent(emit, sc->flags, sc->indent);
+
+	sc->flags &= ~DDNF_ROOT;
+}
+
+static void fy_emit_mapping_epilog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc)
+{
+	if (sc->flow || fy_emit_is_json_mode(emit)) {
+		if (!fy_emit_is_oneline(emit) && !sc->empty)
+			fy_emit_write_indent(emit, sc->old_indent);
+		fy_emit_write_indicator(emit, di_right_brace, sc->flags, sc->old_indent, fyewt_indicator);
+	}
+}
+
+static void fy_emit_mapping_key_prolog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc,
+				       struct fy_token *fyt_key, bool simple_key)
+{
+	sc->flags = DDNF_MAP | (sc->flags & DDNF_FLOW);
+
+	if (simple_key) {
+		sc->flags |= DDNF_SIMPLE;
+		if (fyt_key && fyt_key->type == FYTT_SCALAR)
+			sc->flags |= DDNF_SIMPLE_SCALAR_KEY;
+	} else {
+		/* do not emit the ? in flow modes at all */
+		if (fy_emit_is_flow_mode(emit))
+			sc->flags |= DDNF_SIMPLE;
+	}
+
+	if (!fy_emit_is_oneline(emit))
+		fy_emit_write_indent(emit, sc->indent);
+
+	/* complex? */
+	if (!(sc->flags & DDNF_SIMPLE))
+		fy_emit_write_indicator(emit, di_question_mark, sc->flags, sc->indent, fyewt_indicator);
+}
+
+static void fy_emit_mapping_key_epilog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc,
+				       struct fy_token *fyt_key)
+{
+	int tmp_indent;
+
+	/* if the key is an alias, always output an extra whitespace */
+	if (fyt_key && fyt_key->type == FYTT_ALIAS)
+		fy_emit_write_ws(emit);
+
+	sc->flags &= ~DDNF_MAP;
+
+	fy_emit_write_indicator(emit, di_colon, sc->flags, sc->indent, fyewt_indicator);
+
+	tmp_indent = sc->indent;
+	if (fy_emit_token_has_comment(emit, fyt_key, fycp_right)) {
+
+		if (!sc->flow && !fy_emit_is_json_mode(emit))
+			tmp_indent = fy_emit_increase_indent(emit, sc->flags, sc->indent);
+
+		fy_emit_token_comment(emit, fyt_key, sc->flags, tmp_indent, fycp_right);
+		fy_emit_write_indent(emit, tmp_indent);
+	}
+
+	sc->flags = DDNF_MAP | (sc->flags & DDNF_FLOW);
+}
+
+static void fy_emit_mapping_value_prolog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc,
+					 struct fy_token *fyt_value)
+{
+	/* nothing */
+}
+
+static void fy_emit_mapping_value_epilog(struct fy_emitter *emit, struct fy_emit_save_ctx *sc,
+					 bool last, struct fy_token *fyt_value)
+{
+	if ((sc->flow || fy_emit_is_json_mode(emit)) && !last)
+		fy_emit_write_indicator(emit, di_comma, sc->flags, sc->indent, fyewt_indicator);
+
+	fy_emit_token_comment(emit, fyt_value, sc->flags, sc->indent, fycp_right);
+
+	if (last && (sc->flow || fy_emit_is_json_mode(emit)) && !fy_emit_is_oneline(emit) && !sc->empty)
+		fy_emit_write_indent(emit, sc->old_indent);
+
+	sc->flags &= ~DDNF_MAP;
+}
+
+void fy_emit_mapping(struct fy_emitter *emit, struct fy_node *fyn, int flags, int indent)
+{
+	struct fy_node_pair *fynp, *fynpn, **fynpp = NULL;
+	struct fy_token *fyt_key, *fyt_value;
+	bool last, simple_key, used_malloc = false;
+	int aflags, i, count;
+	struct fy_emit_save_ctx sct, *sc = &sct;
+
+	memset(sc, 0, sizeof(*sc));
+
+	sc->flags = flags;
+	sc->indent = indent;
+	sc->empty = fy_node_pair_list_empty(&fyn->mapping);
+	sc->flow_token = fyn->style == FYNS_FLOW;
+	sc->flow = !!(flags & DDNF_FLOW);
+	sc->old_indent = sc->indent;
+
+	fy_emit_mapping_prolog(emit, sc);
+
+	if (!(emit->cfg.flags & (FYECF_SORT_KEYS | FYECF_STRIP_EMPTY_KV))) {
+		fynp = fy_node_pair_list_head(&fyn->mapping);
+		fynpp = NULL;
+	} else {
+		count = fy_node_mapping_item_count(fyn);
+
+		/* heuristic, avoid allocation for small maps */
+		if (count > 64) {
+			fynpp = malloc((count + 1) * sizeof(*fynpp));
+			fyd_error_check(fyn->fyd, fynpp, err_out,
+					"malloc() failed");
+			used_malloc = true;
+		} else
+			fynpp = FY_ALLOCA((count + 1) * sizeof(*fynpp));
+
+		/* fill (removing empty KVs) */
+		i = 0;
+		for (fynp = fy_node_pair_list_head(&fyn->mapping); fynp;
+				fynp = fy_node_pair_next(&fyn->mapping, fynp)) {
+
+			/* strip key/value pair from the output if it's empty */
+			if ((emit->cfg.flags & FYECF_STRIP_EMPTY_KV) && fy_node_is_empty(fynp->value))
+				continue;
+
+			fynpp[i++] = fynp;
+		}
+		count = i;
+		fynpp[count] = NULL;
+
+		/* sort the keys */
+		if (emit->cfg.flags & FYECF_SORT_KEYS)
+			fy_node_mapping_perform_sort(fyn, NULL, NULL, fynpp, count);
+
+		i = 0;
+		fynp = fynpp[i];
+	}
+
+	for (; fynp; fynp = fynpn) {
+
+		if (!fynpp)
+			fynpn = fy_node_pair_next(&fyn->mapping, fynp);
+		else
+			fynpn = fynpp[++i];
+
+		last = !fynpn;
+		fyt_key = fy_node_value_token(fynp->key);
+		fyt_value = fy_node_value_token(fynp->value);
+
+		FYD_NODE_ERROR_CHECK(fynp->fyd, fynp->key, FYEM_INTERNAL,
+				!fy_emit_is_json_mode(emit) ||
+					(fynp->key && fynp->key->type == FYNT_SCALAR),
+					err_out, "Non scalar keys are not allowed in JSON emit mode");
+
+		simple_key = false;
+		if (fynp->key) {
+			switch (fynp->key->type) {
+			case FYNT_SCALAR:
+				aflags = fy_token_text_analyze(fynp->key->scalar);
+				simple_key = fy_emit_is_json_mode(emit) ||
+					     !!(aflags & FYTTAF_CAN_BE_SIMPLE_KEY);
+				break;
+			case FYNT_SEQUENCE:
+				simple_key = fy_node_list_empty(&fynp->key->sequence);
+				break;
+			case FYNT_MAPPING:
+				simple_key = fy_node_pair_list_empty(&fynp->key->mapping);
+				break;
+			}
+		}
+
+		fy_emit_mapping_key_prolog(emit, sc, fyt_key, simple_key);
+		if (fynp->key)
+			fy_emit_node_internal(emit, fynp->key, (sc->flags & ~DDNF_ROOT), sc->indent, true);
+		fy_emit_mapping_key_epilog(emit, sc, fyt_key);
+
+		fy_emit_mapping_value_prolog(emit, sc, fyt_value);
+		if (fynp->value)
+			fy_emit_node_internal(emit, fynp->value, (sc->flags & ~DDNF_ROOT), sc->indent, false);
+		fy_emit_mapping_value_epilog(emit, sc, last, fyt_value);
+	}
+
+	if (fynpp && used_malloc)
+		free(fynpp);
+
+	fy_emit_mapping_epilog(emit, sc);
+
+err_out:
+	return;
+}
+
+int fy_emit_common_document_start(struct fy_emitter *emit,
+				  struct fy_document_state *fyds,
+				  bool root_tag_or_anchor)
+{
+	struct fy_token *fyt_chk;
+	const char *td_handle, *td_prefix;
+	size_t td_handle_size, td_prefix_size;
+	enum fy_emitter_cfg_flags flags = emit->cfg.flags;
+	enum fy_emitter_cfg_flags vd_flags = flags & FYECF_VERSION_DIR(FYECF_VERSION_DIR_MASK);
+	enum fy_emitter_cfg_flags td_flags = flags & FYECF_TAG_DIR(FYECF_TAG_DIR_MASK);
+	enum fy_emitter_cfg_flags dsm_flags = flags & FYECF_DOC_START_MARK(FYECF_DOC_START_MARK_MASK);
+	bool vd, td, dsm;
+	bool had_non_default_tag = false;
+
+	if (!emit || !fyds || emit->fyds)
+		return -1;
+
+	emit->fyds = fyds;
+
+	vd = ((vd_flags == FYECF_VERSION_DIR_AUTO && fyds->version_explicit) ||
+	       vd_flags == FYECF_VERSION_DIR_ON) &&
+	      !(emit->cfg.flags & FYECF_STRIP_DOC);
+	td = ((td_flags == FYECF_TAG_DIR_AUTO && fyds->tags_explicit) ||
+	       td_flags == FYECF_TAG_DIR_ON) &&
+	      !(emit->cfg.flags & FYECF_STRIP_DOC);
+
+	/* if either a version or directive tags exist, and no previous
+	 * explicit document end existed, output one now
+	 */
+	if (!fy_emit_is_json_mode(emit) && (vd || td) && !(emit->flags & FYEF_HAD_DOCUMENT_END)) {
+		if (emit->column)
+			fy_emit_putc(emit, fyewt_linebreak, '\n');
+		if (!(emit->cfg.flags & FYECF_STRIP_DOC)) {
+			fy_emit_puts(emit, fyewt_document_indicator, "...");
+			emit->flags &= ~FYEF_WHITESPACE;
+			emit->flags |= FYEF_HAD_DOCUMENT_END;
+		}
+	}
+
+	if (!fy_emit_is_json_mode(emit) && vd) {
+		if (emit->column)
+			fy_emit_putc(emit, fyewt_linebreak, '\n');
+		fy_emit_printf(emit, fyewt_version_directive, "%%YAML %d.%d",
+					fyds->version.major, fyds->version.minor);
+		fy_emit_putc(emit, fyewt_linebreak, '\n');
+		emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+	}
+
+	if (!fy_emit_is_json_mode(emit) && td) {
+
+		for (fyt_chk = fy_token_list_first(&fyds->fyt_td); fyt_chk; fyt_chk = fy_token_next(&fyds->fyt_td, fyt_chk)) {
+
+			td_handle = fy_tag_directive_token_handle(fyt_chk, &td_handle_size);
+			td_prefix = fy_tag_directive_token_prefix(fyt_chk, &td_prefix_size);
+			assert(td_handle && td_prefix);
+
+			if (fy_tag_is_default_internal(td_handle, td_handle_size, td_prefix, td_prefix_size))
+				continue;
+
+			had_non_default_tag = true;
+
+			if (emit->column)
+				fy_emit_putc(emit, fyewt_linebreak, '\n');
+			fy_emit_printf(emit, fyewt_tag_directive, "%%TAG %.*s %.*s",
+					(int)td_handle_size, td_handle,
+					(int)td_prefix_size, td_prefix);
+			fy_emit_putc(emit, fyewt_linebreak, '\n');
+			emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+		}
+	}
+
+	/* always output document start indicator:
+	 * - was explicit
+	 * - document has tags
+	 * - document has an explicit version
+	 * - root exists & has a tag or an anchor
+	 */
+	dsm = (dsm_flags == FYECF_DOC_START_MARK_AUTO &&
+			(!fyds->start_implicit ||
+			  fyds->tags_explicit || fyds->version_explicit ||
+			  had_non_default_tag)) ||
+	       dsm_flags == FYECF_DOC_START_MARK_ON;
+
+	/* if there was previous output without document end */
+	if (!dsm && (emit->flags & FYEF_HAD_DOCUMENT_OUTPUT) &&
+	           !(emit->flags & FYEF_HAD_DOCUMENT_END))
+		dsm = true;
+
+	/* output document start indicator if we should */
+	if (dsm)
+		fy_emit_document_start_indicator(emit);
+
+	/* clear that in any case */
+	emit->flags &= ~FYEF_HAD_DOCUMENT_END;
+
+	return 0;
+}
+
+int fy_emit_document_start(struct fy_emitter *emit, struct fy_document *fyd,
+			   struct fy_node *fyn_root)
+{
+	struct fy_node *root;
+	bool root_tag_or_anchor;
+	int ret;
+
+	if (!emit || !fyd || !fyd->fyds)
+		return -1;
+
+	root = fyn_root ? fyn_root : fy_document_root(fyd);
+
+	root_tag_or_anchor = root && (root->tag || fy_document_lookup_anchor_by_node(fyd, root));
+
+	ret = fy_emit_common_document_start(emit, fyd->fyds, root_tag_or_anchor);
+	if (ret)
+		return ret;
+
+	emit->fyd = fyd;
+
+	return 0;
+}
+
+int fy_emit_common_document_end(struct fy_emitter *emit, bool override_state, bool implicit_override)
+{
+	const struct fy_document_state *fyds;
+	enum fy_emitter_cfg_flags flags = emit->cfg.flags;
+	enum fy_emitter_cfg_flags dem_flags = flags & FYECF_DOC_END_MARK(FYECF_DOC_END_MARK_MASK);
+	bool implicit, dem;
+
+	if (!emit || !emit->fyds)
+		return -1;
+
+	fyds = emit->fyds;
+
+	implicit = fyds->end_implicit;
+	if (override_state)
+		implicit = implicit_override;
+
+	dem = ((dem_flags == FYECF_DOC_END_MARK_AUTO && !implicit) ||
+		dem_flags == FYECF_DOC_END_MARK_ON) &&
+	       !(emit->cfg.flags & FYECF_STRIP_DOC);
+
+	if (!(emit->cfg.flags & FYECF_NO_ENDING_NEWLINE)) {
+		if (emit->column != 0) {
+			fy_emit_putc(emit, fyewt_linebreak, '\n');
+			emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+		}
+
+		if (!fy_emit_is_json_mode(emit) && dem) {
+			fy_emit_puts(emit, fyewt_document_indicator, "...");
+			fy_emit_putc(emit, fyewt_linebreak, '\n');
+			emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+			emit->flags |= FYEF_HAD_DOCUMENT_END;
+		} else
+			emit->flags &= ~FYEF_HAD_DOCUMENT_END;
+	} else {
+		if (!fy_emit_is_json_mode(emit) && dem) {
+			if (emit->column != 0) {
+				fy_emit_putc(emit, fyewt_linebreak, '\n');
+				emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+			}
+			fy_emit_puts(emit, fyewt_document_indicator, "...");
+			emit->flags &= ~(FYEF_WHITESPACE | FYEF_INDENTATION);
+			emit->flags |= FYEF_HAD_DOCUMENT_END;
+		} else
+			emit->flags &= ~FYEF_HAD_DOCUMENT_END;
+	}
+
+	/* mark that we did output a document earlier */
+	emit->flags |= FYEF_HAD_DOCUMENT_OUTPUT;
+
+	/* stop our association with the document */
+	emit->fyds = NULL;
+
+	return 0;
+}
+
+int fy_emit_document_end(struct fy_emitter *emit)
+{
+	int ret;
+
+	ret = fy_emit_common_document_end(emit, false, false);
+	if (ret)
+		return ret;
+
+	emit->fyd = NULL;
+	return 0;
+}
+
+int fy_emit_common_explicit_document_end(struct fy_emitter *emit)
+{
+	if (!emit)
+		return -1;
+
+	if (emit->column != 0) {
+		fy_emit_putc(emit, fyewt_linebreak, '\n');
+		emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+	}
+
+	if (!fy_emit_is_json_mode(emit)) {
+		fy_emit_puts(emit, fyewt_document_indicator, "...");
+		fy_emit_putc(emit, fyewt_linebreak, '\n');
+		emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+		emit->flags |= FYEF_HAD_DOCUMENT_END;
+	} else
+		emit->flags &= ~FYEF_HAD_DOCUMENT_END;
+
+	/* mark that we did output a document earlier */
+	emit->flags |= FYEF_HAD_DOCUMENT_OUTPUT;
+
+	/* stop our association with the document */
+	emit->fyds = NULL;
+
+	return 0;
+}
+
+int fy_emit_explicit_document_end(struct fy_emitter *emit)
+{
+	int ret;
+
+	ret = fy_emit_common_explicit_document_end(emit);
+	if (ret)
+		return ret;
+
+	emit->fyd = NULL;
+	return 0;
+}
+
+void fy_emit_reset(struct fy_emitter *emit, bool reset_events)
+{
+	struct fy_eventp *fyep;
+
+	emit->line = 0;
+	emit->column = 0;
+	emit->flow_level = 0;
+	emit->output_error = 0;
+	/* start as if there was a previous document with an explicit end */
+	/* this allows implicit documents start without an indicator */
+	emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION | FYEF_HAD_DOCUMENT_END;
+
+	emit->state = FYES_NONE;
+
+	/* reset the accumulator */
+	fy_emit_accum_reset(&emit->ea);
+
+	/* streaming mode indent */
+	emit->s_indent = -1;
+	/* streaming mode flags */
+	emit->s_flags = DDNF_ROOT;
+
+	emit->state_stack_top = 0;
+	emit->sc_stack_top = 0;
+
+	/* and release any queued events */
+	if (reset_events) {
+		while ((fyep = fy_eventp_list_pop(&emit->queued_events)) != NULL)
+			fy_eventp_release(fyep);
+	}
+}
+
+int fy_emit_setup(struct fy_emitter *emit, const struct fy_emitter_cfg *cfg)
+{
+	struct fy_diag *diag;
+
+	if (!cfg)
+		return -1;
+
+	memset(emit, 0, sizeof(*emit));
+
+	emit->cfg = *cfg;
+	if (!emit->cfg.output)
+		emit->cfg.output = fy_emitter_default_output;
+
+	diag = cfg->diag;
+
+	if (!diag) {
+		diag = fy_diag_create(NULL);
+		if (!diag)
+			return -1;
+	} else
+		fy_diag_ref(diag);
+
+	emit->diag = diag;
+
+	fy_emit_accum_init(&emit->ea, emit->ea_inplace_buf, sizeof(emit->ea_inplace_buf), 0, fylb_cr_nl);
+	fy_eventp_list_init(&emit->queued_events);
+
+	emit->state_stack = emit->state_stack_inplace;
+	emit->state_stack_alloc = sizeof(emit->state_stack_inplace)/sizeof(emit->state_stack_inplace[0]);
+
+	emit->sc_stack = emit->sc_stack_inplace;
+	emit->sc_stack_alloc = sizeof(emit->sc_stack_inplace)/sizeof(emit->sc_stack_inplace[0]);
+
+	fy_eventp_list_init(&emit->recycled_eventp);
+	fy_token_list_init(&emit->recycled_token);
+
+	/* suppress recycling if we must */
+	emit->suppress_recycling_force = getenv("FY_VALGRIND") && !getenv("FY_VALGRIND_RECYCLING");
+	emit->suppress_recycling = emit->suppress_recycling_force;
+
+	if (!emit->suppress_recycling) {
+		emit->recycled_eventp_list = &emit->recycled_eventp;
+		emit->recycled_token_list = &emit->recycled_token;
+	} else {
+		emit->recycled_eventp_list = NULL;
+		emit->recycled_token_list = NULL;
+	}
+
+	fy_emit_reset(emit, false);
+
+	return 0;
+}
+
+void fy_emit_cleanup(struct fy_emitter *emit)
+{
+	struct fy_eventp *fyep;
+	struct fy_token *fyt;
+
+	/* call the finalizer if it exists */
+	if (emit->finalizer)
+		emit->finalizer(emit);
+
+	while ((fyt = fy_token_list_pop(&emit->recycled_token)) != NULL)
+		fy_token_free(fyt);
+
+	while ((fyep = fy_eventp_list_pop(&emit->recycled_eventp)) != NULL)
+		fy_eventp_free(fyep);
+
+	if (!emit->fyd && emit->fyds)
+		fy_document_state_unref(emit->fyds);
+
+	fy_emit_accum_cleanup(&emit->ea);
+
+	while ((fyep = fy_eventp_list_pop(&emit->queued_events)) != NULL)
+		fy_eventp_release(fyep);
+
+	if (emit->state_stack && emit->state_stack != emit->state_stack_inplace)
+		free(emit->state_stack);
+
+	if (emit->sc_stack && emit->sc_stack != emit->sc_stack_inplace)
+		free(emit->sc_stack);
+
+	fy_diag_unref(emit->diag);
+}
+
+int fy_emit_node_no_check(struct fy_emitter *emit, struct fy_node *fyn)
+{
+	if (fyn)
+		fy_emit_node_internal(emit, fyn, DDNF_ROOT, -1, false);
+	return 0;
+}
+
+int fy_emit_node(struct fy_emitter *emit, struct fy_node *fyn)
+{
+	int ret;
+
+	ret = fy_emit_node_check(emit, fyn);
+	if (ret)
+		return ret;
+
+	return fy_emit_node_no_check(emit, fyn);
+}
+
+int fy_emit_root_node_no_check(struct fy_emitter *emit, struct fy_node *fyn)
+{
+	if (!emit || !fyn)
+		return -1;
+
+	/* top comment first */
+	fy_emit_node_comment(emit, fyn, DDNF_ROOT, -1, fycp_top);
+
+	fy_emit_node_internal(emit, fyn, DDNF_ROOT, -1, false);
+
+	/* right comment next */
+	fy_emit_node_comment(emit, fyn, DDNF_ROOT, -1, fycp_right);
+
+	/* bottom comment last */
+	fy_emit_node_comment(emit, fyn, DDNF_ROOT, -1, fycp_bottom);
+
+	return 0;
+}
+
+int fy_emit_root_node(struct fy_emitter *emit, struct fy_node *fyn)
+{
+	int ret;
+
+	if (!emit || !fyn)
+		return -1;
+
+	ret = fy_emit_node_check(emit, fyn);
+	if (ret)
+		return ret;
+
+	return fy_emit_root_node_no_check(emit, fyn);
+}
+
+void fy_emit_prepare_document_state(struct fy_emitter *emit, struct fy_document_state *fyds)
+{
+	if (!emit || !fyds)
+		return;
+
+	/* if the original document was JSON and the mode is ORIGINAL turn on JSON mode */
+	emit->source_json = fyds && fyds->json_mode;
+	emit->force_json = (emit->cfg.flags & FYECF_MODE(FYECF_MODE_MASK)) == FYECF_MODE_ORIGINAL &&
+			   emit->source_json;
+}
+
+int fy_emit_document_no_check(struct fy_emitter *emit, struct fy_document *fyd)
+{
+	int rc;
+
+	rc = fy_emit_document_start(emit, fyd, NULL);
+	if (rc)
+		return rc;
+
+	rc = fy_emit_root_node_no_check(emit, fyd->root);
+	if (rc)
+		return rc;
+
+	rc = fy_emit_document_end(emit);
+
+	return rc;
+}
+
+int fy_emit_document(struct fy_emitter *emit, struct fy_document *fyd)
+{
+	int ret;
+
+	if (!emit)
+		return -1;
+
+	if (fyd) {
+		fy_emit_prepare_document_state(emit, fyd->fyds);
+
+		if (fyd->root) {
+			ret = fy_emit_node_check(emit, fyd->root);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return fy_emit_document_no_check(emit, fyd);
+}
+
+struct fy_emitter *fy_emitter_create(const struct fy_emitter_cfg *cfg)
+{
+	struct fy_emitter *emit;
+	int rc;
+
+	if (!cfg)
+		return NULL;
+
+	emit = malloc(sizeof(*emit));
+	if (!emit)
+		return NULL;
+
+	rc = fy_emit_setup(emit, cfg);
+	if (rc) {
+		free(emit);
+		return NULL;
+	}
+
+	return emit;
+}
+
+void fy_emitter_destroy(struct fy_emitter *emit)
+{
+	if (!emit)
+		return;
+
+	fy_emit_cleanup(emit);
+
+	free(emit);
+}
+
+const struct fy_emitter_cfg *fy_emitter_get_cfg(struct fy_emitter *emit)
+{
+	if (!emit)
+		return NULL;
+
+	return &emit->cfg;
+}
+
+struct fy_diag *fy_emitter_get_diag(struct fy_emitter *emit)
+{
+	if (!emit || !emit->diag)
+		return NULL;
+	return fy_diag_ref(emit->diag);
+}
+
+int fy_emitter_set_diag(struct fy_emitter *emit, struct fy_diag *diag)
+{
+	struct fy_diag_cfg dcfg;
+
+	if (!emit)
+		return -1;
+
+	/* default? */
+	if (!diag) {
+		fy_diag_cfg_default(&dcfg);
+		diag = fy_diag_create(&dcfg);
+		if (!diag)
+			return -1;
+	}
+
+	fy_diag_unref(emit->diag);
+	emit->diag = fy_diag_ref(diag);
+
+	return 0;
+}
+
+void fy_emitter_set_finalizer(struct fy_emitter *emit,
+		void (*finalizer)(struct fy_emitter *emit))
+{
+	if (!emit)
+		return;
+	emit->finalizer = finalizer;
+}
+
+struct fy_emit_buffer_state {
+	char **bufp;
+	size_t *sizep;
+	char *buf;
+	size_t size;
+	size_t pos;
+	size_t need;
+	bool allocate_buffer;
+};
+
+static int do_buffer_output(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *str, int leni, void *userdata)
+{
+	struct fy_emit_buffer_state *state = emit->cfg.userdata;
+	size_t left, pagesize, size, len;
+	char *bufnew;
+
+	/* convert to unsigned and use that */
+	len = (size_t)leni;
+
+	/* no funky business */
+	if (len < 0)
+		return -1;
+
+	state->need += len;
+	left = state->size - state->pos;
+	if (left < len) {
+		if (!state->allocate_buffer)
+			return 0;
+
+		pagesize = fy_get_pagesize();
+		size = state->need + pagesize - 1;
+		size = size - size % pagesize;
+
+		bufnew = realloc(state->buf, size);
+		if (!bufnew)
+			return -1;
+		state->buf = bufnew;
+		state->size = size;
+		left = state->size - state->pos;
+
+	}
+
+	if (len > left)
+		len = left;
+	if (state->buf)
+		memcpy(state->buf + state->pos, str, len);
+	state->pos += len;
+
+	return len;
+}
+
+static void
+fy_emitter_str_finalizer(struct fy_emitter *emit)
+{
+	struct fy_emit_buffer_state *state;
+
+	if (!emit || !(state = emit->cfg.userdata))
+		return;
+
+	/* if the buffer is allowed to allocate_buffer... */
+	if (state->allocate_buffer && state->buf)
+		free(state->buf);
+	free(state);
+
+	emit->cfg.userdata = NULL;
+}
+
+static struct fy_emitter *
+fy_emitter_create_str_internal(enum fy_emitter_cfg_flags flags, char **bufp, size_t *sizep, bool allocate_buffer)
+{
+	struct fy_emitter *emit;
+	struct fy_emitter_cfg emit_cfg;
+	struct fy_emit_buffer_state *state;
+
+	state = malloc(sizeof(*state));
+	if (!state)
+		return NULL;
+
+	/* if any of these NULL, it's a allocation case */
+	if ((!bufp || !sizep) && !allocate_buffer)
+		return NULL;
+
+	if (bufp && sizep) {
+		state->bufp = bufp;
+		state->buf = *bufp;
+		state->sizep = sizep;
+		state->size = *sizep;
+	} else {
+		state->bufp = NULL;
+		state->buf = NULL;
+		state->sizep = NULL;
+		state->size = 0;
+	}
+	state->pos = 0;
+	state->need = 0;
+	state->allocate_buffer = allocate_buffer;
+
+	memset(&emit_cfg, 0, sizeof(emit_cfg));
+	emit_cfg.output = do_buffer_output;
+	emit_cfg.userdata = state;
+	emit_cfg.flags = flags;
+
+	emit = fy_emitter_create(&emit_cfg);
+	if (!emit)
+		goto err_out;
+
+	/* set finalizer to cleanup */
+	fy_emitter_set_finalizer(emit, fy_emitter_str_finalizer);
+
+	return emit;
+
+err_out:
+	if (state)
+		free(state);
+	return NULL;
+}
+
+static int
+fy_emitter_collect_str_internal(struct fy_emitter *emit, char **bufp, size_t *sizep)
+{
+	struct fy_emit_buffer_state *state;
+	char *buf;
+	int rc;
+
+	state = emit->cfg.userdata;
+	assert(state);
+
+	/* if NULL, then use the values stored on the state */
+	if (!bufp)
+		bufp = state->bufp;
+	if (!sizep)
+		sizep = state->sizep;
+
+	/* terminating zero */
+	rc = do_buffer_output(emit, fyewt_terminating_zero, "\0", 1, state);
+	if (rc != 1)
+		goto err_out;
+
+	state->size = state->need;
+
+	if (state->allocate_buffer) {
+		/* resize */
+		buf = realloc(state->buf, state->size);
+		/* very likely since we shrink the buffer, but make sure we don't error out */
+		if (buf)
+			state->buf = buf;
+	}
+
+	/* retreive the buffer and size */
+	*sizep = state->size;
+	*bufp = state->buf;
+
+	/* reset the buffer, ownership now to the caller */
+	state->buf = NULL;
+	state->size = 0;
+	state->pos = 0;
+	state->bufp = NULL;
+	state->sizep = NULL;
+
+	return 0;
+
+err_out:
+	*bufp = NULL;
+	*sizep = 0;
+	return -1;
+}
+
+static int fy_emit_str_internal(struct fy_document *fyd,
+				enum fy_emitter_cfg_flags flags,
+				struct fy_node *fyn, char **bufp, size_t *sizep,
+				bool allocate_buffer)
+{
+	struct fy_emitter *emit = NULL;
+	int rc = -1;
+
+	emit = fy_emitter_create_str_internal(flags, bufp, sizep, allocate_buffer);
+	if (!emit)
+		goto out_err;
+
+	if (fyd) {
+		fy_emit_prepare_document_state(emit, fyd->fyds);
+		rc = 0;
+		if (fyd->root)
+			rc = fy_emit_node_check(emit, fyd->root);
+		if (!rc)
+			rc = fy_emit_document_no_check(emit, fyd);
+	} else {
+		rc = fy_emit_node_check(emit, fyn);
+		if (!rc)
+			rc = fy_emit_node_no_check(emit, fyn);
+	}
+
+	if (rc)
+		goto out_err;
+
+	rc = fy_emitter_collect_str_internal(emit, NULL, NULL);
+	if (rc)
+		goto out_err;
+
+	/* OK, all done */
+
+out_err:
+	fy_emitter_destroy(emit);
+	return rc;
+}
+
+int fy_emit_document_to_buffer(struct fy_document *fyd, enum fy_emitter_cfg_flags flags, char *buf, size_t size)
+{
+	int rc;
+
+	rc = fy_emit_str_internal(fyd, flags, NULL, &buf, &size, false);
+	if (rc != 0)
+		return -1;
+	return size;
+}
+
+char *fy_emit_document_to_string(struct fy_document *fyd, enum fy_emitter_cfg_flags flags)
+{
+	char *buf;
+	size_t size;
+	int rc;
+
+	buf = NULL;
+	size = 0;
+	rc = fy_emit_str_internal(fyd, flags, NULL, &buf, &size, true);
+	if (rc != 0)
+		return NULL;
+	return buf;
+}
+
+struct fy_emitter *
+fy_emit_to_buffer(enum fy_emitter_cfg_flags flags, char *buf, size_t size)
+{
+	if (!buf)
+		return NULL;
+
+	return fy_emitter_create_str_internal(flags, &buf, &size, false);
+}
+
+char *
+fy_emit_to_buffer_collect(struct fy_emitter *emit, size_t *sizep)
+{
+	int rc;
+	char *buf;
+
+	if (!emit || !sizep)
+		return NULL;
+
+	rc = fy_emitter_collect_str_internal(emit, &buf, sizep);
+	if (rc) {
+		*sizep = 0;
+		return NULL;
+	}
+	return buf;
+}
+
+struct fy_emitter *
+fy_emit_to_string(enum fy_emitter_cfg_flags flags)
+{
+	return fy_emitter_create_str_internal(flags, NULL, NULL, true);
+}
+
+char *
+fy_emit_to_string_collect(struct fy_emitter *emit, size_t *sizep)
+{
+	int rc;
+	char *buf;
+
+	if (!emit || !sizep)
+		return NULL;
+
+	rc = fy_emitter_collect_str_internal(emit, &buf, sizep);
+	if (rc) {
+		*sizep = 0;
+		return NULL;
+	}
+	return buf;
+}
+
+static int do_file_output(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *str, int leni, void *userdata)
+{
+	FILE *fp = userdata;
+	size_t len;
+
+	len = (size_t)leni;
+
+	/* no funky stuff */
+	if (len < 0)
+		return -1;
+
+	return fwrite(str, 1, len, fp);
+}
+
+int fy_emit_document_to_fp(struct fy_document *fyd, enum fy_emitter_cfg_flags flags,
+			   FILE *fp)
+{
+	struct fy_emitter emit_state, *emit = &emit_state;
+	struct fy_emitter_cfg emit_cfg;
+	int rc;
+
+	if (!fp)
+		return -1;
+
+	memset(&emit_cfg, 0, sizeof(emit_cfg));
+	emit_cfg.output = do_file_output;
+	emit_cfg.userdata = fp;
+	emit_cfg.flags = flags;
+	fy_emit_setup(emit, &emit_cfg);
+
+	fy_emit_prepare_document_state(emit, fyd->fyds);
+
+	rc = 0;
+	if (fyd->root)
+		rc = fy_emit_node_check(emit, fyd->root);
+
+	rc = fy_emit_document_no_check(emit, fyd);
+
+	fy_emit_cleanup(emit);
+
+	return rc ? rc : 0;
+}
+
+int fy_emit_document_to_file(struct fy_document *fyd,
+			     enum fy_emitter_cfg_flags flags,
+			     const char *filename)
+{
+	FILE *fp;
+	int rc;
+
+	fp = filename ? fopen(filename, "wa") : stdout;
+	if (!fp)
+		return -1;
+
+	rc = fy_emit_document_to_fp(fyd, flags, fp);
+
+	if (fp != stdout)
+		fclose(fp);
+
+	return rc ? rc : 0;
+}
+
+static int do_fd_output(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *str, int leni, void *userdata)
+{
+	size_t len;
+	int fd;
+	ssize_t wrn;
+	int total;
+
+	len = (size_t)leni;
+
+	/* no funky stuff */
+	if (len < 0)
+		return -1;
+
+	/* get the file descriptor */
+	fd = (int)(uintptr_t)userdata;
+	if (fd < 0)
+		return -1;
+
+	/* loop output to fd */
+	total = 0;
+	while (len > 0) {
+
+		do {
+			wrn = write(fd, str, len);
+		} while (wrn == -1 && errno == EAGAIN);
+
+		if (wrn == -1)
+			return -1;
+
+		if (wrn == 0)
+			return total;
+
+		len -= wrn;
+		str += wrn;
+		total += wrn;
+	}
+
+	return total;
+}
+
+int fy_emit_document_to_fd(struct fy_document *fyd, enum fy_emitter_cfg_flags flags, int fd)
+{
+	struct fy_emitter emit_state, *emit = &emit_state;
+	struct fy_emitter_cfg emit_cfg;
+	int rc;
+
+	if (fd < 0)
+		return -1;
+
+	memset(&emit_cfg, 0, sizeof(emit_cfg));
+	emit_cfg.output = do_fd_output;
+	emit_cfg.userdata = (void *)(uintptr_t)fd;
+	emit_cfg.flags = flags;
+	fy_emit_setup(emit, &emit_cfg);
+
+	fy_emit_prepare_document_state(emit, fyd->fyds);
+
+	rc = 0;
+	if (fyd->root)
+		rc = fy_emit_node_check(emit, fyd->root);
+
+	rc = fy_emit_document_no_check(emit, fyd);
+
+	fy_emit_cleanup(emit);
+
+	return rc ? rc : 0;
+}
+
+int fy_emit_node_to_buffer(struct fy_node *fyn, enum fy_emitter_cfg_flags flags, char *buf, size_t size)
+{
+	int rc;
+
+	rc = fy_emit_str_internal(NULL, flags, fyn, &buf, &size, false);
+	if (rc != 0)
+		return -1;
+	return size;
+}
+
+char *fy_emit_node_to_string(struct fy_node *fyn, enum fy_emitter_cfg_flags flags)
+{
+	char *buf;
+	size_t size;
+	int rc;
+
+	buf = NULL;
+	size = 0;
+	rc = fy_emit_str_internal(NULL, flags, fyn, &buf, &size, true);
+	if (rc != 0)
+		return NULL;
+	return buf;
+}
+
+static bool fy_emit_ready(struct fy_emitter *emit)
+{
+	struct fy_eventp *fyep;
+	int need, count, level;
+
+	/* no events in the list, not ready */
+	fyep = fy_eventp_list_head(&emit->queued_events);
+	if (!fyep)
+		return false;
+
+	/* some events need more than one */
+	switch (fyep->e.type) {
+	case FYET_DOCUMENT_START:
+		need = 1;
+		break;
+	case FYET_SEQUENCE_START:
+		need = 2;
+		break;
+	case FYET_MAPPING_START:
+		need = 3;
+		break;
+	default:
+		need = 0;
+		break;
+	}
+
+	/* if we don't need any more, that's enough */
+	if (!need)
+		return true;
+
+	level = 0;
+	count = 0;
+	for (; fyep; fyep = fy_eventp_next(&emit->queued_events, fyep)) {
+		count++;
+
+		if (count > need)
+			return true;
+
+		switch (fyep->e.type) {
+		case FYET_STREAM_START:
+		case FYET_DOCUMENT_START:
+		case FYET_SEQUENCE_START:
+		case FYET_MAPPING_START:
+			level++;
+			break;
+		case FYET_STREAM_END:
+		case FYET_DOCUMENT_END:
+		case FYET_SEQUENCE_END:
+		case FYET_MAPPING_END:
+			level--;
+			break;
+		default:
+			break;
+		}
+
+		if (!level)
+			return true;
+	}
+
+	return false;
+}
+
+extern const char *fy_event_type_txt[];
+
+const char *fy_emitter_state_txt[] = {
+	[FYES_NONE]			= "NONE",
+	[FYES_STREAM_START]		= "STREAM_START",
+	[FYES_FIRST_DOCUMENT_START]	= "FIRST_DOCUMENT_START",
+	[FYES_DOCUMENT_START]		= "DOCUMENT_START",
+	[FYES_DOCUMENT_CONTENT]		= "DOCUMENT_CONTENT",
+	[FYES_DOCUMENT_END]		= "DOCUMENT_END",
+	[FYES_SEQUENCE_FIRST_ITEM]	= "SEQUENCE_FIRST_ITEM",
+	[FYES_SEQUENCE_ITEM]		= "SEQUENCE_ITEM",
+	[FYES_MAPPING_FIRST_KEY]	= "MAPPING_FIRST_KEY",
+	[FYES_MAPPING_KEY]		= "MAPPING_KEY",
+	[FYES_MAPPING_SIMPLE_VALUE]	= "MAPPING_SIMPLE_VALUE",
+	[FYES_MAPPING_VALUE]		= "MAPPING_VALUE",
+	[FYES_END]			= "END",
+};
+
+struct fy_eventp *
+fy_emit_next_event(struct fy_emitter *emit)
+{
+	if (!fy_emit_ready(emit))
+		return NULL;
+
+	return fy_eventp_list_pop(&emit->queued_events);
+}
+
+struct fy_eventp *
+fy_emit_peek_next_event(struct fy_emitter *emit)
+{
+	if (!fy_emit_ready(emit))
+		return NULL;
+
+	return fy_eventp_list_head(&emit->queued_events);
+}
+
+bool fy_emit_streaming_sequence_empty(struct fy_emitter *emit)
+{
+	struct fy_eventp *fyepn;
+	struct fy_event *fyen;
+
+	fyepn = fy_emit_peek_next_event(emit);
+	fyen = fyepn ? &fyepn->e : NULL;
+
+	return !fyen || fyen->type == FYET_SEQUENCE_END;
+}
+
+bool fy_emit_streaming_mapping_empty(struct fy_emitter *emit)
+{
+	struct fy_eventp *fyepn;
+	struct fy_event *fyen;
+
+	fyepn = fy_emit_peek_next_event(emit);
+	fyen = fyepn ? &fyepn->e : NULL;
+
+	return !fyen || fyen->type == FYET_MAPPING_END;
+}
+
+static void fy_emit_goto_state(struct fy_emitter *emit, enum fy_emitter_state state)
+{
+	if (emit->state == state)
+		return;
+
+	emit->state = state;
+}
+
+static int fy_emit_push_state(struct fy_emitter *emit, enum fy_emitter_state state)
+{
+	enum fy_emitter_state *states;
+
+	if (emit->state_stack_top >= emit->state_stack_alloc) {
+		states = realloc(emit->state_stack == emit->state_stack_inplace ? NULL : emit->state_stack,
+				sizeof(emit->state_stack[0]) * emit->state_stack_alloc * 2);
+		if (!states)
+			return -1;
+
+		if (emit->state_stack == emit->state_stack_inplace)
+			memcpy(states, emit->state_stack, sizeof(emit->state_stack[0]) * emit->state_stack_top);
+		emit->state_stack = states;
+		emit->state_stack_alloc *= 2;
+	}
+	emit->state_stack[emit->state_stack_top++] = state;
+
+	return 0;
+}
+
+enum fy_emitter_state fy_emit_pop_state(struct fy_emitter *emit)
+{
+	if (!emit->state_stack_top)
+		return FYES_NONE;
+
+	return emit->state_stack[--emit->state_stack_top];
+}
+
+int fy_emit_push_sc(struct fy_emitter *emit, struct fy_emit_save_ctx *sc)
+{
+	struct fy_emit_save_ctx *scs;
+
+	if (emit->sc_stack_top >= emit->sc_stack_alloc) {
+		scs = realloc(emit->sc_stack == emit->sc_stack_inplace ? NULL : emit->sc_stack,
+				sizeof(emit->sc_stack[0]) * emit->sc_stack_alloc * 2);
+		if (!scs)
+			return -1;
+
+		if (emit->sc_stack == emit->sc_stack_inplace)
+			memcpy(scs, emit->sc_stack, sizeof(emit->sc_stack[0]) * emit->sc_stack_top);
+		emit->sc_stack = scs;
+		emit->sc_stack_alloc *= 2;
+	}
+	emit->sc_stack[emit->sc_stack_top++] = *sc;
+
+	return 0;
+}
+
+int fy_emit_pop_sc(struct fy_emitter *emit, struct fy_emit_save_ctx *sc)
+{
+	if (!emit->sc_stack_top)
+		return -1;
+
+	*sc = emit->sc_stack[--emit->sc_stack_top];
+
+	return 0;
+}
+
+static int fy_emit_streaming_node(struct fy_emitter *emit, struct fy_eventp *fyep, int flags)
+{
+	struct fy_event *fye = &fyep->e;
+	struct fy_emit_save_ctx *sc = &emit->s_sc;
+	enum fy_node_style style;
+	int ret, s_flags, s_indent;
+
+	if (fye->type != FYET_ALIAS && fye->type != FYET_SCALAR &&
+			(emit->s_flags & DDNF_ROOT) && emit->column != 0) {
+		fy_emit_putc(emit, fyewt_linebreak, '\n');
+		emit->flags = FYEF_WHITESPACE | FYEF_INDENTATION;
+	}
+
+	emit->s_flags = flags;
+
+	switch (fye->type) {
+	case FYET_ALIAS:
+		fy_emit_token_write_alias(emit, fye->alias.anchor, emit->s_flags, emit->s_indent);
+		fy_emit_goto_state(emit, fy_emit_pop_state(emit));
+		break;
+
+	case FYET_SCALAR:
+		/* if we're pretty and at column 0 (meaning it's a single scalar document) output --- */
+		if ((emit->s_flags & DDNF_ROOT) && fy_emit_is_pretty_mode(emit) && !emit->column &&
+				!fy_emit_is_flow_mode(emit) && !(emit->s_flags & DDNF_FLOW))
+			fy_emit_document_start_indicator(emit);
+		fy_emit_common_node_preamble(emit, fye->scalar.anchor, fye->scalar.tag, emit->s_flags, emit->s_indent);
+		style = fye->scalar.value ?
+				fy_node_style_from_scalar_style(fye->scalar.value->scalar.style) :
+				FYNS_PLAIN;
+		fy_emit_token_scalar(emit, fye->scalar.value, emit->s_flags, emit->s_indent, style, fye->scalar.tag);
+		fy_emit_goto_state(emit, fy_emit_pop_state(emit));
+		break;
+
+	case FYET_SEQUENCE_START:
+
+		/* save this context */
+		ret = fy_emit_push_sc(emit, sc);
+		if (ret)
+			return ret;
+
+		s_flags = emit->s_flags;
+		s_indent = emit->s_indent;
+
+		fy_emit_common_node_preamble(emit, fye->sequence_start.anchor, fye->sequence_start.tag, emit->s_flags, emit->s_indent);
+
+		/* create new context */
+		memset(sc, 0, sizeof(*sc));
+		sc->flags = emit->s_flags & (DDNF_ROOT | DDNF_SEQ | DDNF_MAP);
+		sc->indent = emit->s_indent;
+		sc->empty = fy_emit_streaming_sequence_empty(emit);
+		sc->flow_token = fye->sequence_start.sequence_start &&
+				 fye->sequence_start.sequence_start->type == FYTT_FLOW_SEQUENCE_START;
+		sc->flow = !!(s_flags & DDNF_FLOW);
+		sc->old_indent = sc->indent;
+		sc->s_flags = s_flags;
+		sc->s_indent = s_indent;
+		sc->s_flags = s_flags;
+		sc->s_indent = s_indent;
+
+		fy_emit_sequence_prolog(emit, sc);
+		sc->flags &= ~DDNF_MAP;
+		sc->flags |= DDNF_SEQ;
+
+		emit->s_flags = sc->flags;
+		emit->s_indent = sc->indent;
+
+		fy_emit_goto_state(emit, FYES_SEQUENCE_FIRST_ITEM);
+		break;
+
+	case FYET_MAPPING_START:
+		/* save this context */
+		ret = fy_emit_push_sc(emit, sc);
+		if (ret)
+			return ret;
+
+		s_flags = emit->s_flags;
+		s_indent = emit->s_indent;
+
+		fy_emit_common_node_preamble(emit, fye->mapping_start.anchor, fye->mapping_start.tag, emit->s_flags, emit->s_indent);
+
+		/* create new context */
+		memset(sc, 0, sizeof(*sc));
+		sc->flags = emit->s_flags & (DDNF_ROOT | DDNF_SEQ | DDNF_MAP);
+		sc->indent = emit->s_indent;
+		sc->empty = fy_emit_streaming_mapping_empty(emit);
+		sc->flow_token = fye->mapping_start.mapping_start &&
+				 fye->mapping_start.mapping_start->type == FYTT_FLOW_MAPPING_START;
+		sc->flow = !!(s_flags & DDNF_FLOW);
+		sc->old_indent = sc->indent;
+		sc->s_flags = s_flags;
+		sc->s_indent = s_indent;
+		sc->s_flags = s_flags;
+		sc->s_indent = s_indent;
+
+		fy_emit_mapping_prolog(emit, sc);
+		sc->flags &= ~DDNF_SEQ;
+		sc->flags |= DDNF_MAP;
+
+		emit->s_flags = sc->flags;
+		emit->s_indent = sc->indent;
+
+		fy_emit_goto_state(emit, FYES_MAPPING_FIRST_KEY);
+		break;
+
+	default:
+		fy_error(emit->diag, "%s: expected ALIAS|SCALAR|SEQUENCE_START|MAPPING_START", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int fy_emit_handle_stream_start(struct fy_emitter *emit, struct fy_eventp *fyep)
+{
+	struct fy_event *fye = &fyep->e;
+
+	if (fye->type != FYET_STREAM_START) {
+		fy_error(emit->diag, "%s: expected FYET_STREAM_START", __func__);
+		return -1;
+	}
+
+	fy_emit_reset(emit, false);
+
+	fy_emit_goto_state(emit, FYES_FIRST_DOCUMENT_START);
+
+	return 0;
+}
+
+static int fy_emit_handle_document_start(struct fy_emitter *emit, struct fy_eventp *fyep, bool first)
+{
+	struct fy_event *fye = &fyep->e;
+	struct fy_document_state *fyds;
+
+	if (fye->type != FYET_DOCUMENT_START &&
+	    fye->type != FYET_STREAM_END) {
+		fy_error(emit->diag, "%s: expected FYET_DOCUMENT_START|FYET_STREAM_END", __func__);
+		return -1;
+	}
+
+	if (fye->type == FYET_STREAM_END) {
+		fy_emit_goto_state(emit, FYES_END);
+		return 0;
+	}
+
+	/* transfer ownership to the emitter */
+	fyds = fye->document_start.document_state;
+	fye->document_start.document_state = NULL;
+
+	/* prepare (i.e. adapt to the document state) */
+	fy_emit_prepare_document_state(emit, fyds);
+
+	fy_emit_common_document_start(emit, fyds, false);
+
+	fy_emit_goto_state(emit, FYES_DOCUMENT_CONTENT);
+
+	return 0;
+}
+
+static int fy_emit_handle_document_end(struct fy_emitter *emit, struct fy_eventp *fyep)
+{
+	struct fy_document_state *fyds;
+	struct fy_event *fye = &fyep->e;
+	int ret;
+
+	if (fye->type != FYET_DOCUMENT_END) {
+		fy_error(emit->diag, "%s: expected FYET_DOCUMENT_END", __func__);
+		return -1;
+	}
+
+	fyds = emit->fyds;
+
+	ret = fy_emit_common_document_end(emit, true, fye->document_end.implicit);
+	if (ret)
+		return ret;
+
+	fy_document_state_unref(fyds);
+
+	fy_emit_reset(emit, false);
+	fy_emit_goto_state(emit, FYES_DOCUMENT_START);
+	return 0;
+}
+
+static int fy_emit_handle_document_content(struct fy_emitter *emit, struct fy_eventp *fyep)
+{
+	struct fy_event *fye = &fyep->e;
+	int ret;
+
+	/* empty document? */
+	if (fye->type == FYET_DOCUMENT_END)
+		return fy_emit_handle_document_end(emit, fyep);
+
+	ret = fy_emit_push_state(emit, FYES_DOCUMENT_END);
+	if (ret)
+		return ret;
+
+	return fy_emit_streaming_node(emit, fyep, DDNF_ROOT);
+}
+
+static int fy_emit_handle_sequence_item(struct fy_emitter *emit, struct fy_eventp *fyep, bool first)
+{
+	struct fy_event *fye = &fyep->e;
+	struct fy_emit_save_ctx *sc = &emit->s_sc;
+	struct fy_token *fyt_item = NULL;
+	int ret;
+
+	fy_token_unref_rl(emit->recycled_token_list, sc->fyt_last_value);
+	sc->fyt_last_value = NULL;
+
+	switch (fye->type) {
+	case FYET_SEQUENCE_END:
+		fy_emit_sequence_item_epilog(emit, sc, true, sc->fyt_last_value);
+
+		/* emit epilog */
+		fy_emit_sequence_epilog(emit, sc);
+		/* pop state */
+		ret = fy_emit_pop_sc(emit, sc);
+		/* pop state */
+		fy_emit_goto_state(emit, fy_emit_pop_state(emit));
+
+		/* restore indent and flags */
+		emit->s_indent = sc->s_indent;
+		emit->s_flags = sc->s_flags;
+		return ret;
+
+	case FYET_ALIAS:
+		fyt_item = fye->alias.anchor;
+		break;
+	case FYET_SCALAR:
+		fyt_item = fye->scalar.value;
+		break;
+	case FYET_SEQUENCE_START:
+		fyt_item = fye->sequence_start.sequence_start;
+		break;
+	case FYET_MAPPING_START:
+		fyt_item = fye->mapping_start.mapping_start;
+		break;
+	default:
+		fy_error(emit->diag, "%s: expected SEQUENCE_END|ALIAS|SCALAR|SEQUENCE_START|MAPPING_START", __func__);
+		return -1;
+	}
+
+	ret = fy_emit_push_state(emit, FYES_SEQUENCE_ITEM);
+	if (ret)
+		return ret;
+
+	/* reset indent and flags for each item */
+	emit->s_indent = sc->indent;
+	emit->s_flags = sc->flags;
+
+	if (!first)
+		fy_emit_sequence_item_epilog(emit, sc, false, sc->fyt_last_value);
+
+	sc->fyt_last_value = fyt_item;
+
+	fy_emit_sequence_item_prolog(emit, sc, fyt_item);
+
+	ret = fy_emit_streaming_node(emit, fyep, sc->flags);
+
+	switch (fye->type) {
+	case FYET_ALIAS:
+		fye->alias.anchor = NULL;	/* take ownership */
+		break;
+	case FYET_SCALAR:
+		fye->scalar.value = NULL;	/* take ownership */
+		break;
+	case FYET_SEQUENCE_START:
+		fye->sequence_start.sequence_start = NULL;	/* take ownership */
+		break;
+	case FYET_MAPPING_START:
+		fye->mapping_start.mapping_start = NULL;	/* take ownership */
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static int fy_emit_handle_mapping_key(struct fy_emitter *emit, struct fy_eventp *fyep, bool first)
+{
+	struct fy_event *fye = &fyep->e;
+	struct fy_emit_save_ctx *sc = &emit->s_sc;
+	struct fy_token *fyt_key = NULL;
+	int ret, aflags;
+	bool simple_key;
+
+	fy_token_unref_rl(emit->recycled_token_list, sc->fyt_last_key);
+	sc->fyt_last_key = NULL;
+	fy_token_unref_rl(emit->recycled_token_list, sc->fyt_last_value);
+	sc->fyt_last_value = NULL;
+
+	simple_key = false;
+
+	switch (fye->type) {
+	case FYET_MAPPING_END:
+		fy_emit_mapping_value_epilog(emit, sc, true, sc->fyt_last_value);
+
+		/* emit epilog */
+		fy_emit_mapping_epilog(emit, sc);
+		/* pop state */
+		ret = fy_emit_pop_sc(emit, sc);
+		/* pop state */
+		fy_emit_goto_state(emit, fy_emit_pop_state(emit));
+
+		/* restore indent and flags */
+		emit->s_indent = sc->s_indent;
+		emit->s_flags = sc->s_flags;
+		return ret;
+
+	case FYET_ALIAS:
+		fyt_key = fye->alias.anchor;
+		simple_key = true;
+		break;
+	case FYET_SCALAR:
+		fyt_key = fye->scalar.value;
+		aflags = fy_token_text_analyze(fyt_key);
+		simple_key = !!(aflags & FYTTAF_CAN_BE_SIMPLE_KEY);
+		break;
+	case FYET_SEQUENCE_START:
+		fyt_key = fye->sequence_start.sequence_start;
+		simple_key = fy_emit_streaming_sequence_empty(emit);
+		break;
+	case FYET_MAPPING_START:
+		fyt_key = fye->mapping_start.mapping_start;
+		simple_key = fy_emit_streaming_mapping_empty(emit);
+		break;
+	default:
+		fy_error(emit->diag, "%s: expected MAPPING_END|ALIAS|SCALAR|SEQUENCE_START|MAPPING_START", __func__);
+		return -1;
+	}
+
+	ret = fy_emit_push_state(emit, FYES_MAPPING_VALUE);
+	if (ret)
+		return ret;
+
+	/* reset indent and flags for each key/value pair */
+	emit->s_indent = sc->indent;
+	emit->s_flags = sc->flags;
+
+	if (!first)
+		fy_emit_mapping_value_epilog(emit, sc, false, sc->fyt_last_value);
+
+	sc->fyt_last_key = fyt_key;
+
+	fy_emit_mapping_key_prolog(emit, sc, fyt_key, simple_key);
+
+	ret = fy_emit_streaming_node(emit, fyep, sc->flags);
+
+	switch (fye->type) {
+	case FYET_ALIAS:
+		fye->alias.anchor = NULL;	/* take ownership */
+		break;
+	case FYET_SCALAR:
+		fye->scalar.value = NULL;	/* take ownership */
+		break;
+	case FYET_SEQUENCE_START:
+		fye->sequence_start.sequence_start = NULL;	/* take ownership */
+		break;
+	case FYET_MAPPING_START:
+		fye->mapping_start.mapping_start = NULL;	/* take ownership */
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static int fy_emit_handle_mapping_value(struct fy_emitter *emit, struct fy_eventp *fyep, bool simple)
+{
+	struct fy_event *fye = &fyep->e;
+	struct fy_emit_save_ctx *sc = &emit->s_sc;
+	struct fy_token *fyt_value = NULL;
+	int ret;
+
+	switch (fye->type) {
+	case FYET_ALIAS:
+		fyt_value = fye->alias.anchor;
+		break;
+	case FYET_SCALAR:
+		fyt_value = fye->scalar.value;	/* take ownership */
+		break;
+	case FYET_SEQUENCE_START:
+		fyt_value = fye->sequence_start.sequence_start;
+		break;
+	case FYET_MAPPING_START:
+		fyt_value = fye->mapping_start.mapping_start;
+		break;
+	default:
+		fy_error(emit->diag, "%s: expected ALIAS|SCALAR|SEQUENCE_START|MAPPING_START", __func__);
+		return -1;
+	}
+
+	ret = fy_emit_push_state(emit, FYES_MAPPING_KEY);
+	if (ret)
+		return ret;
+
+	fy_emit_mapping_key_epilog(emit, sc, sc->fyt_last_key);
+
+	sc->fyt_last_value = fyt_value;
+
+	fy_emit_mapping_value_prolog(emit, sc, fyt_value);
+
+	ret = fy_emit_streaming_node(emit, fyep, sc->flags);
+
+	switch (fye->type) {
+	case FYET_ALIAS:
+		fye->alias.anchor = NULL;	/* take ownership */
+		break;
+	case FYET_SCALAR:
+		fye->scalar.value = NULL;	/* take ownership */
+		break;
+	case FYET_SEQUENCE_START:
+		fye->sequence_start.sequence_start = NULL;	/* take ownership */
+		break;
+	case FYET_MAPPING_START:
+		fye->mapping_start.mapping_start = NULL;	/* take ownership */
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+int fy_emit_event_from_parser(struct fy_emitter *emit, struct fy_parser *fyp, struct fy_event *fye)
+{
+	struct fy_eventp *fyep;
+	int ret;
+
+	if (!emit || !fye)
+		return -1;
+
+	/* we're using the raw emitter interface, now mark first state */
+	if (emit->state == FYES_NONE)
+		emit->state = FYES_STREAM_START;
+
+	fyep = fy_container_of(fye, struct fy_eventp, e);
+
+	fy_eventp_list_add_tail(&emit->queued_events, fyep);
+
+	ret = 0;
+	while ((fyep = fy_emit_next_event(emit)) != NULL) {
+
+		switch (emit->state) {
+		case FYES_STREAM_START:
+			ret = fy_emit_handle_stream_start(emit, fyep);
+			break;
+
+		case FYES_FIRST_DOCUMENT_START:
+		case FYES_DOCUMENT_START:
+			ret = fy_emit_handle_document_start(emit, fyep,
+					emit->state == FYES_FIRST_DOCUMENT_START);
+			break;
+
+		case FYES_DOCUMENT_CONTENT:
+			ret = fy_emit_handle_document_content(emit, fyep);
+			break;
+
+		case FYES_DOCUMENT_END:
+			ret = fy_emit_handle_document_end(emit, fyep);
+			break;
+
+		case FYES_SEQUENCE_FIRST_ITEM:
+		case FYES_SEQUENCE_ITEM:
+			ret = fy_emit_handle_sequence_item(emit, fyep,
+					emit->state == FYES_SEQUENCE_FIRST_ITEM);
+			break;
+
+		case FYES_MAPPING_FIRST_KEY:
+		case FYES_MAPPING_KEY:
+			ret = fy_emit_handle_mapping_key(emit, fyep,
+					emit->state == FYES_MAPPING_FIRST_KEY);
+			break;
+
+		case FYES_MAPPING_SIMPLE_VALUE:
+		case FYES_MAPPING_VALUE:
+			ret = fy_emit_handle_mapping_value(emit, fyep,
+					emit->state == FYES_MAPPING_SIMPLE_VALUE);
+			break;
+
+		case FYES_END:
+			ret = -1;
+			break;
+
+		default:
+			assert(1);      /* Invalid state. */
+		}
+
+		/* always release the event */
+		if (!fyp)
+			fy_eventp_release(fyep);
+		else
+			fy_parse_eventp_recycle(fyp, fyep);
+
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+int fy_emit_event(struct fy_emitter *emit, struct fy_event *fye)
+{
+	return fy_emit_event_from_parser(emit, NULL, fye);
+}
+
+struct fy_document_state *
+fy_emitter_get_document_state(struct fy_emitter *emit)
+{
+	return emit ? emit->fyds : NULL;
+}
+
+int fy_emitter_default_output(struct fy_emitter *fye, enum fy_emitter_write_type type, const char *str, int len, void *userdata)
+{
+	struct fy_emitter_default_output_data d_local, *d;
+	FILE *fp;
+	int ret, w;
+	const char *color = NULL;
+	const char *s, *e;
+
+	d = userdata;
+	if (!d) {
+		/* kinda inneficient but should not matter */
+		d = &d_local;
+		d->fp = stdout;
+		d->colorize = isatty(STDOUT_FILENO);
+		d->visible = false;
+	}
+	fp = d->fp;
+
+	s = str;
+	e = str + len;
+	if (d->colorize) {
+		switch (type) {
+		case fyewt_document_indicator:
+			color = "\x1b[36m";
+			break;
+		case fyewt_tag_directive:
+		case fyewt_version_directive:
+			color = "\x1b[33m";
+			break;
+		case fyewt_indent:
+			if (d->visible) {
+				fputs("\x1b[32m", fp);
+				while (s < e && (w = fy_utf8_width_by_first_octet(((uint8_t)*s))) > 0) {
+					/* open box - U+2423 */
+					fputs("\xe2\x90\xa3", fp);
+					s += w;
+				}
+				fputs("\x1b[0m", fp);
+				return len;
+			}
+			break;
+		case fyewt_indicator:
+			if (len == 1 && (str[0] == '\'' || str[0] == '"'))
+				color = "\x1b[33m";
+			else if (len == 1 && str[0] == '&')
+				color = "\x1b[32;1m";
+			else
+				color = "\x1b[35m";
+			break;
+		case fyewt_whitespace:
+			if (d->visible) {
+				fputs("\x1b[32m", fp);
+				while (s < e && (w = fy_utf8_width_by_first_octet(((uint8_t)*s))) > 0) {
+					/* symbol for space - U+2420 */
+					/* symbol for interpunct - U+00B7 */
+					fputs("\xc2\xb7", fp);
+					s += w;
+				}
+				fputs("\x1b[0m", fp);
+				return len;
+			}
+			break;
+		case fyewt_plain_scalar:
+			color = "\x1b[37;1m";
+			break;
+		case fyewt_single_quoted_scalar:
+		case fyewt_double_quoted_scalar:
+			color = "\x1b[33m";
+			break;
+		case fyewt_literal_scalar:
+		case fyewt_folded_scalar:
+			color = "\x1b[33m";
+			break;
+		case fyewt_anchor:
+		case fyewt_tag:
+		case fyewt_alias:
+			color = "\x1b[32;1m";
+			break;
+		case fyewt_linebreak:
+			if (d->visible) {
+				fputs("\x1b[32m", fp);
+				while (s < e && (w = fy_utf8_width_by_first_octet(((uint8_t)*s))) > 0) {
+					/* symbol for space - ^M */
+					/* fprintf(fp, "^M\n"); */
+					/* down arrow - U+2193 */
+					fputs("\xe2\x86\x93\n", fp);
+					s += w;
+				}
+				fputs("\x1b[0m", fp);
+				return len;
+			}
+			color = NULL;
+			break;
+		case fyewt_terminating_zero:
+			color = NULL;
+			break;
+		case fyewt_plain_scalar_key:
+		case fyewt_single_quoted_scalar_key:
+		case fyewt_double_quoted_scalar_key:
+			color = "\x1b[36;1m";
+			break;
+		case fyewt_comment:
+			color = "\x1b[34;1m";
+			break;
+		}
+	}
+
+	/* don't output the terminating zero */
+	if (type == fyewt_terminating_zero)
+		return len;
+
+	if (color)
+		fputs(color, fp);
+
+	ret = fwrite(str, 1, len, fp);
+
+	if (color)
+		fputs("\x1b[0m", fp);
+
+	return ret;
+}
+
+int fy_document_default_emit_to_fp(struct fy_document *fyd, FILE *fp)
+{
+	struct fy_emitter emit_local, *emit = &emit_local;
+	struct fy_emitter_cfg ecfg_local, *ecfg = &ecfg_local;
+	struct fy_emitter_default_output_data d_local, *d = &d_local;
+	int rc;
+
+	memset(d, 0, sizeof(*d));
+	d->fp = fp;
+	d->colorize = isatty(fileno(fp));
+	d->visible = false;
+
+	memset(ecfg, 0, sizeof(*ecfg));
+	ecfg->diag = fyd->diag;
+	ecfg->userdata = d;
+
+	rc = fy_emit_setup(emit, ecfg);
+	if (rc)
+		goto err_setup;
+
+	fy_emit_prepare_document_state(emit, fyd->fyds);
+
+	rc = 0;
+	if (fyd->root)
+		rc = fy_emit_node_check(emit, fyd->root);
+
+	rc = fy_emit_document_no_check(emit, fyd);
+	if (rc)
+		goto err_emit;
+
+	fy_emit_cleanup(emit);
+
+	return 0;
+
+err_emit:
+	fy_emit_cleanup(emit);
+err_setup:
+	return -1;
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-emit.h b/contrib/libs/libfyaml/src/lib/fy-emit.h
new file mode 100644
index 0000000000..3bbd8b5f1c
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-emit.h
@@ -0,0 +1,151 @@
+/*
+ * fy-emit.h - internal YAML emitter header
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_EMIT_H
+#define FY_EMIT_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include <libfyaml.h>
+
+#include "fy-utf8.h"
+#include "fy-event.h"
+#include "fy-emit-accum.h"
+
+#define FYEF_WHITESPACE			0x0001
+#define FYEF_INDENTATION		0x0002
+#define FYEF_OPEN_ENDED			0x0004
+#define FYEF_HAD_DOCUMENT_START		0x0008
+#define FYEF_HAD_DOCUMENT_END		0x0010
+#define FYEF_HAD_DOCUMENT_OUTPUT	0x0020
+
+struct fy_document;
+struct fy_emitter;
+struct fy_document_state;
+
+enum fy_emitter_state {
+	FYES_NONE,		/* when not using the raw emitter interface */
+	FYES_STREAM_START,
+	FYES_FIRST_DOCUMENT_START,
+	FYES_DOCUMENT_START,
+	FYES_DOCUMENT_CONTENT,
+	FYES_DOCUMENT_END,
+	FYES_SEQUENCE_FIRST_ITEM,
+	FYES_SEQUENCE_ITEM,
+	FYES_MAPPING_FIRST_KEY,
+	FYES_MAPPING_KEY,
+	FYES_MAPPING_SIMPLE_VALUE,
+	FYES_MAPPING_VALUE,
+	FYES_END,
+};
+
+struct fy_emit_save_ctx {
+	bool flow_token : 1;
+	bool flow : 1;
+	bool empty : 1;
+	int old_indent;
+	int flags;
+	int indent;
+	struct fy_token *fyt_last_key;
+	struct fy_token *fyt_last_value;
+	int s_flags;
+	int s_indent;
+};
+
+/* internal flags */
+#define DDNF_ROOT		0x0001
+#define DDNF_SEQ		0x0002
+#define DDNF_MAP		0x0004
+#define DDNF_SIMPLE		0x0008
+#define DDNF_FLOW		0x0010
+#define DDNF_INDENTLESS		0x0020
+#define DDNF_SIMPLE_SCALAR_KEY	0x0040
+
+struct fy_emitter {
+	int line;
+	int column;
+	int flow_level;
+	unsigned int flags;
+	bool output_error : 1;
+	bool source_json : 1;		/* the source was json */
+	bool force_json : 1;		/* force JSON mode unconditionally */
+	bool suppress_recycling_force : 1;
+	bool suppress_recycling : 1;
+
+	/* current document */
+	struct fy_emitter_cfg cfg;	/* yeah, it isn't worth just to save a few bytes */
+	struct fy_document *fyd;
+	struct fy_document_state *fyds;	/* fyd->fyds when fyd != NULL */
+	struct fy_emit_accum ea;
+	char ea_inplace_buf[256];	/* the in place accumulator buffer before allocating */
+	struct fy_diag *diag;
+
+	/* streaming event mode */
+	enum fy_emitter_state state;
+	enum fy_emitter_state *state_stack;
+	unsigned int state_stack_alloc;
+	unsigned int state_stack_top;
+	enum fy_emitter_state state_stack_inplace[64];
+	struct fy_eventp_list queued_events;
+	int s_indent;
+	int s_flags;
+	struct fy_emit_save_ctx s_sc;
+	struct fy_emit_save_ctx *sc_stack;
+	unsigned int sc_stack_alloc;
+	unsigned int sc_stack_top;
+	struct fy_emit_save_ctx sc_stack_inplace[16];
+
+	/* recycled */
+	struct fy_eventp_list recycled_eventp;
+	struct fy_token_list recycled_token;
+
+	struct fy_eventp_list *recycled_eventp_list;	/* NULL when suppressing */
+	struct fy_token_list *recycled_token_list;	/* NULL when suppressing */
+
+	/* for special needs */
+	void (*finalizer)(struct fy_emitter *emit);
+};
+
+int fy_emit_setup(struct fy_emitter *emit, const struct fy_emitter_cfg *cfg);
+void fy_emit_cleanup(struct fy_emitter *emit);
+
+void fy_emit_write(struct fy_emitter *emit, enum fy_emitter_write_type type, const char *str, int len);
+
+static inline bool fy_emit_whitespace(struct fy_emitter *emit)
+{
+	return !!(emit->flags & FYEF_WHITESPACE);
+}
+
+static inline bool fy_emit_indentation(struct fy_emitter *emit)
+{
+	return !!(emit->flags & FYEF_INDENTATION);
+}
+
+static inline bool fy_emit_open_ended(struct fy_emitter *emit)
+{
+	return !!(emit->flags & FYEF_OPEN_ENDED);
+}
+
+static inline void
+fy_emit_output_accum(struct fy_emitter *emit, enum fy_emitter_write_type type, struct fy_emit_accum *ea)
+{
+	const char *text;
+	size_t len;
+
+	text = fy_emit_accum_get(ea, &len);
+	if (text && len > 0)
+		fy_emit_write(emit, type, text, len);
+	fy_emit_accum_reset(ea);
+}
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-event.c b/contrib/libs/libfyaml/src/lib/fy-event.c
new file mode 100644
index 0000000000..0e049b475e
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-event.c
@@ -0,0 +1,914 @@
+/*
+ * fy-event.c - YAML event methods
+ *
+ * Copyright (c) 2021 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-emit.h"
+#include "fy-doc.h"
+
+#include "fy-ctype.h"
+#include "fy-utf8.h"
+#include "fy-utils.h"
+
+#include "fy-event.h"
+
+struct fy_eventp *fy_eventp_alloc(void)
+{
+	struct fy_eventp *fyep;
+
+	fyep = malloc(sizeof(*fyep));
+	if (!fyep)
+		return NULL;
+
+	fyep->e.type = FYET_NONE;
+
+	return fyep;
+}
+
+void fy_eventp_clean_rl(struct fy_token_list *fytl, struct fy_eventp *fyep)
+{
+	struct fy_event *fye;
+
+	if (!fyep)
+		return;
+
+	fye = &fyep->e;
+	switch (fye->type) {
+	case FYET_NONE:
+		break;
+	case FYET_STREAM_START:
+		fy_token_unref_rl(fytl, fye->stream_start.stream_start);
+		break;
+	case FYET_STREAM_END:
+		fy_token_unref_rl(fytl, fye->stream_end.stream_end);
+		break;
+	case FYET_DOCUMENT_START:
+		fy_token_unref_rl(fytl, fye->document_start.document_start);
+		fy_document_state_unref(fye->document_start.document_state);
+		break;
+	case FYET_DOCUMENT_END:
+		fy_token_unref_rl(fytl, fye->document_end.document_end);
+		break;
+	case FYET_MAPPING_START:
+		fy_token_unref_rl(fytl, fye->mapping_start.anchor);
+		fy_token_unref_rl(fytl, fye->mapping_start.tag);
+		fy_token_unref_rl(fytl, fye->mapping_start.mapping_start);
+		break;
+	case FYET_MAPPING_END:
+		fy_token_unref_rl(fytl, fye->mapping_end.mapping_end);
+		break;
+	case FYET_SEQUENCE_START:
+		fy_token_unref_rl(fytl, fye->sequence_start.anchor);
+		fy_token_unref_rl(fytl, fye->sequence_start.tag);
+		fy_token_unref_rl(fytl, fye->sequence_start.sequence_start);
+		break;
+	case FYET_SEQUENCE_END:
+		fy_token_unref_rl(fytl, fye->sequence_end.sequence_end);
+		break;
+	case FYET_SCALAR:
+		fy_token_unref_rl(fytl, fye->scalar.anchor);
+		fy_token_unref_rl(fytl, fye->scalar.tag);
+		fy_token_unref_rl(fytl, fye->scalar.value);
+		break;
+	case FYET_ALIAS:
+		fy_token_unref_rl(fytl, fye->alias.anchor);
+		break;
+	}
+
+	fye->type = FYET_NONE;
+}
+
+void fy_parse_eventp_clean(struct fy_parser *fyp, struct fy_eventp *fyep)
+{
+	if (!fyp || !fyep)
+		return;
+
+	fy_eventp_clean_rl(fyp->recycled_token_list, fyep);
+}
+
+void fy_emit_eventp_clean(struct fy_emitter *emit, struct fy_eventp *fyep)
+{
+	if (!emit || !fyep)
+		return;
+
+	fy_eventp_clean_rl(emit->recycled_token_list, fyep);
+}
+
+void fy_eventp_free(struct fy_eventp *fyep)
+{
+	if (!fyep)
+		return;
+
+	/* clean, safe to do */
+	fy_eventp_clean_rl(NULL, fyep);
+
+	free(fyep);
+}
+
+void fy_eventp_release(struct fy_eventp *fyep)
+{
+	fy_eventp_free(fyep);
+}
+
+struct fy_eventp *fy_parse_eventp_alloc(struct fy_parser *fyp)
+{
+	struct fy_eventp *fyep = NULL;
+
+	if (!fyp)
+		return NULL;
+
+	if (fyp->recycled_eventp_list)
+		fyep = fy_eventp_list_pop(fyp->recycled_eventp_list);
+	if (!fyep)
+		fyep = fy_eventp_alloc();
+	if (!fyep)
+		return NULL;
+
+	fyep->e.type = FYET_NONE;
+
+	return fyep;
+}
+
+void fy_parse_eventp_recycle(struct fy_parser *fyp, struct fy_eventp *fyep)
+{
+	if (!fyp || !fyep)
+		return;
+
+	/* clean, safe to do */
+	fy_parse_eventp_clean(fyp, fyep);
+
+	/* and push to the parser recycle list */
+	if (fyp->recycled_eventp_list)
+		fy_eventp_list_push(fyp->recycled_eventp_list, fyep);
+	else
+		fy_eventp_free(fyep);
+}
+
+void fy_parser_event_free(struct fy_parser *fyp, struct fy_event *fye)
+{
+	struct fy_eventp *fyep;
+
+	if (!fyp || !fye)
+		return;
+
+	fyep = fy_container_of(fye, struct fy_eventp, e);
+
+	fy_parse_eventp_recycle(fyp, fyep);
+}
+
+void fy_emit_eventp_recycle(struct fy_emitter *emit, struct fy_eventp *fyep)
+{
+	if (!emit || !fyep)
+		return;
+
+	/* clean, safe to do */
+	fy_emit_eventp_clean(emit, fyep);
+
+	if (emit->recycled_eventp_list)
+		fy_eventp_list_push(emit->recycled_eventp_list, fyep);
+	else
+		fy_eventp_free(fyep);
+}
+
+void fy_emit_event_free(struct fy_emitter *emit, struct fy_event *fye)
+{
+	struct fy_eventp *fyep;
+
+	if (!emit || !fye)
+		return;
+
+	fyep = fy_container_of(fye, struct fy_eventp, e);
+
+	fy_emit_eventp_recycle(emit, fyep);
+}
+
+struct fy_eventp *
+fy_eventp_vcreate_internal(struct fy_eventp_list *recycled_list, struct fy_diag *diag,
+			   struct fy_document_state *fyds, enum fy_event_type type, va_list ap)
+{
+	struct fy_eventp *fyep = NULL;
+	struct fy_event *fye = NULL;
+	struct fy_document_state *fyds_new = NULL;
+	const struct fy_version *vers;
+	const struct fy_tag *tag, * const *tagp;
+	struct fy_token *fyt;
+	enum fy_token_type ttype;
+	int rc, tag_count = 0;
+	enum fy_node_style style;
+	enum fy_scalar_style sstyle;
+	struct fy_token **fyt_anchorp = NULL, **fyt_tagp = NULL;
+	struct fy_input *fyi = NULL;
+	struct fy_atom handle;
+	const char *value;
+	size_t len;
+	char *data = NULL;
+	struct fy_tag_scan_info info;
+	struct fy_token *fyt_td;
+
+	/* try the recycled list first */
+	if (recycled_list)
+		fyep = fy_eventp_list_pop(recycled_list);
+	/* if not there yet, allocate a fresh one */
+	if (!fyep)
+		fyep = fy_eventp_alloc();
+	if (!fyep)
+		return NULL;
+
+	fye = &fyep->e;
+
+	fye->type = type;
+
+	switch (type) {
+	case FYET_NONE:
+		break;
+	case FYET_STREAM_START:
+		fye->stream_start.stream_start = NULL;
+		break;
+	case FYET_STREAM_END:
+		fye->stream_end.stream_end = NULL;
+		break;
+	case FYET_DOCUMENT_START:
+		fye->document_start.document_start = NULL;
+		fyds_new = fy_document_state_default(fy_document_state_version(fyds), NULL);	/* start with the default state */
+		if (!fyds_new) {
+			fy_error(diag, "fy_document_state_alloc() failed\n");
+			goto err_out;
+		}
+		fye->document_start.implicit = va_arg(ap, int);
+		vers = va_arg(ap, const struct fy_version *);
+		if (vers) {
+			fyds_new->version = *vers;
+			fyds_new->version_explicit = true;
+		}
+		fyds_new->start_implicit = fye->document_start.implicit;
+		fyds_new->end_implicit = false;	/* this is not used right now */
+		tag_count = 0;
+		tagp = va_arg(ap, const struct fy_tag * const *);
+		if (tagp) {
+			while ((tag = tagp[tag_count]) != NULL) {
+				tag_count++;
+				rc = fy_document_state_append_tag(fyds_new, tag->handle, tag->prefix, false);
+				if (rc) {
+					fy_error(diag, "fy_document_state_append_tag() failed on handle='%s' prefix='%s'\n",
+							tag->handle, tag->prefix);
+					goto err_out;
+				}
+			}
+		}
+		if (tag_count)
+			fyds_new->tags_explicit = true;
+		fye->document_start.document_state = fyds_new;
+		fyds_new = NULL;
+		break;
+	case FYET_DOCUMENT_END:
+		fye->document_end.document_end = NULL;
+		fye->document_end.implicit = va_arg(ap, int);
+		break;
+	case FYET_MAPPING_START:
+	case FYET_SEQUENCE_START:
+		style = va_arg(ap, enum fy_node_style);
+		ttype = FYTT_NONE;
+
+		if (style != FYNS_ANY && style != FYNS_FLOW && style != FYNS_BLOCK) {
+			fy_error(diag, "illegal style for %s_START\n",
+					type == FYET_MAPPING_START ? "MAPPING" : "SEQUENCE");
+			goto err_out;
+		}
+
+		if (style != FYNS_ANY) {
+			if (style == FYNS_FLOW)
+				ttype = type == FYET_MAPPING_START ?
+							FYTT_FLOW_MAPPING_START :
+							FYTT_FLOW_SEQUENCE_START;
+			else
+				ttype = type == FYET_MAPPING_START ?
+							FYTT_BLOCK_MAPPING_START :
+							FYTT_BLOCK_SEQUENCE_START;
+			fyt = fy_token_create(ttype, NULL);
+			if (!fyt) {
+				fy_error(diag, "fy_token_create() failed for %s_START\n",
+						type == FYET_MAPPING_START ? "MAPPING" : "SEQUENCE");
+				goto err_out;
+			}
+		} else
+			fyt = NULL;
+
+		if (type == FYET_MAPPING_START) {
+			fye->mapping_start.mapping_start = fyt;
+			fye->mapping_start.anchor = NULL;
+			fye->mapping_start.tag = NULL;
+			fyt_anchorp = &fye->mapping_start.anchor;
+			fyt_tagp = &fye->mapping_start.tag;
+		} else {
+			fye->sequence_start.sequence_start = fyt;
+			fye->sequence_start.anchor = NULL;
+			fye->sequence_start.tag = NULL;
+			fyt_anchorp = &fye->sequence_start.anchor;
+			fyt_tagp = &fye->sequence_start.tag;
+		}
+		fyt = NULL;
+		break;
+	case FYET_MAPPING_END:
+		fye->mapping_end.mapping_end = NULL;
+		break;
+	case FYET_SEQUENCE_END:
+		fye->sequence_end.sequence_end = NULL;
+		break;
+
+	case FYET_SCALAR:
+	case FYET_ALIAS:
+
+		if (type == FYET_SCALAR) {
+			sstyle = va_arg(ap, enum fy_scalar_style);
+			value = va_arg(ap, const char *);
+			len = va_arg(ap, size_t);
+			if (!value && len) {
+				fy_error(diag, "NULL value with len > 0, illegal SCALAR\n");
+				goto err_out;
+			}
+			if (len == FY_NT)
+				len = strlen(value);
+		} else {
+			sstyle = FYSS_PLAIN;
+			value = va_arg(ap, const char *);
+			if (!value) {
+				fy_error(diag, "NULL value, illegal ALIAS\n");
+				goto err_out;
+			}
+			len = strlen(value);
+		}
+
+		fyt = NULL;
+		fyi = NULL;
+
+		data = malloc(len + 1);
+		if (!data) {
+			fy_error(diag, "malloc() failed\n");
+			goto err_out;
+		}
+		memcpy(data, value, len);
+		/* always NULL terminate */
+		data[len] = '\0';
+		fyi = fy_input_from_malloc_data(data, len, &handle, sstyle == FYSS_PLAIN);
+		if (!fyi) {
+			fy_error(diag, "fy_input_from_malloc_data() failed\n");
+			goto err_out;
+		}
+		data = NULL;
+
+		if (type == FYET_SCALAR) {
+			fyt = fy_token_create(FYTT_SCALAR, &handle, sstyle);
+			if (!fyt) {
+				fy_error(diag, "fy_token_create() failed for %s\n",
+						"SCALAR");
+				goto err_out;
+			}
+
+			fye->scalar.value = fyt;
+			fyt = NULL;
+
+			fye->scalar.anchor = NULL;
+			fye->scalar.tag = NULL;
+			fyt_anchorp = &fye->scalar.anchor;
+			fyt_tagp = &fye->scalar.tag;
+		} else {
+			fyt = fy_token_create(FYTT_ALIAS, &handle, NULL);
+			if (!fyt) {
+				fy_error(diag, "fy_token_create() failed for %s\n",
+						"ALIAS");
+				goto err_out;
+			}
+
+			fye->alias.anchor = fyt;
+			fyt = NULL;
+		}
+		fy_input_unref(fyi);
+		fyi = NULL;
+		break;
+	}
+
+	if (fyt_anchorp && (value = va_arg(ap, const char *)) != NULL) {
+
+		len = strlen(value);
+		data = malloc(len + 1);
+		if (!data) {
+			fy_error(diag, "malloc() failed\n");
+			goto err_out;
+		}
+		memcpy(data, value, len);
+		/* always NULL terminate */
+		data[len] = '\0';
+
+		fyi = fy_input_from_malloc_data(data, len, &handle, true);
+		if (!fyi) {
+			fy_error(diag, "fy_input_from_malloc_data() failed\n");
+			goto err_out;
+		}
+		data = NULL;
+
+		/* make sure the input as valid as an anchor */
+		if (!handle.valid_anchor) {
+			fy_error(diag, "input was not valid as anchor\n");
+			goto err_out;
+		}
+
+		fyt = fy_token_create(FYTT_ANCHOR, &handle);
+		if (!fyt) {
+			fy_error(diag, "fy_token_create() failed\n");
+			goto err_out;
+		}
+		*fyt_anchorp = fyt;
+		fyt = NULL;
+		fy_input_unref(fyi);
+		fyi = NULL;
+	}
+
+	if (fyt_tagp && (value = va_arg(ap, const char *)) != NULL) {
+
+		len = strlen(value);
+		data = malloc(len + 1);
+		if (!data) {
+			fy_error(diag, "malloc() failed\n");
+			goto err_out;
+		}
+		memcpy(data, value, len);
+		/* always NULL terminate */
+		data[len] = '\0';
+
+		rc = fy_tag_scan(data, len, &info);
+		if (rc) {
+			fy_error(diag, "invalid tag %s (tag_scan)\n", value);
+			goto err_out;
+		}
+
+		fyt_td = fy_document_state_lookup_tag_directive(fyds, data + info.prefix_length, info.handle_length);
+		if (!fyt_td) {
+			fy_error(diag, "invalid tag %s (lookup tag directive)\n", value);
+			goto err_out;
+		}
+
+		fyi = fy_input_from_data(data, len, &handle, true);
+		if (!fyi)
+			goto err_out;
+		data = NULL;
+
+		handle.style = FYAS_URI;
+		handle.direct_output = false;
+		handle.storage_hint = 0;
+		handle.storage_hint_valid = false;
+
+		fyt = fy_token_create(FYTT_TAG, &handle, info.prefix_length,
+				info.handle_length, info.uri_length, fyt_td);
+		if (!fyt) {
+			fy_error(diag, "fy_token_create() failed\n");
+			goto err_out;
+		}
+		*fyt_tagp = fyt;
+		fyt = NULL;
+		fy_input_unref(fyi);
+		fyi = NULL;
+	}
+
+	return fyep;
+
+err_out:
+	fy_input_unref(fyi);
+	if (data)
+		free(data);
+	fy_document_state_unref(fyds_new);
+	/* don't bother with recycling on error */
+	fy_eventp_free(fyep);
+	return NULL;
+}
+
+struct fy_eventp *
+fy_eventp_create_internal(struct fy_eventp_list *recycled_list, struct fy_diag *diag,
+			  struct fy_document_state *fyds,
+			  enum fy_event_type type, ...)
+{
+	struct fy_eventp *fyep;
+	va_list ap;
+
+	va_start(ap, type);
+	fyep = fy_eventp_vcreate_internal(recycled_list, diag, fyds, type, ap);
+	va_end(ap);
+
+	return fyep;
+}
+
+struct fy_event *
+fy_emit_event_vcreate(struct fy_emitter *emit, enum fy_event_type type, va_list ap)
+{
+	struct fy_eventp *fyep;
+
+	if (!emit)
+		return NULL;
+
+	fyep = fy_eventp_vcreate_internal(emit->recycled_eventp_list, emit->diag, emit->fyds, type, ap);
+	if (!fyep)
+		return NULL;
+
+	return &fyep->e;
+}
+
+struct fy_event *
+fy_emit_event_create(struct fy_emitter *emit, enum fy_event_type type, ...)
+{
+	struct fy_event *fye;
+	va_list ap;
+
+	va_start(ap, type);
+	fye = fy_emit_event_vcreate(emit, type, ap);
+	va_end(ap);
+
+	return fye;
+}
+
+struct fy_event *
+fy_parse_event_vcreate(struct fy_parser *fyp, enum fy_event_type type, va_list ap)
+{
+	struct fy_eventp *fyep;
+
+	if (!fyp)
+		return NULL;
+
+	fyep = fy_eventp_vcreate_internal(fyp->recycled_eventp_list, fyp->diag, fyp->current_document_state, type, ap);
+	if (!fyep)
+		return NULL;
+
+	return &fyep->e;
+}
+
+struct fy_event *
+fy_parse_event_create(struct fy_parser *fyp, enum fy_event_type type, ...)
+{
+	struct fy_event *fye;
+	va_list ap;
+
+	va_start(ap, type);
+	fye = fy_parse_event_vcreate(fyp, type, ap);
+	va_end(ap);
+
+	return fye;
+}
+
+bool fy_event_is_implicit(struct fy_event *fye)
+{
+	/* NULL event is implicit */
+	if (!fye)
+		return true;
+
+	switch (fye->type) {
+
+	case FYET_DOCUMENT_START:
+		return fye->document_start.implicit;
+
+	case FYET_DOCUMENT_END:
+		return fye->document_end.implicit;
+
+	case FYET_MAPPING_START:
+	case FYET_MAPPING_END:
+	case FYET_SEQUENCE_START:
+	case FYET_SEQUENCE_END:
+		return fy_event_get_node_style(fye) == FYNS_BLOCK;
+
+	default:
+		break;
+	}
+
+	return false;
+}
+
+bool fy_document_event_is_implicit(const struct fy_event *fye)
+{
+	if (fye->type == FYET_DOCUMENT_START)
+		return fye->document_start.implicit;
+
+	if (fye->type == FYET_DOCUMENT_END)
+		return fye->document_end.implicit;
+
+	return false;
+}
+
+struct fy_token *fy_event_get_token(struct fy_event *fye)
+{
+	if (!fye)
+		return NULL;
+
+	switch (fye->type) {
+	case FYET_NONE:
+		break;
+
+	case FYET_STREAM_START:
+		return fye->stream_start.stream_start;
+
+	case FYET_STREAM_END:
+		return fye->stream_end.stream_end;
+
+	case FYET_DOCUMENT_START:
+		return fye->document_start.document_start;
+
+	case FYET_DOCUMENT_END:
+		return fye->document_end.document_end;
+
+	case FYET_MAPPING_START:
+		return fye->mapping_start.mapping_start;
+
+	case FYET_MAPPING_END:
+		return fye->mapping_end.mapping_end;
+
+	case FYET_SEQUENCE_START:
+		return fye->sequence_start.sequence_start;
+
+	case FYET_SEQUENCE_END:
+		return fye->sequence_end.sequence_end;
+
+	case FYET_SCALAR:
+		return fye->scalar.value;
+
+	case FYET_ALIAS:
+		return fye->alias.anchor;
+
+	}
+
+	return NULL;
+}
+
+struct fy_token *fy_event_get_anchor_token(struct fy_event *fye)
+{
+	if (!fye)
+		return NULL;
+
+	switch (fye->type) {
+	case FYET_MAPPING_START:
+		return fye->mapping_start.anchor;
+	case FYET_SEQUENCE_START:
+		return fye->sequence_start.anchor;
+	case FYET_SCALAR:
+		return fye->scalar.anchor;
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+struct fy_token *fy_event_get_tag_token(struct fy_event *fye)
+{
+	if (!fye)
+		return NULL;
+
+	switch (fye->type) {
+	case FYET_MAPPING_START:
+		return fye->mapping_start.tag;
+	case FYET_SEQUENCE_START:
+		return fye->sequence_start.tag;
+	case FYET_SCALAR:
+		return fye->scalar.tag;
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+const struct fy_mark *fy_event_start_mark(struct fy_event *fye)
+{
+	if (!fye)
+		return NULL;
+
+	switch (fye->type) {
+	case FYET_NONE:
+		break;
+
+	case FYET_STREAM_START:
+		return fy_token_start_mark(fye->stream_start.stream_start);
+
+	case FYET_STREAM_END:
+		return fy_token_start_mark(fye->stream_end.stream_end);
+
+	case FYET_DOCUMENT_START:
+		return fy_token_start_mark(fye->document_start.document_start);
+
+	case FYET_DOCUMENT_END:
+		return fy_token_start_mark(fye->document_end.document_end);
+
+	case FYET_MAPPING_START:
+		return fy_token_start_mark(fye->mapping_start.mapping_start);
+
+	case FYET_MAPPING_END:
+		return fy_token_start_mark(fye->mapping_end.mapping_end);
+
+	case FYET_SEQUENCE_START:
+		return fy_token_start_mark(fye->sequence_start.sequence_start);
+
+	case FYET_SEQUENCE_END:
+		return fy_token_start_mark(fye->sequence_end.sequence_end);
+
+	case FYET_SCALAR:
+		return fy_token_start_mark(fye->scalar.value);
+
+	case FYET_ALIAS:
+		return fy_token_start_mark(fye->alias.anchor);
+
+	}
+
+	return NULL;
+}
+
+const struct fy_mark *fy_event_end_mark(struct fy_event *fye)
+{
+	if (!fye)
+		return NULL;
+
+	switch (fye->type) {
+	case FYET_NONE:
+		break;
+
+	case FYET_STREAM_START:
+		return fy_token_end_mark(fye->stream_start.stream_start);
+
+	case FYET_STREAM_END:
+		return fy_token_end_mark(fye->stream_end.stream_end);
+
+	case FYET_DOCUMENT_START:
+		return fy_token_end_mark(fye->document_start.document_start);
+
+	case FYET_DOCUMENT_END:
+		return fy_token_end_mark(fye->document_end.document_end);
+
+	case FYET_MAPPING_START:
+		return fy_token_end_mark(fye->mapping_start.mapping_start);
+
+	case FYET_MAPPING_END:
+		return fy_token_end_mark(fye->mapping_end.mapping_end);
+
+	case FYET_SEQUENCE_START:
+		return fy_token_end_mark(fye->sequence_start.sequence_start);
+
+	case FYET_SEQUENCE_END:
+		return fy_token_end_mark(fye->sequence_end.sequence_end);
+
+	case FYET_SCALAR:
+		return fy_token_end_mark(fye->scalar.value);
+
+	case FYET_ALIAS:
+		return fy_token_end_mark(fye->alias.anchor);
+
+	}
+
+	return NULL;
+}
+
+enum fy_node_style
+fy_event_get_node_style(struct fy_event *fye)
+{
+	struct fy_token *fyt;
+
+	fyt = fy_event_get_token(fye);
+	if (!fyt)
+		return FYNS_ANY;
+
+	switch (fye->type) {
+		/* unstyled events */
+	case FYET_NONE:
+	case FYET_STREAM_START:
+	case FYET_STREAM_END:
+	case FYET_DOCUMENT_START:
+	case FYET_DOCUMENT_END:
+		return FYNS_ANY;
+
+	case FYET_MAPPING_START:
+		return fyt && fyt->type == FYTT_FLOW_MAPPING_START ? FYNS_FLOW : FYNS_BLOCK;
+
+	case FYET_MAPPING_END:
+		return fyt && fyt->type == FYTT_FLOW_MAPPING_END ? FYNS_FLOW : FYNS_BLOCK;
+
+	case FYET_SEQUENCE_START:
+		return fyt && fyt->type == FYTT_FLOW_SEQUENCE_START ? FYNS_FLOW : FYNS_BLOCK;
+
+	case FYET_SEQUENCE_END:
+		return fyt && fyt->type == FYTT_FLOW_SEQUENCE_END ? FYNS_FLOW : FYNS_BLOCK;
+
+	case FYET_SCALAR:
+		return fyt ? fy_node_style_from_scalar_style(fyt->scalar.style) : FYNS_PLAIN;
+
+	case FYET_ALIAS:
+		return FYNS_ALIAS;
+
+	}
+
+	return FYNS_ANY;
+}
+
+const struct fy_version *
+fy_document_start_event_version(struct fy_event *fye)
+{
+	/* return the default if not set */
+	if (!fye || fye->type != FYET_DOCUMENT_START)
+		return &fy_default_version;
+	return fy_document_state_version(fye->document_start.document_state);
+}
+
+struct fy_eventp *
+fy_document_iterator_eventp_alloc(struct fy_document_iterator *fydi)
+{
+	struct fy_eventp *fyep = NULL;
+
+	if (!fydi)
+		return NULL;
+
+	if (fydi->recycled_eventp_list)
+		fyep = fy_eventp_list_pop(fydi->recycled_eventp_list);
+	if (!fyep)
+		fyep = fy_eventp_alloc();
+	if (!fyep)
+		return NULL;
+
+	fyep->e.type = FYET_NONE;
+
+	return fyep;
+}
+
+void fy_document_iterator_eventp_clean(struct fy_document_iterator *fydi, struct fy_eventp *fyep)
+{
+	if (!fydi || !fyep)
+		return;
+
+	fy_eventp_clean_rl(fydi->recycled_token_list, fyep);
+}
+
+void fy_document_iterator_eventp_recycle(struct fy_document_iterator *fydi, struct fy_eventp *fyep)
+{
+	if (!fydi || !fyep)
+		return;
+
+	/* clean, safe to do */
+	fy_document_iterator_eventp_clean(fydi, fyep);
+
+	if (fydi->recycled_eventp_list)
+		fy_eventp_list_push(fydi->recycled_eventp_list, fyep);
+	else
+		fy_eventp_free(fyep);
+}
+
+struct fy_event *
+fy_document_iterator_event_vcreate(struct fy_document_iterator *fydi, enum fy_event_type type, va_list ap)
+{
+	struct fy_eventp *fyep;
+
+	if (!fydi)
+		return NULL;
+
+	fyep = fy_eventp_vcreate_internal(fydi->recycled_eventp_list,
+			fydi->fyd ? fydi->fyd->diag : NULL,
+			fydi->fyd ? fydi->fyd->fyds : NULL,
+			type, ap);
+	if (!fyep)
+		return NULL;
+
+	return &fyep->e;
+}
+
+struct fy_event *
+fy_document_iterator_event_create(struct fy_document_iterator *fydi, enum fy_event_type type, ...)
+{
+	struct fy_event *fye;
+	va_list ap;
+
+	va_start(ap, type);
+	fye = fy_document_iterator_event_vcreate(fydi, type, ap);
+	va_end(ap);
+
+	return fye;
+}
+
+void fy_document_iterator_event_free(struct fy_document_iterator *fydi, struct fy_event *fye)
+{
+	struct fy_eventp *fyep;
+
+	if (!fydi || !fye)
+		return;
+
+	fyep = fy_container_of(fye, struct fy_eventp, e);
+
+	fy_document_iterator_eventp_recycle(fydi, fyep);
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-event.h b/contrib/libs/libfyaml/src/lib/fy-event.h
new file mode 100644
index 0000000000..4da3c8f58b
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-event.h
@@ -0,0 +1,51 @@
+/*
+ * fy-event.h - YAML parser private event definition
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_EVENT_H
+#define FY_EVENT_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdbool.h>
+
+#include <libfyaml.h>
+
+#include "fy-list.h"
+#include "fy-typelist.h"
+
+/* private event type */
+FY_TYPE_FWD_DECL_LIST(eventp);
+struct fy_eventp {
+	struct fy_list_head node;
+	struct fy_event e;
+};
+FY_TYPE_DECL_LIST(eventp);
+FY_PARSE_TYPE_DECL_ALLOC(eventp);
+
+struct fy_eventp *fy_eventp_alloc(void);
+void fy_eventp_free(struct fy_eventp *fyep);
+
+/* called from internal emitter */
+void fy_eventp_release(struct fy_eventp *fyep);
+
+struct fy_eventp *fy_parse_eventp_alloc(struct fy_parser *fyp);
+void fy_parse_eventp_recycle(struct fy_parser *fyp, struct fy_eventp *fyep);
+
+struct fy_eventp *fy_emit_eventp_alloc(struct fy_emitter *fye);
+void fy_emit_eventp_recycle(struct fy_emitter *emit, struct fy_eventp *fyep);
+
+struct fy_document_iterator;
+
+struct fy_eventp *fy_document_iterator_eventp_alloc(struct fy_document_iterator *fydi);
+void fy_document_iterator_eventp_recycle(struct fy_document_iterator *fydi, struct fy_eventp *fyep);
+struct fy_event *fy_document_iterator_event_create(struct fy_document_iterator *document_iterator, enum fy_event_type type, ...);
+struct fy_event *fy_document_iterator_event_vcreate(struct fy_document_iterator *document_iterator, enum fy_event_type type, va_list ap);
+void fy_document_iterator_event_free(struct fy_document_iterator *document_iterator, struct fy_event *fye);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-input.c b/contrib/libs/libfyaml/src/lib/fy-input.c
new file mode 100644
index 0000000000..ac021ad534
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-input.c
@@ -0,0 +1,1035 @@
+/*
+ * fy-input.c - YAML input methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <fcntl.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <unistd.h>
+#include <sys/mman.h>
+#endif
+#include <sys/types.h>
+#include <sys/stat.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <sys/ioctl.h>
+#endif
+#include <errno.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-ctype.h"
+
+#include "fy-input.h"
+
+/* amount of multiplication of page size for CHOP size
+ * for a 4K page this is 64K blocks
+ */
+#ifndef FYI_CHOP_MULT
+#define FYI_CHOP_MULT	16
+#endif
+
+struct fy_input *fy_input_alloc(void)
+{
+	struct fy_input *fyi;
+
+	fyi = malloc(sizeof(*fyi));
+	if (!fyi)
+		return NULL;
+	memset(fyi, 0, sizeof(*fyi));
+
+	fyi->state = FYIS_NONE;
+	fyi->refs = 1;
+
+	return fyi;
+}
+
+void fy_input_free(struct fy_input *fyi)
+{
+	if (!fyi)
+		return;
+
+	assert(fyi->refs == 1);
+
+	switch (fyi->state) {
+	case FYIS_NONE:
+	case FYIS_QUEUED:
+		/* nothing to do */
+		break;
+	case FYIS_PARSE_IN_PROGRESS:
+	case FYIS_PARSED:
+		fy_input_close(fyi);
+		break;
+	}
+
+	/* always release the memory of the alloc memory */
+	switch (fyi->cfg.type) {
+	case fyit_alloc:
+		free(fyi->cfg.alloc.data);
+		break;
+
+	default:
+		break;
+	}
+	if (fyi->name)
+		free(fyi->name);
+
+	free(fyi);
+}
+
+const char *fy_input_get_filename(struct fy_input *fyi)
+{
+	if (!fyi)
+		return NULL;
+
+	return fyi->name;
+}
+
+static void fy_input_from_data_setup(struct fy_input *fyi,
+				     struct fy_atom *handle, bool simple)
+{
+	const char *data;
+	size_t size;
+	unsigned int aflags;
+
+	/* this is an internal method, you'd better to pass garbage */
+	data = fy_input_start(fyi);
+	size = fy_input_size(fyi);
+
+	fyi->buffer = NULL;
+	fyi->allocated = 0;
+	fyi->read = 0;
+	fyi->chunk = 0;
+	fyi->chop = 0;
+	fyi->fp = NULL;
+
+	if (!handle)
+		goto out;
+
+	memset(handle, 0, sizeof(*handle));
+
+	if (size > 0)
+		aflags = fy_analyze_scalar_content(data, size,
+				false, fylb_cr_nl, fyfws_space_tab);	/* hardcoded yaml mode */
+	else
+		aflags = FYACF_EMPTY | FYACF_FLOW_PLAIN | FYACF_BLOCK_PLAIN | FYACF_SIZE0;
+
+	handle->start_mark.input_pos = 0;
+	handle->start_mark.line = 0;
+	handle->start_mark.column = 0;
+	handle->end_mark.input_pos = size;
+	handle->end_mark.line = 0;
+	handle->end_mark.column = fy_utf8_count(data, size);
+	/* if it's plain, all is good */
+	if (simple || (aflags & FYACF_FLOW_PLAIN)) {
+		handle->storage_hint = size;	/* maximum */
+		handle->storage_hint_valid = false;
+		handle->direct_output = !!(aflags & FYACF_JSON_ESCAPE);
+		handle->style = FYAS_PLAIN;
+	} else {
+		handle->storage_hint = 0;	/* just calculate */
+		handle->storage_hint_valid = false;
+		handle->direct_output = false;
+		handle->style = FYAS_DOUBLE_QUOTED_MANUAL;
+	}
+	handle->empty = !!(aflags & FYACF_EMPTY);
+	handle->has_lb = !!(aflags & FYACF_LB);
+	handle->has_ws = !!(aflags & FYACF_WS);
+	handle->starts_with_ws = !!(aflags & FYACF_STARTS_WITH_WS);
+	handle->starts_with_lb = !!(aflags & FYACF_STARTS_WITH_LB);
+	handle->ends_with_ws = !!(aflags & FYACF_ENDS_WITH_WS);
+	handle->ends_with_lb = !!(aflags & FYACF_ENDS_WITH_LB);
+	handle->trailing_lb = !!(aflags & FYACF_TRAILING_LB);
+	handle->size0 = !!(aflags & FYACF_SIZE0);
+	handle->valid_anchor = !!(aflags & FYACF_VALID_ANCHOR);
+
+	handle->chomp = FYAC_STRIP;
+	handle->increment = 0;
+	handle->fyi = fyi;
+	handle->fyi_generation = fyi->generation;
+	handle->tabsize = 0;
+	handle->json_mode = false;	/* XXX hardcoded */
+	handle->lb_mode = fylb_cr_nl;
+	handle->fws_mode = fyfws_space_tab;
+out:
+	fyi->state = FYIS_PARSED;
+}
+
+struct fy_input *fy_input_from_data(const char *data, size_t size,
+				    struct fy_atom *handle, bool simple)
+{
+	struct fy_input *fyi;
+
+	if (data && size == (size_t)-1)
+		size = strlen(data);
+
+	fyi = fy_input_alloc();
+	if (!fyi)
+		return NULL;
+
+	fyi->cfg.type = fyit_memory;
+	fyi->cfg.userdata = NULL;
+	fyi->cfg.memory.data = data;
+	fyi->cfg.memory.size = size;
+
+	fy_input_from_data_setup(fyi, handle, simple);
+
+	return fyi;
+}
+
+struct fy_input *fy_input_from_malloc_data(char *data, size_t size,
+					   struct fy_atom *handle, bool simple)
+{
+	struct fy_input *fyi;
+
+	if (data && size == (size_t)-1)
+		size = strlen(data);
+
+	fyi = fy_input_alloc();
+	if (!fyi)
+		return NULL;
+
+	fyi->cfg.type = fyit_alloc;
+	fyi->cfg.userdata = NULL;
+	fyi->cfg.alloc.data = data;
+	fyi->cfg.alloc.size = size;
+
+	fy_input_from_data_setup(fyi, handle, simple);
+
+	return fyi;
+}
+
+void fy_input_close(struct fy_input *fyi)
+{
+	if (!fyi)
+		return;
+
+	switch (fyi->cfg.type) {
+
+	case fyit_file:
+	case fyit_fd:
+
+#if !defined(_MSC_VER)
+		if (fyi->addr) {
+			munmap(fyi->addr, fyi->length);
+			fyi->addr = NULL;
+		}
+#endif
+
+		if (fyi->fd != -1) {
+			if (!fyi->cfg.no_close_fd)
+				close(fyi->fd);
+			fyi->fd = -1;
+		}
+
+		if (fyi->buffer) {
+			free(fyi->buffer);
+			fyi->buffer = NULL;
+		}
+		if (fyi->fp) {
+			if (!fyi->cfg.no_fclose_fp)
+				fclose(fyi->fp);
+			fyi->fp = NULL;
+		}
+		break;
+
+	case fyit_stream:
+	case fyit_callback:
+		if (fyi->buffer) {
+			free(fyi->buffer);
+			fyi->buffer = NULL;
+		}
+		break;
+
+	case fyit_memory:
+		/* nothing */
+		break;
+
+	case fyit_alloc:
+		/* nothing */
+		break;
+
+	default:
+		break;
+	}
+}
+
+struct fy_diag *fy_reader_get_diag(struct fy_reader *fyr)
+{
+	if (fyr && fyr->ops && fyr->ops->get_diag)
+		return fyr->ops->get_diag(fyr);
+
+	return NULL;
+}
+
+int fy_reader_file_open(struct fy_reader *fyr, const char *filename)
+{
+	if (!fyr || !filename)
+		return -1;
+
+	if (fyr->ops && fyr->ops->file_open)
+		return fyr->ops->file_open(fyr, filename);
+
+	return open(filename, O_RDONLY);
+}
+
+void fy_reader_reset(struct fy_reader *fyr)
+{
+	const struct fy_reader_ops *ops;
+	struct fy_diag *diag;
+
+	if (!fyr)
+		return;
+
+	ops = fyr->ops;
+	diag = fyr->diag;
+
+	fy_input_unref(fyr->current_input);
+
+	memset(fyr, 0, sizeof(*fyr));
+
+	/* by default we're always in yaml mode */
+	fyr->mode = fyrm_yaml;
+	fyr->ops = ops;
+	fyr->diag = diag;
+	fyr->current_c = -1;
+}
+
+void fy_reader_setup(struct fy_reader *fyr, const struct fy_reader_ops *ops)
+{
+	if (!fyr)
+		return;
+
+	fyr->ops = ops;
+	fyr->diag = fy_reader_get_diag(fyr);
+	fyr->current_input = NULL;
+	fy_reader_reset(fyr);
+}
+
+void fy_reader_cleanup(struct fy_reader *fyr)
+{
+	if (!fyr)
+		return;
+
+	fy_input_unref(fyr->current_input);
+	fyr->current_input = NULL;
+	fy_reader_reset(fyr);
+}
+
+void fy_reader_apply_mode(struct fy_reader *fyr)
+{
+	struct fy_input *fyi;
+
+	assert(fyr);
+
+	/* set input mode from the current reader settings */
+	switch (fyr->mode) {
+	case fyrm_yaml:
+		fyr->json_mode = false;
+		fyr->lb_mode = fylb_cr_nl;
+		fyr->fws_mode = fyfws_space_tab;
+		break;
+	case fyrm_json:
+		fyr->json_mode = true;
+		fyr->lb_mode = fylb_cr_nl;
+		fyr->fws_mode = fyfws_space;
+		break;
+	case fyrm_yaml_1_1:
+		fyr->json_mode = false;
+		fyr->lb_mode = fylb_cr_nl_N_L_P;
+		fyr->fws_mode = fyfws_space_tab;
+		break;
+	}
+	fyi = fyr->current_input;
+	if (fyi) {
+		fyi->json_mode = fyr->json_mode;
+		fyi->lb_mode = fyr->lb_mode;
+		fyi->fws_mode = fyr->fws_mode;
+	}
+}
+
+int fy_reader_input_open(struct fy_reader *fyr, struct fy_input *fyi, const struct fy_reader_input_cfg *icfg)
+{
+	struct stat sb;
+	int rc;
+
+	if (!fyi)
+		return -1;
+
+	/* unref any previous input */
+	fy_input_unref(fyr->current_input);
+	fyr->current_input = fy_input_ref(fyi);
+
+	fy_reader_apply_mode(fyr);
+
+	if (!icfg)
+		memset(&fyr->current_input_cfg, 0, sizeof(fyr->current_input_cfg));
+	else
+		fyr->current_input_cfg = *icfg;
+
+	/* reset common data */
+	fyi->buffer = NULL;
+	fyi->allocated = 0;
+	fyi->read = 0;
+	fyi->chunk = 0;
+	fyi->chop = 0;
+	fyi->fp = NULL;
+
+	switch (fyi->cfg.type) {
+
+	case fyit_file:
+	case fyit_fd:
+
+		switch (fyi->cfg.type) {
+		case fyit_file:
+			fyi->fd = fy_reader_file_open(fyr, fyi->cfg.file.filename);
+			fyr_error_check(fyr, fyi->fd != -1, err_out,
+					"failed to open %s",  fyi->cfg.file.filename);
+			break;
+
+		case fyit_fd:
+			fyi->fd = fyi->cfg.fd.fd;
+			fyr_error_check(fyr, fyi->fd >= 0, err_out,
+					"bad file.fd %d",  fyi->cfg.fd.fd);
+			break;
+		default:
+			assert(0);	// will never happen
+		}
+
+		rc = fstat(fyi->fd, &sb);
+		fyr_error_check(fyr, rc != -1, err_out,
+				"failed to fstat %s", fyi->cfg.file.filename);
+
+		fyi->length = sb.st_size;
+
+		/* only map if not zero (and is not disabled) */
+#if !defined(_MSC_VER)
+		if (sb.st_size > 0 && !fyr->current_input_cfg.disable_mmap_opt) {
+			fyi->addr = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fyi->fd, 0);
+
+			/* convert from MAP_FAILED to NULL */
+			if (fyi->addr == MAP_FAILED) {
+				fyr_debug(fyr, "mmap failed for file %s",
+						fyi->cfg.file.filename);
+				fyi->addr = NULL;
+			}
+		}
+#endif
+		/* if we've managed to mmap, we' good */
+		if (fyi->addr)
+			break;
+
+		/* if we're not ignoring stdio, open a FILE* using the fd */
+		if (!fyi->cfg.ignore_stdio) {
+			fyi->fp = fdopen(fyi->fd, "r");
+			fyr_error_check(fyr, rc != -1, err_out, "failed to fdopen %s", fyi->name);
+		} else
+			fyi->fp = NULL;
+
+		break;
+
+	case fyit_stream:
+		if (!fyi->cfg.ignore_stdio)
+			fyi->fp = fyi->cfg.stream.fp;
+		else
+			fyi->fd = fileno(fyi->cfg.stream.fp);
+		break;
+
+	case fyit_memory:
+		/* nothing to do for memory */
+		break;
+
+	case fyit_alloc:
+		/* nothing to do for memory */
+		break;
+
+	case fyit_callback:
+		break;
+
+	default:
+		assert(0);
+		break;
+	}
+
+	switch (fyi->cfg.type) {
+
+		/* those two need no memory */
+	case fyit_memory:
+	case fyit_alloc:
+		break;
+
+		/* all the rest need it */
+	default:
+		/* if we're not in mmap mode */
+#if !defined(_MSC_VER)
+		if (fyi->addr && !fyr->current_input_cfg.disable_mmap_opt)
+			break;
+#endif
+
+		fyi->chunk = fyi->cfg.chunk;
+		if (!fyi->chunk)
+			fyi->chunk = fy_get_pagesize();
+		fyi->chop = fyi->chunk * FYI_CHOP_MULT;
+		fyi->buffer = malloc(fyi->chunk);
+		fyr_error_check(fyr, fyi->buffer, err_out,
+				"fy_alloc() failed");
+		fyi->allocated = fyi->chunk;
+		break;
+	}
+
+	fyr->this_input_start = 0;
+	fyr->current_input_pos = 0;
+	fyr->line = 0;
+	fyr->column = 0;
+	fyr->current_c = -1;
+	fyr->current_ptr = NULL;
+	fyr->current_w = 0;
+	fyr->current_left = 0;
+
+	fyi->state = FYIS_PARSE_IN_PROGRESS;
+
+	return 0;
+
+err_out:
+	fy_input_close(fyi);
+	return -1;
+}
+
+int fy_reader_input_done(struct fy_reader *fyr)
+{
+	struct fy_input *fyi;
+	void *buf;
+
+	if (!fyr)
+		return -1;
+
+	fyi = fyr->current_input;
+	if (!fyi)
+		return 0;
+
+	switch (fyi->cfg.type) {
+	case fyit_file:
+	case fyit_fd:
+		if (fyi->addr)
+			break;
+
+		/* fall-through */
+
+	case fyit_stream:
+	case fyit_callback:
+		/* chop extra buffer */
+		buf = realloc(fyi->buffer, fyr->current_input_pos);
+		fyr_error_check(fyr, buf || !fyr->current_input_pos, err_out,
+				"realloc() failed");
+
+		fyi->buffer = buf;
+		fyi->allocated = fyr->current_input_pos;
+		/* increate input generation; required for direct input to work */
+		fyi->generation++;
+		break;
+
+	default:
+		break;
+
+	}
+
+	fyi->state = FYIS_PARSED;
+	fy_input_unref(fyi);
+	fyr->current_input = NULL;
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+int fy_reader_input_scan_token_mark_slow_path(struct fy_reader *fyr)
+{
+	struct fy_input *fyi, *fyi_new = NULL;
+
+	assert(fyr);
+
+	if (!fy_reader_input_chop_active(fyr))
+		return 0;
+
+	fyi = fyr->current_input;
+	assert(fyi);
+
+	fyi_new = fy_input_alloc();
+	fyr_error_check(fyr, fyi_new, err_out,
+			"fy_input_alloc() failed\n");
+
+	/* copy the config over */
+	fyi_new->cfg = fyi->cfg;
+	fyi_new->name = strdup(fyi->name);
+	fyr_error_check(fyr, fyi_new->name, err_out,
+			"strdup() failed\n");
+
+	fyi_new->chunk = fyi->chunk;
+	fyi_new->chop = fyi->chop;
+	fyi_new->buffer = malloc(fyi->chunk);
+	fyr_error_check(fyr, fyi_new->buffer, err_out,
+			"fy_alloc() failed");
+	fyi_new->allocated = fyi->chunk;
+	fyi_new->fp = fyi->fp;
+
+	fyi->fp = NULL;	/* the file pointer now assigned to the new */
+
+	fyi_new->lb_mode = fyi->lb_mode;
+	fyi_new->fws_mode = fyi->fws_mode;
+
+	fyi_new->state = FYIS_PARSE_IN_PROGRESS;
+
+	/* adjust and copy the left over reads */
+	assert(fyi->read >= fyr->current_input_pos);
+	fyi_new->read = fyi->read - fyr->current_input_pos;
+	if (fyi_new->read > 0)
+		memcpy(fyi_new->buffer, (char *)fyi->buffer + fyr->current_input_pos, fyi_new->read);
+
+	fyr->this_input_start += fyr->current_input_pos;
+
+	/* update the reader to point to the new input */
+	fyr->current_input = fyi_new;
+	fyr->current_input_pos = 0;
+	fyr->current_ptr = fyi_new->buffer;
+
+	fyr_debug(fyr, "chop at this_input_start=%zu chop=%zu\n", fyr->this_input_start, fyi->chop);
+
+	/* free the old input - while references to it exist it will hang around */
+	fyi->state = FYIS_PARSED;
+	fy_input_unref(fyi);
+	fyi = NULL;
+
+	return 0;
+err_out:
+	fy_input_unref(fyi_new);
+	return -1;
+}
+
+const void *fy_reader_ptr_slow_path(struct fy_reader *fyr, size_t *leftp)
+{
+	struct fy_input *fyi;
+	const void *p;
+	int left;
+
+	if (fyr->current_ptr) {
+		if (leftp)
+			*leftp = fyr->current_left;
+		return fyr->current_ptr;
+	}
+
+	fyi = fyr->current_input;
+	if (!fyi)
+		return NULL;
+
+	/* tokens cannot cross boundaries */
+	switch (fyi->cfg.type) {
+	case fyit_file:
+	case fyit_fd:
+		if (fyi->addr) {
+			left = fyi->length - (fyr->this_input_start + fyr->current_input_pos);
+			p = (char *)fyi->addr + fyr->current_input_pos;
+			break;
+		}
+
+		/* fall-through */
+
+	case fyit_stream:
+	case fyit_callback:
+		left = fyi->read - (fyr->this_input_start + fyr->current_input_pos);
+		p = (char *)fyi->buffer + fyr->current_input_pos;
+		break;
+
+	case fyit_memory:
+		left = fyi->cfg.memory.size - fyr->current_input_pos;
+		p = (char *)fyi->cfg.memory.data + fyr->current_input_pos;
+		break;
+
+	case fyit_alloc:
+		left = fyi->cfg.alloc.size - fyr->current_input_pos;
+		p = (char *)fyi->cfg.alloc.data + fyr->current_input_pos;
+		break;
+
+
+	default:
+		assert(0);	/* no streams */
+		p = NULL;
+		left = 0;
+		break;
+	}
+
+	if (leftp)
+		*leftp = left;
+
+	fyr->current_ptr = p;
+	fyr->current_left = left;
+	fyr->current_c = fy_utf8_get(p, left, &fyr->current_w);
+
+	return p;
+}
+
+const void *fy_reader_input_try_pull(struct fy_reader *fyr, struct fy_input *fyi,
+				     size_t pull, size_t *leftp)
+{
+	const void *p;
+	size_t left, pos, size, nread, nreadreq, missing;
+	ssize_t snread;
+	size_t space __FY_DEBUG_UNUSED__;
+	void *buf;
+
+	if (!fyr || !fyi) {
+		if (leftp)
+			*leftp = 0;
+		return NULL;
+	}
+
+	p = NULL;
+	left = 0;
+	pos = fyr->current_input_pos;
+
+	switch (fyi->cfg.type) {
+	case fyit_file:
+	case fyit_fd:
+
+		if (fyi->addr) {
+			assert(fyi->length >= (fyr->this_input_start + pos));
+
+			left = fyi->length - (fyr->this_input_start + pos);
+			if (!left) {
+				fyr_debug(fyr, "file input exhausted");
+				break;
+			}
+			p = (char *)fyi->addr + pos;
+			break;
+		}
+
+		/* fall-through */
+
+	case fyit_stream:
+	case fyit_callback:
+
+		assert(fyi->read >= pos);
+
+		left = fyi->read - pos;
+		p = (char *)fyi->buffer + pos;
+
+		/* enough to satisfy directly */
+		if (left >= pull)
+			break;
+
+		/* no more */
+		if (fyi->eof) {
+			if (!left) {
+				fyr_debug(fyr, "input exhausted (EOF)");
+				p = NULL;
+			}
+			break;
+		}
+
+		space = fyi->allocated - pos;
+
+		/* if we're missing more than the buffer space */
+		missing = pull - left;
+
+		fyr_debug(fyr, "input: allocated=%zu read=%zu pos=%zu pull=%zu left=%zu space=%zu missing=%zu",
+				fyi->allocated, fyi->read, pos, pull, left, space, missing);
+
+		if (pos + pull > fyi->allocated) {
+
+			/* align size to chunk */
+			size = fyi->allocated + missing + fyi->chunk - 1;
+			size = size - size % fyi->chunk;
+
+			fyr_debug(fyr, "input buffer missing %zu bytes (pull=%zu)", missing, pull);
+
+			buf = realloc(fyi->buffer, size);
+			if (!buf) {
+				fyr_error(fyr, "realloc() failed");
+				goto err_out;
+			}
+
+			fyr_debug(fyr, "input read allocated=%zu new-size=%zu", fyi->allocated, size);
+
+			fyi->buffer = buf;
+			fyi->allocated = size;
+			fyi->generation++;
+
+			space = fyi->allocated - pos;
+			p = (char *)fyi->buffer + pos;
+		}
+
+		/* always try to read up to the allocated space */
+		do {
+			nreadreq = fyi->allocated - fyi->read;
+			assert(nreadreq > 0);
+
+			if (fyi->cfg.type == fyit_callback) {
+
+				fyr_debug(fyr, "performing callback request of %zu", nreadreq);
+
+				nread = fyi->cfg.callback.input(fyi->cfg.userdata, (char *)fyi->buffer + fyi->read, nreadreq);
+
+				fyr_debug(fyr, "callback returned %zu", nread);
+
+				if (nread <= 0) {
+					if (!nread) {
+						fyi->eof = true;
+						fyr_debug(fyr, "callback got EOF");
+					} else {
+						fyi->err = true;
+						fyr_debug(fyr, "callback got error");
+					}
+					break;
+				}
+
+			} else if (fyi->fp) {
+
+				fyr_debug(fyr, "performing fread request of %zu", nreadreq);
+
+				nread = fread((char *)fyi->buffer + fyi->read, 1, nreadreq, fyi->fp);
+
+				fyr_debug(fyr, "fread returned %zu", nread);
+
+				if (nread <= 0) {
+					fyi->err = ferror(fyi->fp);
+					if (fyi->err) {
+						fyi->eof = true;
+						fyr_debug(fyr, "fread got ERROR");
+						goto err_out;
+					}
+
+					fyi->eof = feof(fyi->fp);
+					if (fyi->eof)
+						fyr_debug(fyr, "fread got EOF");
+					nread = 0;
+					break;
+				}
+
+			} else if (fyi->fd >= 0) {
+
+				fyr_debug(fyr, "performing read request of %zu", nreadreq);
+
+				do {
+					snread = read(fyi->fd, (char *)fyi->buffer + fyi->read, nreadreq);
+				} while (snread == -1 && errno == EAGAIN);
+
+				fyr_debug(fyr, "read returned %zd", snread);
+
+				if (snread == -1) {
+					fyi->err = true;
+					fyi->eof = true;
+					fyr_error(fyr, "read() failed: %s", strerror(errno));
+					goto err_out;
+				}
+
+				if (!snread) {
+					fyi->eof = true;
+					nread = 0;
+					break;
+				}
+
+				nread = snread;
+			} else {
+				fyr_error(fyr, "No FILE* nor fd available?");
+				fyi->eof = true;
+				nread = 0;
+				goto err_out;
+			}
+
+			assert(nread > 0);
+
+			fyi->read += nread;
+			left = fyi->read - pos;
+
+		} while (left < pull);
+
+		/* no more, move it to parsed input chunk list */
+		if (!left) {
+			fyr_debug(fyr, "input exhausted");
+			p = NULL;
+		}
+		break;
+
+	case fyit_memory:
+		assert(fyi->cfg.memory.size >= pos);
+
+		left = fyi->cfg.memory.size - pos;
+		if (!left) {
+			fyr_debug(fyr, "memory input exhausted");
+			break;
+		}
+		p = (char *)fyi->cfg.memory.data + pos;
+		break;
+
+	case fyit_alloc:
+		assert(fyi->cfg.alloc.size >= pos);
+
+		left = fyi->cfg.alloc.size - pos;
+		if (!left) {
+			fyr_debug(fyr, "alloc input exhausted");
+			break;
+		}
+		p = (char *)fyi->cfg.alloc.data + pos;
+		break;
+
+
+	default:
+		assert(0);
+		break;
+	}
+
+	if (leftp)
+		*leftp = left;
+	return p;
+
+err_out:
+	if (leftp)
+		*leftp = 0;
+	return NULL;
+}
+
+void
+fy_reader_advance_slow_path(struct fy_reader *fyr, int c)
+{
+	bool is_line_break = false;
+	size_t w;
+
+	/* skip this character (optimize case of being the current) */
+	w = c == fyr->current_c ? (size_t)fyr->current_w : fy_utf8_width(c);
+	fy_reader_advance_octets(fyr, w);
+
+	/* first check for CR/LF */
+	if (c == '\r' && fy_reader_peek(fyr) == '\n') {
+		fy_reader_advance_octets(fyr, 1);
+		is_line_break = true;
+	} else if (fy_reader_is_lb(fyr, c))
+		is_line_break = true;
+
+	if (is_line_break) {
+		fyr->column = 0;
+		fyr->line++;
+	} else if (fyr->tabsize && fy_is_tab(c))
+		fyr->column += (fyr->tabsize - (fyr->column % fyr->tabsize));
+	else
+		fyr->column++;
+}
+
+struct fy_input *fy_input_create(const struct fy_input_cfg *fyic)
+{
+	struct fy_input *fyi = NULL;
+	int ret;
+
+	fyi = fy_input_alloc();
+	if (!fyi)
+		return NULL;
+	fyi->cfg = *fyic;
+
+	/* copy filename pointers and switch */
+	switch (fyic->type) {
+
+	case fyit_file:
+		fyi->name = strdup(fyic->file.filename);
+		break;
+
+	case fyit_fd:
+		ret = asprintf(&fyi->name, "<fd-%d>", fyic->fd.fd);
+		if (ret == -1)
+			fyi->name = NULL;
+		break;
+
+	case fyit_stream:
+		if (fyic->stream.name)
+			fyi->name = strdup(fyic->stream.name);
+		else if (fyic->stream.fp == stdin)
+			fyi->name = strdup("<stdin>");
+		else {
+			ret = asprintf(&fyi->name, "<stream-%d>",
+					fileno(fyic->stream.fp));
+			if (ret == -1)
+				fyi->name = NULL;
+		}
+		break;
+	case fyit_memory:
+		ret = asprintf(&fyi->name, "<memory-@%p-%p>",
+			fyic->memory.data, (char *)fyic->memory.data + fyic->memory.size - 1);
+		if (ret == -1)
+			fyi->name = NULL;
+		break;
+	case fyit_alloc:
+		ret = asprintf(&fyi->name, "<alloc-@%p-%p>",
+			fyic->memory.data, (char *)fyic->memory.data + fyic->memory.size - 1);
+		if (ret == -1)
+			fyi->name = NULL;
+		break;
+	case fyit_callback:
+		ret = asprintf(&fyi->name, "<callback>");
+		if (ret == -1)
+			fyi->name = NULL;
+		break;
+	default:
+		assert(0);
+		break;
+	}
+	if (!fyi->name)
+		goto err_out;
+
+	fyi->buffer = NULL;
+	fyi->allocated = 0;
+	fyi->read = 0;
+	fyi->chunk = 0;
+	fyi->chop = 0;
+	fyi->fp = NULL;
+	fyi->fd = -1;
+	fyi->addr = NULL;
+	fyi->length = -1;
+
+	/* default modes */
+	fyi->lb_mode = fylb_cr_nl;
+	fyi->fws_mode = fyfws_space_tab;
+
+	return fyi;
+
+err_out:
+	fy_input_unref(fyi);
+	return NULL;
+}
+
+/* ensure that there are at least size octets available */
+const void *fy_reader_ensure_lookahead_slow_path(struct fy_reader *fyr, size_t size, size_t *leftp)
+{
+	const void *p;
+	size_t left;
+
+	if (!leftp)
+		leftp = &left;
+
+	p = fy_reader_ptr(fyr, leftp);
+	if (!p || *leftp < size) {
+
+		fyr_debug(fyr, "ensure lookahead size=%zd left=%zd (%s - %zu)",
+				size, *leftp,
+				fy_input_get_filename(fyr->current_input),
+				fyr->current_input_pos);
+
+		p = fy_reader_input_try_pull(fyr, fyr->current_input, size, leftp);
+		if (!p || *leftp < size)
+			return NULL;
+
+		fyr->current_ptr = p;
+		fyr->current_left = *leftp;
+		fyr->current_c = fy_utf8_get(fyr->current_ptr, fyr->current_left, &fyr->current_w);
+	}
+	return p;
+}
+
diff --git a/contrib/libs/libfyaml/src/lib/fy-input.h b/contrib/libs/libfyaml/src/lib/fy-input.h
new file mode 100644
index 0000000000..f8032ec64a
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-input.h
@@ -0,0 +1,683 @@
+/*
+ * fy-input.h - YAML input methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_INPUT_H
+#define FY_INPUT_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+
+#include <libfyaml.h>
+
+#include "fy-utils.h"
+#include "fy-typelist.h"
+#include "fy-ctype.h"
+
+struct fy_atom;
+struct fy_parser;
+
+enum fy_input_type {
+	fyit_file,
+	fyit_stream,
+	fyit_memory,
+	fyit_alloc,
+	fyit_callback,
+	fyit_fd,
+};
+
+struct fy_input_cfg {
+	enum fy_input_type type;
+	void *userdata;
+	size_t chunk;
+	bool ignore_stdio : 1;
+	bool no_fclose_fp : 1;
+	bool no_close_fd : 1;
+	union {
+		struct {
+			const char *filename;
+		} file;
+		struct {
+			const char *name;
+			FILE *fp;
+		} stream;
+		struct {
+			const void *data;
+			size_t size;
+		} memory;
+		struct {
+			void *data;
+			size_t size;
+		} alloc;
+		struct {
+			/* negative return is error, 0 is EOF */
+			ssize_t (*input)(void *user, void *buf, size_t count);
+		} callback;
+		struct {
+			int fd;
+		} fd;
+	};
+};
+
+enum fy_input_state {
+	FYIS_NONE,
+	FYIS_QUEUED,
+	FYIS_PARSE_IN_PROGRESS,
+	FYIS_PARSED,
+};
+
+FY_TYPE_FWD_DECL_LIST(input);
+struct fy_input {
+	struct fy_list_head node;
+	enum fy_input_state state;
+	struct fy_input_cfg cfg;
+	int refs;		/* number of referers */
+	char *name;
+	void *buffer;		/* when the file can't be mmaped */
+	uint64_t generation;
+	size_t allocated;
+	size_t read;
+	size_t chunk;
+	size_t chop;
+	FILE *fp;		/* FILE* for the input if it exists */
+	int fd;			/* fd for file and stream */
+	size_t length;		/* length of file */
+	void *addr;		/* mmaped for files, allocated for streams */
+	bool eof : 1;		/* got EOF */
+	bool err : 1;		/* got an error */
+
+	/* propagated */
+	bool json_mode;
+	enum fy_lb_mode lb_mode;
+	enum fy_flow_ws_mode fws_mode;
+};
+FY_TYPE_DECL_LIST(input);
+
+static inline const void *fy_input_start(const struct fy_input *fyi)
+{
+	const void *ptr = NULL;
+
+	switch (fyi->cfg.type) {
+	case fyit_file:
+		if (fyi->addr) {
+			ptr = fyi->addr;
+			break;
+		}
+		/* fall-through */
+
+	case fyit_stream:
+	case fyit_callback:
+		ptr = fyi->buffer;
+		break;
+
+	case fyit_memory:
+		ptr = fyi->cfg.memory.data;
+		break;
+
+	case fyit_alloc:
+		ptr = fyi->cfg.alloc.data;
+		break;
+
+	default:
+		break;
+	}
+	assert(ptr);
+	return ptr;
+}
+
+static inline size_t fy_input_size(const struct fy_input *fyi)
+{
+	size_t size;
+
+	switch (fyi->cfg.type) {
+	case fyit_file:
+		if (fyi->addr) {
+			size = fyi->length;
+			break;
+		}
+		/* fall-through */
+
+	case fyit_stream:
+	case fyit_callback:
+		size = fyi->read;
+		break;
+
+	case fyit_memory:
+		size = fyi->cfg.memory.size;
+		break;
+
+	case fyit_alloc:
+		size = fyi->cfg.alloc.size;
+		break;
+
+	default:
+		size = 0;
+		break;
+	}
+	return size;
+}
+
+struct fy_input *fy_input_alloc(void);
+void fy_input_free(struct fy_input *fyi);
+
+static inline enum fy_input_state fy_input_get_state(struct fy_input *fyi)
+{
+	return fyi->state;
+}
+
+struct fy_input *fy_input_create(const struct fy_input_cfg *fyic);
+
+const char *fy_input_get_filename(struct fy_input *fyi);
+
+struct fy_input *fy_input_from_data(const char *data, size_t size,
+				    struct fy_atom *handle, bool simple);
+struct fy_input *fy_input_from_malloc_data(char *data, size_t size,
+					   struct fy_atom *handle, bool simple);
+
+void fy_input_close(struct fy_input *fyi);
+
+static inline struct fy_input *
+fy_input_ref(struct fy_input *fyi)
+{
+	if (!fyi)
+		return NULL;
+
+
+	assert(fyi->refs + 1 > 0);
+
+	fyi->refs++;
+
+	return fyi;
+}
+
+static inline void
+fy_input_unref(struct fy_input *fyi)
+{
+	if (!fyi)
+		return;
+
+	assert(fyi->refs > 0);
+
+	if (fyi->refs == 1)
+		fy_input_free(fyi);
+	else
+		fyi->refs--;
+}
+
+struct fy_reader;
+
+enum fy_reader_mode {
+	fyrm_yaml,
+	fyrm_json,
+	fyrm_yaml_1_1,	/* yaml 1.1 mode */
+};
+
+struct fy_reader_ops {
+	struct fy_diag *(*get_diag)(struct fy_reader *fyr);
+	int (*file_open)(struct fy_reader *fyr, const char *filename);
+};
+
+struct fy_reader_input_cfg {
+	bool disable_mmap_opt;
+};
+
+struct fy_reader {
+	const struct fy_reader_ops *ops;
+	enum fy_reader_mode mode;
+
+	struct fy_reader_input_cfg current_input_cfg;
+	struct fy_input *current_input;
+
+	size_t this_input_start;	/* this input start */
+	size_t current_input_pos;	/* from start of input */
+	const void *current_ptr;	/* current pointer into the buffer */
+	int current_c;			/* current utf8 character at current_ptr (-1 if not cached) */
+	int current_w;			/* current utf8 character width */
+	size_t current_left;		/* currently left characters into the buffer */
+
+	int line;			/* always on input */
+	int column;
+
+	int tabsize;			/* very experimental tab size for indent purposes */
+
+	struct fy_diag *diag;
+
+	/* decoded mode variables; update when changing modes */
+	bool json_mode;
+	enum fy_lb_mode lb_mode;
+	enum fy_flow_ws_mode fws_mode;
+};
+
+void fy_reader_reset(struct fy_reader *fyr);
+void fy_reader_setup(struct fy_reader *fyr, const struct fy_reader_ops *ops);
+void fy_reader_cleanup(struct fy_reader *fyr);
+
+int fy_reader_input_open(struct fy_reader *fyr, struct fy_input *fyi, const struct fy_reader_input_cfg *icfg);
+int fy_reader_input_done(struct fy_reader *fyr);
+int fy_reader_input_scan_token_mark_slow_path(struct fy_reader *fyr);
+
+static inline bool
+fy_reader_input_chop_active(struct fy_reader *fyr)
+{
+	struct fy_input *fyi;
+
+	assert(fyr);
+
+	fyi = fyr->current_input;
+	assert(fyi);
+
+	if (!fyi->chop)
+		return false;
+
+	switch (fyi->cfg.type) {
+	case fyit_file:
+		return !fyi->addr && fyi->fp;	/* non-mmap mode */
+
+	case fyit_stream:
+	case fyit_callback:
+		return true;
+
+	default:
+		/* all the others do not support chop */
+		break;
+	}
+
+	return false;
+}
+
+static inline int
+fy_reader_input_scan_token_mark(struct fy_reader *fyr)
+{
+	/* don't chop until ready */
+	if (!fy_reader_input_chop_active(fyr) ||
+	    fyr->current_input->chop > fyr->current_input_pos)
+		return 0;
+
+	return fy_reader_input_scan_token_mark_slow_path(fyr);
+}
+
+const void *fy_reader_ptr_slow_path(struct fy_reader *fyr, size_t *leftp);
+const void *fy_reader_ensure_lookahead_slow_path(struct fy_reader *fyr, size_t size, size_t *leftp);
+
+void fy_reader_apply_mode(struct fy_reader *fyr);
+
+static FY_ALWAYS_INLINE inline enum fy_reader_mode
+fy_reader_get_mode(const struct fy_reader *fyr)
+{
+	assert(fyr);
+	return fyr->mode;
+}
+
+static FY_ALWAYS_INLINE inline void
+fy_reader_set_mode(struct fy_reader *fyr, enum fy_reader_mode mode)
+{
+	assert(fyr);
+	fyr->mode = mode;
+	fy_reader_apply_mode(fyr);
+}
+
+static FY_ALWAYS_INLINE inline struct fy_input *
+fy_reader_current_input(const struct fy_reader *fyr)
+{
+	assert(fyr);
+	return fyr->current_input;
+}
+
+static FY_ALWAYS_INLINE inline uint64_t
+fy_reader_current_input_generation(const struct fy_reader *fyr)
+{
+	assert(fyr);
+	assert(fyr->current_input);
+	return fyr->current_input->generation;
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_reader_column(const struct fy_reader *fyr)
+{
+	assert(fyr);
+	return fyr->column;
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_reader_tabsize(const struct fy_reader *fyr)
+{
+	assert(fyr);
+	return fyr->tabsize;
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_reader_line(const struct fy_reader *fyr)
+{
+	assert(fyr);
+	return fyr->line;
+}
+
+/* force new line at the end of stream */
+static inline void fy_reader_stream_end(struct fy_reader *fyr)
+{
+	assert(fyr);
+
+	/* force new line */
+	if (fyr->column) {
+		fyr->column = 0;
+		fyr->line++;
+	}
+}
+
+static FY_ALWAYS_INLINE inline void
+fy_reader_get_mark(struct fy_reader *fyr, struct fy_mark *fym)
+{
+	assert(fyr);
+	fym->input_pos = fyr->current_input_pos;
+	fym->line = fyr->line;
+	fym->column = fyr->column;
+}
+
+static FY_ALWAYS_INLINE inline const void *
+fy_reader_ptr(struct fy_reader *fyr, size_t *leftp)
+{
+	if (fyr->current_ptr) {
+		if (leftp)
+			*leftp = fyr->current_left;
+		return fyr->current_ptr;
+	}
+
+	return fy_reader_ptr_slow_path(fyr, leftp);
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_json_mode(const struct fy_reader *fyr)
+{
+	assert(fyr);
+	return fyr->json_mode;
+}
+
+static FY_ALWAYS_INLINE inline enum fy_lb_mode
+fy_reader_lb_mode(const struct fy_reader *fyr)
+{
+	assert(fyr);
+	return fyr->lb_mode;
+}
+
+static FY_ALWAYS_INLINE inline enum fy_flow_ws_mode
+fy_reader_flow_ws_mode(const struct fy_reader *fyr)
+{
+	assert(fyr);
+	return fyr->fws_mode;
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_lb(const struct fy_reader *fyr, int c)
+{
+	return fy_is_lb_m(c, fy_reader_lb_mode(fyr));
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_lbz(const struct fy_reader *fyr, int c)
+{
+	return fy_is_lbz_m(c, fy_reader_lb_mode(fyr));
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_blankz(const struct fy_reader *fyr, int c)
+{
+	return fy_is_blankz_m(c, fy_reader_lb_mode(fyr));
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_generic_lb(const struct fy_reader *fyr, int c)
+{
+	return fy_is_generic_lb_m(c, fy_reader_lb_mode(fyr));
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_generic_lbz(const struct fy_reader *fyr, int c)
+{
+	return fy_is_generic_lbz_m(c, fy_reader_lb_mode(fyr));
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_generic_blankz(const struct fy_reader *fyr, int c)
+{
+	return fy_is_generic_blankz_m(c, fy_reader_lb_mode(fyr));
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_flow_ws(const struct fy_reader *fyr, int c)
+{
+	return fy_is_flow_ws_m(c, fy_reader_flow_ws_mode(fyr));
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_flow_blank(const struct fy_reader *fyr, int c)
+{
+	return fy_reader_is_flow_ws(fyr, c);	/* same */
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_flow_blankz(const struct fy_reader *fyr, int c)
+{
+	return fy_is_flow_ws_m(c, fy_reader_flow_ws_mode(fyr)) ||
+	       fy_is_generic_lbz_m(c, fy_reader_lb_mode(fyr));
+}
+
+static FY_ALWAYS_INLINE inline const void *
+fy_reader_ensure_lookahead(struct fy_reader *fyr, size_t size, size_t *leftp)
+{
+	if (fyr->current_ptr && fyr->current_left >= size) {
+		if (leftp)
+			*leftp = fyr->current_left;
+		return fyr->current_ptr;
+	}
+	return fy_reader_ensure_lookahead_slow_path(fyr, size, leftp);
+}
+
+/* compare string at the current point (n max) */
+static inline int
+fy_reader_strncmp(struct fy_reader *fyr, const char *str, size_t n)
+{
+	const char *p;
+	int ret;
+
+	assert(fyr);
+	p = fy_reader_ensure_lookahead(fyr, n, NULL);
+	if (!p)
+		return -1;
+	ret = strncmp(p, str, n);
+	return ret ? 1 : 0;
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_reader_peek_at_offset(struct fy_reader *fyr, size_t offset)
+{
+	const uint8_t *p;
+	size_t left;
+	int w;
+
+	assert(fyr);
+	if (offset == 0 && fyr->current_c >= 0)
+		return fyr->current_c;
+
+	/* ensure that the first octet at least is pulled in */
+	p = fy_reader_ensure_lookahead(fyr, offset + 1, &left);
+	if (!p)
+		return FYUG_EOF;
+
+	/* get width by first octet */
+	w = fy_utf8_width_by_first_octet(p[offset]);
+	if (!w)
+		return FYUG_INV;
+
+	/* make sure that there's enough to cover the utf8 width */
+	if (offset + w > left) {
+		p = fy_reader_ensure_lookahead(fyr, offset + w, &left);
+		if (!p)
+			return FYUG_PARTIAL;
+	}
+
+	return fy_utf8_get(p + offset, left - offset, &w);
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_reader_peek_at_internal(struct fy_reader *fyr, int pos, ssize_t *offsetp)
+{
+	int i, c;
+	size_t offset;
+
+	assert(fyr);
+	if (!offsetp || *offsetp < 0) {
+		for (i = 0, offset = 0; i < pos; i++, offset += fy_utf8_width(c)) {
+			c = fy_reader_peek_at_offset(fyr, offset);
+			if (c < 0)
+				return c;
+		}
+	} else
+		offset = (size_t)*offsetp;
+
+	c = fy_reader_peek_at_offset(fyr, offset);
+
+	if (offsetp)
+		*offsetp = offset + fy_utf8_width(c);
+
+	return c;
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_blank_at_offset(struct fy_reader *fyr, size_t offset)
+{
+	return fy_is_blank(fy_reader_peek_at_offset(fyr, offset));
+}
+
+static FY_ALWAYS_INLINE inline bool
+fy_reader_is_blankz_at_offset(struct fy_reader *fyr, size_t offset)
+{
+	return fy_reader_is_blankz(fyr, fy_reader_peek_at_offset(fyr, offset));
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_reader_peek_at(struct fy_reader *fyr, int pos)
+{
+	return fy_reader_peek_at_internal(fyr, pos, NULL);
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_reader_peek(struct fy_reader *fyr)
+{
+	if (fyr->current_c >= 0)
+		return fyr->current_c;
+
+	return fy_reader_peek_at_offset(fyr, 0);
+}
+
+static FY_ALWAYS_INLINE inline const void *
+fy_reader_peek_block(struct fy_reader *fyr, size_t *lenp)
+{
+	const void *p;
+
+	/* try to pull at least one utf8 character usually */
+	p = fy_reader_ensure_lookahead(fyr, 4, lenp);
+
+	/* not a utf8 character available? try a single byte */
+	if (!p)
+		p = fy_reader_ensure_lookahead(fyr, 1, lenp);
+	if (!*lenp)
+		p = NULL;
+	return p;
+}
+
+static FY_ALWAYS_INLINE inline void
+fy_reader_advance_octets(struct fy_reader *fyr, size_t advance)
+{
+	assert(fyr);
+	assert(fyr->current_left >= advance);
+
+	fyr->current_input_pos += advance;
+	fyr->current_ptr = (char *)fyr->current_ptr + advance;
+	fyr->current_left -= advance;
+
+	fyr->current_c = fy_utf8_get(fyr->current_ptr, fyr->current_left, &fyr->current_w);
+}
+
+void fy_reader_advance_slow_path(struct fy_reader *fyr, int c);
+
+static FY_ALWAYS_INLINE inline void
+fy_reader_advance_printable_ascii(struct fy_reader *fyr, int c)
+{
+	assert(fyr);
+	fy_reader_advance_octets(fyr, 1);
+	fyr->column++;
+}
+
+static FY_ALWAYS_INLINE inline void
+fy_reader_advance(struct fy_reader *fyr, int c)
+{
+	if (fy_utf8_is_printable_ascii(c))
+		fy_reader_advance_printable_ascii(fyr, c);
+	else
+		fy_reader_advance_slow_path(fyr, c);
+}
+
+static FY_ALWAYS_INLINE inline void
+fy_reader_advance_ws(struct fy_reader *fyr, int c)
+{
+	/* skip this character */
+	fy_reader_advance_octets(fyr, fy_utf8_width(c));
+
+	if (fyr->tabsize && fy_is_tab(c))
+		fyr->column += (fyr->tabsize - (fyr->column % fyr->tabsize));
+	else
+		fyr->column++;
+}
+
+static FY_ALWAYS_INLINE inline void
+fy_reader_advance_space(struct fy_reader *fyr)
+{
+	fy_reader_advance_octets(fyr, 1);
+	fyr->column++;
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_reader_get(struct fy_reader *fyr)
+{
+	int value;
+
+	value = fy_reader_peek(fyr);
+	if (value < 0)
+		return value;
+
+	fy_reader_advance(fyr, value);
+
+	return value;
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_reader_advance_by(struct fy_reader *fyr, int count)
+{
+	int i, c;
+
+	for (i = 0; i < count; i++) {
+		c = fy_reader_get(fyr);
+		if (c < 0)
+			break;
+	}
+	return i ? i : -1;
+}
+
+/* compare string at the current point */
+static inline bool
+fy_reader_strcmp(struct fy_reader *fyr, const char *str)
+{
+	return fy_reader_strncmp(fyr, str, strlen(str));
+}
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-list.h b/contrib/libs/libfyaml/src/lib/fy-list.h
new file mode 100644
index 0000000000..df35cb28e0
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-list.h
@@ -0,0 +1,79 @@
+/*
+ * fy-list.h - simple doubly linked list implementation
+ *
+ * Copyright (c) 2022 Innokentii Mokin <iam@justregular.dev>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_LIST_H
+#define FY_LIST_H
+
+#include <stddef.h>
+
+#define fy_container_of(ptr, type, member) \
+    ( (void)sizeof(0 ? (ptr) : &((type *)0)->member), \
+      (type *)((char*)(ptr) - offsetof(type, member)) )
+
+struct fy_list_head {
+	struct fy_list_head *prev;
+	struct fy_list_head *next;
+};
+
+static inline void fy_list_init_head(struct fy_list_head *lh) 
+{
+	lh->prev = lh;
+	lh->next = lh;
+}
+
+static inline void fy_list_add_head(struct fy_list_head *ln, struct fy_list_head *lh)
+{
+	struct fy_list_head *second = lh->next;
+
+	second->prev = ln;
+	ln->next = second;
+	lh->next = ln;
+	ln->prev = lh;
+}
+
+static inline void fy_list_add_tail(struct fy_list_head *ln, struct fy_list_head *lh)
+{
+	struct fy_list_head *tail = lh->prev;
+
+	lh->prev = ln;
+	ln->next = lh;
+	tail->next = ln;
+	ln->prev = tail;
+}
+
+static inline bool fy_list_is_empty(struct fy_list_head *lh)
+{
+	return lh == lh->next;
+}
+
+static inline bool fy_list_is_singular(struct fy_list_head *lh)
+{
+	return lh != lh->next && lh == lh->next->next;
+}
+
+static inline void fy_list_del(struct fy_list_head *ln) {
+	ln->prev->next = ln->next;
+	ln->next->prev = ln->prev;
+	ln->prev = NULL;
+	ln->next = NULL;
+}
+
+static inline void fy_list_splice(struct fy_list_head *nlh, struct fy_list_head *lh) {
+	struct fy_list_head *prev = lh, *next = lh->next,
+						*head = nlh->next, *tail = nlh->prev;
+
+	if (nlh == nlh->next) {
+		return;
+	}
+
+	head->prev = prev;
+	tail->next = next;
+	prev->next = head;
+	next->prev = tail;
+}
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-parse.c b/contrib/libs/libfyaml/src/lib/fy-parse.c
new file mode 100644
index 0000000000..07b5045efc
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-parse.c
@@ -0,0 +1,7044 @@
+/*
+ * fy-parse.c - Internal parse interface
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <sys/mman.h>
+#endif
+#include <sys/types.h>
+#include <sys/stat.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <sys/ioctl.h>
+#endif
+#include <fcntl.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <unistd.h>
+#endif
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <limits.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+
+#include "fy-utils.h"
+
+/* only check atom sizes on debug */
+#ifndef NDEBUG
+#define ATOM_SIZE_CHECK
+#endif
+
+const char *fy_library_version(void)
+{
+#ifndef VERSION
+#warn No version defined
+	return "UNKNOWN";
+#else
+	return VERSION;
+#endif
+}
+
+int fy_parse_input_append(struct fy_parser *fyp, const struct fy_input_cfg *fyic)
+{
+	struct fy_input *fyi = NULL;
+
+	fyi = fy_input_create(fyic);
+	fyp_error_check(fyp, fyp != NULL, err_out,
+			"fy_parse_input_create() failed!");
+
+	fyi->state = FYIS_QUEUED;
+	fy_input_list_add_tail(&fyp->queued_inputs, fyi);
+
+	return 0;
+
+err_out:
+	fy_input_unref(fyi);
+	return -1;
+}
+
+bool fy_parse_have_more_inputs(struct fy_parser *fyp)
+{
+	return !fy_input_list_empty(&fyp->queued_inputs);
+}
+
+int fy_parse_get_next_input(struct fy_parser *fyp)
+{
+	const char *s;
+	struct fy_reader_input_cfg icfg;
+	struct fy_input *fyi;
+	int rc;
+	bool json_mode;
+	enum fy_reader_mode rdmode;
+
+	assert(fyp);
+
+	if (fy_reader_current_input(fyp->reader)) {
+		fyp_scan_debug(fyp, "get next input: already exists");
+		return 1;
+	}
+
+	/* get next queued input */
+	fyi = fy_input_list_pop(&fyp->queued_inputs);
+
+	/* none left? we're done */
+	if (!fyi) {
+		fyp_scan_debug(fyp, "get next input: all inputs exhausted");
+		return 0;
+	}
+
+	json_mode = false;
+	if ((fyp->cfg.flags & (FYPCF_JSON_MASK << FYPCF_JSON_SHIFT)) == FYPCF_JSON_AUTO) {
+		/* detection only works for filenames (sucks) */
+		if (fyi->cfg.type == fyit_file) {
+			s = fyi->cfg.file.filename;
+			if (s)
+				s = strrchr(s, '.');
+			json_mode = s && !strcmp(s, ".json");
+		}
+	} else if ((fyp->cfg.flags & (FYPCF_JSON_MASK << FYPCF_JSON_SHIFT)) == FYPCF_JSON_FORCE)
+		json_mode = true;
+
+	/* set the initial reader mode according to json option and default version */
+	if (!json_mode)
+		rdmode = fy_version_compare(&fyp->default_version, fy_version_make(1, 1)) <= 0 ? fyrm_yaml_1_1 : fyrm_yaml;
+	else
+		rdmode = fyrm_json;
+
+	fy_reader_set_mode(fyp->reader, rdmode);
+
+	memset(&icfg, 0, sizeof(icfg));
+	icfg.disable_mmap_opt = !!(fyp->cfg.flags & FYPCF_DISABLE_MMAP_OPT);
+
+	rc = fy_reader_input_open(fyp->reader, fyi, &icfg);
+	fyp_error_check(fyp, !rc, err_out,
+			"failed to open input");
+
+	/* take off the reference; reader now owns */
+	fy_input_unref(fyi);
+
+	// inherit the JSON mode
+	if (fyp->current_document_state)
+		fyp->current_document_state->json_mode = fyp_json_mode(fyp);
+
+	fyp_scan_debug(fyp, "get next input: new input - %s mode", json_mode ? "JSON" : "YAML");
+
+	return 1;
+
+err_out:
+	fy_input_unref(fyi);
+	return -1;
+}
+
+static inline void
+fy_token_queue_epilogue(struct fy_parser *fyp, struct fy_token *fyt)
+{
+	/* special handling for zero indented scalars */
+	fyp->token_activity_counter++;
+	if (fyt->type == FYTT_DOCUMENT_START)
+		fyp->document_first_content_token = true;
+	else if (fyp->document_first_content_token && fy_token_type_is_content(fyt->type))
+		fyp->document_first_content_token = false;
+}
+
+static inline struct fy_token *
+fy_token_queue_simple_internal(struct fy_parser *fyp, struct fy_token_list *fytl, enum fy_token_type type, int advance_octets)
+{
+	struct fy_reader *fyr = fyp->reader;
+	struct fy_token *fyt;
+
+	/* allocate and copy in place */
+	fyt = fy_token_alloc_rl(fyp->recycled_token_list);
+	if (!fyt)
+		return NULL;
+
+	fyt->type = type;
+
+	/* the advance is always octets */
+	fy_reader_fill_atom_start(fyr, &fyt->handle);
+	if (advance_octets > 0) {
+		fy_reader_advance_octets(fyr, advance_octets);
+		fyr->column += advance_octets;
+	}
+	fy_reader_fill_atom_end(fyr, &fyt->handle);
+
+	fy_input_ref(fyt->handle.fyi);
+
+	fy_token_list_add_tail(fytl, fyt);
+
+	return fyt;
+}
+
+static inline struct fy_token *
+fy_token_queue_simple(struct fy_parser *fyp, struct fy_token_list *fytl, enum fy_token_type type, int advance_octets)
+{
+	struct fy_token *fyt;
+
+	fyt = fy_token_queue_simple_internal(fyp, fytl, type, advance_octets);
+	if (!fyt)
+		return NULL;
+
+	fy_token_queue_epilogue(fyp, fyt);
+	return fyt;
+}
+
+struct fy_token *
+fy_token_vqueue_internal(struct fy_parser *fyp, struct fy_token_list *fytl,
+			 enum fy_token_type type, va_list ap)
+{
+	struct fy_token *fyt;
+
+	fyt = fy_token_vcreate_rl(fyp->recycled_token_list, type, ap);
+	if (!fyt)
+		return NULL;
+	fy_token_list_add_tail(fytl, fyt);
+
+	fy_token_queue_epilogue(fyp, fyt);
+	return fyt;
+}
+
+struct fy_token *fy_token_queue_internal(struct fy_parser *fyp, struct fy_token_list *fytl,
+					 enum fy_token_type type, ...)
+{
+	va_list ap;
+	struct fy_token *fyt;
+
+	va_start(ap, type);
+	fyt = fy_token_vqueue_internal(fyp, fytl, type, ap);
+	va_end(ap);
+
+	return fyt;
+}
+
+struct fy_token *fy_token_vqueue(struct fy_parser *fyp, enum fy_token_type type, va_list ap)
+{
+	struct fy_token *fyt;
+
+	fyt = fy_token_vqueue_internal(fyp, &fyp->queued_tokens, type, ap);
+	if (fyt)
+		fyp->token_activity_counter++;
+	return fyt;
+}
+
+struct fy_token *fy_token_queue(struct fy_parser *fyp, enum fy_token_type type, ...)
+{
+	va_list ap;
+	struct fy_token *fyt;
+
+	va_start(ap, type);
+	fyt = fy_token_vqueue(fyp, type, ap);
+	va_end(ap);
+
+	return fyt;
+}
+
+const struct fy_version fy_default_version = {
+	.major = 1,
+	.minor = 2
+};
+
+int fy_version_compare(const struct fy_version *va, const struct fy_version *vb)
+{
+	unsigned int vanum, vbnum;
+
+	if (!va)
+		va = &fy_default_version;
+	if (!vb)
+		vb = &fy_default_version;
+
+#define FY_VERSION_UINT(_major, _minor) \
+	((((unsigned int)(_major) & 0xff) << 8) | ((unsigned int)((_minor) & 0xff)))
+
+	vanum = FY_VERSION_UINT(va->major, va->minor);
+	vbnum = FY_VERSION_UINT(vb->major, vb->minor);
+
+#undef FY_VERSION_UINT
+
+	return vanum == vbnum ?  0 :
+	       vanum <  vbnum ? -1 : 1;
+}
+
+const struct fy_version *
+fy_version_default(void)
+{
+	return &fy_default_version;
+}
+
+static const struct fy_version * const fy_map_option_to_version[] = {
+	[FYPCF_DEFAULT_VERSION_AUTO >> FYPCF_DEFAULT_VERSION_SHIFT] = &fy_default_version,
+	[FYPCF_DEFAULT_VERSION_1_1  >> FYPCF_DEFAULT_VERSION_SHIFT] = fy_version_make(1, 1),
+	[FYPCF_DEFAULT_VERSION_1_2  >> FYPCF_DEFAULT_VERSION_SHIFT] = fy_version_make(1, 2),
+	[FYPCF_DEFAULT_VERSION_1_3  >> FYPCF_DEFAULT_VERSION_SHIFT] = fy_version_make(1, 3),
+};
+
+bool fy_version_is_supported(const struct fy_version *vers)
+{
+	unsigned int i;
+	const struct fy_version *vers_chk;
+
+	if (!vers)
+		return true;	/* NULL means default, which is supported */
+
+	for (i = 0; i < sizeof(fy_map_option_to_version)/sizeof(fy_map_option_to_version[0]); i++) {
+
+		vers_chk = fy_map_option_to_version[i];
+		if (!vers_chk)
+			continue;
+
+		if (fy_version_compare(vers, vers_chk) == 0)
+			return true;
+	}
+
+	return false;
+}
+
+static const struct fy_version *
+fy_parse_cfg_to_version(enum fy_parse_cfg_flags flags)
+{
+	unsigned int idx;
+
+	idx = (flags >> FYPCF_DEFAULT_VERSION_SHIFT) & FYPCF_DEFAULT_VERSION_MASK;
+
+	if (idx >= sizeof(fy_map_option_to_version)/sizeof(fy_map_option_to_version[0]))
+		return NULL;
+
+	return fy_map_option_to_version[idx];
+}
+
+const struct fy_version *fy_version_supported_iterate(void **prevp)
+{
+	const struct fy_version * const *versp;
+	const struct fy_version *vers;
+	unsigned int idx;
+
+	if (!prevp)
+		return NULL;
+
+	versp = (const struct fy_version * const *)*prevp;
+	if (!versp) {
+		/* we skip over the first (which is the default) */
+		versp = fy_map_option_to_version;
+	}
+
+	versp++;
+
+	idx = versp - fy_map_option_to_version;
+	if (idx >= sizeof(fy_map_option_to_version)/sizeof(fy_map_option_to_version[0]))
+		return NULL;
+
+	vers = *versp;
+	*prevp = (void **)versp;
+
+	return vers;
+}
+
+const struct fy_tag * const fy_default_tags[] = {
+	&(struct fy_tag) { .handle = "!",  .prefix = "!", },
+	&(struct fy_tag) { .handle = "!!", .prefix = "tag:yaml.org,2002:", },
+	&(struct fy_tag) { .handle = "",   .prefix = "", },
+	NULL
+};
+
+bool fy_tag_handle_is_default(const char *handle, size_t handle_size)
+{
+	int i;
+	const struct fy_tag *fytag;
+
+	if (handle_size == (size_t)-1)
+		handle_size = strlen(handle);
+
+	for (i = 0; (fytag = fy_default_tags[i]) != NULL; i++) {
+
+		if (handle_size == strlen(fytag->handle) &&
+		    !memcmp(handle, fytag->handle, handle_size))
+			return true;
+
+	}
+	return false;
+}
+
+bool fy_tag_is_default_internal(const char *handle, size_t handle_size,
+				const char *prefix, size_t prefix_size)
+{
+	int i;
+	const struct fy_tag *fytag;
+
+	if (handle_size == (size_t)-1)
+		handle_size = strlen(handle);
+
+	if (prefix_size == (size_t)-1)
+		prefix_size = strlen(prefix);
+
+	for (i = 0; (fytag = fy_default_tags[i]) != NULL; i++) {
+
+		if (handle_size == strlen(fytag->handle) &&
+		    !memcmp(handle, fytag->handle, handle_size) &&
+		    prefix_size == strlen(fytag->prefix) &&
+		    !memcmp(prefix, fytag->prefix, prefix_size))
+			return true;
+
+	}
+	return false;
+}
+
+bool fy_document_state_tag_is_default(struct fy_document_state *fyds, const struct fy_tag *tag)
+{
+	struct fy_token *fyt_td;
+
+	/* default tag, but it might be overriden */
+	fyt_td = fy_document_state_lookup_tag_directive(fyds, tag->handle, strlen(tag->handle));
+	if (!fyt_td)
+		return false;	/* Huh? */
+
+	return fyt_td->tag_directive.is_default;
+}
+
+bool fy_token_tag_directive_is_overridable(struct fy_token *fyt_td)
+{
+	const struct fy_tag *fytag;
+	const char *handle, *prefix;
+	size_t handle_size, prefix_size;
+	int i;
+
+	if (!fyt_td)
+		return false;
+
+	handle = fy_tag_directive_token_handle(fyt_td, &handle_size);
+	prefix = fy_tag_directive_token_prefix(fyt_td, &prefix_size);
+	if (!handle || !prefix)
+		return false;
+
+	for (i = 0; (fytag = fy_default_tags[i]) != NULL; i++) {
+
+		if (handle_size == strlen(fytag->handle) &&
+		    !memcmp(handle, fytag->handle, handle_size) &&
+		    prefix_size == strlen(fytag->prefix) &&
+		    !memcmp(prefix, fytag->prefix, prefix_size))
+			return true;
+
+	}
+	return false;
+}
+
+int fy_reset_document_state(struct fy_parser *fyp)
+{
+	struct fy_document_state *fyds_new = NULL;
+
+	fyp_scan_debug(fyp, "resetting document state");
+
+	if (!fyp->default_document_state) {
+		fyds_new = fy_document_state_default(&fyp->default_version, NULL);
+		fyp_error_check(fyp, fyds_new, err_out,
+				"fy_document_state_default() failed");
+	} else {
+		fyds_new = fy_document_state_copy(fyp->default_document_state);
+		fyp_error_check(fyp, fyds_new, err_out,
+				"fy_document_state_copy() failed");
+	}
+	// inherit the JSON mode
+	fyds_new->json_mode = fyp_json_mode(fyp);
+
+	if (fyp->current_document_state)
+		fy_document_state_unref(fyp->current_document_state);
+	fyp->current_document_state = fyds_new;
+
+	/* TODO check when cleaning flow lists */
+	fyp->flow_level = 0;
+	fyp->flow = FYFT_NONE;
+	fy_parse_flow_list_recycle_all(fyp, &fyp->flow_stack);
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+int fy_parser_set_default_document_state(struct fy_parser *fyp,
+					 struct fy_document_state *fyds)
+{
+	if (!fyp)
+		return -1;
+
+	/* only in a safe state */
+	if (fyp->state != FYPS_NONE && fyp->state != FYPS_END)
+		return -1;
+
+	if (fyp->default_document_state != fyds) {
+		if (fyp->default_document_state) {
+			fy_document_state_unref(fyp->default_document_state);
+			fyp->default_document_state = NULL;
+		}
+
+		if (fyds)
+			fyp->default_document_state = fy_document_state_ref(fyds);
+	}
+
+	fy_reset_document_state(fyp);
+
+	return 0;
+}
+
+void fy_parser_set_next_single_document(struct fy_parser *fyp)
+{
+	if (!fyp)
+		return;
+
+	fyp->next_single_document = true;
+}
+
+int fy_check_document_version(struct fy_parser *fyp)
+{
+	int major, minor;
+
+	major = fyp->current_document_state->version.major;
+	minor = fyp->current_document_state->version.minor;
+
+	/* we only support YAML version 1.x */
+	if (major == 1) {
+		/* 1.1 is supported without warnings */
+		if (minor == 1)
+			goto ok;
+
+		if (minor == 2 || minor == 3)
+			goto experimental;
+	}
+
+	return -1;
+
+experimental:
+	fyp_scan_debug(fyp, "Experimental support for version %d.%d",
+			major, minor);
+ok:
+	return 0;
+}
+
+int fy_parse_version_directive(struct fy_parser *fyp, struct fy_token *fyt, bool scan_mode)
+{
+	struct fy_document_state *fyds;
+	const char *vs;
+	size_t vs_len;
+	char *vs0;
+	char *s, *e;
+	long v;
+	int rc;
+
+	fyp_error_check(fyp, fyt && fyt->type == FYTT_VERSION_DIRECTIVE, err_out,
+			"illegal token (or missing) version directive token");
+
+	fyds = fyp->current_document_state;
+	fyp_error_check(fyp, fyds, err_out,
+			"no current document state error");
+
+	if (!scan_mode) {
+		FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+				!fyds->fyt_vd, err_out,
+				"duplicate version directive");
+	} else {
+		/* in scan mode, we just override everything */
+		fy_token_unref_rl(fyp->recycled_token_list, fyds->fyt_vd);
+		fyds->fyt_vd = NULL;
+	}
+
+	/* version directive of the form: MAJ.MIN */
+	vs = fy_token_get_text(fyt, &vs_len);
+	fyp_error_check(fyp, vs, err_out,
+			"fy_token_get_text() failed");
+	vs0 = FY_ALLOCA(vs_len + 1);
+	memcpy(vs0, vs, vs_len);
+	vs0[vs_len] = '\0';
+
+	/* parse version numbers */
+	v = strtol(vs0, &e, 10);
+	fyp_error_check(fyp, e > vs0 && v >= 0 && v <= INT_MAX, err_out,
+			"illegal major version number (%s)", vs0);
+	fyp_error_check(fyp, *e == '.', err_out,
+			"illegal version separator");
+	fyds->version.major = (int)v;
+
+	s = e + 1;
+	v = strtol(s, &e, 10);
+	fyp_error_check(fyp, e > s && v >= 0 && v <= INT_MAX, err_out,
+			"illegal minor version number");
+	fyp_error_check(fyp, *e == '\0', err_out,
+			"garbage after version number");
+	fyds->version.minor = (int)v;
+
+	fyp_scan_debug(fyp, "document parsed YAML version: %d.%d",
+			fyds->version.major,
+			fyds->version.minor);
+
+	rc = fy_check_document_version(fyp);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"unsupport version number %d.%d",
+			fyds->version.major,
+			fyds->version.minor);
+
+	fyds->version_explicit = true;
+	fyds->fyt_vd = fyt;
+
+	return 0;
+err_out:
+	rc = -1;
+err_out_rc:
+	fy_token_unref_rl(fyp->recycled_token_list, fyt);
+	return rc;
+}
+
+int fy_parse_tag_directive(struct fy_parser *fyp, struct fy_token *fyt, bool scan_mode)
+{
+	struct fy_document_state *fyds;
+	struct fy_token *fyt_td;
+	const char *handle, *prefix;
+	size_t handle_size, prefix_size;
+	bool can_override;
+
+	fyds = fyp->current_document_state;
+	fyp_error_check(fyp, fyds, err_out,
+			"no current document state error");
+
+	handle = fy_tag_directive_token_handle(fyt, &handle_size);
+	fyp_error_check(fyp, handle, err_out,
+			"bad tag directive token (handle)");
+
+	prefix = fy_tag_directive_token_prefix(fyt, &prefix_size);
+	fyp_error_check(fyp, prefix, err_out,
+			"bad tag directive token (prefix)");
+
+	fyt_td = fy_document_state_lookup_tag_directive(fyds, handle, handle_size);
+
+	can_override = fyt_td && (fy_token_tag_directive_is_overridable(fyt_td) || scan_mode);
+
+	FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+			!fyt_td || can_override, err_out,
+			"duplicate tag directive");
+
+	if (fyt_td) {
+		/* fyp_notice(fyp, "overriding tag"); */
+		fy_token_list_del(&fyds->fyt_td, fyt_td);
+		fy_token_unref_rl(fyp->recycled_token_list, fyt_td);
+		/* when we override a default tag the tags are explicit */
+		fyds->tags_explicit = true;
+	}
+
+	fy_token_list_add_tail(&fyds->fyt_td, fyt);
+	fyt = NULL;
+
+	fyp_scan_debug(fyp, "document parsed tag directive with handle=%.*s",
+			(int)handle_size, handle);
+
+	if (!fy_tag_is_default_internal(handle, handle_size, prefix, prefix_size))
+		fyds->tags_explicit = true;
+
+	return 0;
+err_out:
+	fy_token_unref_rl(fyp->recycled_token_list, fyt);
+	return -1;
+}
+
+static const struct fy_parse_cfg default_parse_cfg = {
+	.flags = FYPCF_DEFAULT_PARSE,
+};
+
+static struct fy_diag *fy_parser_reader_get_diag(struct fy_reader *fyr)
+{
+	struct fy_parser *fyp = fy_container_of(fyr, struct fy_parser, builtin_reader);
+	return fyp->diag;
+}
+
+static int fy_parser_reader_file_open(struct fy_reader *fyr, const char *name)
+{
+	struct fy_parser *fyp = fy_container_of(fyr, struct fy_parser, builtin_reader);
+	char *sp, *s, *e, *t, *newp;
+	size_t len, maxlen;
+	int fd;
+
+	if (!fyp || !name || name[0] == '\0')
+		return -1;
+
+	/* for a full path, or no search path, open directly */
+	if (name[0] == '/' || !fyp->cfg.search_path || !fyp->cfg.search_path[0]) {
+		fd = open(name, O_RDONLY);
+		if (fd == -1)
+			fyp_scan_debug(fyp, "failed to open file %s\n", name);
+		else
+			fyp_scan_debug(fyp, "opened file %s\n", name);
+		return fd;
+	}
+
+	len = strlen(fyp->cfg.search_path);
+	sp = FY_ALLOCA(len + 1);
+	memcpy(sp, fyp->cfg.search_path, len + 1);
+
+	/* allocate the maximum possible so that we don't deal with reallocations */
+	maxlen = len + 1 + strlen(name);
+	newp = malloc(maxlen + 1);
+	if (!newp)
+		return -1;
+
+	s = sp;
+	e = sp + strlen(s);
+	while (s < e) {
+		/* skip completely empty */
+		if (*s == ':') {
+			s++;
+			continue;
+		}
+
+		t = strchr(s, ':');
+		if (t)
+			*t++ = '\0';
+		else
+			t = e;
+
+		len = strlen(s) + 1 + strlen(name) + 1;
+		snprintf(newp, maxlen, "%s/%s", s, name);
+
+		/* try opening */
+		fd = open(newp, O_RDONLY);
+		if (fd != -1) {
+			fyp_scan_debug(fyp, "opened file %s at %s", name, newp);
+			free(newp);
+			return fd;
+		}
+
+		s = t;
+	}
+
+	if (newp)
+		free(newp);
+	return -1;
+}
+
+static const struct fy_reader_ops fy_parser_reader_ops = {
+	.get_diag = fy_parser_reader_get_diag,
+	.file_open = fy_parser_reader_file_open,
+};
+
+int fy_parse_setup(struct fy_parser *fyp, const struct fy_parse_cfg *cfg)
+{
+	struct fy_diag *diag;
+	struct fy_diag_cfg dcfg;
+	const struct fy_version *vers;
+	int rc;
+
+	if (!fyp)
+		return -1;
+
+	memset(fyp, 0, sizeof(*fyp));
+
+	diag = cfg ? cfg->diag : NULL;
+	fyp->cfg = cfg ? *cfg : default_parse_cfg;
+
+	/* supported version? */
+	vers = fy_parse_cfg_to_version(fyp->cfg.flags);
+	if (!vers)
+		return -1;
+
+	if (!diag) {
+		fy_diag_cfg_default(&dcfg);
+		diag = fy_diag_create(&dcfg);
+		if (!diag)
+			return -1;
+	} else
+		fy_diag_ref(diag);
+
+	fyp->diag = diag;
+
+	fy_reader_setup(&fyp->builtin_reader, &fy_parser_reader_ops);
+	fyp->reader = &fyp->builtin_reader;
+
+	fyp->default_version = *vers;
+
+	fy_indent_list_init(&fyp->indent_stack);
+	fy_indent_list_init(&fyp->recycled_indent);
+	fyp->indent = -2;
+	fyp->indent_line = -1;
+	fyp->generated_block_map = false;
+	fyp->last_was_comma = false;
+
+	fy_simple_key_list_init(&fyp->simple_keys);
+	fy_simple_key_list_init(&fyp->recycled_simple_key);
+
+	fy_token_list_init(&fyp->queued_tokens);
+
+	fy_input_list_init(&fyp->queued_inputs);
+
+	fyp->state = FYPS_NONE;
+	fy_parse_state_log_list_init(&fyp->state_stack);
+	fy_parse_state_log_list_init(&fyp->recycled_parse_state_log);
+
+	fy_eventp_list_init(&fyp->recycled_eventp);
+	fy_token_list_init(&fyp->recycled_token);
+
+	fy_flow_list_init(&fyp->flow_stack);
+	fyp->flow = FYFT_NONE;
+	fy_flow_list_init(&fyp->recycled_flow);
+
+	fyp->pending_complex_key_column = -1;
+	fyp->last_block_mapping_key_line = -1;
+
+	fyp->suppress_recycling = !!(fyp->cfg.flags & FYPCF_DISABLE_RECYCLING) ||
+		                  (getenv("FY_VALGRIND") &&
+				   !getenv("FY_VALGRIND_RECYCLING"));
+
+	if (fyp->suppress_recycling)
+		fyp_parse_debug(fyp, "Suppressing recycling");
+
+	if (!fyp->suppress_recycling) {
+		fyp->recycled_eventp_list = &fyp->recycled_eventp;
+		fyp->recycled_token_list = &fyp->recycled_token;
+	} else {
+		fyp->recycled_eventp_list = NULL;
+		fyp->recycled_token_list = NULL;
+	}
+
+	fyp->current_document_state = NULL;
+
+	rc = fy_reset_document_state(fyp);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_reset_document_state() failed");
+	return 0;
+
+err_out_rc:
+	return rc;
+}
+
+void fy_parse_cleanup(struct fy_parser *fyp)
+{
+	struct fy_input *fyi, *fyin;
+	struct fy_eventp *fyep;
+	struct fy_token *fyt;
+
+	fy_composer_destroy(fyp->fyc);
+	fy_document_builder_destroy(fyp->fydb);
+
+	fy_parse_indent_list_recycle_all(fyp, &fyp->indent_stack);
+	fy_parse_simple_key_list_recycle_all(fyp, &fyp->simple_keys);
+	fy_token_list_unref_all(&fyp->queued_tokens);
+
+	fy_parse_parse_state_log_list_recycle_all(fyp, &fyp->state_stack);
+	fy_parse_flow_list_recycle_all(fyp, &fyp->flow_stack);
+
+	fy_token_unref_rl(fyp->recycled_token_list, fyp->stream_end_token);
+
+	fy_document_state_unref(fyp->current_document_state);
+	fy_document_state_unref(fyp->default_document_state);
+
+	for (fyi = fy_input_list_head(&fyp->queued_inputs); fyi; fyi = fyin) {
+		fyin = fy_input_next(&fyp->queued_inputs, fyi);
+		fy_input_unref(fyi);
+	}
+
+	/* clean the builtin reader */
+	fy_reader_cleanup(&fyp->builtin_reader);
+
+	/* and vacuum (free everything) */
+	fy_parse_indent_vacuum(fyp);
+	fy_parse_simple_key_vacuum(fyp);
+	fy_parse_parse_state_log_vacuum(fyp);
+	fy_parse_flow_vacuum(fyp);
+
+	/* free the recycled events */
+	while ((fyep = fy_eventp_list_pop(&fyp->recycled_eventp)) != NULL) {
+		/* catch double recycles */
+		/* assert(fy_eventp_list_head(&fyp->recycled_eventp)!= fyep); */
+		fy_eventp_free(fyep);
+	}
+
+	/* and the recycled tokens */
+	while ((fyt = fy_token_list_pop(&fyp->recycled_token)) != NULL)
+		fy_token_free(fyt);
+
+	fy_diag_unref(fyp->diag);
+}
+
+static const char *state_txt[] __FY_DEBUG_UNUSED__ = {
+	[FYPS_NONE] = "NONE",
+	[FYPS_STREAM_START] = "STREAM_START",
+	[FYPS_IMPLICIT_DOCUMENT_START] = "IMPLICIT_DOCUMENT_START",
+	[FYPS_DOCUMENT_START] = "DOCUMENT_START",
+	[FYPS_DOCUMENT_CONTENT] = "DOCUMENT_CONTENT",
+	[FYPS_DOCUMENT_END] = "DOCUMENT_END",
+	[FYPS_BLOCK_NODE] = "BLOCK_NODE",
+	[FYPS_BLOCK_SEQUENCE_FIRST_ENTRY] = "BLOCK_SEQUENCE_FIRST_ENTRY",
+	[FYPS_BLOCK_SEQUENCE_ENTRY] = "BLOCK_SEQUENCE_ENTRY",
+	[FYPS_INDENTLESS_SEQUENCE_ENTRY] = "INDENTLESS_SEQUENCE_ENTRY",
+	[FYPS_BLOCK_MAPPING_FIRST_KEY] = "BLOCK_MAPPING_FIRST_KEY",
+	[FYPS_BLOCK_MAPPING_KEY] = "BLOCK_MAPPING_KEY",
+	[FYPS_BLOCK_MAPPING_VALUE] = "BLOCK_MAPPING_VALUE",
+	[FYPS_FLOW_SEQUENCE_FIRST_ENTRY] = "FLOW_SEQUENCE_FIRST_ENTRY",
+	[FYPS_FLOW_SEQUENCE_ENTRY] = "FLOW_SEQUENCE_ENTRY",
+	[FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_KEY] = "FLOW_SEQUENCE_ENTRY_MAPPING_KEY",
+	[FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_VALUE] = "FLOW_SEQUENCE_ENTRY_MAPPING_VALUE",
+	[FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_END] = "FLOW_SEQUENCE_ENTRY_MAPPING_END",
+	[FYPS_FLOW_MAPPING_FIRST_KEY] = "FLOW_MAPPING_FIRST_KEY",
+	[FYPS_FLOW_MAPPING_KEY] = "FLOW_MAPPING_KEY",
+	[FYPS_FLOW_MAPPING_VALUE] = "FLOW_MAPPING_VALUE",
+	[FYPS_FLOW_MAPPING_EMPTY_VALUE] = "FLOW_MAPPING_EMPTY_VALUE",
+	[FYPS_SINGLE_DOCUMENT_END] = "SINGLE_DOCUMENT_END",
+	[FYPS_END] = "END"
+};
+
+int fy_scan_comment(struct fy_parser *fyp, struct fy_atom *handle, bool single_line)
+{
+	int c, column, start_column, lines, scan_ahead;
+	bool has_ws;
+
+	c = fy_parse_peek(fyp);
+	if (c != '#')
+		return -1;
+
+	/* if it's no comment parsing is enabled just consume it */
+	if (!(fyp->cfg.flags & FYPCF_PARSE_COMMENTS) || !handle) {
+		fy_advance(fyp, c);
+		while (!(fyp_is_lbz(fyp, c = fy_parse_peek(fyp))))
+			fy_advance(fyp, c);
+		return 0;
+	}
+
+	if (handle->fyi)
+		fy_input_unref(handle->fyi);
+
+	memset(handle, 0, sizeof(*handle));
+
+	fy_fill_atom_start(fyp, handle);
+
+	lines = 0;
+	start_column = fyp_column(fyp);
+	column = fyp_column(fyp);
+	scan_ahead = 0;
+
+	has_ws = false;
+
+	/* continuation must be a # on the same column */
+	while (c == '#' && column == start_column) {
+
+		lines++;
+		if (c == '#') {
+			/* chomp until line break */
+			fy_advance(fyp, c);
+			while (!(fyp_is_lbz(fyp, c = fy_parse_peek(fyp)))) {
+				if (fy_is_ws(c))
+					has_ws = true;
+				fy_advance(fyp, c);
+			}
+
+			/* end of input break */
+			if (fy_is_z(c))
+				break;
+		}
+
+		if (fy_is_ws(c))
+			has_ws = true;
+
+		if (!fyp_is_lb(fyp, c))
+			break;
+
+		column = 0;
+
+		scan_ahead = 1;	/* skipping over lb */
+		while (fy_is_blank(c = fy_parse_peek_at(fyp, scan_ahead))) {
+			scan_ahead++;
+			column++;
+		}
+
+		if (fy_is_z(c) || single_line)
+			break;
+
+		if (c == '#' && column == start_column) {
+			fy_advance_by(fyp, scan_ahead);
+			c = fy_parse_peek(fyp);
+		}
+	}
+
+	fy_fill_atom_end(fyp, handle);
+	handle->style = FYAS_COMMENT;
+	handle->direct_output = false;
+	handle->storage_hint = 0;
+	handle->storage_hint_valid = false;
+	handle->empty = false;
+	handle->has_lb = true;
+	handle->has_ws = has_ws;
+	handle->starts_with_ws = false; /* no-one cares for those */
+	handle->starts_with_lb = false;
+	handle->ends_with_ws = false;
+	handle->ends_with_lb = false;
+	handle->trailing_lb = false;
+	handle->size0 = lines > 0;
+	handle->valid_anchor = false;
+
+	/* and take the ref */
+	fy_input_ref(handle->fyi);
+
+	return 0;
+}
+
+int fy_attach_comments_if_any(struct fy_parser *fyp, struct fy_token *fyt)
+{
+	struct fy_atom *handle;
+	struct fy_mark fym;
+	int c, rc;
+
+	if (!fyp || !fyt)
+		return -1;
+
+	if (!(fyp->cfg.flags & FYPCF_PARSE_COMMENTS))
+		return 0;
+
+	/* if a last comment exists and is valid */
+	if (fy_atom_is_set(&fyp->last_comment) &&
+	    (handle = fy_token_comment_handle(fyt, fycp_top, true)) != NULL) {
+		assert (!fy_atom_is_set(handle));
+		*handle = fyp->last_comment;
+		/* erase last comment */
+		fy_atom_reset(&fyp->last_comment);
+	}
+
+	/* right hand comment */
+
+	/* skip white space */
+	while (fy_is_ws(c = fy_parse_peek(fyp)))
+		fy_advance(fyp, c);
+
+	if (c == '#') {
+		fy_get_mark(fyp, &fym);
+
+		/* it's a right comment only if it's on the same line */
+		if (fym.line == fyt->handle.end_mark.line)
+			handle = fy_token_comment_handle(fyt, fycp_right, true);
+		else
+			handle = &fyp->last_comment;	/* otherwise, last comment */
+
+		rc = fy_scan_comment(fyp, handle, false);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_scan_comment() failed");
+	}
+	return 0;
+
+err_out_rc:
+	return rc;
+}
+
+int fy_scan_to_next_token(struct fy_parser *fyp)
+{
+	int c, c_after_ws, i, rc = 0;
+	bool tabs_allowed, sloppy_flow, no_indent;
+	ssize_t offset;
+	struct fy_atom *handle;
+	struct fy_reader *fyr;
+	char *str;
+
+	fyr = fyp->reader;
+
+	rc = fy_reader_input_scan_token_mark(fyr);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_reader_input_scan_token_mark() failed");
+
+	/* skip BOM at the start of the stream */
+	if (fyr->current_input_pos == 0 && (c = fy_parse_peek(fyp)) == FY_UTF8_BOM) {
+
+		fy_advance(fyp, c);
+		/* reset column */
+		fyr->column = 0;
+	}
+
+	/* json does not have comments or tab handling... */
+	if (fyp_json_mode(fyp)) {
+		fy_reader_skip_ws_cr_nl(fyr);
+		goto done;
+	}
+
+	tabs_allowed = fyp->flow_level > 0 || !fyp->simple_key_allowed || fyp_tabsize(fyp) > 0;
+	sloppy_flow = fyp->flow_level > 0 && (fyp->cfg.flags & FYPCF_SLOPPY_FLOW_INDENTATION);
+
+	for (;;) {
+
+		/* skip white space, tabs are allowed in flow context */
+		/* tabs also allowed in block context but not at start of line or after -?: */
+
+		/* if we're not in sloppy flow indent mode, a tab may not be used as indentation */
+		if (!sloppy_flow) {
+			// fyp_notice(fyp, "not sloppy flow check c='%c' col=%d indent=%d\n", fy_parse_peek(fyp), fyp_column(fyp), fyp->indent);
+			c = -1;
+			while (fyp_column(fyp) <= fyp->indent && fy_is_ws(c = fy_parse_peek(fyp))) {
+				if (fy_is_tab(c))
+					break;
+				fy_advance(fyp, c);
+			}
+
+			/* it's an error, only if it is used for intentation */
+			/* comments and empty lines are OK */
+			if (fy_is_tab(c)) {
+
+				/* skip all space and tabs */
+				i = 0;
+				offset = -1;
+				while (fy_is_ws(c_after_ws = fy_parse_peek_at_internal(fyp, i, &offset)))
+					i++;
+
+				no_indent = c_after_ws == '#' || fyp_is_lb(fyp, c_after_ws);
+
+				FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+						no_indent, err_out,
+						"tab character may not be used as indentation");
+
+				/* advance by that amount */
+				fy_advance_by(fyp, i);
+			}
+		}
+
+		if (!tabs_allowed) {
+			/* skip space only */
+			fy_reader_skip_space(fyr);
+			c = fy_parse_peek(fyp);
+
+			/* it's a tab, here we go */
+			if (fy_is_tab(c)) {
+
+				/* we need to see if after ws follows a flow start marker */
+
+				/* skip all space and tabs */
+				i = 0;
+				offset = -1;
+				while (fy_is_ws(c_after_ws = fy_parse_peek_at_internal(fyp, i, &offset)))
+					i++;
+
+				/* flow start marker after spaces? allow tabs */
+				if (c_after_ws == '{' || c_after_ws == '[') {
+					fy_advance_by(fyp, i);
+					c = fy_parse_peek(fyp);
+				}
+			}
+		} else {
+			fy_reader_skip_ws(fyr);
+			c = fy_parse_peek(fyp);
+		}
+
+		/* comment? */
+		if (c == '#') {
+
+			handle = NULL;
+			if (fyp->cfg.flags & FYPCF_PARSE_COMMENTS)
+				handle = &fyp->last_comment;
+
+			rc = fy_scan_comment(fyp, handle, false);
+			fyp_error_check(fyp, !rc, err_out_rc,
+					"fy_scan_comment() failed");
+
+			tabs_allowed = (fyp->flow_level || !fyp->simple_key_allowed) || fyp_tabsize(fyp);
+		}
+
+		c = fy_parse_peek(fyp);
+
+		/* not linebreak? we're done */
+		if (!fyp_is_lb(fyp, c))
+			goto done;
+
+		/* line break */
+		fy_advance(fyp, c);
+
+		/* may start simple key (in block ctx) */
+		if (!fyp->flow_level && !fyp->simple_key_allowed) {
+			fyp->simple_key_allowed = true;
+			fyp->tab_used_for_ws = false;
+			tabs_allowed = fyp->flow_level || !fyp->simple_key_allowed || fyp_tabsize(fyp);
+			fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+		}
+	}
+
+	fyp_scan_debug(fyp, "%s: no-next-token", __func__);
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+
+done:
+	rc = fy_reader_input_scan_token_mark(fyr);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_reader_input_scan_token_mark() failed");
+
+    fy_utf8_format_a(fy_parse_peek(fyp), fyue_singlequote, &str);
+	fyp_scan_debug(fyp, "%s: next token starts with c='%s'", __func__, str);
+	return 0;
+}
+
+static void fy_purge_required_simple_key_report(struct fy_parser *fyp,
+		struct fy_token *fyt, enum fy_token_type next_type)
+{
+	bool is_anchor, is_tag;
+
+	is_anchor = fyt && fyt->type == FYTT_ANCHOR;
+	is_tag = fyt && fyt->type == FYTT_TAG;
+
+	if (is_anchor || is_tag) {
+		if ((fyp->state == FYPS_BLOCK_MAPPING_VALUE ||
+		     fyp->state == FYPS_BLOCK_MAPPING_FIRST_KEY) &&
+			next_type == FYTT_BLOCK_ENTRY) {
+
+			FYP_TOKEN_ERROR(fyp, fyt, FYEM_SCAN,
+					"invalid %s indent for sequence",
+					is_anchor ? "anchor" : "tag");
+			return;
+		}
+
+		if (fyp->state == FYPS_BLOCK_MAPPING_VALUE && next_type == FYTT_SCALAR) {
+			FYP_TOKEN_ERROR(fyp, fyt, FYEM_SCAN,
+					"invalid %s indent for mapping",
+					is_anchor ? "anchor" : "tag");
+			return;
+		}
+	}
+
+	if (fyt)
+		FYP_TOKEN_ERROR(fyp, fyt, FYEM_SCAN,
+			"could not find expected ':'");
+	else
+		FYP_PARSE_ERROR(fyp, 0, 1, FYEM_SCAN,
+			"could not find expected ':'");
+}
+
+static inline bool
+fy_any_simple_keys(struct fy_parser *fyp)
+{
+	return !fy_simple_key_list_empty(&fyp->simple_keys);
+}
+
+static int fy_purge_stale_simple_keys(struct fy_parser *fyp, bool *did_purgep,
+		enum fy_token_type next_type)
+{
+	struct fy_simple_key *fysk;
+	bool purge;
+	int line;
+
+	*did_purgep = false;
+	while ((fysk = fy_simple_key_list_head(&fyp->simple_keys)) != NULL) {
+
+#ifdef FY_DEVMODE
+		fyp_scan_debug(fyp, "purge-check: flow_level=%d fysk->flow_level=%d fysk->mark.line=%d line=%d",
+				fyp->flow_level, fysk->flow_level,
+				fysk->mark.line, fyp_line(fyp));
+
+		fyp_debug_dump_simple_key(fyp, fysk, "purge-check: ");
+#endif
+
+		line = fysk->mark.line;
+
+		/* in non-flow context we purge keys that are on different line */
+		/* in flow context we purge only those with higher flow level */
+		if (!fyp->flow_level) {
+			purge = fyp_line(fyp) > line;
+		} else {
+			purge = fyp->flow_level < fysk->flow_level;
+			/* also purge implicit complex keys on a different line */
+			if (!purge && fysk->implicit_complex) {
+				purge = fyp_line(fyp) > line;
+			}
+		}
+
+		if (!purge)
+			break;
+
+		if (fysk->required) {
+			fy_purge_required_simple_key_report(fyp, fysk->token, next_type);
+			goto err_out;
+		}
+
+#ifdef FY_DEVMODE
+		fyp_debug_dump_simple_key(fyp, fysk, "purging: ");
+#endif
+
+		fy_simple_key_list_del(&fyp->simple_keys, fysk);
+		fy_parse_simple_key_recycle(fyp, fysk);
+
+		*did_purgep = true;
+	}
+
+	if (*did_purgep && fy_simple_key_list_empty(&fyp->simple_keys))
+		fyp_scan_debug(fyp, "(purge) simple key list is now empty!");
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+int fy_push_indent(struct fy_parser *fyp, int indent, bool generated_block_map, int indent_line)
+{
+	struct fy_indent *fyit;
+
+	fyit = fy_parse_indent_alloc(fyp);
+	fyp_error_check(fyp, fyit != NULL, err_out,
+		"fy_indent_alloc() failed");
+
+	fyit->indent = fyp->indent;
+	fyit->indent_line = fyp->indent_line;
+	fyit->generated_block_map = fyp->generated_block_map;
+
+	/* push */
+	fy_indent_list_push(&fyp->indent_stack, fyit);
+
+	/* update current state */
+	fyp->parent_indent = fyp->indent;
+	fyp->indent = indent;
+	fyp->indent_line = indent_line;
+	fyp->generated_block_map = generated_block_map;
+
+	fyp_scan_debug(fyp, "push_indent %d -> %d - generated_block_map=%s\n",
+			fyp->parent_indent, fyp->indent,
+			fyp->generated_block_map ? "true" : "false");
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+int fy_pop_indent(struct fy_parser *fyp)
+{
+	struct fy_indent *fyit;
+	int prev_indent __FY_DEBUG_UNUSED__;
+
+	fyit = fy_indent_list_pop(&fyp->indent_stack);
+	if (!fyit)
+		return -1;
+
+	prev_indent = fyp->indent;
+
+	/* pop the indent and update */
+	fyp->indent = fyit->indent;
+	fyp->generated_block_map = fyit->generated_block_map;
+	fyp->indent_line = fyit->indent_line;
+
+	/* pop and recycle */
+	fy_parse_indent_recycle(fyp, fyit);
+
+	/* update the parent indent */
+	fyit = fy_indent_list_head(&fyp->indent_stack);
+	fyp->parent_indent = fyit ? fyit->indent : -2;
+
+	fyp_scan_debug(fyp, "pop indent %d -> %d (parent %d) - generated_block_map=%s\n",
+			prev_indent, fyp->indent, fyp->parent_indent,
+			fyp->generated_block_map ? "true" : "false");
+
+	return 0;
+}
+
+int fy_parse_unroll_indent(struct fy_parser *fyp, int column)
+{
+	struct fy_token *fyt;
+	int rc;
+
+	/* do nothing in flow context */
+	if (fyp->flow_level)
+		return 0;
+
+	/* pop while indentation level greater than argument */
+	while (fyp->indent > column) {
+
+		fyp_scan_debug(fyp, "unrolling: %d/%d", fyp->indent, column);
+
+		/* create a block end token */
+		fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, FYTT_BLOCK_END, 0);
+		fyp_error_check(fyp, fyt, err_out,
+				"fy_token_queue_simple() failed");
+
+		rc = fy_pop_indent(fyp);
+		fyp_error_check(fyp, !rc, err_out,
+				"fy_pop_indent() failed");
+
+		/* the ident line has now moved */
+		fyp->indent_line = fyp_line(fyp);
+	}
+	return 0;
+err_out:
+	return -1;
+}
+
+void fy_remove_all_simple_keys(struct fy_parser *fyp)
+{
+	struct fy_simple_key *fysk;
+
+	fyp_scan_debug(fyp, "SK: removing all");
+
+	while ((fysk = fy_simple_key_list_pop(&fyp->simple_keys)) != NULL)
+		fy_parse_simple_key_recycle(fyp, fysk);
+
+	fyp->simple_key_allowed = true;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+}
+
+struct fy_simple_key *fy_would_remove_required_simple_key(struct fy_parser *fyp)
+{
+	struct fy_simple_key *fysk;
+
+	/* no simple key? */
+	for (fysk = fy_simple_key_list_head(&fyp->simple_keys);
+			fysk && fysk->flow_level >= fyp->flow_level;
+			fysk = fy_simple_key_next(&fyp->simple_keys, fysk)) {
+		if (fysk->required)
+			return fysk;
+	}
+
+	return NULL;
+}
+
+int fy_remove_simple_key(struct fy_parser *fyp, enum fy_token_type next_type)
+{
+	struct fy_simple_key *fysk;
+
+	/* no simple key? */
+	while ((fysk = fy_simple_key_list_first(&fyp->simple_keys)) != NULL &&
+		fysk->flow_level >= fyp->flow_level) {
+
+#ifdef FY_DEVMODE
+		fyp_debug_dump_simple_key(fyp, fysk, "removing: ");
+#endif
+
+		/* remove it from the list */
+		fy_simple_key_list_del(&fyp->simple_keys, fysk);
+
+		if (fysk->required) {
+			fy_purge_required_simple_key_report(fyp, fysk->token, next_type);
+			goto err_out;
+		}
+
+		fy_parse_simple_key_recycle(fyp, fysk);
+	}
+
+	return 0;
+
+err_out:
+	fy_parse_simple_key_recycle(fyp, fysk);
+	return -1;
+}
+
+struct fy_simple_key *fy_simple_key_find(struct fy_parser *fyp, const struct fy_token *fyt)
+{
+	struct fy_simple_key *fysk;
+
+	if (!fyt)
+		return NULL;
+
+	/* no simple key? */
+	for (fysk = fy_simple_key_list_head(&fyp->simple_keys); fysk;
+			fysk = fy_simple_key_next(&fyp->simple_keys, fysk))
+		if (fysk->token == fyt)
+			return fysk;
+
+	return NULL;
+}
+
+int fy_save_simple_key(struct fy_parser *fyp, struct fy_mark *mark, struct fy_mark *end_mark,
+		struct fy_token *fyt, bool required, int flow_level,
+		enum fy_token_type next_type)
+{
+	struct fy_simple_key *fysk;
+	bool did_purge;
+	int rc;
+
+	fyp_error_check(fyp, fyt && mark && end_mark, err_out,
+			"illegal arguments to fy_save_simple_key");
+
+	if (fy_any_simple_keys(fyp)) {
+		rc = fy_purge_stale_simple_keys(fyp, &did_purge, next_type);
+		fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_purge_stale_simple_keys() failed");
+	}
+
+	/* if no simple key is allowed, don't save */
+	if (!fyp->simple_key_allowed) {
+		fyp_scan_debug(fyp, "not saving simple key; not allowed");
+		return 0;
+	}
+
+	/* remove pending complex key mark if in non flow context and a new line */
+	if (!fyp->flow_level && fyp->pending_complex_key_column >= 0 &&
+	    mark->line > fyp->pending_complex_key_mark.line &&
+	    mark->column <= fyp->pending_complex_key_mark.column ) {
+
+		fyp_scan_debug(fyp, "resetting pending_complex_key mark->line=%d line=%d\n",
+				mark->line, fyp->pending_complex_key_mark.line);
+
+		fyp->pending_complex_key_column = -1;
+		fyp_scan_debug(fyp, "pending_complex_key_column -> %d",
+				fyp->pending_complex_key_column);
+	}
+
+	fysk = fy_simple_key_list_head(&fyp->simple_keys);
+
+	/* create new simple key if it does not exist or if has flow level less */
+	if (!fysk || fysk->flow_level < fyp->flow_level) {
+
+		fysk = fy_parse_simple_key_alloc(fyp);
+		fyp_error_check(fyp, fysk != NULL, err_out,
+			"fy_simple_key_alloc()");
+
+		fyp_scan_debug(fyp, "new simple key");
+
+		fy_simple_key_list_push(&fyp->simple_keys, fysk);
+
+	} else {
+		fyp_error_check(fyp, !fysk->required, err_out,
+				"cannot save simple key, top is required");
+
+		if (fysk == fy_simple_key_list_tail(&fyp->simple_keys))
+			fyp_scan_debug(fyp, "(reuse) simple key list is now empty!");
+
+		fyp_scan_debug(fyp, "reusing simple key");
+
+	}
+
+	fysk->mark = *mark;
+	fysk->end_mark = *end_mark;
+
+	fysk->required = required;
+	fysk->token = fyt;
+	fysk->flow_level = flow_level;
+
+	/* if this is a an implicit flow collection key */
+	fysk->implicit_complex = fyp->pending_complex_key_column < 0 &&
+				 (fyt->type == FYTT_FLOW_MAPPING_START || fyt->type == FYTT_FLOW_SEQUENCE_START);
+
+
+#ifdef FY_DEVMODE
+	fyp_debug_dump_simple_key_list(fyp, &fyp->simple_keys, fysk, "fyp->simple_keys (saved): ");
+#endif
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+struct fy_simple_key_mark {
+	struct fy_mark mark;
+	bool required;
+	int flow_level;
+};
+
+void fy_get_simple_key_mark(struct fy_parser *fyp, struct fy_simple_key_mark *fyskm)
+{
+	fy_get_mark(fyp, &fyskm->mark);
+	fyskm->flow_level = fyp->flow_level;
+	fyskm->required = !fyp->flow_level && fyp->indent == fyp_column(fyp);
+}
+
+int fy_save_simple_key_mark(struct fy_parser *fyp,
+			struct fy_simple_key_mark *fyskm,
+			enum fy_token_type next_type,
+			struct fy_mark *end_markp)
+{
+	struct fy_mark end_mark;
+
+	if (!end_markp) {
+		fy_get_mark(fyp, &end_mark);
+		end_markp = &end_mark;
+	}
+
+	return fy_save_simple_key(fyp, &fyskm->mark, end_markp,
+			fy_token_list_last(&fyp->queued_tokens),
+			fyskm->required, fyskm->flow_level,
+			next_type);
+}
+
+int fy_parse_flow_push(struct fy_parser *fyp)
+{
+	struct fy_flow *fyf;
+
+	fyf = fy_parse_flow_alloc(fyp);
+	fyp_error_check(fyp, fyf != NULL, err_out,
+			"fy_flow_alloc() failed!");
+	fyf->flow = fyp->flow;
+
+	fyf->pending_complex_key_column = fyp->pending_complex_key_column;
+	fyf->pending_complex_key_mark = fyp->pending_complex_key_mark;
+
+	fyp_scan_debug(fyp, "flow_push: flow=%d pending_complex_key_column=%d",
+			(int)fyf->flow,
+			fyf->pending_complex_key_column);
+
+	fy_flow_list_push(&fyp->flow_stack, fyf);
+
+	if (fyp->pending_complex_key_column >= 0) {
+		fyp->pending_complex_key_column = -1;
+		fyp_scan_debug(fyp, "pending_complex_key_column -> %d",
+				fyp->pending_complex_key_column);
+	}
+
+	return 0;
+err_out:
+	return -1;
+}
+
+int fy_parse_flow_pop(struct fy_parser *fyp)
+{
+	struct fy_flow *fyf;
+
+	fyf = fy_flow_list_pop(&fyp->flow_stack);
+	fyp_error_check(fyp, fyf, err_out,
+			"no flow to pop");
+
+	fyp->flow = fyf->flow;
+	fyp->pending_complex_key_column = fyf->pending_complex_key_column;
+	fyp->pending_complex_key_mark = fyf->pending_complex_key_mark;
+
+	fy_parse_flow_recycle(fyp, fyf);
+
+	fyp_scan_debug(fyp, "flow_pop: flow=%d pending_complex_key_column=%d",
+			(int)fyp->flow,
+			fyp->pending_complex_key_column);
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+/* special case for allowing whitespace (including tabs) after -?: */
+static int fy_ws_indentation_check(struct fy_parser *fyp, bool *found_tabp, struct fy_mark *tab_mark)
+{
+	int c, adv, tab_adv;
+	bool indentation, found_tab;
+
+	found_tab = false;
+
+	/* not meaning in flow mode */
+	if (fyp->flow_level)
+		goto out;
+
+	/* scan forward, keeping track if we found a tab */
+	adv = 0;
+	tab_adv = -1;
+	if (tab_mark)
+		fy_get_mark(fyp, tab_mark);
+	while (fy_is_ws(c = fy_parse_peek_at(fyp, adv))) {
+		if (!found_tab && fy_is_tab(c)) {
+			found_tab = true;
+			tab_adv = adv;
+			/* XXX somewhat hacky, space is 1 char only so adjust */
+			if (tab_mark) {
+				tab_mark->input_pos += adv;
+				tab_mark->column += adv;
+			}
+		}
+		adv++;
+	}
+
+	if (found_tab) {
+		indentation = fy_utf8_strchr("?:|>", c) ||
+				(c == '-' && fyp_is_blankz(fyp, fy_parse_peek_at(fyp, adv + 1)));
+
+		/* any kind of block indentation is not allowed */
+		FYP_PARSE_ERROR_CHECK(fyp, tab_adv, 1, FYEM_SCAN,
+				!indentation, err_out,
+				"cannot use tab for indentation of block entry");
+		fy_advance_by(fyp, tab_adv + 1);
+	}
+
+	/* now chomp spaces only afterwards */
+	while (fy_is_space(c = fy_parse_peek(fyp)))
+		fy_advance(fyp, c);
+
+out:
+	if (found_tabp)
+		*found_tabp = found_tab;
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+int fy_fetch_stream_start(struct fy_parser *fyp)
+{
+	struct fy_token *fyt;
+
+	/* simple key is allowed */
+	fyp->simple_key_allowed = true;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, FYTT_STREAM_START, 0);
+	fyp_error_check(fyp, fyt, err_out,
+			"fy_token_queue_simple() failed");
+	return 0;
+
+err_out:
+	return -1;
+}
+
+int fy_fetch_stream_end(struct fy_parser *fyp)
+{
+	struct fy_token *fyt;
+	int rc;
+
+	/* only reset the stream in regular mode */
+	if (!fyp->parse_flow_only)
+		fy_reader_stream_end(fyp->reader);
+
+	fy_remove_all_simple_keys(fyp);
+
+	if (fyp_block_mode(fyp)) {
+		rc = fy_parse_unroll_indent(fyp, -1);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_parse_unroll_indent() failed");
+	}
+
+	fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, FYTT_STREAM_END, 0);
+	fyp_error_check(fyp, fyt, err_out,
+			"fy_token_queue_simple() failed");
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_scan_tag_uri_length(struct fy_parser *fyp, int start)
+{
+	int c, cn, length;
+	ssize_t offset, offset1;
+
+	/* first find the utf8 length of the uri */
+	length = 0;
+	offset = -1;
+	while (fy_is_uri(c = fy_parse_peek_at_internal(fyp, start + length, &offset))) {
+
+		offset1 = offset;
+		cn = fy_parse_peek_at_internal(fyp, start + length + 1, &offset1);
+
+		/* special handling for detecting URIs ending in ,}] */
+		if (fyp_is_blankz(fyp, cn) && fy_utf8_strchr(",}]", c))
+			break;
+
+		length++;
+	}
+
+	return length;
+}
+
+bool fy_scan_tag_uri_is_valid(struct fy_parser *fyp, int start, int length)
+{
+	int i, j, k, width, c, w;
+	uint8_t octet, esc_octets[4];
+	ssize_t offset;
+
+	offset = -1;
+	for (i = 0; i < length; i++) {
+		c = fy_parse_peek_at_internal(fyp, start + i, &offset);
+		if (c != '%')
+			continue;
+		/* reset cursor */
+		offset = -1;
+
+		width = 0;
+		k = 0;
+		do {
+			/* % escape */
+			FYP_PARSE_ERROR_CHECK(fyp, start + i, 1, FYEM_SCAN,
+					(length - i) >= 3, err_out,
+					"short URI escape");
+
+			if (width > 0) {
+				c = fy_parse_peek_at(fyp, start + i);
+
+				FYP_PARSE_ERROR_CHECK(fyp, start + i, 1, FYEM_SCAN,
+						c == '%', err_out,
+						"missing URI escape");
+			}
+
+			octet = 0;
+
+			for (j = 0; j < 2; j++) {
+				c = fy_parse_peek_at(fyp, start + i + 1 + j);
+
+				FYP_PARSE_ERROR_CHECK(fyp, start + i + 1 + j, 1, FYEM_SCAN,
+						fy_is_hex(c), err_out,
+						"non hex URI escape");
+				octet <<= 4;
+				if (c >= '0' && c <= '9')
+					octet |= c - '0';
+				else if (c >= 'a' && c <= 'f')
+					octet |= 10 + c - 'a';
+				else
+					octet |= 10 + c - 'A';
+			}
+			if (!width) {
+				width = fy_utf8_width_by_first_octet(octet);
+
+				FYP_PARSE_ERROR_CHECK(fyp, start + i + 1 + j, 1, FYEM_SCAN,
+						width >= 1 && width <= 4, err_out,
+						"bad width for hex URI escape");
+				k = 0;
+			}
+			esc_octets[k++] = octet;
+
+			/* skip over the 3 character escape */
+			i += 3;
+
+		} while (--width > 0);
+
+		/* now convert to utf8 */
+		c = fy_utf8_get(esc_octets, k, &w);
+
+		FYP_PARSE_ERROR_CHECK(fyp, start + i,  1 + j, FYEM_SCAN,
+				c >= 0, err_out,
+				 "bad utf8 URI escape");
+	}
+	return true;
+err_out:
+	return false;
+}
+
+int fy_scan_tag_handle_length(struct fy_parser *fyp, int start)
+{
+	int c, length, i, width;
+	ssize_t offset;
+	uint8_t octet;
+	bool first, was_esc;
+
+	length = 0;
+
+	offset = -1;
+	c = fy_parse_peek_at_internal(fyp, start + length, &offset);
+
+	FYP_PARSE_ERROR_CHECK(fyp, start + length, 1, FYEM_SCAN,
+			c == '!', err_out,
+			"invalid tag handle start");
+	length++;
+
+	/* get first character of the tag */
+	c = fy_parse_peek_at_internal(fyp, start + length, &offset);
+
+	if (fy_is_ws(c))
+		return length;
+
+	/* if first character is !, empty handle */
+	if (c == '!') {
+		length++;
+		return length;
+	}
+
+	first = true;
+	was_esc = false;
+
+	/* now loop while it's alphanumeric */
+	for (;;) {
+		if (c == '%') {
+
+			octet = 0;
+
+			for (i = 0; i < 2; i++) {
+				c = fy_parse_peek_at_internal(fyp, start + length + 1 + i, &offset);
+				FYP_PARSE_ERROR_CHECK(fyp, start + length + 1 + i, 1, FYEM_SCAN,
+						fy_is_hex(c), err_out,
+						"non hex URI escape");
+				octet <<= 4;
+				if (c >= '0' && c <= '9')
+					octet |= c - '0';
+				else if (c >= 'a' && c <= 'f')
+					octet |= 10 + c - 'a';
+				else
+					octet |= 10 + c - 'A';
+			}
+
+			width = fy_utf8_width_by_first_octet(octet);
+			FYP_PARSE_ERROR_CHECK(fyp, start + length, 3, FYEM_SCAN,
+					width == 1, err_out,
+					"Illegal non 1 byte utf8 tag handle character");
+			c = octet;
+			was_esc = true;
+
+		} else
+			was_esc = false;
+
+		if ((first && fy_is_first_alnum(c)) || (!first && fy_is_alnum(c)))
+			length += was_esc ? 3 : 1;
+		else
+			break;
+
+		first = false;
+		c = fy_parse_peek_at_internal(fyp, start + length, &offset);
+	}
+
+	/* if last character is !, copy it */
+	if (c == '!')
+		length++;
+
+	return length;
+
+err_out:
+	return -1;
+}
+
+int fy_scan_yaml_version(struct fy_parser *fyp, struct fy_version *vers)
+{
+	int c, length, start_length, num;
+	ssize_t offset;
+
+	memset(vers, 0, sizeof(*vers));
+
+	/* now loop while it's numeric */
+	length = 0;
+	offset = -1;
+	num = 0;
+	while (fy_is_num(c = fy_parse_peek_at_internal(fyp, length, &offset))) {
+		length++;
+		num = num * 10;
+		num += c - '0';
+	}
+	vers->major = num;
+
+	FYP_PARSE_ERROR_CHECK(fyp, length, 1, FYEM_SCAN,
+			length > 0, err_out,
+			"version directive missing major number");
+
+	FYP_PARSE_ERROR_CHECK(fyp, length, 1, FYEM_SCAN,
+			c == '.', err_out,
+			"version directive missing dot separator");
+	length++;
+
+	start_length = length;
+	num = 0;
+	while (fy_is_num(c = fy_parse_peek_at_internal(fyp, length, &offset))) {
+		length++;
+		num = num * 10;
+		num += c - '0';
+	}
+	vers->minor = num;
+
+	/* note that the version is not checked for validity here */
+
+	FYP_PARSE_ERROR_CHECK(fyp, length, 1, FYEM_SCAN,
+			length > start_length, err_out,
+			"version directive missing minor number");
+
+	return length;
+
+err_out:
+	return -1;
+}
+
+int fy_scan_tag_handle(struct fy_parser *fyp, bool is_directive,
+		struct fy_atom *handle)
+{
+	int length;
+
+	length = fy_scan_tag_handle_length(fyp, 0);
+	fyp_error_check(fyp, length > 0, err_out,
+			"fy_scan_tag_handle_length() failed");
+
+	fy_fill_atom(fyp, length, handle);
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+
+int fy_scan_tag_uri(struct fy_parser *fyp, bool is_directive,
+		struct fy_atom *handle)
+{
+	int length;
+	bool is_valid;
+
+	length = fy_scan_tag_uri_length(fyp, 0);
+	fyp_error_check(fyp, length > 0, err_out,
+			"fy_scan_tag_uri_length() failed");
+
+	is_valid = fy_scan_tag_uri_is_valid(fyp, 0, length);
+	fyp_error_check(fyp, is_valid, err_out,
+			"tag URI is invalid");
+
+	fy_fill_atom(fyp, length, handle);
+	handle->style = FYAS_URI;	/* this is a URI, need to handle URI escapes */
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+int fy_scan_directive(struct fy_parser *fyp)
+{
+	int c, advance, version_length, tag_length, uri_length;
+	struct fy_version vers;
+	enum fy_reader_mode rdmode;
+	enum fy_token_type type = FYTT_NONE;
+	struct fy_atom handle;
+	bool is_uri_valid;
+	struct fy_token *fyt;
+	int i, lastc;
+
+	if (!fy_parse_strcmp(fyp, "YAML") && fy_is_ws(fy_parse_peek_at(fyp, 4))) {
+		advance = 5;
+		type = FYTT_VERSION_DIRECTIVE;
+	} else if (!fy_parse_strcmp(fyp, "TAG") && fy_is_ws(fy_parse_peek_at(fyp, 3))) {
+		advance = 4;
+		type = FYTT_TAG_DIRECTIVE;
+	} else {
+		/* skip until linebreak (or #) */
+		i = 0;
+		lastc = -1;
+		while ((c = fy_parse_peek_at(fyp, i)) != -1 && !fyp_is_lb(fyp, c)) {
+			if (fy_is_ws(lastc) && c == '#')
+				break;
+			lastc = c;
+			i++;
+		}
+
+		FYP_PARSE_WARNING(fyp, 0, i, FYEM_SCAN,
+			"Unsupported directive");
+
+		if (fy_is_ws(lastc) && c == '#') {
+			while ((c = fy_parse_peek_at(fyp, i)) != -1 && !fyp_is_lb(fyp, c))
+				i++;
+		}
+
+		fy_advance_by(fyp, i);
+
+		/* skip over linebreak too */
+		if (fyp_is_lb(fyp, c))
+			fy_advance(fyp, c);
+
+		/* bump activity counter */
+		fyp->token_activity_counter++;
+
+		return 0;
+	}
+
+	fyp_error_check(fyp, type != FYTT_NONE, err_out,
+			"neither YAML|TAG found");
+
+	/* advance */
+	fy_advance_by(fyp, advance);
+
+	/* skip white space */
+	while (fy_is_ws(c = fy_parse_peek(fyp)))
+		fy_advance(fyp, c);
+
+	fy_fill_atom_start(fyp, &handle);
+
+	/* for version directive, parse it */
+	if (type == FYTT_VERSION_DIRECTIVE) {
+
+		version_length = fy_scan_yaml_version(fyp, &vers);
+		fyp_error_check(fyp, version_length > 0, err_out,
+				"fy_scan_yaml_version() failed");
+
+		/* set the reader's mode according to the version just scanned */
+		rdmode = fy_version_compare(&vers, fy_version_make(1, 1)) <= 0 ? fyrm_yaml_1_1 : fyrm_yaml;
+		fy_reader_set_mode(fyp->reader, rdmode);
+
+		fy_advance_by(fyp, version_length);
+
+		fy_fill_atom_end(fyp, &handle);
+
+		fyt = fy_token_queue(fyp, FYTT_VERSION_DIRECTIVE, &handle, &vers);
+		fyp_error_check(fyp, fyt, err_out,
+				"fy_token_queue() failed");
+
+	} else {
+
+		tag_length = fy_scan_tag_handle_length(fyp, 0);
+		fyp_error_check(fyp, tag_length > 0, err_out,
+				"fy_scan_tag_handle_length() failed");
+
+		fy_advance_by(fyp, tag_length);
+
+		c = fy_parse_peek(fyp);
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				fy_is_ws(c), err_out,
+				"missing whitespace after TAG");
+
+		/* skip white space */
+		while (fy_is_ws(c = fy_parse_peek(fyp)))
+			fy_advance(fyp, c);
+
+		uri_length = fy_scan_tag_uri_length(fyp, 0);
+		fyp_error_check(fyp, uri_length > 0, err_out,
+				"fy_scan_tag_uri_length() failed");
+
+		is_uri_valid = fy_scan_tag_uri_is_valid(fyp, 0, uri_length);
+		fyp_error_check(fyp, is_uri_valid, err_out,
+				"tag URI is invalid");
+
+		fy_advance_by(fyp, uri_length);
+
+		fy_fill_atom_end(fyp, &handle);
+		handle.style = FYAS_URI;
+
+		fyt = fy_token_queue(fyp, FYTT_TAG_DIRECTIVE, &handle, tag_length, uri_length, false);
+		fyp_error_check(fyp, fyt, err_out,
+				"fy_token_queue() failed");
+	}
+
+	/* skip until linebreak (or #) */
+	i = 0;
+	lastc = -1;
+	while ((c = fy_parse_peek_at(fyp, i)) != -1 && !fyp_is_lb(fyp, c)) {
+		if (fy_is_ws(lastc) && c == '#')
+			break;
+
+		FYP_PARSE_ERROR_CHECK(fyp, i, 1, FYEM_SCAN,
+				fy_is_ws(c) || fyp_is_lb(fyp, c), err_out,
+				"garbage after %s directive",
+				type == FYTT_VERSION_DIRECTIVE ? "version" : "tag");
+		lastc = c;
+		i++;
+	}
+
+	fy_advance_by(fyp, i);
+
+	/* skip over linebreak */
+	if (fyp_is_lb(fyp, c))
+		fy_advance(fyp, c);
+
+	return 0;
+err_out:
+	return -1;
+}
+
+int fy_fetch_directive(struct fy_parser *fyp)
+{
+	int rc;
+
+	fy_remove_all_simple_keys(fyp);
+
+	if (fyp_block_mode(fyp)) {
+		rc = fy_parse_unroll_indent(fyp, -1);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_parse_unroll_indent() failed");
+	}
+
+	rc = fy_scan_directive(fyp);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_scan_directive() failed");
+
+	return 0;
+
+err_out_rc:
+	return rc;
+}
+
+int fy_fetch_document_indicator(struct fy_parser *fyp, enum fy_token_type type)
+{
+	int rc, c;
+	struct fy_token *fyt;
+
+	fy_remove_all_simple_keys(fyp);
+
+	if (fyp_block_mode(fyp)) {
+		rc = fy_parse_unroll_indent(fyp, -1);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_parse_unroll_indent() failed");
+	}
+
+	fyp->simple_key_allowed = false;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, type, 3);
+	fyp_error_check(fyp, fyt, err_out,
+			"fy_token_queue_simple() failed");
+
+	/* skip whitespace after the indicator */
+	while (fy_is_ws(c = fy_parse_peek(fyp)))
+		fy_advance(fyp, c);
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+static inline bool fy_flow_indent_check_internal(struct fy_parser *fyp, int column, int indent)
+{
+	return (!fyp->flow_level || column > indent) ||
+		((fyp->cfg.flags & FYPCF_SLOPPY_FLOW_INDENTATION) && fyp->flow_level);
+}
+
+static inline bool fy_flow_indent_check(struct fy_parser *fyp)
+{
+	return fy_flow_indent_check_internal(fyp, fyp_column(fyp), fyp->indent);
+}
+
+static inline bool fy_block_indent_check(struct fy_parser *fyp)
+{
+	return fyp->flow_level > 0 || fyp_column(fyp) > fyp->indent;
+}
+
+int fy_fetch_flow_collection_mark_start(struct fy_parser *fyp, int c)
+{
+	enum fy_token_type type;
+	struct fy_simple_key_mark skm;
+	const char *typestr;
+	int rc = -1;
+	struct fy_token *fyt;
+
+	if (c == '[') {
+		type = FYTT_FLOW_SEQUENCE_START;
+		typestr = "sequence";
+	} else {
+		type = FYTT_FLOW_MAPPING_START;
+		typestr = "mapping";
+	}
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented %s start in flow mode", typestr);
+
+	fy_get_simple_key_mark(fyp, &skm);
+
+	fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, type, 1);
+	fyp_error_check(fyp, fyt, err_out,
+			"fy_token_queue_simple() failed");
+
+	rc = fy_save_simple_key_mark(fyp, &skm, type, NULL);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_save_simple_key_mark() failed");
+
+	/* increase flow level */
+	fyp->flow_level++;
+	fyp_error_check(fyp, fyp->flow_level, err_out,
+			"overflow for the flow level counter");
+
+	/* push the current flow to the stack */
+	rc = fy_parse_flow_push(fyp);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_parse_flow_push() failed");
+	/* set the current flow mode */
+	fyp->flow = c == '[' ? FYFT_SEQUENCE : FYFT_MAP;
+
+	fyp->simple_key_allowed = true;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	/* the comment indicator must have at least a space */
+	c = fy_parse_peek(fyp);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			c != '#', err_out,
+			"invalid comment after %s start", typestr);
+	return 0;
+
+err_out:
+	rc = -1;
+
+err_out_rc:
+	return rc;
+}
+
+int fy_fetch_flow_collection_mark_end(struct fy_parser *fyp, int c)
+{
+	enum fy_token_type type = FYTT_NONE;
+	enum fy_flow_type flow;
+	const char *typestr, *markerstr;
+	int i, rc;
+	bool did_purge;
+	struct fy_mark mark;
+	struct fy_token *fyt;
+
+	fy_get_mark(fyp, &mark);
+
+	if (c == ']') {
+		flow = FYFT_SEQUENCE;
+		type = FYTT_FLOW_SEQUENCE_END;
+		typestr = "sequence";
+		markerstr = "bracket";
+	} else {
+		flow = FYFT_MAP;
+		type = FYTT_FLOW_MAPPING_END;
+		typestr = "mapping";
+		markerstr = "brace";
+	}
+
+	FYP_MARK_ERROR_CHECK(fyp, &fyp->last_comma_mark, &fyp->last_comma_mark, FYEM_SCAN,
+			!fyp_json_mode(fyp) || !fyp->last_was_comma, err_out,
+			"JSON disallows trailing comma before closing %s", markerstr);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented %s end in flow mode", typestr);
+
+	rc = fy_remove_simple_key(fyp, type);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_remove_simple_key() failed");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fyp->flow_level, err_out,
+			"flow %s with invalid extra closing %s",
+				typestr, markerstr);
+
+	fyp->flow_level--;
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fyp->flow == flow, err_out,
+			"mismatched flow %s end", typestr);
+
+	/* pop the flow type */
+	rc = fy_parse_flow_pop(fyp);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_parse_flow_pop() failed");
+
+	fyp->simple_key_allowed = false;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n",
+				fyp->simple_key_allowed ? "true" : "false");
+
+	fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, type, 1);
+	fyp_error_check(fyp, fyt, err_out,
+			"fy_token_queue_simple() failed");
+
+	if (fyp->parse_flow_only && fyp->flow_level == 0) {
+		rc = fy_fetch_stream_end(fyp);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_stream_end() failed");
+		return 0;
+	}
+
+	/* the comment indicator must have at least a space */
+	c = fy_parse_peek(fyp);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			c != '#', err_out,
+			"invalid comment after end of flow %s", typestr);
+
+	/* due to the weirdness with simple keys and multiline flow keys scan forward
+	* until a linebreak, ';', or anything else */
+	for (i = 0; ; i++) {
+		c = fy_parse_peek_at(fyp, i);
+		if (c < 0 || c == ':' || fyp_is_lb(fyp, c) || !fy_is_ws(c))
+			break;
+	}
+
+	/* we must be a key, purge */
+	if (c == ':') {
+		if (fy_any_simple_keys(fyp)) {
+			rc = fy_purge_stale_simple_keys(fyp, &did_purge, type);
+			fyp_error_check(fyp, !rc, err_out_rc,
+					"fy_purge_stale_simple_keys() failed");
+
+			/* if we did purge and the the list is now empty, we're hosed */
+			if (did_purge && fy_simple_key_list_empty(&fyp->simple_keys)) {
+				FYP_PARSE_ERROR(fyp, 0, 1, FYEM_SCAN,
+						"invalid multiline flow %s key ", typestr);
+				goto err_out;
+			}
+		}
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_fetch_flow_collection_entry(struct fy_parser *fyp, int c)
+{
+	enum fy_token_type type = FYTT_NONE;
+	struct fy_token *fyt, *fyt_last;
+	struct fy_atom *handle;
+	int rc;
+
+	type = FYTT_FLOW_ENTRY;
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented entry seperator in flow mode");
+
+	/* transform '? a,' to '? a: ,' */
+	if (fyp->pending_complex_key_column >= 0) {
+
+		fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, FYTT_VALUE, 0);
+		fyp_error_check(fyp, fyt, err_out,
+				"fy_token_queue_simple() failed");
+
+		fyp->pending_complex_key_column = -1;
+
+	}
+
+	rc = fy_remove_simple_key(fyp, type);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_remove_simple_key() failed");
+
+	fyp->simple_key_allowed = true;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	fyt_last = fy_token_list_tail(&fyp->queued_tokens);
+
+	fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, type, 1);
+	fyp_error_check(fyp, fyt, err_out,
+			"fy_token_queue_simple() failed");
+
+	/* the comment indicator must have at least a space */
+	c = fy_parse_peek(fyp);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			c != '#', err_out,
+			"invalid comment after comma");
+
+	/* skip white space */
+	while (fy_is_ws(c = fy_parse_peek(fyp)))
+		fy_advance(fyp, c);
+
+	if (c == '#') {
+		if (fyt_last)
+			fyt = fyt_last;
+
+		handle = NULL;
+		if (fyp->cfg.flags & FYPCF_PARSE_COMMENTS)
+			handle = fy_token_comment_handle(fyt, fycp_right, true);
+
+		rc = fy_scan_comment(fyp, handle, true);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_scan_comment() failed");
+	}
+
+	return 0;
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_fetch_block_entry(struct fy_parser *fyp, int c)
+{
+	int rc;
+	struct fy_mark mark;
+	struct fy_simple_key *fysk;
+	struct fy_token *fyt;
+
+	fyp_error_check(fyp, c == '-', err_out,
+			"illegal block entry");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			(!fyp->flow_level || (fyp_column(fyp) + 2) > fyp->indent) ||
+			((fyp->cfg.flags & FYPCF_SLOPPY_FLOW_INDENTATION) && fyp->flow_level), err_out,
+			"wrongly indented block sequence in flow mode");
+
+	if (!(fyp->flow_level || fyp->simple_key_allowed)) {
+		if (!fyp->simple_key_allowed && fyp->state == FYPS_BLOCK_MAPPING_VALUE)
+			FYP_PARSE_ERROR(fyp, 0, 1, FYEM_SCAN,
+					"block sequence on the same line as a mapping key");
+		else if (fyp->state == FYPS_BLOCK_SEQUENCE_FIRST_ENTRY ||
+			 fyp->state == FYPS_BLOCK_SEQUENCE_ENTRY)
+			FYP_PARSE_ERROR(fyp, 0, 1, FYEM_SCAN,
+					"block sequence on the same line as a previous item");
+		else
+			FYP_PARSE_ERROR(fyp, 0, 1, FYEM_SCAN,
+					"block sequence entries not allowed in this context");
+		goto err_out;
+	}
+
+	/* we have to save the start mark */
+	fy_get_mark(fyp, &mark);
+
+	if (fyp_block_mode(fyp) && fyp->indent < fyp_column(fyp)) {
+
+		/* push the new indent level */
+		rc = fy_push_indent(fyp, fyp_column(fyp), false, fyp_line(fyp));
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_push_indent() failed");
+
+		fyt = fy_token_queue_simple_internal(fyp, &fyp->queued_tokens, FYTT_BLOCK_SEQUENCE_START, 0);
+		fyp_error_check(fyp, fyt, err_out,
+				"fy_token_queue_simple_internal() failed");
+	}
+
+	if (c == '-' && fyp->flow_level) {
+		/* this is an error, but we let the parser catch it */
+		;
+	}
+
+	fysk = fy_would_remove_required_simple_key(fyp);
+
+	if (fysk) {
+		if (fysk->token) {
+			if (fysk->token->type == FYTT_ANCHOR || fysk->token->type == FYTT_TAG)
+				FYP_TOKEN_ERROR(fyp, fysk->token, FYEM_SCAN,
+					"invalid %s indent for sequence",
+						fysk->token->type == FYTT_ANCHOR	?
+							"anchor" : "tag");
+			else
+				FYP_TOKEN_ERROR(fyp, fysk->token, FYEM_SCAN,
+					"missing ':'");
+		} else
+			FYP_PARSE_ERROR(fyp, 0, 1, FYEM_SCAN,
+				"missing ':'");
+		goto err_out;
+	}
+
+	rc = fy_remove_simple_key(fyp, FYTT_BLOCK_ENTRY);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_remove_simple_key() failed");
+
+	fyp->simple_key_allowed = true;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, FYTT_BLOCK_ENTRY, 1);
+	fyp_error_check(fyp, fyt, err_out,
+			"fy_token_queue_simple() failed");
+
+	rc = fy_ws_indentation_check(fyp, NULL, NULL);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_ws_indentation_check() failed");
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_fetch_key(struct fy_parser *fyp, int c)
+{
+	int rc;
+	struct fy_mark mark;
+	struct fy_simple_key_mark skm;
+	bool target_simple_key_allowed;
+	struct fy_token *fyt;
+	struct fy_atom *handle;
+	bool found_tab;
+	struct fy_mark tab_mark;
+
+	fyp_error_check(fyp, c == '?', err_out,
+			"illegal block entry or key mark");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented mapping key in flow mode");
+
+	fy_get_simple_key_mark(fyp, &skm);
+
+	/* we have to save the start mark */
+	fy_get_mark(fyp, &mark);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fyp->flow_level || fyp->simple_key_allowed, err_out,
+			"invalid mapping key (not allowed in this context)");
+
+	if (fyp_block_mode(fyp) && fyp->indent < fyp_column(fyp)) {
+
+		/* push the new indent level */
+		rc = fy_push_indent(fyp, fyp_column(fyp), true, fyp_line(fyp));
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_push_indent() failed");
+
+		fyt = fy_token_queue_simple_internal(fyp, &fyp->queued_tokens, FYTT_BLOCK_MAPPING_START, 0);
+		fyp_error_check(fyp, fyt, err_out,
+				"fy_token_queue_simple_internal() failed");
+	}
+
+	rc = fy_remove_simple_key(fyp, FYTT_KEY);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_remove_simple_key() failed");
+
+	target_simple_key_allowed = !fyp->flow_level;
+
+	fyp->pending_complex_key_column = fyp_column(fyp);
+	fyp->pending_complex_key_mark = mark;
+	fyp_scan_debug(fyp, "pending_complex_key_column %d",
+			fyp->pending_complex_key_column);
+
+	fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, FYTT_KEY, 1);
+	fyp_error_check(fyp, fyt, err_out_rc,
+			"fy_token_queue_simple() failed");
+	/* extra KEY data */
+	fyt->key.flow_level = fyp->flow_level;
+
+	fyp->simple_key_allowed = target_simple_key_allowed;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	rc = fy_ws_indentation_check(fyp, &found_tab, &tab_mark);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_ws_indentation_check() failed");
+
+	/* record whether a tab was used for indentation */
+	if (fyp->simple_key_allowed && found_tab) {
+		fyp->tab_used_for_ws = true;
+		fyp->last_tab_used_for_ws_mark = tab_mark;
+	} else
+		fyp->tab_used_for_ws = false;	// XXX
+
+	/* comment? */
+	if (c == '#') {
+
+		handle = NULL;
+		if (fyp->cfg.flags & FYPCF_PARSE_COMMENTS)
+			handle = fy_token_comment_handle(fyt, fycp_right, true);
+
+		rc = fy_scan_comment(fyp, handle, false);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_scan_comment() failed");
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_fetch_value(struct fy_parser *fyp, int c)
+{
+	struct fy_token_list sk_tl;
+	struct fy_simple_key *fysk = NULL;
+	struct fy_mark mark, mark_insert, mark_end_insert;
+	struct fy_token *fyt_insert, *fyt;
+	bool target_simple_key_allowed, is_complex, has_bmap;
+	bool push_bmap_start, push_key_only, did_purge, final_complex_key;
+	bool is_multiline __FY_DEBUG_UNUSED__;
+	struct fy_atom *chandle;
+	bool found_tab;
+	struct fy_mark tab_mark;
+	int rc;
+
+	fyp_error_check(fyp, c == ':', err_out,
+		"illegal value mark");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			!fyp_json_mode(fyp) || fyp->flow == FYFT_MAP, err_out,
+			"JSON considers keys when not in mapping context invalid");
+
+	/* special handling for :: weirdness */
+	if (!fyp_json_mode(fyp) && fyp->flow_level > 0) {
+		int adv, nextc, nextcol, tabsize, indent;
+
+		/* this requires some explanation...
+		 * we need to detect x::x, x: :x, and x:\n:x as the same
+		 */
+		adv = 1;
+		indent = fyp->indent;
+		nextcol = fyp_column(fyp) + 1;
+		tabsize = fyp_tabsize(fyp);
+
+		while ((nextc = fy_parse_peek_at(fyp, adv)) > 0) {
+
+			if (fyp_is_lb(fyp, nextc))
+				nextcol = 0;
+			else if (fy_is_tab(nextc)) {
+				if (tabsize)
+					nextcol += tabsize - (nextcol % tabsize);
+				else
+					nextcol++;
+			} else if (fy_is_space(nextc))
+				nextcol++;
+			else {
+				if (!fy_flow_indent_check_internal(fyp, nextcol, indent))
+					nextc = -1;
+				break;
+			}
+
+			adv++;
+		}
+
+		fyp->colon_follows_colon = nextc == ':';
+	} else
+		fyp->colon_follows_colon = false;
+
+	fy_get_mark(fyp, &mark);
+
+	fy_token_list_init(&sk_tl);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented mapping value in flow mode");
+
+	if (fy_any_simple_keys(fyp)) {
+		rc = fy_purge_stale_simple_keys(fyp, &did_purge, FYTT_VALUE);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_purge_stale_simple_keys() failed");
+	}
+
+	/* get the simple key (if available) for the value */
+	fysk = fy_simple_key_list_head(&fyp->simple_keys);
+	if (fysk && fysk->flow_level == fyp->flow_level)
+		fy_simple_key_list_del(&fyp->simple_keys, fysk);
+	else
+		fysk = NULL;
+
+	if (!fysk) {
+		fyp_scan_debug(fyp, "no simple key flow_level=%d", fyp->flow_level);
+
+		fyt_insert = fy_token_list_tail(&fyp->queued_tokens);
+		mark_insert = mark;
+		mark_end_insert = mark;
+	} else {
+		assert(fysk->flow_level == fyp->flow_level);
+		fyt_insert = fysk->token;
+		mark_insert = fysk->mark;
+		mark_end_insert = fysk->end_mark;
+
+		fyp_scan_debug(fyp, "have simple key flow_level=%d", fyp->flow_level);
+	}
+
+	fyp_scan_debug(fyp, "flow_level=%d, column=%d parse_indent=%d",
+			fyp->flow_level, mark_insert.column, fyp->indent);
+
+	is_complex = fyp->pending_complex_key_column >= 0;
+	final_complex_key = is_complex && (fyp->flow_level || fyp_column(fyp) <= fyp->pending_complex_key_mark.column);
+	is_multiline = mark_end_insert.line < fyp_line(fyp);
+	has_bmap = fyp->generated_block_map;
+	push_bmap_start = (!fyp->flow_level && mark_insert.column > fyp->indent);
+	push_key_only = (!is_complex && (fyp->flow_level || has_bmap)) ||
+		        (is_complex && !final_complex_key);
+
+	fyp_scan_debug(fyp, "mark_insert.line=%d/%d mark_end_insert.line=%d/%d fyp->line=%d",
+			mark_insert.line, mark_insert.column,
+			mark_end_insert.line, mark_end_insert.column,
+			fyp_line(fyp));
+
+	fyp_scan_debug(fyp, "simple_key_allowed=%s is_complex=%s final_complex_key=%s is_multiline=%s has_bmap=%s push_bmap_start=%s push_key_only=%s",
+			fyp->simple_key_allowed ? "true" : "false",
+			is_complex ? "true" : "false",
+			final_complex_key ? "true" : "false",
+			is_multiline ? "true" : "false",
+			has_bmap ? "true" : "false",
+			push_bmap_start ? "true" : "false",
+			push_key_only ? "true" : "false");
+
+	if (!is_complex && is_multiline && (!fyp->flow_level || fyp->flow != FYFT_MAP)) {
+		FYP_PARSE_ERROR(fyp, 0, 1, FYEM_SCAN, "Illegal placement of ':' indicator");
+		goto err_out;
+	}
+
+	/* special handling for ?: */
+	if (fyp->tab_used_for_ws) {
+		FYP_PARSE_ERROR(fyp, 0, 1, FYEM_SCAN, "Indentation used tabs for ':' indicator");
+		goto err_out;
+	}
+
+	if (push_bmap_start) {
+
+		assert(!fyp->flow_level);
+
+		fyp_scan_debug(fyp, "--- parse_roll");
+
+		/* push the new indent level */
+		rc = fy_push_indent(fyp, mark_insert.column, true, mark_insert.line);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_push_indent() failed");
+
+		fyt = fy_token_queue_simple_internal(fyp, &sk_tl, FYTT_BLOCK_MAPPING_START, 0);
+		fyp_error_check(fyp, fyt, err_out,
+				"fy_token_queue_simple_internal() failed");
+
+		/* update with this mark */
+		fyt->handle.start_mark = fyt->handle.end_mark = mark_insert;
+	}
+
+	if (push_bmap_start || push_key_only) {
+
+		fyt = fy_token_queue_simple_internal(fyp, &sk_tl, FYTT_KEY, 0);
+		fyp_error_check(fyp, fyt, err_out,
+				"fy_token_queue_simple_internal() failed");
+
+		/* update with the flow level */
+		fyt->key.flow_level = fyp->flow_level;
+	}
+
+#ifdef FY_DEVMODE
+	fyp_debug_dump_token(fyp, fyt_insert, "insert-token: ");
+	fyp_debug_dump_token_list(fyp, &fyp->queued_tokens, fyt_insert, "fyp->queued_tokens (before): ");
+	fyp_debug_dump_token_list(fyp, &sk_tl, NULL, "sk_tl: ");
+#endif
+
+	if (fyt_insert) {
+
+		if (fysk)
+			fy_token_list_splice_before(&fyp->queued_tokens, fyt_insert, &sk_tl);
+		else
+			fy_token_list_splice_after(&fyp->queued_tokens, fyt_insert, &sk_tl);
+	} else
+		fy_token_lists_splice(&fyp->queued_tokens, &sk_tl);
+
+#ifdef FY_DEVMODE
+	fyp_debug_dump_token_list(fyp, &fyp->queued_tokens, fyt_insert, "fyp->queued_tokens (after): ");
+#endif
+
+	target_simple_key_allowed = fysk ? false : !fyp->flow_level;
+
+	fyt = fy_token_queue_simple(fyp, &fyp->queued_tokens, FYTT_VALUE, 1);
+	fyp_error_check(fyp, fyt, err_out,
+			"fy_token_queue_simple() failed");
+
+	if (fysk) {
+		fy_parse_simple_key_recycle(fyp, fysk);
+		fysk = NULL;
+	}
+
+
+	fyp->simple_key_allowed = target_simple_key_allowed;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	if (is_complex) {
+		rc = fy_ws_indentation_check(fyp, &found_tab, &tab_mark);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_ws_indentation_check() failed");
+
+		/* record whether a tab was used for indentation */
+		if (fyp->simple_key_allowed && found_tab) {
+			fyp->tab_used_for_ws = true;
+			fyp->last_tab_used_for_ws_mark = tab_mark;
+		} else
+			fyp->tab_used_for_ws = false;	// XXX
+	} else
+		fyp->tab_used_for_ws = false;
+
+	if (final_complex_key) {
+		fyp->pending_complex_key_column = -1;
+		fyp_scan_debug(fyp, "pending_complex_key_column -> %d",
+				fyp->pending_complex_key_column);
+	}
+
+	if (fyt_insert) {
+		/* eat whitespace */
+		while (fy_is_blank(c = fy_parse_peek(fyp)))
+			fy_advance(fyp, c);
+
+		/* comment? */
+		if (c == '#') {
+			chandle = NULL;
+			if (fyp->cfg.flags & FYPCF_PARSE_COMMENTS)
+				chandle = fy_token_comment_handle(fyt_insert, fycp_right, true);
+
+			rc = fy_scan_comment(fyp, chandle, false);
+			fyp_error_check(fyp, !rc, err_out_rc,
+					"fy_scan_comment() failed");
+		}
+
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	fy_parse_simple_key_recycle(fyp, fysk);
+	return rc;
+}
+
+int fy_fetch_anchor_or_alias(struct fy_parser *fyp, int c)
+{
+	struct fy_atom handle;
+	enum fy_token_type type;
+	int i = 0, rc = -1, length;
+	struct fy_simple_key_mark skm;
+	struct fy_token *fyt;
+	const char *typestr;
+
+	fyp_error_check(fyp, c == '*' || c == '&', err_out,
+			"illegal anchor mark (not '*' or '&')");
+
+	if (c == '*') {
+		type = FYTT_ALIAS;
+		typestr = "alias";
+	} else {
+		type = FYTT_ANCHOR;
+		typestr = "anchor";
+	}
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented %s in flow mode", typestr);
+
+	/* we have to save the start mark (including the anchor/alias start) */
+	fy_get_simple_key_mark(fyp, &skm);
+
+	/* skip over the anchor mark */
+	fy_advance(fyp, c);
+
+	/* start mark */
+	fy_fill_atom_start(fyp, &handle);
+
+	length = 0;
+
+	while ((c = fy_parse_peek(fyp)) >= 0) {
+		if (fyp_is_blankz(fyp, c) || fy_is_flow_indicator(c) ||
+		    fy_is_unicode_control(c) || fy_is_unicode_space(c))
+			break;
+		fy_advance(fyp, c);
+		length++;
+	}
+
+	if (!fyp_is_blankz(fyp, c) && !fy_is_flow_indicator(c)) {
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				fy_is_unicode_control(c), err_out,
+				"illegal unicode control character in %s", typestr);
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				fy_is_unicode_space(c), err_out,
+				"illegal unicode space character in %s", typestr);
+	}
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			c != FYUG_INV, err_out,
+			"invalid character in %s", typestr);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			c != FYUG_PARTIAL, err_out,
+			"partial character in %s", typestr);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			length > 0, err_out,
+			"invalid %s detected", typestr);
+
+	fy_fill_atom_end(fyp, &handle);
+
+	handle.storage_hint = length;
+	handle.storage_hint_valid = true;
+	handle.direct_output = true;
+	handle.empty = false;
+	handle.has_lb = false;
+	handle.has_ws = false;
+	handle.starts_with_ws = false;
+	handle.starts_with_lb = false;
+	handle.ends_with_ws = false;
+	handle.ends_with_lb = false;
+	handle.trailing_lb = false;
+	handle.size0 = false;
+	handle.valid_anchor = true;
+
+	if (type == FYTT_ALIAS)
+		fyt = fy_token_queue(fyp, type, &handle, NULL);
+	else
+		fyt = fy_token_queue(fyp, type, &handle);
+	fyp_error_check(fyp, fyt, err_out_rc,
+			"fy_token_queue() failed");
+
+	/* scan forward for '-' block sequence indicator */
+	if (type == FYTT_ANCHOR && !fyp->flow_level) {
+		for (i = 0; ; i++) {
+			c = fy_parse_peek_at(fyp, i);
+			if (c < 0 || fyp_is_lb(fyp, c) || !fy_is_ws(c))
+				break;
+		}
+
+		/* if it's '-' followed by ws we have a problem */
+		FYP_PARSE_ERROR_CHECK(fyp, i, 1, FYEM_SCAN,
+				!(c == '-' && fy_is_ws(fy_parse_peek_at(fyp, i + 1))), err_out,
+				"illegal block sequence on the same line as anchor");
+	}
+
+
+	rc = fy_save_simple_key_mark(fyp, &skm, type, NULL);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_save_simple_key_mark() failed");
+
+	fyp->simple_key_allowed = false;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_fetch_tag(struct fy_parser *fyp, int c)
+{
+	struct fy_atom handle;
+	int rc = -1, total_length, handle_length, uri_length, i, prefix_length, suffix_length;
+	const char *handlep;
+	bool is_valid;
+	struct fy_simple_key_mark skm;
+	struct fy_document_state *fyds;
+	struct fy_token *fyt_td;
+	struct fy_token *fyt;
+
+	fyp_error_check(fyp, c == '!', err_out,
+			"illegal tag mark (not '!')");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0 ,1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented tag in flow mode");
+
+	fyds = fyp->current_document_state;
+
+	fy_get_simple_key_mark(fyp, &skm);
+
+	if (fy_parse_peek_at(fyp, 1) == '<') {
+		/* skip over '!<' and '>' */
+		prefix_length = 2;
+		suffix_length = 1;
+	} else
+		prefix_length = suffix_length = 0;
+
+	if (prefix_length)
+		handle_length = 0; /* set the handle to '' */
+	else {
+		/* either !suffix or !handle!suffix */
+		/* we scan back to back, and split handle/suffix */
+		handle_length = fy_scan_tag_handle_length(fyp, prefix_length);
+		fyp_error_check(fyp, handle_length > 0, err_out,
+				"fy_scan_tag_handle_length() failed");
+	}
+
+	uri_length = fy_scan_tag_uri_length(fyp, prefix_length + handle_length);
+	fyp_error_check(fyp, uri_length >= 0, err_out,
+			"fy_scan_tag_uri_length() failed");
+
+	/* a handle? */
+	if (!prefix_length && (handle_length == 0 || fy_parse_peek_at(fyp, handle_length - 1) != '!')) {
+		/* special case, '!', handle set to '' and suffix to '!' */
+		if (handle_length == 1 && uri_length == 0) {
+			handle_length = 0;
+			uri_length = 1;
+		} else {
+			uri_length = handle_length - 1 + uri_length;
+			handle_length = 1;
+		}
+	}
+
+	is_valid = fy_scan_tag_uri_is_valid(fyp, prefix_length + handle_length, uri_length);
+	fyp_error_check(fyp, is_valid, err_out,
+			"tag URI is invalid");
+
+	if (suffix_length > 0) {
+		c = fy_parse_peek_at(fyp, prefix_length + handle_length + uri_length);
+
+		FYP_PARSE_ERROR_CHECK(fyp, prefix_length + handle_length + uri_length, 1, FYEM_SCAN,
+				c == '>', err_out,
+				"missing '>' uri terminator");
+	}
+
+	total_length = prefix_length + handle_length + uri_length + suffix_length;
+	fy_fill_atom(fyp, total_length, &handle);
+	handle.style = FYAS_URI;	/* this is a URI, need to handle URI escapes */
+
+	c = fy_parse_peek(fyp);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fyp_is_blankz(fyp, c) || fy_utf8_strchr(",}]", c), err_out,
+			"invalid tag terminator");
+
+	handlep = fy_atom_data(&handle) + prefix_length;
+
+	fyt_td = fy_document_state_lookup_tag_directive(fyds, handlep, handle_length);
+
+	FYP_MARK_ERROR_CHECK(fyp, &handle.start_mark, &handle.end_mark, FYEM_PARSE,
+			fyt_td, err_out,
+			"undefined tag prefix");
+
+	fyt = fy_token_queue(fyp, FYTT_TAG, &handle, prefix_length, handle_length, uri_length, fyt_td);
+	fyp_error_check(fyp, fyt, err_out_rc,
+			"fy_token_queue() failed");
+
+	/* scan forward for '-' block sequence indicator */
+	if (!fyp->flow_level) {
+		for (i = 0; ; i++) {
+			c = fy_parse_peek_at(fyp, i);
+			if (c < 0 || fyp_is_lb(fyp, c) || !fy_is_ws(c))
+				break;
+		}
+
+		/* if it's '-' followed by ws we have a problem */
+		FYP_PARSE_ERROR_CHECK(fyp, i ,1, FYEM_SCAN,
+				!(c == '-' && fy_is_ws(fy_parse_peek_at(fyp, i + 1))), err_out,
+				"illegal block sequence on the same line as the tag");
+	}
+
+	rc = fy_save_simple_key_mark(fyp, &skm, FYTT_TAG, NULL);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_save_simple_key_mark() failed");
+
+	fyp->simple_key_allowed = false;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_scan_block_scalar_indent(struct fy_parser *fyp, int indent, int *breaks, int *breaks_length,
+				int *presentation_breaks_length, int *first_break_length, int *lastc)
+{
+	int c, max_indent = 0, min_indent, break_length;
+
+	*breaks = 0;
+	*breaks_length = 0;
+	*presentation_breaks_length = 0;
+	*first_break_length = 0;
+
+	/* minimum indent is 0 for zero indent scalars */
+	min_indent = fyp->document_first_content_token ? 0 : 1;
+
+	/* scan over the indentation spaces */
+	/* we don't format content for display */
+	for (;;) {
+
+		/* skip over indentation */
+
+		if (!fyp_tabsize(fyp)) {
+			/* we must respect the enclosed indent */
+			while (fyp_column(fyp) <= fyp->indent && fy_is_ws(c = fy_parse_peek(fyp))) {
+				FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+						!fy_is_tab(c), err_out,
+						"invalid tab character as indent instead of space");
+				fy_advance(fyp, c);
+			}
+
+			/* skip over spaces only */
+			while ((c = fy_parse_peek(fyp)) == ' ' &&
+					(!indent || fyp_column(fyp) < indent)) {
+				fy_advance(fyp, c);
+			}
+		} else {
+			while (fy_is_ws((c = fy_parse_peek(fyp))) &&
+				(!indent || fyp_column(fyp) < indent))
+				fy_advance(fyp, c);
+		}
+
+		if (fyp_column(fyp) > max_indent)
+			max_indent = fyp_column(fyp);
+
+		/* non-empty line or EOF */
+		if (!fyp_is_lb(fyp, c)) {
+			*lastc = c;
+			break;
+		}
+
+		fy_advance(fyp, c);
+
+		break_length = fy_utf8_width(c);
+
+		(*breaks)++;
+		(*breaks_length) += 1;
+
+		if (fy_is_lb_LS_PS(c))
+			(*presentation_breaks_length) += break_length;
+
+		if (!*first_break_length)
+			*first_break_length = break_length;
+	}
+
+	if (!indent) {
+		indent = max_indent;
+		if (indent < fyp->indent)
+			indent = fyp->indent;
+		if (indent < min_indent)
+			indent = min_indent;
+	}
+
+	return indent;
+
+err_out:
+	return -1;
+}
+
+int fy_fetch_block_scalar(struct fy_parser *fyp, bool is_literal, int c)
+{
+	struct fy_atom handle;
+	enum fy_atom_chomp chomp = FYAC_CLIP;	/* default */
+	int lastc, rc, increment = 0, current_indent, new_indent, indent = 0;
+	int breaks, breaks_length, presentation_breaks_length, first_break_length;
+	bool doc_start_end_detected, empty, empty_line, prev_empty_line, indented, prev_indented, first;
+	bool has_ws, has_lb, starts_with_ws, starts_with_lb, ends_with_ws, ends_with_lb, trailing_lb;
+	bool pending_nl, ends_with_eof, starts_with_eof;
+	struct fy_token *fyt;
+	size_t length, line_length, trailing_ws, trailing_breaks_length;
+	size_t leading_ws;
+	size_t prefix_length, suffix_length;
+	unsigned int chomp_amt;
+	int actual_lb_length, pending_lb_length;
+	struct fy_mark indicator_mark;
+	bool generated_indent;
+	char *str;
+#ifdef ATOM_SIZE_CHECK
+	size_t tlength;
+#endif
+
+    fy_utf8_format_a(c, fyue_singlequote, &str);
+	fyp_error_check(fyp, c == '|' || c == '>', err_out,
+			"bad start of block scalar ('%s')",
+				str);
+
+	fy_get_mark(fyp, &indicator_mark);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented block scalar in flow mode");
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_block_indent_check(fyp), err_out,
+			"wrongly indented block scalar in block mode");
+
+	rc = fy_remove_simple_key(fyp, FYTT_SCALAR);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_remove_simple_key() failed");
+
+	fyp->simple_key_allowed = true;
+	fyp->tab_used_for_ws = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	/* skip over block scalar start */
+	fy_advance(fyp, c);
+
+	/* intentation indicator (either [-+]<digit> or <digit>[-+] */
+	c = fy_parse_peek(fyp);
+	if (c == '+' || c == '-') {
+
+		chomp = c == '+' ? FYAC_KEEP : FYAC_STRIP;
+
+		fy_advance(fyp, c);
+
+		c = fy_parse_peek(fyp);
+		if (fy_is_num(c)) {
+			increment = c - '0';
+			fyp_error_check(fyp, increment != 0, err_out,
+					"indentation indicator 0");
+			fy_advance(fyp, c);
+		}
+	} else if (fy_is_num(c)) {
+
+		increment = c - '0';
+		fyp_error_check(fyp, increment != 0, err_out,
+				"indentation indicator 0");
+		fy_advance(fyp, c);
+
+		c = fy_parse_peek(fyp);
+		if (c == '+' || c == '-') {
+			chomp = c == '+' ? FYAC_KEEP : FYAC_STRIP;
+			fy_advance(fyp, c);
+		}
+	}
+
+	/* the comment indicator must have at least a space */
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			c != '#', err_out,
+			"invalid comment without whitespace after block scalar indicator");
+
+	/* eat whitespace */
+	while (fy_is_blank(c = fy_parse_peek(fyp)))
+		fy_advance(fyp, c);
+
+	/* comment? */
+	if (c == '#') {
+		/* XXX just ignore this one */
+		rc = fy_scan_comment(fyp, NULL, true);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_scan_comment() failed");
+	}
+
+	c = fy_parse_peek(fyp);
+
+	/* end of the line? */
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fyp_is_lbz(fyp, c), err_out,
+			"block scalar no linebreak found");
+
+	/* if the block scalar indicator is on a different line we need a new indent */
+	generated_indent = false;
+	if (!increment && indicator_mark.line != fyp->indent_line) {
+		fyp_scan_debug(fyp, "generating indent %d/%d\n", indicator_mark.line, fyp->indent_line);
+		rc = fy_push_indent(fyp, indicator_mark.column, false, indicator_mark.line);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_push_indent() failed");
+		generated_indent = true;
+	}
+
+	/* advance */
+	fy_advance(fyp, c);
+
+	fy_fill_atom_start(fyp, &handle);
+
+	starts_with_eof = c < 0;
+
+	current_indent = fyp->indent >= 0 ? fyp->indent : 0;
+	indent = increment ? current_indent + increment : 0;
+
+	length = 0;
+	trailing_breaks_length = 0;
+
+	empty = true;
+	has_ws = false;
+	has_lb = false;
+	starts_with_ws = false;
+	starts_with_lb = false;
+	ends_with_ws = false;
+	ends_with_lb = false;
+	trailing_lb = false;
+
+	new_indent = fy_scan_block_scalar_indent(fyp, indent, &breaks, &breaks_length, &presentation_breaks_length, &first_break_length, &lastc);
+	fyp_error_check(fyp, new_indent >= 0, err_out,
+			"fy_scan_block_scalar_indent() failed");
+
+	length = breaks_length;
+	length += presentation_breaks_length;
+	indent = new_indent;
+
+	doc_start_end_detected = false;
+	prev_empty_line = true;
+
+	prefix_length = 0;
+	suffix_length = 0;
+
+	prev_indented = false;
+	first = true;
+	pending_nl = false;
+	pending_lb_length = 0;
+
+	chomp_amt = increment ? (unsigned int)(current_indent + increment) : (unsigned int)-1;
+
+	actual_lb_length = 1;
+	while ((c = fy_parse_peek(fyp)) > 0 && fyp_column(fyp) >= indent) {
+
+		lastc = c;
+
+		if (first) {
+			if (fy_is_ws(c))
+				starts_with_ws = true;
+			else if (fyp_is_lb(fyp, c))
+				starts_with_lb = true;
+		}
+
+		/* consume the list */
+		line_length = 0;
+		trailing_ws = 0;
+		empty_line = true;
+		leading_ws = 0;
+
+		indented = fy_is_ws(fy_parse_peek(fyp));
+
+		while (!(fyp_is_lbz(fyp, c = fy_parse_peek(fyp)))) {
+
+			lastc = c;
+
+			if (fyp_column(fyp) == 0 &&
+			    (!fy_parse_strncmp(fyp, "...", 3) ||
+			     !fy_parse_strncmp(fyp, "---", 3)) &&
+			    fy_is_blankz_at_offset(fyp, 3)) {
+				doc_start_end_detected = true;
+				break;
+			}
+
+			if (!fy_is_space(c)) {
+				empty = false;
+				empty_line = false;
+				trailing_ws = 0;
+				if (chomp_amt == (unsigned int)-1)
+					chomp_amt = fyp_column(fyp);
+			} else {
+				has_ws = true;
+				if (empty_line)
+					leading_ws++;
+				trailing_ws++;
+			}
+
+			fy_advance(fyp, c);
+
+			line_length += fy_utf8_width(c);
+		}
+
+		if (doc_start_end_detected)
+			break;
+
+		if (!fy_is_z(c)) {
+			/* eat line break */
+			actual_lb_length = fy_utf8_width(c);
+			fy_advance(fyp, c);
+
+			has_lb = true;
+			new_indent = fy_scan_block_scalar_indent(fyp, indent, &breaks, &breaks_length, &presentation_breaks_length, &first_break_length, &lastc);
+			fyp_error_check(fyp, new_indent >= 0, err_out,
+					"fy_scan_block_scalar_indent() failed");
+			if (fy_is_lb_LS_PS(c))
+				presentation_breaks_length += actual_lb_length;
+		} else {
+			has_lb = false;
+			new_indent = indent;
+			// was chomp = FYAC_STRIP, very very wrong
+
+			breaks = 0;
+			breaks_length = 0;
+			presentation_breaks_length = 0;
+			first_break_length = 0;
+
+			actual_lb_length = 0;
+
+		}
+
+		if (is_literal) {
+
+			prefix_length = 0;
+
+			if (pending_nl) {
+				pending_nl = false;
+				prefix_length += pending_lb_length;
+				pending_lb_length = 0;
+			}
+
+			prefix_length += trailing_breaks_length;
+			trailing_breaks_length = 0;
+
+			suffix_length = 0;
+
+			if (fy_is_lb_LS_PS(c)) {
+				trailing_breaks_length += breaks_length;
+				trailing_breaks_length += presentation_breaks_length;
+
+				if (actual_lb_length > 1)
+					presentation_breaks_length -= actual_lb_length;
+
+				pending_nl = true;
+				pending_lb_length = 0;
+			} else {
+				trailing_breaks_length += breaks_length;
+				trailing_breaks_length += presentation_breaks_length;
+
+				pending_nl = !empty_line || indented;
+				pending_lb_length = pending_nl ? 1 : 0;
+			}
+
+		} else {
+
+			prefix_length = 0;
+
+			if (!trailing_breaks_length) {
+				if (prev_indented || (prev_empty_line && !first) || indented) {
+					/* previous line was indented or empty, force output newline */
+					if (pending_nl) {
+						pending_nl = false;
+						prefix_length += 1; // pending_lb_length;
+						pending_lb_length = 0;
+					}
+				} else if (!prev_empty_line && !prev_indented && !indented && !empty_line) {
+					/* previous line was not empty and not indented
+					* while this is not indented and not empty need sep */
+					if (pending_nl) {
+						pending_nl = false;
+						prefix_length += 1; // pending_lb_length;
+						pending_lb_length = 0;
+					}
+				}
+			} else {
+				prefix_length += trailing_breaks_length;
+				if (prev_indented || indented)
+					prefix_length++;
+			}
+			pending_nl = true;
+			pending_lb_length = actual_lb_length;
+
+			trailing_breaks_length = 0;
+
+			suffix_length = 0;
+			trailing_breaks_length += breaks_length;
+			trailing_breaks_length += presentation_breaks_length;
+		}
+
+
+		length += prefix_length + line_length + suffix_length;
+		indent = new_indent;
+
+		prev_empty_line = empty_line;
+		prev_indented = indented;
+
+		prefix_length = 0;
+		suffix_length = 0;
+
+		first = false;
+	}
+
+	if (empty) {
+		trailing_breaks_length = breaks_length;
+		trailing_breaks_length += presentation_breaks_length;
+		length = 0;
+	}
+
+	/* end... */
+	fy_fill_atom_end(fyp, &handle);
+
+	if (c == FYUG_INV || c == FYUG_PARTIAL) {
+		FYP_MARK_ERROR(fyp, &handle.start_mark, &handle.end_mark, FYEM_SCAN,
+			"block scalar is malformed UTF8");
+		goto err_out;
+	}
+
+	/* are we ended with EOF? */
+	ends_with_eof = starts_with_eof || (c == FYUG_EOF && !fyp_is_lb(fyp, lastc) && !breaks);
+
+	/* detect wrongly indented block scalar */
+	if (c != FYUG_EOF && !(!empty || fyp_column(fyp) <= fyp->indent || c == '#' || doc_start_end_detected)) {
+		FYP_MARK_ERROR(fyp, &handle.start_mark, &handle.end_mark, FYEM_SCAN,
+			"block scalar with wrongly indented line after spaces only");
+		goto err_out;
+	}
+
+	if (empty && c == '#' && fyp_column(fyp) > fyp->indent) {
+		FYP_MARK_ERROR(fyp, &handle.start_mark, &handle.end_mark, FYEM_SCAN,
+			"empty block scalar with wrongly indented comment line after spaces only");
+		goto err_out;
+	}
+
+	if (chomp_amt == (unsigned int)-1)
+		chomp_amt = current_indent;
+
+	switch (chomp) {
+	case FYAC_CLIP:
+		if (pending_nl || (!starts_with_eof && ends_with_eof)) {
+			if (actual_lb_length <= 2)
+				length += 1;
+			else
+				length += actual_lb_length;
+
+			ends_with_lb = true;
+			ends_with_ws = false;
+		} else {
+			if (trailing_breaks_length > 0)
+				ends_with_lb = true;
+			else if (fy_is_ws(lastc))
+				ends_with_ws = true;
+		}
+		break;
+	case FYAC_KEEP:
+		if (pending_nl || (!starts_with_eof && ends_with_eof))
+			length += actual_lb_length;
+
+		length += breaks + presentation_breaks_length;
+
+		trailing_lb = trailing_breaks_length > 0;
+		if (pending_nl || (!starts_with_eof && ends_with_eof) || trailing_breaks_length) {
+			ends_with_lb = true;
+			ends_with_ws = false;
+		} else if (fy_is_ws(lastc)) {
+			ends_with_ws = true;
+			ends_with_lb = false;
+		}
+		break;
+	case FYAC_STRIP:
+		ends_with_lb = false;
+		if (fy_is_ws(lastc))
+			ends_with_ws = true;
+		break;
+	}
+
+	/* need to process to present */
+	handle.style = is_literal ? FYAS_LITERAL : FYAS_FOLDED;
+	handle.chomp = chomp;
+	handle.increment = increment ? (unsigned int)(current_indent + increment) : chomp_amt;
+
+	/* no point in trying to do direct output in a block scalar */
+	/* TODO maybe revisit in the future */
+	handle.direct_output = false;
+	handle.empty = empty;
+	handle.has_lb = has_lb;
+	handle.has_ws = has_ws;
+	handle.starts_with_ws = starts_with_ws;
+	handle.starts_with_lb = starts_with_lb;
+	handle.ends_with_ws = ends_with_ws;
+	handle.ends_with_lb = ends_with_lb;
+	handle.trailing_lb = trailing_lb;
+	handle.size0 = length == 0;
+	handle.valid_anchor = false;
+	handle.json_mode = fyp_json_mode(fyp);
+	handle.lb_mode = fyp_lb_mode(fyp);
+	handle.fws_mode = fyp_fws_mode(fyp);
+	handle.tabsize = fyp_tabsize(fyp);
+	handle.ends_with_eof = ends_with_eof;
+
+#ifdef ATOM_SIZE_CHECK
+	tlength = fy_atom_format_text_length(&handle);
+	if (tlength != length) {
+        fy_utf8_format_text_a(fy_atom_data(&handle), fy_atom_size(&handle), fyue_doublequote, &str);
+		fyp_warning(fyp, "%s: storage hint calculation failed real %zu != hint %zu - \"%s\"", __func__,
+			tlength, length,
+			str);
+		length = tlength;
+	}
+#endif
+
+	handle.storage_hint = length;
+	handle.storage_hint_valid = true;
+
+	fyt = fy_token_queue(fyp, FYTT_SCALAR, &handle, is_literal ? FYSS_LITERAL : FYSS_FOLDED);
+	fyp_error_check(fyp, fyt, err_out_rc,
+			"fy_token_queue() failed");
+
+	if (fyp->cfg.flags & FYPCF_PARSE_COMMENTS) {
+		rc = fy_attach_comments_if_any(fyp, fyt);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_attach_right_hand_comment() failed");
+	}
+
+	if (generated_indent) {
+		rc = fy_pop_indent(fyp);
+		fyp_error_check(fyp, !rc, err_out,
+				"fy_pop_indent() failed");
+
+		/* the ident line has now moved */
+		fyp->indent_line = fyp_line(fyp);
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_reader_fetch_flow_scalar_handle(struct fy_reader *fyr, int c, int indent, struct fy_atom *handle, bool sloppy_indent)
+{
+	size_t length;
+	int code_length, i = 0, j, end_c, last_line, lastc;
+	int breaks_found, blanks_found, break_run, total_code_length;
+	int breaks_found_length, first_break_length, value;
+	uint32_t hi_surrogate, lo_surrogate;
+	bool is_single, is_multiline, esc_lb, ws_lb_only, has_ws, has_lb, has_esc;
+	bool first, starts_with_ws, starts_with_lb, ends_with_ws, ends_with_lb, trailing_lb = false;
+	bool unicode_esc, is_json_unesc, has_json_esc;
+	int last_esc_lb, break_length, presentation_breaks_length;
+	struct fy_mark mark, mark2;
+	char escbuf[1 + FY_UTF8_FORMAT_BUFMIN];
+	size_t escbuf_len;
+	enum fy_utf8_escape esc_mode;
+	const char *ep;
+	char *str;
+#ifdef ATOM_SIZE_CHECK
+	size_t tlength;
+#endif
+
+	(void)last_esc_lb;
+
+	is_single = c == '\'';
+	end_c = c;
+
+    fy_utf8_format_a(c, fyue_singlequote, &str);
+	fyr_error_check(fyr, c == '\'' || c == '"', err_out,
+			"bad start of flow scalar ('%s')",
+				str);
+
+	fy_reader_get_mark(fyr, &mark);
+
+	/* skip over block scalar start */
+	fy_reader_advance(fyr, c);
+
+	fy_reader_fill_atom_start(fyr, handle);
+
+	length = 0;
+	breaks_found = 0;
+	breaks_found_length = 0;
+	first_break_length = 0;
+	presentation_breaks_length = 0;
+	blanks_found = 0;
+	esc_lb = false;
+	last_esc_lb = -1;
+	ws_lb_only = true;
+	has_ws = false;
+	has_lb = false;
+	starts_with_ws = false;
+	starts_with_lb = false;
+	ends_with_ws = false;
+	ends_with_lb = false;
+	has_esc = false;
+	break_run = 0;
+	first = true;
+	has_json_esc = false;
+
+	esc_mode = fy_reader_json_mode(fyr) ? fyue_doublequote_json :
+			fy_reader_lb_mode(fyr) == fylb_cr_nl ? fyue_doublequote : fyue_doublequote_yaml_1_1;
+
+	last_line = -1;
+	lastc = -1;
+	for (;;) {
+		if (!fy_reader_json_mode(fyr)) {
+			/* no document indicators please */
+			FYR_PARSE_ERROR_CHECK(fyr, 0, 3, FYEM_SCAN,
+				!(fy_reader_column(fyr) == 0 &&
+					(!fy_reader_strncmp(fyr, "---", 3) ||
+					!fy_reader_strncmp(fyr, "...", 3)) &&
+					fy_reader_is_blankz_at_offset(fyr, 3)), err_out,
+				"invalid document-%s marker in %s scalar",
+					c == '-' ? "start" : "end",
+					is_single ? "single-quoted" : "double-quoted");
+		}
+
+		/* no EOF either */
+		c = fy_reader_peek(fyr);
+
+		if (c <= 0) {
+			fy_reader_get_mark(fyr, &mark);
+
+			if (!c || c == FYUG_EOF)
+				FYR_MARK_ERROR(fyr, &handle->start_mark, &mark, FYEM_SCAN,
+						"%s scalar without closing quote",
+							is_single ? "single-quoted" : "double-quoted");
+			else
+				FYR_MARK_ERROR(fyr, &handle->start_mark, &mark, FYEM_SCAN,
+						"%s scalar is malformed UTF8",
+							is_single ? "single-quoted" : "double-quoted");
+			goto err_out;
+		}
+
+		if (first) {
+			if (fy_reader_is_flow_ws(fyr, c))
+				starts_with_ws = true;
+			else if (fy_reader_is_lb(fyr, c))
+				starts_with_lb = true;
+		}
+
+		while (!fy_reader_is_flow_blankz(fyr, c = fy_reader_peek(fyr))) {
+
+			if (ws_lb_only && !(fy_reader_is_flow_ws(fyr, c) || fy_reader_is_lb(fyr, c)) && c != end_c)
+				ws_lb_only = false;
+
+			esc_lb = false;
+			last_esc_lb = -1;
+			/* track line change (and first non blank) */
+			if (last_line != fy_reader_line(fyr)) {
+				last_line = fy_reader_line(fyr);
+
+				if ((indent >= 0 && fy_reader_column(fyr) <= indent) && !sloppy_indent) {
+
+					fy_reader_advance(fyr, c);
+					fy_reader_get_mark(fyr, &mark2);
+					FYR_MARK_ERROR(fyr, &mark, &mark2, FYEM_SCAN,
+						"wrongly indented %s scalar",
+							is_single ? "single-quoted" : "double-quoted");
+					goto err_out;
+				}
+			}
+
+			if (breaks_found) {
+				length += breaks_found > 1 ? (breaks_found_length - first_break_length) : 1;
+				length += presentation_breaks_length;
+				breaks_found = 0;
+				blanks_found = 0;
+				presentation_breaks_length = 0;
+			} else if (blanks_found) {
+				length += blanks_found;
+				lastc = ' ';
+				blanks_found = 0;
+			}
+
+			if (c >= 0 && c <= 0x7f && (fy_utf8_low_ascii_flags[c] & F_SIMPLE_SCALAR)) {
+				size_t len, consumed;
+				const char *p, *s, *e;
+				int8_t cc;
+				int run;
+
+				run = 0;
+				while ((p = fy_reader_ensure_lookahead(fyr, 1, &len)) != NULL) {
+
+					s = p;
+					e = s + len;
+
+					while (s < e && (cc = (int8_t)*s) >= 0 && (fy_utf8_low_ascii_flags[cc] & F_SIMPLE_SCALAR))
+						s++;
+
+					consumed = s - p;
+					if (consumed) {
+						fy_reader_advance_octets(fyr, consumed);
+						fyr->column += consumed;
+						lastc = (int)cc;
+					}
+					run += consumed;
+
+					/* we're done if stopped earlier */
+					if (s < e)
+						break;
+				}
+				length += run;
+				break_run = 0;
+				continue;
+			}
+
+			/* escaped single quote? */
+			if (is_single && c == '\'' && fy_reader_peek_at(fyr, 1) == '\'') {
+				length++;
+				fy_reader_advance_by(fyr, 2);
+				break_run = 0;
+				lastc = '\'';
+				continue;
+			}
+
+			/* right quote? */
+			if (c == end_c)
+				break;
+
+			/* escaped line break (any linebreak will do) */
+			if (!is_single && c == '\\' && fy_reader_is_lb(fyr, fy_reader_peek_at(fyr, 1))) {
+
+				esc_lb = true;
+				last_esc_lb = fy_reader_peek_at(fyr, 1);
+
+				fy_reader_advance_by(fyr, 2);
+
+				c = fy_reader_peek(fyr);
+				break_run = 0;
+				lastc = c;
+
+				has_esc = true;
+
+				break;
+			}
+
+			/* escaped sequence? */
+			if (!is_single && c == '\\') {
+
+				/* note we don't generate formatted output */
+				/* we are merely checking for validity */
+				c = fy_reader_peek_at(fyr, 1);
+
+				/* hex, unicode marks - json only supports u */
+				unicode_esc = !fy_reader_json_mode(fyr) ?
+						(c == 'x' || c == 'u' || c == 'U') :
+						c == 'u';
+				if (unicode_esc) {
+
+					total_code_length = 0;
+					j = 0;
+					hi_surrogate = lo_surrogate = 0;
+					for (;;) {
+						total_code_length += 2;
+
+						code_length = c == 'x' ? 2 :
+							c == 'u' ? 4 : 8;
+						value = 0;
+						for (i = 0; i < code_length; i++) {
+							c = fy_reader_peek_at(fyr, total_code_length + i);
+
+							FYR_PARSE_ERROR_CHECK(fyr, 0, total_code_length + i + 1, FYEM_SCAN,
+								fy_is_hex(c), err_out,
+								"double-quoted scalar has invalid hex escape");
+
+							value <<= 4;
+							if (c >= '0' && c <= '9')
+								value |= c - '0';
+							else if (c >= 'a' && c <= 'f')
+								value |= 10 + c - 'a';
+							else
+								value |= 10 + c - 'A';
+						}
+
+						total_code_length += code_length;
+						j++;
+
+						/* 0x10000 + (HI - 0xd800) * 0x400 + (LO - 0xdc00) */
+
+						/* high surrogate */
+						if (j == 1 && code_length == 4 && value >= 0xd800 && value <= 0xdbff &&
+						    fy_reader_peek_at(fyr, total_code_length) == '\\' &&
+						    fy_reader_peek_at(fyr, total_code_length + 1) == 'u') {
+							hi_surrogate = value;
+							c = 'u';
+							continue;
+						}
+
+						if (j == 2 && code_length == 4 && hi_surrogate) {
+
+							FYR_PARSE_ERROR_CHECK(fyr, total_code_length - 6, 6, FYEM_SCAN,
+								value >= 0xdc00 && value <= 0xdfff, err_out,
+								"Invalid low surrogate value");
+
+							lo_surrogate = value;
+							value = 0x10000 + (hi_surrogate - 0xd800) * 0x400 + (lo_surrogate - 0xdc00);
+						}
+
+						break;
+					}
+
+					/* check for validity */
+					FYR_PARSE_ERROR_CHECK(fyr, 0, total_code_length, FYEM_SCAN,
+						!(value < 0 || (value >= 0xd800 && value <= 0xdfff) ||
+							value > 0x10ffff), err_out,
+						"double-quoted scalar has invalid UTF8 escape");
+
+					fy_reader_advance_by(fyr, total_code_length);
+
+				} else {
+					escbuf[0] = '\\';
+					fy_utf8_put_unchecked(escbuf + 1, c);
+					escbuf_len = 1 + fy_utf8_width(c);
+
+					ep = escbuf;
+
+					fy_utf8_format_a(c, fyue_singlequote, &str);
+					value = fy_utf8_parse_escape(&ep, escbuf_len, esc_mode);
+					FYR_PARSE_ERROR_CHECK(fyr, 0, 2, FYEM_SCAN,
+						value >= 0, err_out,
+						"invalid escape '%s' in %s string",
+						   str,
+							is_single ? "single-quoted" : "double-quoted");
+
+					fy_reader_advance_by(fyr, 2);
+				}
+
+				length += fy_utf8_width(value);
+
+				lastc = value;
+
+				if (lastc == '\n')
+					break_run++;
+
+				has_esc = true;
+
+				continue;
+			}
+
+			/* check whether we have a JSON unescaped character */
+			is_json_unesc = fy_is_json_unescaped_range_only(c);
+			if (!is_json_unesc)
+				has_json_esc = true;
+
+			if (!is_single && fy_reader_json_mode(fyr) && has_json_esc) {
+				FYR_PARSE_ERROR(fyr, 0, 2, FYEM_SCAN,
+					"Invalid JSON unescaped character");
+				goto err_out;
+			}
+
+			lastc = c;
+
+			/* regular character */
+			fy_reader_advance(fyr, c);
+
+			length += fy_utf8_width(c);
+			break_run = 0;
+		}
+
+		/* end of scalar */
+		if (c == end_c)
+			break;
+
+		/* consume blanks */
+		breaks_found = 0;
+		breaks_found_length = 0;
+		blanks_found = 0;
+		while (fy_reader_is_flow_blank(fyr, c = fy_reader_peek(fyr)) || fy_reader_is_lb(fyr, c)) {
+
+			if (!has_json_esc && !fy_is_json_unescaped(c))
+				has_json_esc = true;
+
+			break_run = 0;
+
+			/* check for tab used as indentation */
+			if (!fy_reader_tabsize(fyr) && fy_is_tab(c)) {
+				FYR_PARSE_ERROR_CHECK(fyr, 0, 1, FYEM_SCAN,
+						fy_reader_column(fyr) > indent, err_out,
+						"invalid tab used as indentation");
+			}
+
+			fy_reader_advance(fyr, c);
+
+			if (fy_reader_is_lb(fyr, c)) {
+
+				if (!fy_is_lb_LS_PS(c)) {
+					break_length = 1;
+				} else {
+					break_length = fy_utf8_width(c);
+					presentation_breaks_length += break_length;
+				}
+
+				has_lb = true;
+				if (!breaks_found)
+					first_break_length = break_length;
+				breaks_found++;
+				breaks_found_length += break_length;
+				blanks_found = 0;
+				esc_lb = false;
+			} else {
+				has_ws = true;
+				if (!esc_lb)
+					blanks_found++;
+			}
+		}
+		first = false;
+	}
+
+	if (break_run > 0)
+		ends_with_lb = true;
+	else if (fy_reader_is_flow_ws(fyr, lastc))
+		ends_with_ws = true;
+	trailing_lb = break_run > 1;
+
+	/* end... */
+	fy_reader_fill_atom_end(fyr, handle);
+
+	is_multiline = handle->end_mark.line > handle->start_mark.line;
+
+	/* need to process to present */
+	handle->style = is_single ? FYAS_SINGLE_QUOTED : FYAS_DOUBLE_QUOTED;
+	handle->direct_output = !is_multiline && !has_esc && !has_json_esc &&
+				fy_atom_size(handle) == length;
+	handle->empty = ws_lb_only;
+	handle->has_lb = has_lb;
+	handle->has_ws = has_ws;
+	handle->starts_with_ws = starts_with_ws;
+	handle->starts_with_lb = starts_with_lb;
+	handle->ends_with_ws = ends_with_ws;
+	handle->ends_with_lb = ends_with_lb;
+	handle->trailing_lb = trailing_lb;
+	handle->size0 = length == 0;
+	handle->valid_anchor = false;
+	handle->json_mode = fy_reader_json_mode(fyr);
+	handle->lb_mode = fy_reader_lb_mode(fyr);
+	handle->fws_mode = fy_reader_flow_ws_mode(fyr);
+	handle->tabsize = fy_reader_tabsize(fyr);
+	handle->ends_with_eof = false;	/* flow scalars never end with EOF and be valid */
+
+	/* skip over block scalar end */
+	fy_reader_advance_by(fyr, 1);
+
+#ifdef ATOM_SIZE_CHECK
+	tlength = fy_atom_format_text_length(handle);
+	fy_utf8_format_text_a(fy_atom_data(handle), fy_atom_size(handle), fyue_doublequote, &str);
+	if (tlength != length) {
+		fyr_warning(fyr, "%s: storage hint calculation failed real %zu != hint %zu - \"%s\"", __func__,
+			tlength, length,
+			str);
+		length = tlength;
+	}
+#endif
+
+	handle->storage_hint = length;
+	handle->storage_hint_valid = true;
+
+	FYR_MARK_ERROR_CHECK(fyr, &handle->start_mark, &handle->end_mark, FYEM_SCAN,
+			!fy_reader_json_mode(fyr) || !is_multiline, err_out,
+			"Multi line double quoted scalars not supported in JSON mode");
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+int fy_reader_fetch_plain_scalar_handle(struct fy_reader *fyr, int c, int indent, int flow_level, struct fy_atom *handle, bool directive0)
+{
+	size_t length;
+	int rc = -1, run, nextc, lastc, breaks_found, blanks_found;
+	int breaks_found_length, first_break_length, break_length, presentation_breaks_length;
+	bool has_leading_blanks;
+	bool last_ptr;
+	struct fy_mark mark, last_mark;
+	bool is_multiline, has_lb, has_ws, ends_with_eof;
+	bool has_json_esc;
+	char *str;
+#ifdef ATOM_SIZE_CHECK
+	size_t tlength;
+#endif
+
+	FYR_PARSE_ERROR_CHECK(fyr, 0, 1, FYEM_SCAN,
+			!fy_reader_is_blankz(fyr, c), err_out,
+			"plain scalar cannot start with blank or zero");
+
+	/* may not start with any of ,[]{}#&*!|>'\"%@` */
+	FYR_PARSE_ERROR_CHECK(fyr, 0, 1, FYEM_SCAN,
+			!fy_utf8_strchr(",[]{}#&*!|>'\"%@`", c), err_out,
+			"plain scalar cannot start with '%c'", c);
+
+	/* may not start with - not followed by blankz */
+	FYR_PARSE_ERROR_CHECK(fyr, 0, 2, FYEM_SCAN,
+			c != '-' || !fy_reader_is_blank_at_offset(fyr, 1), err_out,
+			"plain scalar cannot start with '%c' followed by blank", c);
+
+	/* may not start with -?: not followed by blankz (in block context) */
+	FYR_PARSE_ERROR_CHECK(fyr, 0, 2, FYEM_SCAN,
+			flow_level > 0 || !((c == '?' || c == ':') && fy_reader_is_blank_at_offset(fyr, 1)), err_out,
+			"plain scalar cannot start with '%c' followed by blank (in block context)", c);
+
+	/* may not start with - followed by ",[]{}" in flow context */
+	FYR_PARSE_ERROR_CHECK(fyr, 0, 2, FYEM_SCAN,
+			flow_level == 0 || !(c == '-' && fy_utf8_strchr(",[]{}", fy_reader_peek_at(fyr, 1))), err_out,
+			"plain scalar cannot start with '%c' followed by ,[]{} (in flow context)", c);
+
+	fy_reader_get_mark(fyr, &mark);
+
+	fy_reader_fill_atom_start(fyr, handle);
+
+	has_leading_blanks = false;
+	has_lb = false;
+	has_ws = false;
+	has_json_esc = false;
+
+	length = 0;
+	breaks_found = 0;
+	breaks_found_length = 0;
+	first_break_length = 0;
+	presentation_breaks_length = 0;
+	blanks_found = 0;
+	last_ptr = false;
+	memset(&last_mark, 0, sizeof(last_mark));
+	c = FYUG_EOF;
+	lastc = FYUG_EOF;
+
+	for (;;) {
+		/* break for document indicators */
+		if (fy_reader_column(fyr) == 0 &&
+		    ((!fy_reader_strncmp(fyr, "---", 3) || !fy_reader_strncmp(fyr, "...", 3)) &&
+			fy_reader_is_blankz_at_offset(fyr, 3)))
+			break;
+
+		c = fy_reader_peek(fyr);
+		if (c == '#')
+			break;
+
+		/* for YAML 1.1 check % directive break */
+		if (directive0 && fy_reader_column(fyr) == 0 && c == '%')
+			break;
+
+		/* quickly deal with runs */
+		run = 0;
+		if (c >= 0 && c <= 0x7f && (fy_utf8_low_ascii_flags[c] & F_SIMPLE_SCALAR)) {
+			size_t len, consumed;
+			const char *p, *s, *e;
+			int8_t cc;
+
+			while ((p = fy_reader_ensure_lookahead(fyr, 1, &len)) != NULL) {
+
+				s = p;
+				e = s + len;
+
+				while (s < e && (cc = (int8_t)*s) >= 0 && (fy_utf8_low_ascii_flags[cc] & F_SIMPLE_SCALAR))
+					s++;
+
+				consumed = s - p;
+				if (consumed) {
+					fy_reader_advance_octets(fyr, consumed);
+					fyr->column += consumed;
+				}
+				run += consumed;
+
+				/* we're done if stopped earlier */
+				if (s < e)
+					break;
+			}
+
+		}
+		if (run > 0) {
+			length += run;
+			if (breaks_found) {
+				/* minimum 1 sep, or more for consecutive */
+				length += breaks_found > 1 ? (breaks_found_length - first_break_length) : 1;
+				length += presentation_breaks_length;
+				breaks_found = 0;
+				blanks_found = 0;
+				presentation_breaks_length = 0;
+			} else if (blanks_found) {
+				/* just the blanks mam' */
+				length += blanks_found;
+				blanks_found = 0;
+			}
+		}
+
+		while (!fy_reader_is_blankz(fyr, c = fy_reader_peek(fyr))) {
+
+
+			if (c == ':') {
+
+				nextc = fy_reader_peek_at(fyr, 1);
+
+				/* ':' followed by space terminates */
+				if (fy_reader_is_blankz(fyr, nextc)) {
+					/* super rare case :: not followed by space  */
+					/* :: not followed by space */
+					if (lastc != ':' || fy_reader_is_blankz(fyr, nextc))
+						break;
+				}
+
+				/* in flow context ':' followed by flow markers */
+				if (flow_level > 0 && fy_utf8_strchr(",[]{}", nextc))
+					break;
+			}
+
+			/* in flow context any or , [ ] { } */
+			if (flow_level > 0 && (c == ',' || c == '[' || c == ']' || c == '{' || c == '}'))
+				break;
+
+			if (breaks_found) {
+				/* minimum 1 sep, or more for consecutive */
+				length += breaks_found > 1 ? (breaks_found_length - first_break_length) : 1;
+				length += presentation_breaks_length;
+				breaks_found = 0;
+				blanks_found = 0;
+				presentation_breaks_length = 0;
+			} else if (blanks_found) {
+				/* just the blanks mam' */
+				length += blanks_found;
+				blanks_found = 0;
+			}
+
+			/* check whether we have a JSON unescaped character */
+			if (!has_json_esc && !fy_is_json_unescaped(c))
+				has_json_esc = true;
+
+			fy_reader_advance(fyr, c);
+			run++;
+
+			length += fy_utf8_width(c);
+
+			lastc = c;
+		}
+
+		/* save end mark if we processed more than one non-blank */
+		if (run > 0) {
+			/* fyp_scan_debug(fyp, "saving mark"); */
+			last_ptr = true;
+			fy_reader_get_mark(fyr, &last_mark);
+		}
+
+		/* end? */
+		if (!(fy_is_blank(c) || fy_reader_is_lb(fyr, c)))
+			break;
+
+		has_json_esc = true;
+
+		/* consume blanks */
+		breaks_found = 0;
+		breaks_found_length = 0;
+		first_break_length = 0;
+		blanks_found = 0;
+		do {
+			fy_reader_advance(fyr, c);
+
+			if (!fy_reader_tabsize(fyr)) {
+				/* check for tab */
+				FYR_PARSE_ERROR_CHECK(fyr, 0, 1, FYEM_SCAN,
+						c != '\t' || !has_leading_blanks || indent < 0 || fy_reader_column(fyr) >= (indent + 1), err_out,
+						"invalid tab used as indentation");
+			}
+
+			nextc = fy_reader_peek(fyr);
+
+			/* if it's a break */
+			if (fy_reader_is_lb(fyr, c)) {
+
+				if (!fy_is_lb_LS_PS(c)) {
+					break_length = 1;
+				} else {
+					break_length = fy_utf8_width(c);
+					presentation_breaks_length += break_length;
+				}
+
+				/* first break, turn on leading blanks */
+				if (!has_leading_blanks)
+					has_leading_blanks = true;
+				if (!breaks_found)
+					first_break_length = break_length;
+				breaks_found++;
+				breaks_found_length += break_length;
+				blanks_found = 0;
+				has_lb = true;
+			} else {
+				blanks_found++;
+				has_ws = true;
+			}
+
+			c = nextc;
+
+		} while (fy_is_blank(c) || fy_reader_is_lb(fyr, c));
+
+		/* break out if indentation is less */
+		if (flow_level <= 0 && indent >= 0 && fy_reader_column(fyr) < (indent + 1))
+			break;
+	}
+
+	/* end... */
+	if (!last_ptr)
+		fy_reader_fill_atom_end(fyr, handle);
+	else
+		fy_reader_fill_atom_end_at(fyr, handle, &last_mark);
+
+	if (c == FYUG_INV || c == FYUG_PARTIAL) {
+		FYR_MARK_ERROR(fyr, &handle->start_mark, &handle->end_mark, FYEM_SCAN,
+			"plain scalar is malformed UTF8");
+		goto err_out;
+	}
+	ends_with_eof = c == FYUG_EOF && !fy_reader_is_lb(fyr, lastc);
+
+	is_multiline = handle->end_mark.line > handle->start_mark.line;
+
+	handle->style = FYAS_PLAIN;
+	handle->chomp = FYAC_STRIP;
+	handle->direct_output = !is_multiline && !has_json_esc && fy_atom_size(handle) == length;
+	handle->empty = false;
+	handle->has_lb = has_lb;
+	handle->has_ws = has_ws;
+	handle->starts_with_ws = false;
+	handle->starts_with_lb = false;
+	handle->ends_with_ws = false;
+	handle->ends_with_lb = false;
+	handle->trailing_lb = false;
+	handle->size0 = length == 0;
+	handle->valid_anchor = false;
+	handle->json_mode = fy_reader_json_mode(fyr);
+	handle->lb_mode = fy_reader_lb_mode(fyr);
+	handle->fws_mode = fy_reader_flow_ws_mode(fyr);
+	handle->tabsize = fy_reader_tabsize(fyr);
+	handle->ends_with_eof = ends_with_eof;
+
+#ifdef ATOM_SIZE_CHECK
+	tlength = fy_atom_format_text_length(handle);
+	if (tlength != length) {
+		fy_utf8_format_text_a(fy_atom_data(handle), fy_atom_size(handle), fyue_doublequote, &str);
+		fyr_warning(fyr, "%s: storage hint calculation failed real %zu != hint %zu - \"%s\"", __func__,
+			tlength, length,
+			str);
+		length = tlength;
+	}
+#endif
+
+	handle->storage_hint = length;
+	handle->storage_hint_valid = true;
+
+	/* extra check in json mode */
+	if (fy_reader_json_mode(fyr)) {
+		FYR_MARK_ERROR_CHECK(fyr, &handle->start_mark, &handle->end_mark, FYEM_SCAN,
+				!is_multiline, err_out,
+				"Multi line plain scalars not supported in JSON mode");
+
+		FYR_MARK_ERROR_CHECK(fyr, &handle->start_mark, &handle->end_mark, FYEM_SCAN,
+				!fy_atom_strcmp(handle, "false") ||
+				!fy_atom_strcmp(handle, "true") ||
+				!fy_atom_strcmp(handle, "null") ||
+				fy_atom_is_number(handle), err_out,
+				"Invalid JSON plain scalar");
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+	return rc;
+}
+
+
+int fy_fetch_flow_scalar(struct fy_parser *fyp, int c)
+{
+	struct fy_atom handle;
+	bool is_single, is_complex, is_multiline;
+	struct fy_mark mark;
+	struct fy_simple_key_mark skm;
+	struct fy_token *fyt;
+	int i = 0, rc = -1;
+	char *str;
+
+	is_single = c == '\'';
+
+	fy_utf8_format_a(c, fyue_singlequote, &str);
+	fyp_error_check(fyp, c == '\'' || c == '"', err_out,
+			"bad start of flow scalar ('%s')",
+			str);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented %s scalar in flow mode",
+				is_single ? "single-quoted" : "double-quoted");
+
+	fy_get_mark(fyp, &mark);
+	fy_get_simple_key_mark(fyp, &skm);
+
+	/* errors are generated by reader */
+	rc = fy_reader_fetch_flow_scalar_handle(fyp->reader, c, fyp->indent, &handle, !!(fyp->cfg.flags & FYPCF_SLOPPY_FLOW_INDENTATION));
+	if (rc) {
+		fyp->stream_error = true;
+		goto err_out_rc;
+	}
+
+	/* and we're done */
+	fyt = fy_token_queue(fyp, FYTT_SCALAR, &handle, is_single ? FYSS_SINGLE_QUOTED : FYSS_DOUBLE_QUOTED);
+	fyp_error_check(fyp, fyt, err_out_rc,
+			"fy_token_queue() failed");
+
+	if (fyp->parse_flow_only && fyp->flow_level == 0) {
+		rc = fy_fetch_stream_end(fyp);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_stream_end() failed");
+		return 0;
+	}
+
+	is_complex = fyp->pending_complex_key_column >= 0;
+	is_multiline = handle.end_mark.line > handle.start_mark.line;
+
+	if (!fyp->flow_level) {
+		/* due to the weirdness with simple keys scan forward
+		* until a linebreak, ';', or anything else */
+		for (i = 0; ; i++) {
+			c = fy_parse_peek_at(fyp, i);
+			if (c < 0 || c == ':' || fyp_is_lb(fyp, c) || !fyp_is_flow_ws(fyp, c))
+				break;
+		}
+
+		/* if we're a multiline key that's bad */
+		FYP_MARK_ERROR_CHECK(fyp, &mark, &mark, FYEM_SCAN,
+			!(is_multiline && !is_complex && c == ':'), err_out,
+				"invalid multiline %s scalar used as key",
+					is_single ? "single-quoted" : "double-quoted");
+
+		FYP_PARSE_ERROR_CHECK(fyp, i, 1, FYEM_SCAN,
+				c < 0 || c == ':' || c == '#' || fyp_is_lb(fyp, c), err_out,
+				"invalid trailing content after %s scalar",
+					is_single ? "single-quoted" : "double-quoted");
+	}
+
+	/* a plain scalar could be simple key */
+	rc = fy_save_simple_key_mark(fyp, &skm, FYTT_SCALAR, &handle.end_mark);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_save_simple_key_mark() failed");
+
+	/* cannot follow a flow scalar */
+	fyp->simple_key_allowed = false;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	/* make sure that no comment follows directly afterwards */
+	c = fy_parse_peek(fyp);
+
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			c != '#', err_out,
+			"invalid comment without whitespace after %s scalar",
+				is_single ? "single-quoted" : "double-quoted");
+
+	if (fyp->cfg.flags & FYPCF_PARSE_COMMENTS) {
+		rc = fy_attach_comments_if_any(fyp, fyt);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_attach_right_hand_comment() failed");
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+void fy_reader_skip_ws_cr_nl(struct fy_reader *fyr)
+{
+	const char *p, *s, *e;
+	char cc;
+	size_t len;
+	int line, column;
+
+	assert(fyr);
+
+	column = fyr->column;
+	line = fyr->line;
+	while ((p = fy_reader_ensure_lookahead(fyr, 1, &len)) != NULL) {
+
+		s = p;
+		e = s + len;
+
+		while (s < e) {
+			cc = *s;
+			if (cc == ' ') {
+				column++;
+			} else if (cc == '\n') {
+				column = 0;
+				line++;
+			} else if (cc == '\t') {
+				if (fyr->tabsize)
+					column += (fyr->tabsize - (column % fyr->tabsize));
+				else
+					column++;
+			} else if (cc == '\r') {
+				column = 0;
+				line++;
+
+				if (s + 1 > e) {
+					/* we have a dangling cr at the end of a block */
+
+					/* advance up to the point here */
+					fy_reader_advance_octets(fyr, s - p);
+
+					/* try again (should return enough or NULL) */
+					p = fy_reader_ensure_lookahead(fyr, 1, &len);
+
+					/* if we couldn't pull enough we're done */
+					if (!p || len < 1)
+						goto done;
+
+					s = p;
+					e = s + len;
+
+					if (*s == '\n')
+						s++;
+				}
+				/* \n followed, gulp it down */
+				if (*s == '\n')
+					s++;
+			} else {
+				if (s > p)
+					fy_reader_advance_octets(fyr, s - p);
+				goto done;
+			}
+
+			s++;
+		}
+
+		fy_reader_advance_octets(fyr, s - p);
+	}
+
+done:
+	fyr->line = line;
+	fyr->column = column;
+}
+
+void fy_reader_skip_ws(struct fy_reader *fyr)
+{
+	const char *p, *s, *e;
+	size_t len, consumed;
+	int column;
+
+	assert(fyr);
+
+	while ((p = fy_reader_ensure_lookahead(fyr, 1, &len)) != NULL) {
+
+		s = p;
+		e = s + len;
+
+		column = fyr->column;
+		if (!fyr->tabsize) {
+			while (s < e && fy_is_ws(*s)) {
+				column++;
+				s++;
+			}
+		} else {
+			while (s < e && fy_is_ws(*s)) {
+				if (fy_is_tab(*s))
+					column += fyr->tabsize - (column % fyr->tabsize);
+				else
+					column++;
+				s++;
+			}
+		}
+
+		consumed = s - p;
+		if (consumed) {
+			fy_reader_advance_octets(fyr, consumed);
+			fyr->column = column;
+		}
+
+		/* we're done if stopped earlier */
+		if (s < e)
+			break;
+	}
+}
+
+void fy_reader_skip_space(struct fy_reader *fyr)
+{
+	const char *p, *s, *e;
+	size_t len, consumed;
+
+	assert(fyr);
+
+	while ((p = fy_reader_ensure_lookahead(fyr, 1, &len)) != NULL) {
+
+		s = p;
+		e = s + len;
+
+		while (s < e && fy_is_space(*s))
+			s++;
+
+		consumed = s - p;
+		if (consumed) {
+			fy_reader_advance_octets(fyr, consumed);
+			fyr->column += consumed;
+		}
+
+		if (s < e)
+			break;
+	}
+}
+
+void fy_reader_skip_ws_lb(struct fy_reader *fyr)
+{
+	const char *p, *s, *e;
+	size_t len, consumed;
+	int line, column, c, w;
+	bool dangling_cr;
+	enum fy_lb_mode lb_mode;
+
+	assert(fyr);
+
+	/* punt to json mode */
+	lb_mode = fy_reader_lb_mode(fyr);
+
+	if (fy_reader_json_mode(fyr) || lb_mode == fylb_cr_nl) {
+		fy_reader_skip_ws_cr_nl(fyr);
+		return;
+	}
+
+	column = fyr->column;
+	line = fyr->line;
+	dangling_cr = false;
+	while ((p = fy_reader_ensure_lookahead(fyr, 1, &len)) != NULL) {
+
+		s = p;
+		e = s + len;
+
+		if (dangling_cr) {
+			if (*s == '\n')
+				s++;
+			dangling_cr = false;
+		}
+
+		while (s < e) {
+			c = (int)*s;
+
+			/* single byte utf8? */
+			if (c < 0x80) {
+				if (c == ' ') {
+					column++;
+				} else if (c == '\n') {
+					column = 0;
+					line++;
+				} else if (c == '\t') {
+					if (fyr->tabsize)
+						column += (fyr->tabsize - (column % fyr->tabsize));
+					else
+						column++;
+				} else if (c == '\r') {
+					column = 0;
+					line++;
+					/* check for '\n' following */
+					if (s < e) {
+						if (*s == '\n')
+							s++;
+					} else {
+						/* we have a dangling cr at the end of a block */
+						dangling_cr = true;
+					}
+				} else {
+					consumed = s - p;
+					if (consumed)
+						fy_reader_advance_octets(fyr, consumed);
+					goto done;
+				}
+				s++;
+			} else {
+				c = fy_utf8_get(s, (int)(e - s), &w);
+
+				if (c == FYUG_PARTIAL) {
+					/* get the width (from the first octet */
+					w = fy_utf8_width_by_first_octet((uint8_t)*s);
+					/* copy the partial utf8 in the buffer */
+
+					/* advance up to the point here */
+					consumed = s - p;
+					if (consumed)
+						fy_reader_advance_octets(fyr, consumed);
+
+					/* try again (should return enough or NULL) */
+					p = fy_reader_ensure_lookahead(fyr, w, &len);
+					if (!p)
+						break;
+
+					/* if we couldn't pull enough we're done */
+					if (len < (size_t)w)
+						goto done;
+
+					continue;
+				}
+
+				if (lb_mode == fylb_cr_nl_N_L_P && fy_is_unicode_lb(c)) {
+					column = 0;
+					line++;
+				} else {
+					consumed = s - p;
+					if (consumed)
+						fy_reader_advance_octets(fyr, consumed);
+					goto done;
+				}
+
+				s += w;
+			}
+		}
+
+		consumed = s - p;
+		if (consumed)
+			fy_reader_advance_octets(fyr, consumed);
+	}
+
+done:
+	fyr->line = line;
+	fyr->column = column;
+}
+
+int fy_fetch_plain_scalar(struct fy_parser *fyp, int c)
+{
+	struct fy_atom handle;
+	struct fy_simple_key_mark skm;
+	struct fy_token *fyt;
+	bool is_multiline, is_complex, is_tab_start = false;
+	struct fy_mark tab_mark;
+	int rc = -1, i;
+
+	/* Extremely bad case, a tab... so, either an indentation or separation space in block mode */
+	if (!fyp->flow && fy_is_tab(c)) {
+
+		fy_get_mark(fyp, &tab_mark);
+		is_tab_start = true;
+
+		/* skip all whitespace now */
+		fy_reader_skip_ws(fyp->reader);
+		c = fy_parse_peek(fyp);
+
+		/* if it's a linebreak or a comment start, just try again */
+		if (fyp_is_lb(fyp, c) || c == '#') {
+			/* will need to scan more */
+			fyp->token_activity_counter++;
+			return 0;
+		}
+	}
+
+	/* check indentation */
+	FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+			fy_flow_indent_check(fyp), err_out,
+			"wrongly indented flow %s",
+				fyp->flow == FYFT_SEQUENCE ? "sequence" : "mapping");
+
+	fy_get_simple_key_mark(fyp, &skm);
+
+	rc = fy_reader_fetch_plain_scalar_handle(fyp->reader, c, fyp->indent, fyp->flow_level, &handle,
+						fy_document_state_version_compare(fyp->current_document_state, fy_version_make(1, 1)) <= 0);
+	if (rc) {
+		fyp->stream_error = true;
+		goto err_out_rc;
+	}
+
+	is_multiline = handle.end_mark.line > handle.start_mark.line;
+	is_complex = fyp->pending_complex_key_column >= 0;
+
+	/* and we're done */
+	fyt = fy_token_queue(fyp, FYTT_SCALAR, &handle, FYSS_PLAIN);
+	fyp_error_check(fyp, fyt, err_out_rc,
+			"fy_token_queue() failed");
+
+	if (fyp->parse_flow_only && fyp->flow_level == 0) {
+		rc = fy_fetch_stream_end(fyp);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_stream_end() failed");
+		return 0;
+	}
+
+	if (!fyp->flow_level && !is_complex && (is_multiline || is_tab_start)) {
+		/* due to the weirdness with simple keys scan forward
+		* until a linebreak, ':', or anything else */
+		for (i = 0; ; i++) {
+			c = fy_parse_peek_at(fyp, i);
+			if (c < 0 || (c == ':' && fy_is_blankz_at_offset(fyp, i + 1)) ||
+					fyp_is_lb(fyp, c) || !fy_is_ws(c))
+				break;
+		}
+
+		/* if we're a key, that's invalid */
+		if (c == ':') {
+
+			if (is_multiline)
+				FYP_MARK_ERROR(fyp, &handle.start_mark, &handle.end_mark, FYEM_SCAN,
+						"invalid multiline plain key");
+			else
+				FYP_MARK_ERROR(fyp, &tab_mark, &tab_mark, FYEM_SCAN,
+						"invalid tab as indendation in a mapping");
+
+			goto err_out;
+		}
+	}
+
+	rc = fy_save_simple_key_mark(fyp, &skm, FYTT_SCALAR, &handle.end_mark);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_save_simple_key_mark() failed");
+
+	fyp->simple_key_allowed = handle.has_lb;
+	fyp_scan_debug(fyp, "simple_key_allowed -> %s\n", fyp->simple_key_allowed ? "true" : "false");
+
+	if (fyp->cfg.flags & FYPCF_PARSE_COMMENTS) {
+		rc = fy_attach_comments_if_any(fyp, fyt);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_attach_right_hand_comment() failed");
+	}
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_fetch_tokens(struct fy_parser *fyp)
+{
+	struct fy_mark m;
+	bool was_double_colon;
+	int c, rc;
+
+	/* do not fetch any more when stream end is reached */
+	if (fyp->stream_end_reached)
+		return 0;
+
+	if (!fyp->stream_start_produced) {
+		rc = fy_parse_get_next_input(fyp);
+		fyp_error_check(fyp, rc >= 0, err_out_rc,
+			"fy_parse_get_next_input() failed");
+
+		if (rc > 0) {
+			rc = fy_fetch_stream_start(fyp);
+			fyp_error_check(fyp, !rc, err_out_rc,
+					"fy_fetch_stream_start() failed");
+		}
+		return 0;
+	}
+
+	fyp_scan_debug(fyp, "-------------------------------------------------");
+	rc = fy_scan_to_next_token(fyp);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_scan_to_next_token() failed");
+
+	if (fyp_block_mode(fyp)) {
+		rc = fy_parse_unroll_indent(fyp, fyp_column(fyp));
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_parse_unroll_indent() failed");
+	}
+
+	c = fy_parse_peek(fyp);
+	if (c < 0 || c == '\0') {
+
+		fyp->stream_end_reached = true;
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				!fyp_json_mode(fyp) || c != '\0', err_out,
+				"JSON disallows '\\0' in the input stream");
+
+		if (c >= 0)
+			fy_advance(fyp, c);
+		rc = fy_fetch_stream_end(fyp);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_stream_end() failed");
+		return 0;
+	}
+
+	if (fyp_column(fyp) == 0 && c == '%') {
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				!fyp_json_mode(fyp), err_out,
+				"directives not supported in JSON mode");
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				!fyp->bare_document_only, err_out,
+				"invalid directive in bare document mode");
+
+		fy_advance(fyp, c);
+		rc = fy_fetch_directive(fyp);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_directive() failed");
+		goto out;
+	}
+
+	/* probable document start/end indicator */
+	if (fyp_column(fyp) == 0 &&
+	    (!fy_parse_strncmp(fyp, "---", 3) ||
+	     !fy_parse_strncmp(fyp, "...", 3)) &&
+	    fy_is_blankz_at_offset(fyp, 3)) {
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 3, FYEM_SCAN,
+				!fyp_json_mode(fyp), err_out,
+				"document %s indicator not supported in JSON mode",
+					c == '-' ? "start" : "end");
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 3, FYEM_SCAN,
+				!fyp->bare_document_only, err_out,
+				"invalid document %s indicator in bare document mode",
+					c == '-' ? "start" : "end");
+
+		rc = fy_fetch_document_indicator(fyp,
+				c == '-' ? FYTT_DOCUMENT_START :
+					FYTT_DOCUMENT_END);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_document_indicator() failed");
+
+		fyp->indent_line = fyp_line(fyp);
+
+		/* for document end, nothing must follow except whitespace and comment */
+		if (c == '.') {
+			c = fy_parse_peek(fyp);
+
+			FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+					c == -1 || c == '#' || fyp_is_lb(fyp, c), err_out,
+					"invalid content after document end marker");
+		}
+
+		goto out;
+	}
+
+	fyp_scan_debug(fyp, "indent=%d, parent indent=%d\n",
+			fyp->indent, fyp->parent_indent);
+
+	if (c == '[' || c == '{') {
+
+		fyp->indent_line = fyp_line(fyp);
+
+		fyp_scan_debug(fyp, "calling fy_fetch_flow_collection_mark_start(%c)", c);
+		rc = fy_fetch_flow_collection_mark_start(fyp, c);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_flow_collection_mark_start() failed");
+		goto out;
+	}
+
+	if (c == ']' || c == '}') {
+
+		fyp->indent_line = fyp_line(fyp);
+
+		fyp_scan_debug(fyp, "fy_fetch_flow_collection_mark_end(%c)", c);
+		rc = fy_fetch_flow_collection_mark_end(fyp, c);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_flow_collection_mark_end() failed");
+		goto out;
+	}
+
+
+	if (c == ',') {
+
+		fyp->indent_line = fyp_line(fyp);
+
+		fy_get_mark(fyp, &m);
+
+		fyp_scan_debug(fyp, "fy_fetch_flow_collection_entry(%c)", c);
+		rc = fy_fetch_flow_collection_entry(fyp, c);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_flow_collection_entry() failed");
+
+		fyp->last_was_comma = true;
+		fyp->last_comma_mark = m;
+
+		goto out;
+	}
+
+	if (c == '-' && fy_is_blankz_at_offset(fyp, 1)) {
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				!fyp_json_mode(fyp), err_out,
+				"block entries not supported in JSON mode");
+
+		fyp->indent_line = fyp_line(fyp);
+
+		fyp_scan_debug(fyp, "fy_fetch_block_entry(%c)", c);
+		rc = fy_fetch_block_entry(fyp, c);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_block_entry() failed");
+		goto out;
+	}
+
+	if (c == '?' && fy_is_blankz_at_offset(fyp, 1)) {
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				!fyp_json_mode(fyp), err_out,
+				"complex keys not supported in JSON mode");
+
+		fyp->indent_line = fyp_line(fyp);
+
+		fyp_scan_debug(fyp, "fy_fetch_key(%c)", c);
+		rc = fy_fetch_key(fyp, c);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_key() failed");
+		goto out;
+	}
+
+	if (c == ':') {
+		was_double_colon = c == ':' && fyp->colon_follows_colon && fyp->flow_level > 0;
+		fyp->colon_follows_colon = false;
+
+		if (((fyp->flow_level && !fyp->simple_key_allowed) || fy_is_blankz_at_offset(fyp, 1)) &&
+				!was_double_colon) {
+
+			fyp->indent_line = fyp_line(fyp);
+
+			fyp_scan_debug(fyp, "fy_fetch_value(%c)", c);
+			rc = fy_fetch_value(fyp, c);
+			fyp_error_check(fyp, !rc, err_out_rc,
+					"fy_fetch_value() failed");
+			goto out;
+		}
+	}
+
+	if (c == '*' || c == '&') {
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				!fyp_json_mode(fyp), err_out,
+				"%s not supported in JSON mode",
+					c == '&' ? "anchor" : "alias");
+
+		fyp_scan_debug(fyp, "fy_fetch_anchor_or_alias(%c)", c);
+		rc = fy_fetch_anchor_or_alias(fyp, c);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_anchor_or_alias() failed");
+		goto out;
+	}
+
+	if (c == '!') {
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				!fyp_json_mode(fyp), err_out,
+				"tag not supported in JSON mode");
+
+		fyp_scan_debug(fyp, "fy_fetch_tag(%c)", c);
+		rc = fy_fetch_tag(fyp, c);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_tag() failed");
+		goto out;
+	}
+
+	if (!fyp->flow_level && (c == '|' || c == '>')) {
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				!fyp_json_mode(fyp), err_out,
+				"block scalars not supported in JSON mode");
+
+		fyp_scan_debug(fyp, "fy_fetch_block_scalar(%c)", c);
+		rc = fy_fetch_block_scalar(fyp, c == '|', c);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_block_scalar() failed");
+		goto out;
+	}
+
+	if (c == '\'' || c == '"') {
+
+		FYP_PARSE_ERROR_CHECK(fyp, 0, 1, FYEM_SCAN,
+				c == '"' || !fyp_json_mode(fyp), err_out,
+				"single quoted scalars not supported in JSON mode");
+
+		fyp_scan_debug(fyp, "fy_fetch_flow_scalar(%c)", c);
+		rc = fy_fetch_flow_scalar(fyp, c);
+		fyp_error_check(fyp, !rc, err_out_rc,
+				"fy_fetch_flow_scalar() failed");
+		goto out;
+	}
+
+	fyp_scan_debug(fyp, "fy_fetch_plain_scalar(%c)", c);
+	rc = fy_fetch_plain_scalar(fyp, c);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_fetch_plain_scalar() failed");
+
+out:
+	if (c != ',' && fyp->last_was_comma)
+		fyp->last_was_comma = false;
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+struct fy_token *fy_scan_peek(struct fy_parser *fyp)
+{
+	struct fy_token *fyt;
+	int rc, last_token_activity_counter;
+	bool have_simple_keys;
+
+	/* nothing if stream end produced (and no stream end token in queue) */
+	if (fyp->stream_end_produced) {
+		fyt = fy_token_list_head(&fyp->queued_tokens);
+		if (fyt && fyt->type == FYTT_STREAM_END)
+			return fyt;
+
+		/* OK, we're done, flush everything */
+		fy_token_list_unref_all(&fyp->queued_tokens);
+
+		/* try to get the next input */
+		rc = fy_parse_get_next_input(fyp);
+		fyp_error_check(fyp, rc >= 0, err_out,
+			"fy_parse_get_next_input() failed");
+
+		/* no more inputs */
+		if (rc == 0) {
+			fyp_scan_debug(fyp, "token stream ends");
+			return NULL;
+		}
+
+		fyp_scan_debug(fyp, "starting new token stream");
+
+		fyp->stream_start_produced = false;
+		fyp->stream_end_produced = false;
+		fyp->stream_end_reached = false;
+	}
+
+	/* we loop until we have a token and the simple key list is empty */
+	for (;;) {
+		fyt = fy_token_list_head(&fyp->queued_tokens);
+		have_simple_keys = !fy_simple_key_list_empty(&fyp->simple_keys);
+
+		/* we can produce a token when:
+		* a) one exists
+		* b) no simple keys exist at all
+		*/
+		if (fyt && !have_simple_keys)
+			break;
+
+		/* on stream error we're done */
+		if (fyp->stream_error)
+			return NULL;
+
+		/* keep track of token activity, if it didn't change
+		* after the fetch tokens call, the state machine is stuck
+		*/
+		last_token_activity_counter = fyp->token_activity_counter;
+
+		/* fetch more then */
+		rc = fy_fetch_tokens(fyp);
+		fyp_error_check(fyp, !rc, err_out,
+				"fy_fetch_tokens() failed");
+
+		fyp_error_check(fyp, last_token_activity_counter != fyp->token_activity_counter, err_out,
+				"out of tokens and failed to produce anymore");
+	}
+
+	switch (fyt->type) {
+	case FYTT_STREAM_START:
+		fyp_scan_debug(fyp, "setting stream_start_produced to true");
+		fyp->stream_start_produced = true;
+		break;
+	case FYTT_STREAM_END:
+		fyp_scan_debug(fyp, "setting stream_end_produced to true");
+		fyp->stream_end_produced = true;
+
+		if (!fyp->parse_flow_only) {
+			rc = fy_reader_input_done(fyp->reader);
+			fyp_error_check(fyp, !rc, err_out,
+					"fy_parse_input_done() failed");
+		}
+		break;
+	default:
+		break;
+	}
+
+	return fyt;
+
+err_out:
+	return NULL;
+}
+
+static inline struct fy_token *
+fy_scan_remove(struct fy_parser *fyp, struct fy_token *fyt)
+{
+	if (!fyp || !fyt)
+		return NULL;
+
+	fy_token_list_del(&fyp->queued_tokens, fyt);
+
+	return fyt;
+}
+
+static inline struct fy_token *
+fy_scan_remove_peek(struct fy_parser *fyp, struct fy_token *fyt)
+{
+	if (fyt != NULL) {
+		(void)fy_scan_remove(fyp, fyt);
+		fy_token_unref_rl(fyp->recycled_token_list, fyt);
+	}
+
+	return fy_scan_peek(fyp);
+}
+
+struct fy_token *fy_scan(struct fy_parser *fyp)
+{
+	struct fy_token *fyt;
+
+	fyt = fy_scan_remove(fyp, fy_scan_peek(fyp));
+
+	if (fyt && (fyt->type == FYTT_VERSION_DIRECTIVE || fyt->type == FYTT_TAG_DIRECTIVE)) {
+
+		/*
+		* NOTE: we need to update the document state with the contents of
+		* directives, so that tags etc, work correctly.
+		* This is arguably a big hack, but so is using the scanner in such
+		* a low level.
+		*
+		* This is not very good because we don't keep track of parser state
+		* so tag directives in the middle of the document are AOK.
+		* But we don't really care, if you care about stream validity do
+		* a proper parse.
+		*/
+
+		/* we take a reference because the parse methods take ownership */
+		fy_token_ref(fyt);
+
+		/* we ignore errors, because... they are parse errors, not scan errors */
+
+		if (fyt->type == FYTT_VERSION_DIRECTIVE)
+			(void)fy_parse_version_directive(fyp, fyt, true);
+		else
+			(void)fy_parse_tag_directive(fyp, fyt, true);
+	}
+
+#ifdef FY_DEVMODE
+	if (fyt)
+		fyp_debug_dump_token(fyp, fyt, "producing: ");
+#endif
+	return fyt;
+}
+
+void fy_scan_token_free(struct fy_parser *fyp, struct fy_token *fyt)
+{
+	fy_token_unref_rl(fyp->recycled_token_list, fyt);
+}
+
+int fy_parse_state_push(struct fy_parser *fyp, enum fy_parser_state state)
+{
+	struct fy_parse_state_log *fypsl;
+
+	fypsl = fy_parse_parse_state_log_alloc(fyp);
+	fyp_error_check(fyp, fypsl != NULL, err_out,
+			"fy_parse_state_log_alloc() failed!");
+	fypsl->state = state;
+	fy_parse_state_log_list_push(&fyp->state_stack, fypsl);
+
+	return 0;
+err_out:
+	return -1;
+}
+
+enum fy_parser_state fy_parse_state_pop(struct fy_parser *fyp)
+{
+	struct fy_parse_state_log *fypsl;
+	enum fy_parser_state state;
+
+	fypsl = fy_parse_state_log_list_pop(&fyp->state_stack);
+	if (!fypsl)
+		return FYPS_NONE;
+
+	state = fypsl->state;
+
+	fy_parse_parse_state_log_recycle(fyp, fypsl);
+
+	return state;
+}
+
+void fy_parse_state_set(struct fy_parser *fyp, enum fy_parser_state state)
+{
+	fyp_parse_debug(fyp, "state %s -> %s\n", state_txt[fyp->state], state_txt[state]);
+	fyp->state = state;
+}
+
+enum fy_parser_state fy_parse_state_get(struct fy_parser *fyp)
+{
+	return fyp->state;
+}
+
+static struct fy_eventp *
+fy_parse_node(struct fy_parser *fyp, struct fy_token *fyt, bool is_block)
+{
+	struct fy_eventp *fyep = NULL;
+	struct fy_event *fye = NULL;
+	struct fy_document_state *fyds = NULL;
+	struct fy_token *anchor = NULL, *tag = NULL;
+	const char *handle;
+	size_t handle_size;
+	struct fy_token *fyt_td;
+	struct fy_token *fytn;
+
+	fyds = fyp->current_document_state;
+	assert(fyds);
+
+	fyp_parse_debug(fyp, "parse_node: is_block=%s - fyt %s",
+			is_block ? "true" : "false",
+			fy_token_type_txt[fyt->type]);
+
+	if (fyt->type == FYTT_ALIAS) {
+		fy_parse_state_set(fyp, fy_parse_state_pop(fyp));
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_ALIAS;
+		fye->alias.anchor = fy_scan_remove(fyp, fyt);
+
+		goto return_ok;
+	}
+
+	while ((!anchor && fyt->type == FYTT_ANCHOR) || (!tag && fyt->type == FYTT_TAG)) {
+		if (fyt->type == FYTT_ANCHOR)
+			anchor = fy_scan_remove(fyp, fyt);
+		else
+			tag = fy_scan_remove(fyp, fyt);
+
+		fyt = fy_scan_peek(fyp);
+		fyp_error_check(fyp, fyt, err_out,
+				"failed to peek token");
+
+		fyp_parse_debug(fyp, "parse_node: ANCHOR|TAG got -  fyt %s",
+			fy_token_type_txt[fyt->type]);
+
+		FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+				fyt->type != FYTT_ALIAS, err_out,
+				"unexpected alias");
+	}
+
+	/* check tag prefix */
+	if (tag && tag->tag.handle_length) {
+		handle = fy_atom_data(&tag->handle) + tag->tag.skip;
+		handle_size = tag->tag.handle_length;
+
+		fyt_td = fy_document_state_lookup_tag_directive(fyds, handle, handle_size);
+
+		FYP_TOKEN_ERROR_CHECK(fyp, tag, FYEM_PARSE,
+				fyt_td, err_out,
+				"undefined tag prefix '%.*s'", (int)handle_size, handle);
+	}
+
+	if ((fyp->state == FYPS_BLOCK_MAPPING_VALUE ||
+	     fyp->state == FYPS_BLOCK_MAPPING_FIRST_KEY)
+		&& fyt->type == FYTT_BLOCK_ENTRY) {
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_SEQUENCE_START;
+		fye->sequence_start.anchor = anchor;
+		fye->sequence_start.tag = tag;
+
+		/* allocate and copy in place */
+		fytn = fy_token_alloc_rl(fyp->recycled_token_list);
+		fyp_error_check(fyp, fytn, err_out,
+				"fy_token_alloc_rl() failed!");
+		fytn->type = FYTT_BLOCK_SEQUENCE_START;
+		fytn->handle = fyt->handle;
+		fytn->handle.end_mark = fytn->handle.start_mark;	/* no extent */
+		fy_input_ref(fytn->handle.fyi);
+
+		fye->sequence_start.sequence_start = fytn;
+
+		fy_parse_state_set(fyp, FYPS_INDENTLESS_SEQUENCE_ENTRY);
+		goto return_ok;
+	}
+
+	if (fyt->type == FYTT_SCALAR) {
+		fy_parse_state_set(fyp, fy_parse_state_pop(fyp));
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_SCALAR;
+		fye->scalar.anchor = anchor;
+		fye->scalar.tag = tag;
+		fye->scalar.value = fy_scan_remove(fyp, fyt);
+		goto return_ok;
+	}
+
+	if (fyt->type == FYTT_FLOW_SEQUENCE_START) {
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_SEQUENCE_START;
+		fye->sequence_start.anchor = anchor;
+		fye->sequence_start.tag = tag;
+		fye->sequence_start.sequence_start = fy_scan_remove(fyp, fyt);
+		fy_parse_state_set(fyp, FYPS_FLOW_SEQUENCE_FIRST_ENTRY);
+		goto return_ok;
+	}
+
+	if (fyt->type == FYTT_FLOW_MAPPING_START) {
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_MAPPING_START;
+		fye->mapping_start.anchor = anchor;
+		fye->mapping_start.tag = tag;
+		fye->mapping_start.mapping_start = fy_scan_remove(fyp, fyt);
+		fy_parse_state_set(fyp, FYPS_FLOW_MAPPING_FIRST_KEY);
+		goto return_ok;
+	}
+
+	if (is_block && fyt->type == FYTT_BLOCK_SEQUENCE_START) {
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_SEQUENCE_START;
+		fye->sequence_start.anchor = anchor;
+		fye->sequence_start.tag = tag;
+		fye->sequence_start.sequence_start = fy_scan_remove(fyp, fyt);
+		fy_parse_state_set(fyp, FYPS_BLOCK_SEQUENCE_FIRST_ENTRY);
+		goto return_ok;
+	}
+
+	if (is_block && fyt->type == FYTT_BLOCK_MAPPING_START) {
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_MAPPING_START;
+		fye->mapping_start.anchor = anchor;
+		fye->mapping_start.tag = tag;
+		fye->mapping_start.mapping_start = fy_scan_remove(fyp, fyt);
+		fy_parse_state_set(fyp, FYPS_BLOCK_MAPPING_FIRST_KEY);
+		goto return_ok;
+	}
+
+	if (!anchor && !tag) {
+
+		if (fyt->type == FYTT_FLOW_ENTRY &&
+			(fyp->state == FYPS_FLOW_SEQUENCE_FIRST_ENTRY ||
+			fyp->state == FYPS_FLOW_SEQUENCE_ENTRY))
+
+			FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+					"flow sequence with invalid %s",
+						fyp->state == FYPS_FLOW_SEQUENCE_FIRST_ENTRY ?
+						"comma in the beginning" : "extra comma");
+
+		else if ((fyt->type == FYTT_DOCUMENT_START || fyt->type == FYTT_DOCUMENT_END) &&
+				(fyp->state == FYPS_FLOW_SEQUENCE_FIRST_ENTRY ||
+				fyp->state == FYPS_FLOW_SEQUENCE_ENTRY))
+
+			FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+					"invalid document %s indicator in a flow sequence",
+						fyt->type == FYTT_DOCUMENT_START ?
+							"start" : "end");
+		else
+			FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+					"did not find expected node content");
+
+		goto err_out;
+	}
+
+	fyp_parse_debug(fyp, "parse_node: empty scalar...");
+
+	/* empty scalar */
+	fy_parse_state_set(fyp, fy_parse_state_pop(fyp));
+
+	fyep = fy_parse_eventp_alloc(fyp);
+	fyp_error_check(fyp, fyep, err_out,
+			"fy_eventp_alloc() failed!");
+	fye = &fyep->e;
+
+	fye->type = FYET_SCALAR;
+	fye->scalar.anchor = anchor;
+	fye->scalar.tag = tag;
+	fye->scalar.value = NULL;
+
+return_ok:
+	fyp_parse_debug(fyp, "parse_node: > %s",
+			fy_event_type_txt[fye->type]);
+
+	return fyep;
+
+err_out:
+	fy_token_unref_rl(fyp->recycled_token_list, anchor);
+	fy_token_unref_rl(fyp->recycled_token_list, tag);
+	fy_parse_eventp_recycle(fyp, fyep);
+
+	return NULL;
+}
+
+static struct fy_eventp *
+fy_parse_empty_scalar(struct fy_parser *fyp)
+{
+	struct fy_eventp *fyep;
+	struct fy_event *fye;
+
+	fyep = fy_parse_eventp_alloc(fyp);
+	fyp_error_check(fyp, fyep, err_out,
+			"fy_eventp_alloc() failed!");
+	fye = &fyep->e;
+
+	fye->type = FYET_SCALAR;
+	fye->scalar.anchor = NULL;
+	fye->scalar.tag = NULL;
+	fye->scalar.value = NULL;
+	return fyep;
+err_out:
+	return NULL;
+}
+
+int fy_parse_stream_start(struct fy_parser *fyp)
+{
+	fyp->indent = -2;
+	fyp->indent_line = -1;
+	fyp->generated_block_map = false;
+	fyp->last_was_comma = false;
+	fyp->flow = FYFT_NONE;
+	fyp->pending_complex_key_column = -1;
+
+	fy_parse_indent_list_recycle_all(fyp, &fyp->indent_stack);
+	fy_parse_simple_key_list_recycle_all(fyp, &fyp->simple_keys);
+	fy_parse_parse_state_log_list_recycle_all(fyp, &fyp->state_stack);
+	fy_parse_flow_list_recycle_all(fyp, &fyp->flow_stack);
+
+	fy_token_unref_rl(fyp->recycled_token_list, fyp->stream_end_token);
+	fyp->stream_end_token = NULL;
+
+	return 0;
+}
+
+int fy_parse_stream_end(struct fy_parser *fyp)
+{
+	fy_token_unref_rl(fyp->recycled_token_list, fyp->stream_end_token);
+	fyp->stream_end_token = NULL;
+
+	return 0;
+}
+
+static struct fy_eventp *fy_parse_internal(struct fy_parser *fyp)
+{
+	struct fy_eventp *fyep = NULL;
+	struct fy_event *fye = NULL;
+	struct fy_token *fyt = NULL;
+	struct fy_document_state *fyds = NULL;
+	bool is_block, is_seq, is_value, is_first, had_doc_end, had_directives;
+	enum fy_parser_state orig_state;
+	struct fy_token *version_directive;
+	struct fy_token_list tag_directives;
+	const struct fy_mark *fym;
+	struct fy_token *fytn;
+	char tbuf[16] __FY_DEBUG_UNUSED__;
+	int rc;
+
+	version_directive = NULL;
+	fy_token_list_init(&tag_directives);
+
+	/* are we done? */
+	if (fyp->stream_error || fyp->state == FYPS_END)
+		return NULL;
+
+	fyt = fy_scan_peek(fyp);
+
+	/* special case without an error message for start */
+	if (!fyt && fyp->state == FYPS_NONE)
+		return NULL;
+
+	/* keep a copy of stream end */
+	if (fyt && fyt->type == FYTT_STREAM_END && !fyp->stream_end_token) {
+		fyp->stream_end_token = fy_token_ref(fyt);
+		fyp_parse_debug(fyp, "kept copy of STRM-");
+	}
+
+	/* keep on producing STREAM_END */
+	if (!fyt && fyp->stream_end_token) {
+		fyt = fyp->stream_end_token;
+		fy_token_list_add_tail(&fyp->queued_tokens, fyt);
+
+		fyp_parse_debug(fyp, "generated copy of STRM-");
+	}
+
+	fyp_error_check(fyp, fyt, err_out,
+			"failed to peek token");
+
+	assert(fyt->handle.fyi);
+
+	fyp_parse_debug(fyp, "[%s] <- %s", state_txt[fyp->state],
+			fy_token_dump_format(fyt, tbuf, sizeof(tbuf)));
+
+	is_first = false;
+	had_doc_end = false;
+
+	fyep = NULL;
+	fye = NULL;
+
+	orig_state = fyp->state;
+	switch (fyp->state) {
+	case FYPS_NONE:
+		fy_parse_state_set(fyp, FYPS_STREAM_START);
+		/* fallthrough */
+
+	case FYPS_STREAM_START:
+
+		fyp_error_check(fyp, fyt->type == FYTT_STREAM_START, err_out,
+				"failed to get valid stream start token");
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_STREAM_START;
+
+		fye->stream_start.stream_start = fy_scan_remove(fyp, fyt);
+
+		rc = fy_parse_stream_start(fyp);
+		fyp_error_check(fyp, !rc, err_out,
+				"stream start failed");
+
+		fy_parse_state_set(fyp, FYPS_IMPLICIT_DOCUMENT_START);
+
+		fyp->stream_has_content = false;
+
+		return fyep;
+
+	case FYPS_IMPLICIT_DOCUMENT_START:
+
+		/* fallthrough */
+
+	case FYPS_DOCUMENT_START:
+
+		had_doc_end = false;
+
+		if (!fyp->stream_has_content && fyt->type != FYTT_STREAM_END)
+			fyp->stream_has_content = true;
+
+		/* remove all extra document end indicators */
+		while (fyt->type == FYTT_DOCUMENT_END) {
+
+			/* reset document has content flag */
+			fyp->document_has_content = false;
+			fyp->document_first_content_token = true;
+
+			/* explicit end indicator, no more directives checking */
+			fyp->had_directives = false;
+
+			fyt = fy_scan_remove_peek(fyp, fyt);
+			fyp_error_check(fyp, fyt, err_out,
+					"failed to peek token");
+
+#ifdef FY_DEVMODE
+			fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+
+			had_doc_end = true;
+		}
+
+		if (!fyp->current_document_state) {
+
+			rc = fy_reset_document_state(fyp);
+			fyp_error_check(fyp, !rc, err_out,
+					"fy_reset_document_state() failed");
+		}
+
+		fyds = fyp->current_document_state;
+		fyp_error_check(fyp, fyds, err_out,
+				"no current document state error");
+
+		/* process directives */
+		had_directives = false;
+		while (fyt->type == FYTT_VERSION_DIRECTIVE ||
+			fyt->type == FYTT_TAG_DIRECTIVE) {
+
+			had_directives = true;
+			fyp->had_directives = true;
+
+			if (fyt->type == FYTT_VERSION_DIRECTIVE) {
+
+				rc = fy_parse_version_directive(fyp, fy_scan_remove(fyp, fyt), false);
+				fyt = NULL;
+				fyp_error_check(fyp, !rc, err_out,
+						"failed to fy_parse_version_directive()");
+			} else {
+				rc = fy_parse_tag_directive(fyp, fy_scan_remove(fyp, fyt), false);
+				fyt = NULL;
+
+				fyp_error_check(fyp, !rc, err_out,
+						"failed to fy_parse_tag_directive()");
+			}
+
+			fyt = fy_scan_peek(fyp);
+			fyp_error_check(fyp, fyt, err_out,
+					"failed to peek token");
+#ifdef FY_DEVMODE
+			fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+		}
+
+		/* the end */
+		if (fyt->type == FYTT_STREAM_END) {
+
+			/* empty content is not allowed in JSON mode */
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+					!fyp_json_mode(fyp) ||
+						fyp->stream_has_content, err_out,
+					"JSON does not allow empty root content");
+
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+					!fyp->had_directives || fyp->document_has_content ||
+					!fyds->start_implicit, err_out,
+					"stream with directives without content");
+
+			rc = fy_parse_stream_end(fyp);
+			fyp_error_check(fyp, !rc, err_out,
+					"stream end failed");
+
+			fyep = fy_parse_eventp_alloc(fyp);
+			fyp_error_check(fyp, fyep, err_out,
+					"fy_eventp_alloc() failed!");
+			fye = &fyep->e;
+
+			fye->type = FYET_STREAM_END;
+			fye->stream_end.stream_end = fy_scan_remove(fyp, fyt);
+
+			fy_parse_state_set(fyp,
+				fy_parse_have_more_inputs(fyp) ? FYPS_NONE : FYPS_END);
+
+			return fyep;
+		}
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		/* document start */
+		fye->type = FYET_DOCUMENT_START;
+		fye->document_start.document_start = NULL;
+		fye->document_start.document_state = NULL;
+
+		if (!(fyp->state == FYPS_IMPLICIT_DOCUMENT_START || had_doc_end || fyt->type == FYTT_DOCUMENT_START)) {
+			fyds = fyp->current_document_state;
+
+			/* not BLOCK_MAPPING_START */
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+					fyt->type == FYTT_BLOCK_MAPPING_START, err_out,
+					"missing document start");
+
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+					fyds->start_implicit ||
+					fyds->start_mark.line != fy_token_start_line(fyt), err_out,
+					"invalid mapping starting at --- line");
+
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+					false, err_out,
+					"invalid mapping in plain multiline");
+		}
+
+		fym = fy_token_start_mark(fyt);
+		if (fym)
+			fyds->start_mark = *fym;
+		else
+			memset(&fyds->start_mark, 0, sizeof(fyds->start_mark));
+
+		if (fyt->type != FYTT_DOCUMENT_START) {
+			fye->document_start.document_start = NULL;
+
+			fyds->start_implicit = true;
+			fyp_parse_debug(fyp, "document_start_implicit=true");
+
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+					fyt->type != FYTT_DOCUMENT_END || !had_directives, err_out,
+					"directive(s) without a document");
+
+			fy_parse_state_set(fyp, FYPS_BLOCK_NODE);
+		} else {
+			fye->document_start.document_start = fy_scan_remove(fyp, fyt);
+
+			fyds->start_implicit = false;
+			fyp_parse_debug(fyp, "document_start_implicit=false");
+
+			fy_parse_state_set(fyp, FYPS_DOCUMENT_CONTENT);
+		}
+
+		rc = fy_parse_state_push(fyp, FYPS_DOCUMENT_END);
+		fyp_error_check(fyp, !rc, err_out,
+				"failed to fy_parse_state_push()");
+
+		// update document state with json mode
+		fyds->json_mode = fyp_json_mode(fyp);
+		fye->document_start.document_state = fy_document_state_ref(fyds);
+		fye->document_start.implicit = fyds->start_implicit;
+
+		return fyep;
+
+	case FYPS_DOCUMENT_END:
+
+		fyds = fyp->current_document_state;
+		fyp_error_check(fyp, fyds, err_out,
+				"no current document state error");
+
+		if (fyt && (fyt->type == FYTT_VERSION_DIRECTIVE ||
+			    fyt->type == FYTT_TAG_DIRECTIVE)) {
+			int cmpval = fy_document_state_version_compare(fyds, fy_version_make(1, 1));
+
+			fyp_scan_debug(fyp, "version %d.%d %s %d.%d\n",
+				fyds->version.major, fyds->version.minor,
+				cmpval == 0 ? "=" : cmpval > 0 ? ">" : "<",
+				1, 1);
+
+			/* YAML 1.1 allows directives without document end */
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+				cmpval <= 0, err_out,
+				"missing explicit document end marker before directive(s)");
+
+		}
+
+		fym = fy_token_end_mark(fyt);
+		if (fym)
+			fyds->end_mark = *fym;
+		else
+			memset(&fyds->end_mark, 0, sizeof(fyds->end_mark));
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		/* document end */
+		fye->type = FYET_DOCUMENT_END;
+		if (fyt->type == FYTT_DOCUMENT_END) {
+			/* TODO pull the document end token and deliver */
+			fye->document_end.document_end = NULL;
+			fyds->end_implicit = false;
+
+			/* reset document has content flag */
+			fyp->document_has_content = false;
+			fyp->document_first_content_token = true;
+
+			/* reset directives */
+			fyp->had_directives = false;
+
+		} else {
+			fye->document_end.document_end = NULL;
+			fyds->end_implicit = true;
+		}
+
+		fye->document_end.implicit = fyds->end_implicit;
+
+		if (!fyp->next_single_document) {
+			/* multi document mode */
+			fy_parse_state_set(fyp, FYPS_DOCUMENT_START);
+			fyp->had_directives = false;
+
+			/* and reset document state */
+			rc = fy_reset_document_state(fyp);
+			fyp_error_check(fyp, !rc, err_out,
+					"fy_reset_document_state() failed");
+		} else {
+			/* single document mode */
+			fyp->next_single_document = false;
+
+			fy_parse_state_set(fyp, FYPS_SINGLE_DOCUMENT_END);
+		}
+
+		return fyep;
+
+	case FYPS_DOCUMENT_CONTENT:
+
+		if (fyt->type == FYTT_VERSION_DIRECTIVE ||
+		    fyt->type == FYTT_TAG_DIRECTIVE ||
+		    fyt->type == FYTT_DOCUMENT_START ||
+		    fyt->type == FYTT_DOCUMENT_END ||
+		    fyt->type == FYTT_STREAM_END) {
+
+			if (fyt->type == FYTT_DOCUMENT_START ||
+			    fyt->type == FYTT_DOCUMENT_END) {
+				fyp->document_has_content = false;
+				fyp->document_first_content_token = true;
+				fyp->had_directives = false;
+			}
+
+			fy_parse_state_set(fyp, fy_parse_state_pop(fyp));
+
+			fyep = fy_parse_empty_scalar(fyp);
+			fyp_error_check(fyp, fyep, err_out,
+					"fy_parse_empty_scalar() failed");
+			return fyep;
+		}
+
+		fyp->document_has_content = true;
+		fyp_parse_debug(fyp, "document has content now");
+		/* fallthrough */
+
+	case FYPS_BLOCK_NODE:
+
+		fyep = fy_parse_node(fyp, fyt,
+				fyp->state == FYPS_BLOCK_NODE ||
+				fyp->state == FYPS_DOCUMENT_CONTENT);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_parse_node() failed");
+		return fyep;
+
+	case FYPS_BLOCK_SEQUENCE_FIRST_ENTRY:
+		is_first = true;
+		/* fallthrough */
+
+	case FYPS_BLOCK_SEQUENCE_ENTRY:
+	case FYPS_INDENTLESS_SEQUENCE_ENTRY:
+
+		if ((fyp->state == FYPS_BLOCK_SEQUENCE_ENTRY ||
+		     fyp->state == FYPS_BLOCK_SEQUENCE_FIRST_ENTRY) &&
+		    !(fyt->type == FYTT_BLOCK_ENTRY ||
+		      fyt->type == FYTT_BLOCK_END)) {
+
+
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+					!(fyt->type == FYTT_SCALAR), err_out,
+					"invalid scalar at the end of block sequence");
+
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+					!(fyt->type == FYTT_BLOCK_SEQUENCE_START), err_out,
+					"wrongly indented sequence item");
+
+			FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+					false, err_out,
+					"did not find expected '-' indicator");
+		}
+
+		if (fyt->type == FYTT_BLOCK_ENTRY) {
+
+			/* BLOCK entry */
+			fyt = fy_scan_remove_peek(fyp, fyt);
+			fyp_error_check(fyp, fyt, err_out,
+					"failed to peek token");
+#ifdef FY_DEVMODE
+			fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+
+			/* check whether it's a sequence entry or not */
+			is_seq = fyt->type != FYTT_BLOCK_ENTRY && fyt->type != FYTT_BLOCK_END;
+			if (!is_seq && fyp->state == FYPS_INDENTLESS_SEQUENCE_ENTRY)
+				is_seq = fyt->type != FYTT_KEY && fyt->type != FYTT_VALUE;
+
+			if (is_seq) {
+				rc = fy_parse_state_push(fyp, fyp->state);
+				fyp_error_check(fyp, !rc, err_out,
+						"failed to push state");
+
+				fyep = fy_parse_node(fyp, fyt, true);
+				fyp_error_check(fyp, fyep, err_out,
+						"fy_parse_node() failed");
+				return fyep;
+			}
+			fy_parse_state_set(fyp, FYPS_BLOCK_SEQUENCE_ENTRY);
+
+			fyep = fy_parse_empty_scalar(fyp);
+			fyp_error_check(fyp, fyep, err_out,
+					"fy_parse_empty_scalar() failed");
+			return fyep;
+		}
+
+		/* FYTT_BLOCK_END */
+		fy_parse_state_set(fyp, fy_parse_state_pop(fyp));
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_SEQUENCE_END;
+		if (orig_state == FYPS_INDENTLESS_SEQUENCE_ENTRY) {
+
+			/* allocate and copy in place */
+			fytn = fy_token_alloc_rl(fyp->recycled_token_list);
+			fyp_error_check(fyp, fytn, err_out,
+					"fy_token_alloc_rl() failed!");
+			fytn->type = FYTT_BLOCK_END;
+			fytn->handle = fyt->handle;
+			fytn->handle.end_mark = fytn->handle.start_mark;	/* no extent */
+			fy_input_ref(fytn->handle.fyi);
+
+			fye->sequence_end.sequence_end = fytn;
+		} else
+			fye->sequence_end.sequence_end = fy_scan_remove(fyp, fyt);
+
+		return fyep;
+
+	case FYPS_BLOCK_MAPPING_FIRST_KEY:
+		is_first = true;
+		/* fallthrough */
+
+	case FYPS_BLOCK_MAPPING_KEY:
+
+		if (!(fyt->type == FYTT_KEY || fyt->type == FYTT_BLOCK_END || fyt->type == FYTT_STREAM_END)) {
+
+			if (fyt->type == FYTT_SCALAR)
+				FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+						!fyp->simple_key_allowed && !fyp->flow_level && fy_parse_peek(fyp) == ':' ?
+							"invalid block mapping key on same line as previous key" :
+							"invalid value after mapping");
+			else if (fyt->type == FYTT_BLOCK_SEQUENCE_START)
+				FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+						"wrong indendation in sequence while in mapping");
+			else if (fyt->type == FYTT_ANCHOR)
+				FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+						"two anchors for a single value while in mapping");
+			else if (fyt->type == FYTT_BLOCK_MAPPING_START)
+				FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+						!fyp->flow_level && fyp->last_block_mapping_key_line == fy_token_start_line(fyt) ?
+							"invalid nested block mapping on the same line" :
+							"invalid indentation in mapping");
+			else if (fyt->type == FYTT_ALIAS)
+				FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+						"invalid combination of anchor plus alias");
+			else
+				FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+						"did not find expected key");
+			goto err_out;
+		}
+
+		if (fyt->type == FYTT_KEY) {
+
+			fyp->last_block_mapping_key_line = fy_token_end_line(fyt);
+
+			/* KEY entry */
+			fyt = fy_scan_remove_peek(fyp, fyt);
+			fyp_error_check(fyp, fyt, err_out,
+					"failed to peek token");
+#ifdef FY_DEVMODE
+			fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+
+			/* check whether it's a block entry or not */
+			is_block = fyt->type != FYTT_KEY && fyt->type != FYTT_VALUE &&
+				fyt->type != FYTT_BLOCK_END;
+
+			if (is_block) {
+				rc = fy_parse_state_push(fyp, FYPS_BLOCK_MAPPING_VALUE);
+				fyp_error_check(fyp, !rc, err_out,
+						"failed to push state");
+
+				fyep = fy_parse_node(fyp, fyt, true);
+				fyp_error_check(fyp, fyep, err_out,
+						"fy_parse_node() failed");
+				return fyep;
+			}
+			fy_parse_state_set(fyp, FYPS_BLOCK_MAPPING_VALUE);
+
+			fyep = fy_parse_empty_scalar(fyp);
+			fyp_error_check(fyp, fyep, err_out,
+					"fy_parse_empty_scalar() failed");
+			return fyep;
+		}
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		/* FYTT_BLOCK_END */
+		fy_parse_state_set(fyp, fy_parse_state_pop(fyp));
+		fye->type = FYET_MAPPING_END;
+		fye->mapping_end.mapping_end = fy_scan_remove(fyp, fyt);
+		return fyep;
+
+	case FYPS_BLOCK_MAPPING_VALUE:
+
+		if (fyt->type == FYTT_VALUE) {
+
+			/* VALUE entry */
+			fyt = fy_scan_remove_peek(fyp, fyt);
+			fyp_error_check(fyp, fyt, err_out,
+					"failed to peek token");
+#ifdef FY_DEVMODE
+			fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+
+			/* check whether it's a block entry or not */
+			is_value = fyt->type != FYTT_KEY && fyt->type != FYTT_VALUE &&
+				fyt->type != FYTT_BLOCK_END;
+
+			if (is_value) {
+				rc = fy_parse_state_push(fyp, FYPS_BLOCK_MAPPING_KEY);
+				fyp_error_check(fyp, !rc, err_out,
+						"failed to push state");
+
+				fyep = fy_parse_node(fyp, fyt, true);
+				fyp_error_check(fyp, fyep, err_out,
+						"fy_parse_node() failed");
+				return fyep;
+			}
+		}
+
+		fy_parse_state_set(fyp, FYPS_BLOCK_MAPPING_KEY);
+
+		fyep = fy_parse_empty_scalar(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_parse_empty_scalar() failed");
+		return fyep;
+
+	case FYPS_FLOW_SEQUENCE_FIRST_ENTRY:
+		is_first = true;
+		/* fallthrough */
+
+	case FYPS_FLOW_SEQUENCE_ENTRY:
+
+		if (fyt->type != FYTT_FLOW_SEQUENCE_END &&
+		    fyt->type != FYTT_STREAM_END) {
+
+			if (!is_first) {
+				FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+						fyt->type == FYTT_FLOW_ENTRY, err_out,
+						"missing comma in flow %s",
+							fyp->state == FYPS_FLOW_SEQUENCE_ENTRY ?
+								"sequence" : "mapping");
+
+				fyt = fy_scan_remove_peek(fyp, fyt);
+				fyp_error_check(fyp, fyt, err_out,
+						"failed to peek token");
+#ifdef FY_DEVMODE
+				fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+			}
+
+			if (fyt->type == FYTT_KEY) {
+				fy_parse_state_set(fyp, FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_KEY);
+
+				fyep = fy_parse_eventp_alloc(fyp);
+				fyp_error_check(fyp, fyep, err_out,
+						"fy_eventp_alloc() failed!");
+				fye = &fyep->e;
+
+				/* convert KEY token to either block or flow mapping start */
+				if (!fyt->key.flow_level)
+					fyt->type = FYTT_BLOCK_MAPPING_START;
+				else
+					fyt->type = FYTT_FLOW_MAPPING_START;
+
+				fye->type = FYET_MAPPING_START;
+				fye->mapping_start.anchor = NULL;
+				fye->mapping_start.tag = NULL;
+				fye->mapping_start.mapping_start = fy_scan_remove(fyp, fyt);
+				return fyep;
+			}
+
+			if (fyt->type != FYTT_FLOW_SEQUENCE_END) {
+				rc = fy_parse_state_push(fyp, FYPS_FLOW_SEQUENCE_ENTRY);
+				fyp_error_check(fyp, !rc, err_out,
+						"failed to push state");
+
+				fyep = fy_parse_node(fyp, fyt, false);
+				fyp_error_check(fyp, fyep, err_out,
+						"fy_parse_node() failed");
+				return fyep;
+			}
+		}
+
+		if (fyt->type == FYTT_STREAM_END && fyp->flow_level) {
+			FYP_TOKEN_ERROR(fyp, fyt, FYEM_PARSE,
+					"flow sequence without a closing bracket");
+			goto err_out;
+		}
+
+		/* FYTT_FLOW_SEQUENCE_END */
+		fy_parse_state_set(fyp, fy_parse_state_pop(fyp));
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_SEQUENCE_END;
+		fye->sequence_end.sequence_end = fy_scan_remove(fyp, fyt);
+		return fyep;
+
+	case FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_KEY:
+		if (fyt->type != FYTT_VALUE && fyt->type != FYTT_FLOW_ENTRY &&
+		    fyt->type != FYTT_FLOW_SEQUENCE_END) {
+			rc = fy_parse_state_push(fyp, FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_VALUE);
+			fyp_error_check(fyp, !rc, err_out,
+					"failed to push state");
+
+			fyep = fy_parse_node(fyp, fyt, false);
+			fyp_error_check(fyp, fyep, err_out,
+					"fy_parse_node() failed");
+			return fyep;
+		}
+
+		/* empty keys are not allowed in JSON mode */
+		FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+				!fyp_json_mode(fyp), err_out,
+				"JSON does not allow empty keys of a mapping");
+
+		fy_parse_state_set(fyp, FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_VALUE);
+
+		fyep = fy_parse_empty_scalar(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_parse_empty_scalar() failed");
+		return fyep;
+
+	case FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_VALUE:
+		if (fyt->type == FYTT_VALUE) {
+			fyt = fy_scan_remove_peek(fyp, fyt);
+			fyp_error_check(fyp, fyt, err_out,
+					"failed to peek token");
+#ifdef FY_DEVMODE
+			fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+
+			if (fyt->type != FYTT_FLOW_ENTRY && fyt->type != FYTT_FLOW_SEQUENCE_END) {
+				rc = fy_parse_state_push(fyp, FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_END);
+				fyp_error_check(fyp, !rc, err_out,
+						"failed to push state");
+
+				fyep = fy_parse_node(fyp, fyt, false);
+				fyp_error_check(fyp, fyep, err_out,
+						"fy_parse_node() failed");
+				return fyep;
+			}
+		}
+
+		/* empty values are not allowed in JSON mode */
+		FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+				!fyp_json_mode(fyp), err_out,
+				"JSON does not allow empty values in a mapping");
+
+		fy_parse_state_set(fyp, FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_END);
+
+		fyep = fy_parse_empty_scalar(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_parse_empty_scalar() failed");
+		return fyep;
+
+	case FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_END:
+		fy_parse_state_set(fyp, FYPS_FLOW_SEQUENCE_ENTRY);
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_MAPPING_END;
+
+		/* allocate and copy in place */
+		fytn = fy_token_alloc_rl(fyp->recycled_token_list);
+		fyp_error_check(fyp, fytn, err_out,
+				"fy_token_alloc_rl() failed!");
+		fytn->type = FYTT_BLOCK_END;
+		fytn->handle = fyt->handle;
+		fytn->handle.end_mark = fytn->handle.start_mark;	/* no extent */
+		fy_input_ref(fytn->handle.fyi);
+
+		fye->mapping_end.mapping_end = fytn;
+
+		return fyep;
+
+	case FYPS_FLOW_MAPPING_FIRST_KEY:
+		is_first = true;
+		/* fallthrough */
+
+	case FYPS_FLOW_MAPPING_KEY:
+		if (fyt->type != FYTT_FLOW_MAPPING_END) {
+
+			if (!is_first) {
+				FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+						fyt->type == FYTT_FLOW_ENTRY, err_out,
+						"missing comma in flow %s",
+							fyp->state == FYPS_FLOW_SEQUENCE_ENTRY ?
+								"sequence" : "mapping");
+
+				fyt = fy_scan_remove_peek(fyp, fyt);
+				fyp_error_check(fyp, fyt, err_out,
+						"failed to peek token");
+#ifdef FY_DEVMODE
+				fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+			}
+
+			if (fyt->type == FYTT_KEY) {
+				/* next token */
+				fyt = fy_scan_remove_peek(fyp, fyt);
+				fyp_error_check(fyp, fyt, err_out,
+						"failed to peek token");
+#ifdef FY_DEVMODE
+				fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+
+				/* JSON key checks */
+				FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+						!fyp_json_mode(fyp) || fyt->type != FYTT_VALUE,
+						err_out, "JSON does not allow empty keys");
+				FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+						!fyp_json_mode(fyp) ||
+							(fyt->type == FYTT_SCALAR &&
+							 fyt->scalar.style == FYSS_DOUBLE_QUOTED),
+						err_out, "JSON only allows double quoted scalar keys");
+
+				if (fyt->type != FYTT_VALUE &&
+				    fyt->type != FYTT_FLOW_ENTRY &&
+				    fyt->type != FYTT_FLOW_MAPPING_END) {
+
+					rc = fy_parse_state_push(fyp, FYPS_FLOW_MAPPING_VALUE);
+					fyp_error_check(fyp, !rc, err_out,
+							"failed to push state");
+
+					fyep = fy_parse_node(fyp, fyt, false);
+					fyp_error_check(fyp, fyep, err_out,
+							"fy_parse_node() failed");
+					return fyep;
+				}
+
+				fy_parse_state_set(fyp, FYPS_FLOW_MAPPING_VALUE);
+
+				fyep = fy_parse_empty_scalar(fyp);
+				fyp_error_check(fyp, fyep, err_out,
+						"fy_parse_empty_scalar() failed");
+				return fyep;
+			}
+
+			if (fyt->type != FYTT_FLOW_MAPPING_END) {
+
+				/* empty values are not allowed in JSON mode */
+				FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+						!fyp_json_mode(fyp), err_out,
+						"JSON does not allow empty values in a mapping");
+
+				rc = fy_parse_state_push(fyp, FYPS_FLOW_MAPPING_EMPTY_VALUE);
+				fyp_error_check(fyp, !rc, err_out,
+						"failed to push state");
+
+				fyep = fy_parse_node(fyp, fyt, false);
+				fyp_error_check(fyp, fyep, err_out,
+						"fy_parse_node() failed");
+				return fyep;
+			}
+		}
+
+		/* FYTT_FLOW_MAPPING_END */
+		fy_parse_state_set(fyp, fy_parse_state_pop(fyp));
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out, "fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_MAPPING_END;
+		fye->mapping_end.mapping_end = fy_scan_remove(fyp, fyt);
+
+		return fyep;
+
+	case FYPS_FLOW_MAPPING_VALUE:
+		if (fyt->type == FYTT_VALUE) {
+			/* next token */
+			fyt = fy_scan_remove_peek(fyp, fyt);
+			fyp_error_check(fyp, fyt, err_out,
+					"failed to peek token");
+#ifdef FY_DEVMODE
+			fyp_debug_dump_token(fyp, fyt, "next: ");
+#endif
+
+			if (fyt->type != FYTT_FLOW_ENTRY &&
+			    fyt->type != FYTT_FLOW_MAPPING_END) {
+
+				rc = fy_parse_state_push(fyp, FYPS_FLOW_MAPPING_KEY);
+				fyp_error_check(fyp, !rc, err_out,
+						"failed to push state");
+
+				fyep = fy_parse_node(fyp, fyt, false);
+				fyp_error_check(fyp, fyep, err_out,
+						"fy_parse_node() failed");
+				return fyep;
+			}
+		}
+
+		/* empty values are not allowed in JSON mode */
+		FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+				!fyp_json_mode(fyp), err_out,
+				"JSON does not allow empty values in a mapping");
+
+		fy_parse_state_set(fyp, FYPS_FLOW_MAPPING_KEY);
+
+		fyep = fy_parse_empty_scalar(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_parse_empty_scalar() failed");
+		return fyep;
+
+	case FYPS_FLOW_MAPPING_EMPTY_VALUE:
+		fy_parse_state_set(fyp, FYPS_FLOW_MAPPING_KEY);
+
+		fyep = fy_parse_empty_scalar(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_parse_empty_scalar() failed");
+		return fyep;
+
+	case FYPS_SINGLE_DOCUMENT_END:
+
+		FYP_TOKEN_ERROR_CHECK(fyp, fyt, FYEM_PARSE,
+				fyt->type == FYTT_STREAM_END, err_out,
+				"Did not find expected stream end");
+
+		rc = fy_parse_stream_end(fyp);
+		fyp_error_check(fyp, !rc, err_out,
+				"stream end failed");
+
+		fyep = fy_parse_eventp_alloc(fyp);
+		fyp_error_check(fyp, fyep, err_out,
+				"fy_eventp_alloc() failed!");
+		fye = &fyep->e;
+
+		fye->type = FYET_STREAM_END;
+		fye->stream_end.stream_end = fy_scan_remove(fyp, fyt);
+
+		fy_parse_state_set(fyp,
+			fy_parse_have_more_inputs(fyp) ? FYPS_NONE : FYPS_END);
+
+		return fyep;
+
+	case FYPS_END:
+		/* should never happen */
+		assert(0);
+		break;
+	}
+
+err_out:
+	fy_token_unref_rl(fyp->recycled_token_list, version_directive);
+	fy_token_list_unref_all_rl(fyp->recycled_token_list, &tag_directives);
+	fy_parse_eventp_recycle(fyp, fyep);
+	fyp->stream_error = true;
+	return NULL;
+}
+
+const char *fy_event_type_txt[] = {
+	[FYET_NONE]		= "NONE",
+	[FYET_STREAM_START]	= "+STR",
+	[FYET_STREAM_END]	= "-STR",
+	[FYET_DOCUMENT_START]	= "+DOC",
+	[FYET_DOCUMENT_END]	= "-DOC",
+	[FYET_MAPPING_START]	= "+MAP",
+	[FYET_MAPPING_END]	= "-MAP",
+	[FYET_SEQUENCE_START]	= "+SEQ",
+	[FYET_SEQUENCE_END]	= "-SEQ",
+	[FYET_SCALAR]		= "=VAL",
+	[FYET_ALIAS]		= "=ALI",
+};
+
+const char *fy_event_type_get_text(enum fy_event_type type)
+{
+	if ((unsigned int)type >= ARRAY_SIZE(fy_event_type_txt))
+		return "*BAD";
+	return fy_event_type_txt[type];
+}
+
+struct fy_eventp *fy_parse_private(struct fy_parser *fyp)
+{
+	struct fy_eventp *fyep = NULL;
+
+	fyep = fy_parse_internal(fyp);
+	fyp_parse_debug(fyp, "> %s", fyep ? fy_event_type_txt[fyep->e.type] : "NULL");
+
+	return fyep;
+}
+
+struct fy_parser *fy_parser_create(const struct fy_parse_cfg *cfg)
+{
+	struct fy_parser *fyp;
+	int rc;
+
+	if (!cfg)
+		return NULL;
+
+	fyp = malloc(sizeof(*fyp));
+	if (!fyp)
+		return NULL;
+
+	rc = fy_parse_setup(fyp, cfg);
+	if (rc) {
+		free(fyp);
+		return NULL;
+	}
+
+	return fyp;
+}
+
+void fy_parser_destroy(struct fy_parser *fyp)
+{
+	if (!fyp)
+		return;
+
+	fy_parse_cleanup(fyp);
+
+	free(fyp);
+}
+
+const struct fy_parse_cfg *fy_parser_get_cfg(struct fy_parser *fyp)
+{
+	if (!fyp)
+		return NULL;
+	return &fyp->cfg;
+}
+
+struct fy_diag *fy_parser_get_diag(struct fy_parser *fyp)
+{
+	if (!fyp || !fyp->diag)
+		return NULL;
+	return fy_diag_ref(fyp->diag);
+}
+
+int fy_parser_set_diag(struct fy_parser *fyp, struct fy_diag *diag)
+{
+	struct fy_diag_cfg dcfg;
+
+	if (!fyp)
+		return -1;
+
+	/* default? */
+	if (!diag) {
+		fy_diag_cfg_default(&dcfg);
+		diag = fy_diag_create(&dcfg);
+		if (!diag)
+			return -1;
+	}
+
+	fy_diag_unref(fyp->diag);
+	fyp->diag = fy_diag_ref(diag);
+
+	return 0;
+}
+
+static void fy_parse_input_reset(struct fy_parser *fyp)
+{
+	struct fy_input *fyi, *fyin;
+
+	for (fyi = fy_input_list_head(&fyp->queued_inputs); fyi; fyi = fyin) {
+		fyin = fy_input_next(&fyp->queued_inputs, fyi);
+		fy_input_unref(fyi);
+	}
+
+	fy_parse_parse_state_log_list_recycle_all(fyp, &fyp->state_stack);
+
+	fyp->stream_start_produced = false;
+	fyp->stream_end_produced = false;
+	fyp->stream_end_reached = false;
+	fyp->state = FYPS_NONE;
+
+	fyp->pending_complex_key_column = -1;
+	fyp->last_block_mapping_key_line = -1;
+}
+
+int fy_parser_set_input_file(struct fy_parser *fyp, const char *file)
+{
+	struct fy_input_cfg fyic;
+	int rc;
+
+	if (!fyp || !file)
+		return -1;
+
+	memset(&fyic, 0, sizeof(fyic));
+
+	if (!strcmp(file, "-")) {
+		fyic.type = fyit_stream;
+		fyic.stream.name = "stdin";
+		fyic.stream.fp = stdin;
+	} else {
+		fyic.type = fyit_file;
+		fyic.file.filename = file;
+	}
+	fyic.ignore_stdio = !!(fyp->cfg.flags & FYPCF_DISABLE_BUFFERING);
+
+	/* must not be in the middle of something */
+	fyp_error_check(fyp, fyp->state == FYPS_NONE || fyp->state == FYPS_END,
+			err_out, "parser cannot be reset at state '%s'",
+				state_txt[fyp->state]);
+
+	fy_parse_input_reset(fyp);
+
+	rc = fy_parse_input_append(fyp, &fyic);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_parse_input_append() failed");
+
+	return 0;
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_parser_set_string(struct fy_parser *fyp, const char *str, size_t len)
+{
+	struct fy_input_cfg fyic;
+	int rc;
+
+	if (!fyp || !str)
+		return -1;
+
+	if (len == (size_t)-1)
+		len = strlen(str);
+
+	memset(&fyic, 0, sizeof(fyic));
+
+	fyic.type = fyit_memory;
+	fyic.memory.data = str;
+	fyic.memory.size = len;
+
+	/* must not be in the middle of something */
+	fyp_error_check(fyp, fyp->state == FYPS_NONE || fyp->state == FYPS_END,
+			err_out, "parser cannot be reset at state '%s'",
+				state_txt[fyp->state]);
+
+	fy_parse_input_reset(fyp);
+
+	rc = fy_parse_input_append(fyp, &fyic);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_parse_input_append() failed");
+
+	return 0;
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_parser_set_malloc_string(struct fy_parser *fyp, char *str, size_t len)
+{
+	struct fy_input_cfg fyic;
+	int rc;
+
+	if (!fyp || !str)
+		return -1;
+
+	if (len == (size_t)-1)
+		len = strlen(str);
+
+	memset(&fyic, 0, sizeof(fyic));
+
+	fyic.type = fyit_alloc;
+	fyic.alloc.data = str;
+	fyic.alloc.size = len;
+
+	/* must not be in the middle of something */
+	fyp_error_check(fyp, fyp->state == FYPS_NONE || fyp->state == FYPS_END,
+			err_out, "parser cannot be reset at state '%s'",
+				state_txt[fyp->state]);
+
+	fy_parse_input_reset(fyp);
+
+	rc = fy_parse_input_append(fyp, &fyic);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_parse_input_append() failed");
+
+	return 0;
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_parser_set_input_fp(struct fy_parser *fyp, const char *name, FILE *fp)
+{
+	struct fy_input_cfg fyic;
+	int rc;
+
+	if (!fyp || !fp)
+		return -1;
+
+	memset(&fyic, 0, sizeof(fyic));
+
+	fyic.type = fyit_stream;
+	fyic.stream.name = name ? name : "<stream>";
+	fyic.stream.fp = fp;
+	fyic.ignore_stdio = !!(fyp->cfg.flags & FYPCF_DISABLE_BUFFERING);
+
+	/* must not be in the middle of something */
+	fyp_error_check(fyp, fyp->state == FYPS_NONE || fyp->state == FYPS_END,
+			err_out, "parser cannot be reset at state '%s'",
+				state_txt[fyp->state]);
+
+	fy_parse_input_reset(fyp);
+
+	rc = fy_parse_input_append(fyp, &fyic);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_parse_input_append() failed");
+
+	return 0;
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_parser_set_input_callback(struct fy_parser *fyp, void *user,
+		ssize_t (*callback)(void *user, void *buf, size_t count))
+{
+	struct fy_input_cfg fyic;
+	int rc;
+
+	if (!fyp || !callback)
+		return -1;
+
+	memset(&fyic, 0, sizeof(fyic));
+
+	fyic.type = fyit_callback;
+	fyic.userdata = user;
+	fyic.callback.input = callback;
+	fyic.ignore_stdio = !!(fyp->cfg.flags & FYPCF_DISABLE_BUFFERING);
+
+	/* must not be in the middle of something */
+	fyp_error_check(fyp, fyp->state == FYPS_NONE || fyp->state == FYPS_END,
+			err_out, "parser cannot be reset at state '%s'",
+				state_txt[fyp->state]);
+
+	fy_parse_input_reset(fyp);
+
+	rc = fy_parse_input_append(fyp, &fyic);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_parse_input_append() failed");
+
+	return 0;
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_parser_set_input_fd(struct fy_parser *fyp, int fd)
+{
+	struct fy_input_cfg fyic;
+	int rc;
+
+	if (!fyp || fd < 0)
+		return -1;
+
+	memset(&fyic, 0, sizeof(fyic));
+
+	fyic.type = fyit_fd;
+	fyic.fd.fd = fd;
+	fyic.ignore_stdio = !!(fyp->cfg.flags & FYPCF_DISABLE_BUFFERING);
+
+	/* must not be in the middle of something */
+	fyp_error_check(fyp, fyp->state == FYPS_NONE || fyp->state == FYPS_END,
+			err_out, "parser cannot be reset at state '%s'",
+				state_txt[fyp->state]);
+
+	fy_parse_input_reset(fyp);
+
+	rc = fy_parse_input_append(fyp, &fyic);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_parse_input_append() failed");
+
+	return 0;
+err_out:
+	rc = -1;
+err_out_rc:
+	return rc;
+}
+
+int fy_parser_reset(struct fy_parser *fyp)
+{
+	int rc;
+
+	if (!fyp)
+		return -1;
+
+	fy_parse_input_reset(fyp);
+
+	fy_reader_reset(fyp->reader);
+
+	fyp->next_single_document = false;
+	fyp->stream_error = false;
+	fyp->generated_block_map = false;
+	fyp->last_was_comma = false;
+	fyp->document_has_content = false;
+	fyp->document_first_content_token = false;
+	fyp->bare_document_only = false;
+	fyp->stream_has_content = false;
+	fyp->had_directives = false;
+
+	assert(fyp->diag);
+	fyp->diag->on_error = false;
+
+	rc = fy_reset_document_state(fyp);
+	fyp_error_check(fyp, !rc, err_out_rc,
+			"fy_parse_input_reset() failed");
+
+	return 0;
+err_out_rc:
+	return rc;
+}
+
+struct fy_event *fy_parser_parse(struct fy_parser *fyp)
+{
+	struct fy_eventp *fyep;
+	enum fy_composer_return ret;
+
+	if (!fyp)
+		return NULL;
+
+	fyep = fy_parse_private(fyp);
+	if (!fyep)
+		return NULL;
+
+	if (fyp->fyc) {
+		ret = fy_composer_process_event(fyp->fyc, &fyep->e);
+		if (ret == FYCR_ERROR) {
+			fyp->stream_error = true;
+			fy_parse_eventp_recycle(fyp, fyep);
+			return NULL;
+		}
+		/* note that the stop should be handled by
+		 * an out of band mechanism */
+	}
+
+	return &fyep->e;
+}
+
+bool fy_parser_get_stream_error(struct fy_parser *fyp)
+{
+	if (!fyp)
+		return true;
+
+	return fyp->stream_error;
+}
+
+enum fy_parse_cfg_flags fy_parser_get_cfg_flags(const struct fy_parser *fyp)
+{
+	if (!fyp)
+		return 0;
+
+	return fyp->cfg.flags;
+}
+
+struct fy_document_state *fy_parser_get_document_state(struct fy_parser *fyp)
+{
+	return fyp ? fyp->current_document_state : NULL;
+}
+
+static enum fy_composer_return
+parse_process_event(struct fy_composer *fyc, struct fy_path *path, struct fy_event *fye)
+{
+	struct fy_parser *fyp = fy_composer_get_cfg_userdata(fyc);
+
+	assert(fyp);
+	assert(fyp->fyc_cb);
+	return fyp->fyc_cb(fyp, fye, path, fyp->fyc_userdata);
+}
+
+struct fy_document_builder *
+parse_create_document_builder(struct fy_composer *fyc)
+{
+	struct fy_parser *fyp = fy_composer_get_cfg_userdata(fyc);
+	struct fy_document_builder *fydb = NULL;
+	struct fy_document_builder_cfg cfg;
+	struct fy_document_state *fyds;
+	int rc;
+
+	memset(&cfg, 0, sizeof(cfg));
+	cfg.parse_cfg = fyp->cfg;
+	cfg.diag = fy_diag_ref(fyp->diag);
+
+	fydb = fy_document_builder_create(&cfg);
+	fyp_error_check(fyp, fydb, err_out,
+			"fy_document_builder_create() failed\n");
+
+	/* start with this document state */
+	fyds = fy_parser_get_document_state(fyp);
+	rc = fy_document_builder_set_in_document(fydb, fyds, true);
+	fyp_error_check(fyp, !rc, err_out,
+			"fy_document_builder_set_in_document() failed\n");
+
+	return fydb;
+
+err_out:
+	fy_document_builder_destroy(fydb);
+	return NULL;
+}
+
+static const struct fy_composer_ops parser_composer_ops = {
+	.process_event = parse_process_event,
+	.create_document_builder = parse_create_document_builder,
+};
+
+int fy_parse_set_composer(struct fy_parser *fyp, fy_parse_composer_cb cb, void *userdata)
+{
+	struct fy_composer_cfg ccfg;
+
+	if (!fyp)
+		return -1;
+
+	/* must not be in the middle of something */
+	fyp_error_check(fyp, fyp->state == FYPS_NONE || fyp->state == FYPS_END,
+			err_out, "cannot change composer state at state '%s'",
+				state_txt[fyp->state]);
+
+	/* clear */
+	if (!cb) {
+		if (fyp->fyc) {
+			fy_composer_destroy(fyp->fyc);
+			fyp->fyc = NULL;
+		}
+		fyp->fyc_cb = NULL;
+		fyp->fyc_userdata = NULL;
+		return 0;
+	}
+
+	/* already exists */
+	if (fyp->fyc) {
+		fyp->fyc_cb = cb;
+		fyp->fyc_userdata = userdata;
+		return 0;
+	}
+
+	/* prepare the composer configuration */
+	memset(&ccfg, 0, sizeof(ccfg));
+	ccfg.ops = &parser_composer_ops;
+	ccfg.userdata = fyp;
+	ccfg.diag = fy_parser_get_diag(fyp);
+	fyp->fyc = fy_composer_create(&ccfg);
+	fyp_error_check(fyp, fyp->fyc, err_out,
+			"fy_composer_create() failed");
+
+	fyp->fyc_cb = cb;
+	fyp->fyc_userdata = userdata;
+
+	return 0;
+err_out:
+	return -1;
+}
+
+static enum fy_composer_return fy_parse_compose_internal(struct fy_parser *fyp)
+{
+	struct fy_composer *fyc;
+	struct fy_document_iterator *fydi;
+	struct fy_event *fye;
+	struct fy_eventp *fyep;
+	struct fy_document *fyd = NULL;
+	enum fy_composer_return ret;
+
+	assert(fyp);
+
+	fyc = fyp->fyc;
+	assert(fyc);
+
+	/* simple, without resolution */
+	if (!(fyp->cfg.flags & FYPCF_RESOLVE_DOCUMENT)) {
+
+		ret = FYCR_OK_STOP;
+		while ((fyep = fy_parse_private(fyp)) != NULL) {
+			ret = fy_composer_process_event(fyc, &fyep->e);
+			fy_parse_eventp_recycle(fyp, fyep);
+			if (ret != FYCR_OK_CONTINUE)
+				break;
+		}
+		return ret;
+	}
+
+	fydi = fy_document_iterator_create();
+	fyp_error_check(fyp, fydi, err_out,
+			"fy_document_iterator_create() failed");
+
+	/* stream start event generation and processing */
+	fye = fy_document_iterator_stream_start(fydi);
+	fyp_error_check(fyp, fye, err_out,
+			"fy_document_iterator_stream_start() failed");
+	ret = fy_composer_process_event(fyc, fye);
+	fy_document_iterator_event_free(fydi, fye);
+	fye = NULL;
+	if (ret != FYCR_OK_CONTINUE)
+		goto out;
+
+	/* convert to document and then process the generator event stream it */
+	while ((fyd = fy_parse_load_document(fyp)) != NULL) {
+
+		/* document start event generation and processing */
+		fye = fy_document_iterator_document_start(fydi, fyd);
+		fyp_error_check(fyp, fye, err_out,
+				"fy_document_iterator_document_start() failed");
+		ret = fy_composer_process_event(fyc, fye);
+		fy_document_iterator_event_free(fydi, fye);
+		fye = NULL;
+		if (ret != FYCR_OK_CONTINUE)
+			goto out;
+
+		/* and now process the body */
+		ret = FYCR_OK_CONTINUE;
+		while ((fye = fy_document_iterator_body_next(fydi)) != NULL) {
+			ret = fy_composer_process_event(fyc, fye);
+			fy_document_iterator_event_free(fydi, fye);
+			fye = NULL;
+			if (ret != FYCR_OK_CONTINUE)
+				goto out;
+		}
+
+		/* document end event generation and processing */
+		fye = fy_document_iterator_document_end(fydi);
+		fyp_error_check(fyp, fye, err_out,
+				"fy_document_iterator_document_end() failed");
+		ret = fy_composer_process_event(fyc, fye);
+		fy_document_iterator_event_free(fydi, fye);
+		fye = NULL;
+		if (ret != FYCR_OK_CONTINUE)
+			goto out;
+
+		/* and destroy the document */
+		fy_parse_document_destroy(fyp, fyd);
+		fyd = NULL;
+	}
+
+	/* stream end event generation and processing */
+	fye = fy_document_iterator_stream_end(fydi);
+	fyp_error_check(fyp, fye, err_out,
+			"fy_document_iterator_stream_end() failed");
+	ret = fy_composer_process_event(fyc, fye);
+	fy_document_iterator_event_free(fydi, fye);
+	fye = NULL;
+	if (ret != FYCR_OK_CONTINUE)
+		goto out;
+
+out:
+	/* NULLs are OK */
+	fy_parse_document_destroy(fyp, fyd);
+	fy_document_iterator_destroy(fydi);
+	return ret;
+
+err_out:
+	ret = FYCR_ERROR;
+	goto out;
+}
+
+int fy_parse_compose(struct fy_parser *fyp, fy_parse_composer_cb cb, void *userdata)
+{
+	enum fy_composer_return ret;
+	int rc, rc_out;
+
+	if (!fyp || !cb)
+		return -1;
+
+	/* set the composer callback */
+	rc = fy_parse_set_composer(fyp, cb, userdata);
+	fyp_error_check(fyp, !rc, err_out,
+			"fy_parse_set_composer() failed\n");
+
+	/* use the composer to parse */
+	ret = fy_parse_compose_internal(fyp);
+	/* on error set the stream error */
+	if (ret == FYCR_ERROR) {
+		fyp->stream_error = true;
+		rc_out = -1;
+	} else
+		rc_out = 0;
+
+	/* reset the parser; the composer clear must always succeed */
+	fy_parser_reset(fyp);
+
+	/* clear composer */
+	rc = fy_parse_set_composer(fyp, NULL, NULL);
+	fyp_error_check(fyp, !rc, err_out,
+			"fy_parse_set_composer() failed\n");
+
+	return rc_out;
+
+err_out:
+	return -1;
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-parse.h b/contrib/libs/libfyaml/src/lib/fy-parse.h
new file mode 100644
index 0000000000..8ffae8c93d
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-parse.h
@@ -0,0 +1,592 @@
+/*
+ * fy-parse.h - YAML parser internal header file
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_PARSE_H
+#define FY_PARSE_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include <libfyaml.h>
+
+#include "fy-ctype.h"
+#include "fy-utf8.h"
+#include "fy-list.h"
+#include "fy-typelist.h"
+#include "fy-types.h"
+#include "fy-diag.h"
+#include "fy-dump.h"
+#include "fy-atom.h"
+#include "fy-input.h"
+#include "fy-ctype.h"
+#include "fy-token.h"
+#include "fy-event.h"
+#include "fy-docstate.h"
+#include "fy-doc.h"
+#include "fy-docbuilder.h"
+#include "fy-emit.h"
+#include "fy-accel.h"
+#include "fy-emit-accum.h"
+#include "fy-path.h"
+#include "fy-composer.h"
+
+struct fy_parser;
+struct fy_input;
+
+enum fy_flow_type {
+	FYFT_NONE,
+	FYFT_MAP,
+	FYFT_SEQUENCE,
+};
+
+struct fy_flow {
+	struct fy_list_head node;
+	enum fy_flow_type flow;
+	int pending_complex_key_column;
+	struct fy_mark pending_complex_key_mark;
+	int parent_indent;
+};
+FY_PARSE_TYPE_DECL(flow);
+
+struct fy_indent {
+	struct fy_list_head node;
+	int indent;
+	int indent_line;
+	bool generated_block_map : 1;
+};
+FY_PARSE_TYPE_DECL(indent);
+
+struct fy_token;
+
+struct fy_simple_key {
+	struct fy_list_head node;
+	struct fy_mark mark;
+	struct fy_mark end_mark;
+	struct fy_token *token;	/* associated token */
+	int flow_level;
+	bool required : 1;
+	bool implicit_complex : 1;
+};
+FY_PARSE_TYPE_DECL(simple_key);
+
+struct fy_document_state;
+
+enum fy_parser_state {
+	/** none state */
+	FYPS_NONE,
+	/** Expect STREAM-START. */
+	FYPS_STREAM_START,
+	/** Expect the beginning of an implicit document. */
+	FYPS_IMPLICIT_DOCUMENT_START,
+	/** Expect DOCUMENT-START. */
+	FYPS_DOCUMENT_START,
+	/** Expect the content of a document. */
+	FYPS_DOCUMENT_CONTENT,
+	/** Expect DOCUMENT-END. */
+	FYPS_DOCUMENT_END,
+	/** Expect a block node. */
+	FYPS_BLOCK_NODE,
+	/** Expect the first entry of a block sequence. */
+	FYPS_BLOCK_SEQUENCE_FIRST_ENTRY,
+	/** Expect an entry of a block sequence. */
+	FYPS_BLOCK_SEQUENCE_ENTRY,
+	/** Expect an entry of an indentless sequence. */
+	FYPS_INDENTLESS_SEQUENCE_ENTRY,
+	/** Expect the first key of a block mapping. */
+	FYPS_BLOCK_MAPPING_FIRST_KEY,
+	/** Expect a block mapping key. */
+	FYPS_BLOCK_MAPPING_KEY,
+	/** Expect a block mapping value. */
+	FYPS_BLOCK_MAPPING_VALUE,
+	/** Expect the first entry of a flow sequence. */
+	FYPS_FLOW_SEQUENCE_FIRST_ENTRY,
+	/** Expect an entry of a flow sequence. */
+	FYPS_FLOW_SEQUENCE_ENTRY,
+	/** Expect a key of an ordered mapping. */
+	FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_KEY,
+	/** Expect a value of an ordered mapping. */
+	FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_VALUE,
+	/** Expect the and of an ordered mapping entry. */
+	FYPS_FLOW_SEQUENCE_ENTRY_MAPPING_END,
+	/** Expect the first key of a flow mapping. */
+	FYPS_FLOW_MAPPING_FIRST_KEY,
+	/** Expect a key of a flow mapping. */
+	FYPS_FLOW_MAPPING_KEY,
+	/** Expect a value of a flow mapping. */
+	FYPS_FLOW_MAPPING_VALUE,
+	/** Expect an empty value of a flow mapping. */
+	FYPS_FLOW_MAPPING_EMPTY_VALUE,
+	/** Expect only stream end */
+	FYPS_SINGLE_DOCUMENT_END,
+	/** Expect nothing. */
+	FYPS_END
+};
+
+struct fy_parse_state_log {
+	struct fy_list_head node;
+	enum fy_parser_state state;
+};
+FY_PARSE_TYPE_DECL(parse_state_log);
+
+struct fy_parser {
+	struct fy_parse_cfg cfg;
+
+	struct fy_input_list queued_inputs;	/* all the inputs queued */
+	struct fy_reader builtin_reader;	/* the builtin reader */
+	struct fy_reader *reader;		/* the external reader, or ptr to builtin_reader */
+
+	struct fy_version default_version;
+	bool suppress_recycling : 1;
+	bool stream_start_produced : 1;
+	bool stream_end_produced : 1;
+	bool stream_end_reached : 1;
+	bool simple_key_allowed : 1;
+	bool tab_used_for_ws : 1;
+	bool stream_error : 1;
+	bool generated_block_map : 1;
+	bool last_was_comma : 1;
+	bool document_has_content : 1;
+	bool document_first_content_token : 1;
+	bool bare_document_only : 1;		/* no document start indicators allowed, no directives */
+	bool stream_has_content : 1;
+	bool parse_flow_only : 1;	/* document is in flow form, and stop parsing at the end */
+	bool colon_follows_colon : 1;	/* "foo"::bar -> "foo": :bar */
+	bool had_directives : 1;	/* document had directives */
+	int flow_level;
+	int pending_complex_key_column;
+	struct fy_mark pending_complex_key_mark;
+	int last_block_mapping_key_line;
+	struct fy_mark last_comma_mark;
+	struct fy_mark last_tab_used_for_ws_mark;
+
+	/* copy of stream_end token */
+	struct fy_token *stream_end_token;
+
+	/* produced tokens, but not yet consumed */
+	struct fy_token_list queued_tokens;
+	int token_activity_counter;
+
+	/* last comment */
+	struct fy_atom last_comment;
+
+	/* indent stack */
+	struct fy_indent_list indent_stack;
+	int indent;
+	int parent_indent;
+	int indent_line;
+	/* simple key stack */
+	struct fy_simple_key_list simple_keys;
+	/* state stack */
+	enum fy_parser_state state;
+	struct fy_parse_state_log_list state_stack;
+
+	/* current parse document */
+	struct fy_document_state *current_document_state;
+	struct fy_document_state *default_document_state;
+	bool next_single_document;
+
+	/* flow stack */
+	enum fy_flow_type flow;
+	struct fy_flow_list flow_stack;
+
+	/* recycling lists */
+	struct fy_indent_list recycled_indent;
+	struct fy_simple_key_list recycled_simple_key;
+	struct fy_parse_state_log_list recycled_parse_state_log;
+	struct fy_flow_list recycled_flow;
+
+	struct fy_eventp_list recycled_eventp;
+	struct fy_token_list recycled_token;
+
+	struct fy_eventp_list *recycled_eventp_list;
+	struct fy_token_list *recycled_token_list;
+
+	/* the diagnostic object */
+	struct fy_diag *diag;
+
+	int err_term_width;
+	int err_term_height;
+
+	/* for when using the built-in document builder */
+	struct fy_document_builder *fydb;
+
+	/* when using the composer interface */
+	struct fy_composer *fyc;
+	fy_parse_composer_cb fyc_cb;
+	void *fyc_userdata;
+};
+
+static inline struct fy_input *
+fyp_current_input(const struct fy_parser *fyp)
+{
+	assert(fyp);
+	return fy_reader_current_input(fyp->reader);
+}
+
+static inline uint64_t
+fyp_current_input_generation(const struct fy_parser *fyp)
+{
+	assert(fyp);
+	return fy_reader_current_input_generation(fyp->reader);
+}
+
+static inline int fyp_column(const struct fy_parser *fyp)
+{
+	assert(fyp);
+	return fy_reader_column(fyp->reader);
+}
+
+static inline int fyp_line(const struct fy_parser *fyp)
+{
+	return fy_reader_line(fyp->reader);
+}
+
+static inline int fyp_tabsize(const struct fy_parser *fyp)
+{
+	return fy_reader_tabsize(fyp->reader);
+}
+
+static inline bool fyp_json_mode(const struct fy_parser *fyp)
+{
+	assert(fyp);
+	return fy_reader_json_mode(fyp->reader);
+}
+
+static inline enum fy_lb_mode fyp_lb_mode(const struct fy_parser *fyp)
+{
+	assert(fyp);
+	return fy_reader_lb_mode(fyp->reader);
+}
+
+static inline enum fy_flow_ws_mode fyp_fws_mode(const struct fy_parser *fyp)
+{
+	assert(fyp);
+	return fy_reader_flow_ws_mode(fyp->reader);
+}
+
+static inline bool fyp_block_mode(struct fy_parser *fyp)
+{
+	return !fyp_json_mode(fyp) && !fyp->flow_level;
+}
+
+static inline bool fyp_is_lb(const struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	return fy_reader_is_lb(fyp->reader, c);
+}
+
+static inline bool fyp_is_lbz(const struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	return fy_reader_is_lbz(fyp->reader, c);
+}
+
+static inline bool fyp_is_blankz(const struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	return fy_reader_is_blankz(fyp->reader, c);
+}
+
+static inline bool fyp_is_generic_lb(const struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	return fy_reader_is_generic_lb(fyp->reader, c);
+}
+
+static inline bool fyp_is_generic_lbz(const struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	return fy_reader_is_generic_lbz(fyp->reader, c);
+}
+
+static inline bool fyp_is_generic_blankz(const struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	return fy_reader_is_generic_blankz(fyp->reader, c);
+}
+
+static inline bool fyp_is_flow_ws(const struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	return fy_reader_is_flow_ws(fyp->reader, c);
+}
+
+static inline bool fyp_is_flow_blank(const struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	return fy_reader_is_flow_blank(fyp->reader, c);
+}
+
+static inline bool fyp_is_flow_blankz(const struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	return fy_reader_is_flow_blankz(fyp->reader, c);
+}
+
+static inline const void *
+fy_ptr_slow_path(struct fy_parser *fyp, size_t *leftp)
+{
+	assert(fyp);
+	return fy_reader_ptr_slow_path(fyp->reader, leftp);
+}
+
+static inline const void *
+fy_ensure_lookahead_slow_path(struct fy_parser *fyp, size_t size, size_t *leftp)
+{
+	assert(fyp);
+	return fy_reader_ensure_lookahead_slow_path(fyp->reader, size, leftp);
+}
+
+/* only allowed if input does not update */
+static inline void
+fy_get_mark(struct fy_parser *fyp, struct fy_mark *fym)
+{
+	assert(fyp);
+	return fy_reader_get_mark(fyp->reader, fym);
+}
+
+static inline const void *
+fy_ptr(struct fy_parser *fyp, size_t *leftp)
+{
+	assert(fyp);
+	return fy_reader_ptr(fyp->reader, leftp);
+}
+
+static inline const void *
+fy_ensure_lookahead(struct fy_parser *fyp, size_t size, size_t *leftp)
+{
+	assert(fyp);
+	return fy_reader_ensure_lookahead(fyp->reader, size, leftp);
+}
+
+/* advance the given number of ascii characters, not utf8 */
+static inline void
+fy_advance_octets(struct fy_parser *fyp, size_t advance)
+{
+	assert(fyp);
+	return fy_reader_advance_octets(fyp->reader, advance);
+}
+
+/* compare string at the current point (n max) */
+static inline int
+fy_parse_strncmp(struct fy_parser *fyp, const char *str, size_t n)
+{
+	assert(fyp);
+	return fy_reader_strncmp(fyp->reader, str, n);
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_parse_peek_at_offset(struct fy_parser *fyp, size_t offset)
+{
+	assert(fyp);
+	return fy_reader_peek_at_offset(fyp->reader, offset);
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_parse_peek_at_internal(struct fy_parser *fyp, int pos, ssize_t *offsetp)
+{
+	assert(fyp);
+	return fy_reader_peek_at_internal(fyp->reader, pos, offsetp);
+}
+
+static inline bool
+fy_is_blank_at_offset(struct fy_parser *fyp, size_t offset)
+{
+	assert(fyp);
+	return fy_is_blank(fy_reader_peek_at_offset(fyp->reader, offset));
+}
+
+static inline bool
+fy_is_blankz_at_offset(struct fy_parser *fyp, size_t offset)
+{
+	assert(fyp);
+	return fy_reader_is_blankz(fyp->reader, fy_reader_peek_at_offset(fyp->reader, offset));
+}
+
+static inline bool
+fy_is_generic_blankz_at_offset(struct fy_parser *fyp, size_t offset)
+{
+	assert(fyp);
+	return fy_reader_is_generic_blankz(fyp->reader, fy_reader_peek_at_offset(fyp->reader, offset));
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_parse_peek_at(struct fy_parser *fyp, int pos)
+{
+	assert(fyp);
+	return fy_reader_peek_at_internal(fyp->reader, pos, NULL);
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_parse_peek(struct fy_parser *fyp)
+{
+	assert(fyp);
+	return fy_reader_peek(fyp->reader);
+}
+
+static FY_ALWAYS_INLINE inline void
+fy_advance(struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	fy_reader_advance(fyp->reader, c);
+}
+
+static FY_ALWAYS_INLINE inline void
+fy_advance_ws(struct fy_parser *fyp, int c)
+{
+	assert(fyp);
+	fy_reader_advance_ws(fyp->reader, c);
+}
+
+static FY_ALWAYS_INLINE inline void
+fy_advance_space(struct fy_parser *fyp)
+{
+	assert(fyp);
+	fy_reader_advance_space(fyp->reader);
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_parse_get(struct fy_parser *fyp)
+{
+	assert(fyp);
+	return fy_reader_get(fyp->reader);
+}
+
+static FY_ALWAYS_INLINE inline int
+fy_advance_by(struct fy_parser *fyp, int count)
+{
+	assert(fyp);
+	return fy_reader_advance_by(fyp->reader, count);
+}
+
+/* compare string at the current point */
+static inline bool
+fy_parse_strcmp(struct fy_parser *fyp, const char *str)
+{
+	assert(fyp);
+	return fy_reader_strcmp(fyp->reader, str);
+}
+
+static inline void
+fy_fill_atom_start(struct fy_parser *fyp, struct fy_atom *handle)
+{
+	assert(fyp);
+	fy_reader_fill_atom_start(fyp->reader, handle);
+}
+
+static inline void
+fy_fill_atom_end_at(struct fy_parser *fyp, struct fy_atom *handle, struct fy_mark *end_mark)
+{
+	assert(fyp);
+	fy_reader_fill_atom_end_at(fyp->reader, handle, end_mark);
+}
+
+static inline void
+fy_fill_atom_end(struct fy_parser *fyp, struct fy_atom *handle)
+{
+	assert(fyp);
+	fy_reader_fill_atom_end(fyp->reader, handle);
+}
+
+static inline struct fy_atom *
+fy_fill_atom(struct fy_parser *fyp, int advance, struct fy_atom *handle)
+{
+	assert(fyp);
+	return fy_reader_fill_atom(fyp->reader, advance, handle);
+}
+
+static inline struct fy_atom *
+fy_fill_atom_mark(struct fy_parser *fyp, const struct fy_mark *start_mark,
+		  const struct fy_mark *end_mark, struct fy_atom *handle)
+{
+	assert(fyp);
+	return fy_reader_fill_atom_mark(fyp->reader, start_mark, end_mark, handle);
+}
+
+static inline struct fy_atom *
+fy_fill_atom_at(struct fy_parser *fyp, int advance, int count, struct fy_atom *handle)
+{
+	assert(fyp);
+	return fy_reader_fill_atom_at(fyp->reader, advance, count, handle);
+}
+
+static inline void
+fy_parser_set_reader(struct fy_parser *fyp, struct fy_reader *fyr)
+{
+	if (!fyp)
+		return;
+	fyp->reader = fyr ? fyr : &fyp->builtin_reader;
+}
+
+static inline void
+fy_parser_set_flow_only_mode(struct fy_parser *fyp, bool flow_only_mode)
+{
+	fyp->parse_flow_only = flow_only_mode;
+}
+
+#define fy_fill_atom_a(_fyp, _advance) \
+	fy_fill_atom((_fyp), (_advance), FY_ALLOCA(sizeof(struct fy_atom)))
+
+struct fy_token *fy_token_vqueue(struct fy_parser *fyp, enum fy_token_type type, va_list ap);
+struct fy_token *fy_token_queue(struct fy_parser *fyp, enum fy_token_type type, ...);
+
+struct fy_token *
+fy_token_vqueue_internal(struct fy_parser *fyp, struct fy_token_list *fytl,
+			 enum fy_token_type type, va_list ap);
+struct fy_token *
+fy_token_queue_internal(struct fy_parser *fyp, struct fy_token_list *fytl,
+			enum fy_token_type type, ...);
+
+int fy_parse_setup(struct fy_parser *fyp, const struct fy_parse_cfg *cfg);
+void fy_parse_cleanup(struct fy_parser *fyp);
+
+int fy_parse_input_append(struct fy_parser *fyp, const struct fy_input_cfg *fyic);
+
+struct fy_eventp *fy_parse_private(struct fy_parser *fyp);
+
+extern const char *fy_event_type_txt[];
+
+enum fy_parse_cfg_flags fy_parser_get_cfg_flags(const struct fy_parser *fyp);
+
+extern const struct fy_tag * const fy_default_tags[];
+
+extern const struct fy_version fy_default_version;	/* usually highest stable */
+
+bool fy_tag_handle_is_default(const char *handle, size_t handle_size);
+bool fy_tag_is_default_internal(const char *handle, size_t handle_size,
+				const char *prefix, size_t prefix_size);
+bool fy_token_tag_directive_is_overridable(struct fy_token *fyt_td);
+
+int fy_parser_set_default_document_state(struct fy_parser *fyp,
+					 struct fy_document_state *fyds);
+void fy_parser_set_next_single_document(struct fy_parser *fyp);
+
+void *fy_alloc_default(void *userdata, size_t size);
+void fy_free_default(void *userdata, void *ptr);
+void *fy_realloc_default(void *userdata, void *ptr, size_t size);
+
+int fy_reader_fetch_flow_scalar_handle(struct fy_reader *fyr, int c, int indent, struct fy_atom *handle, bool sloppy_indent);
+int fy_reader_fetch_plain_scalar_handle(struct fy_reader *fyr, int c, int indent, int flow_level, struct fy_atom *handle, bool directive0);
+
+void fy_reader_skip_ws_cr_nl(struct fy_reader *fyr);
+
+void fy_reader_skip_ws(struct fy_reader *fyr);
+void fy_reader_skip_space(struct fy_reader *fyr);
+
+static inline int fy_document_state_version_compare(struct fy_document_state *fyds, const struct fy_version *vb)
+{
+	return fy_version_compare(fy_document_state_version(fyds), vb);
+}
+
+int fy_parse_set_composer(struct fy_parser *fyp, fy_parse_composer_cb cb, void *userdata);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-path.c b/contrib/libs/libfyaml/src/lib/fy-path.c
new file mode 100644
index 0000000000..f9d9f99a41
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-path.c
@@ -0,0 +1,660 @@
+/*
+ * fy-path.c - Internal ypath support
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-doc.h"
+
+#include "fy-utils.h"
+
+#undef DBG
+// #define DBG fyp_notice
+#define DBG fyp_scan_debug
+
+static int fy_path_setup(struct fy_path *fypp)
+{
+	memset(fypp, 0, sizeof(*fypp));
+
+	fy_path_component_list_init(&fypp->recycled_component);
+	fy_path_component_list_init(&fypp->components);
+
+	return 0;
+}
+
+static void fy_path_cleanup(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc;
+
+	if (!fypp)
+		return;
+
+	if (fypp->fydb) {
+		fy_document_builder_destroy(fypp->fydb);
+		fypp->fydb = NULL;
+	}
+
+	while ((fypc = fy_path_component_list_pop(&fypp->components)) != NULL)
+		fy_path_component_free(fypc);
+
+	while ((fypc = fy_path_component_list_pop(&fypp->recycled_component)) != NULL)
+		fy_path_component_free(fypc);
+}
+
+struct fy_path *fy_path_create(void)
+{
+	struct fy_path *fypp;
+	int rc;
+
+	fypp = malloc(sizeof(*fypp));
+	if (!fypp)
+		return NULL;
+
+	rc = fy_path_setup(fypp);
+	if (rc)
+		return NULL;
+
+	return fypp;
+}
+
+void fy_path_destroy(struct fy_path *fypp)
+{
+	if (!fypp)
+		return;
+
+	fy_path_cleanup(fypp);
+
+	free(fypp);
+}
+
+void fy_path_reset(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc;
+
+	if (!fypp)
+		return;
+
+	while ((fypc = fy_path_component_list_pop(&fypp->components)) != NULL)
+		fy_path_component_free(fypc);
+}
+
+struct fy_path_component *fy_path_component_alloc(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc;
+
+	if (!fypp)
+		return NULL;
+
+	fypc = fy_path_component_list_pop(&fypp->recycled_component);
+	if (!fypc) {
+		fypc = malloc(sizeof(*fypc));
+		if (!fypc)
+			return NULL;
+		memset(fypc, 0, sizeof(*fypc));
+	}
+
+	/* not yet instantiated */
+	fypc->type = FYPCT_NONE;
+
+	return fypc;
+}
+
+void fy_path_component_clear_state(struct fy_path_component *fypc)
+{
+	if (!fypc)
+		return;
+
+	switch (fypc->type) {
+	case FYPCT_NONE:
+		/* nothing */
+		break;
+
+	case FYPCT_MAP:
+		if (fypc->map.has_key) {
+			if (fypc->map.is_complex_key) {
+				if (fypc->map.complex_key_complete)
+					fy_document_destroy(fypc->map.complex_key);
+				fypc->map.complex_key = NULL;
+			} else {
+				fy_token_unref(fypc->map.scalar.tag);
+				fy_token_unref(fypc->map.scalar.key);
+				fypc->map.scalar.tag = NULL;
+				fypc->map.scalar.key = NULL;
+			}
+		}
+		fypc->map.root = true;
+		fypc->map.has_key = false;
+		fypc->map.await_key = true;
+		fypc->map.is_complex_key = false;
+		fypc->map.accumulating_complex_key = false;
+		fypc->map.complex_key_complete = false;
+		break;
+
+	case FYPCT_SEQ:
+		fypc->seq.idx = -1;
+		break;
+	}
+}
+
+void fy_path_component_cleanup(struct fy_path_component *fypc)
+{
+	if (!fypc)
+		return;
+
+	fy_path_component_clear_state(fypc);
+	fypc->type = FYPCT_NONE;
+}
+
+void fy_path_component_free(struct fy_path_component *fypc)
+{
+	if (!fypc)
+		return;
+
+	fy_path_component_cleanup(fypc);
+	free(fypc);
+}
+
+void fy_path_component_destroy(struct fy_path_component *fypc)
+{
+	if (!fypc)
+		return;
+
+	fy_path_component_cleanup(fypc);
+	fy_path_component_free(fypc);
+}
+
+void fy_path_component_recycle(struct fy_path *fypp, struct fy_path_component *fypc)
+{
+	if (!fypc)
+		return;
+
+	fy_path_component_cleanup(fypc);
+
+	if (!fypp)
+		fy_path_component_free(fypc);
+	else
+		fy_path_component_list_push(&fypp->recycled_component, fypc);
+}
+
+struct fy_path_component *fy_path_component_create_mapping(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc;
+
+	if (!fypp)
+		return NULL;
+
+	fypc = fy_path_component_alloc(fypp);
+	if (!fypc)
+		return NULL;
+
+	fypc->type = FYPCT_MAP;
+
+	fypc->map.root = true;
+	fypc->map.await_key = true;
+	fypc->map.is_complex_key = false;
+	fypc->map.accumulating_complex_key = false;
+	fypc->map.complex_key_complete = false;
+
+	return fypc;
+}
+
+struct fy_path_component *fy_path_component_create_sequence(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc;
+
+	if (!fypp)
+		return NULL;
+
+	fypc = fy_path_component_alloc(fypp);
+	if (!fypc)
+		return NULL;
+
+	fypc->type = FYPCT_SEQ;
+
+	fypc->seq.idx = -1;
+
+	return fypc;
+}
+
+bool fy_path_component_is_mapping(struct fy_path_component *fypc)
+{
+	return fypc && fypc->type == FYPCT_MAP;
+}
+
+int fy_path_component_sequence_get_index(struct fy_path_component *fypc)
+{
+	return fypc && fypc->type == FYPCT_SEQ ? fypc->seq.idx : -1;
+}
+
+struct fy_token *fy_path_component_mapping_get_scalar_key(struct fy_path_component *fypc)
+{
+	return fypc && fypc->type == FYPCT_MAP &&
+	       fypc->map.has_key && !fypc->map.is_complex_key ? fypc->map.scalar.key : NULL;
+}
+
+struct fy_token *fy_path_component_mapping_get_scalar_key_tag(struct fy_path_component *fypc)
+{
+	return fypc && fypc->type == FYPCT_MAP &&
+	       fypc->map.has_key && !fypc->map.is_complex_key ? fypc->map.scalar.tag : NULL;
+}
+
+struct fy_document *fy_path_component_mapping_get_complex_key(struct fy_path_component *fypc)
+{
+	return fypc && fypc->type == FYPCT_MAP &&
+	       fypc->map.has_key && fypc->map.is_complex_key ? fypc->map.complex_key : NULL;
+}
+
+bool fy_path_component_is_sequence(struct fy_path_component *fypc)
+{
+	return fypc && fypc->type == FYPCT_SEQ;
+}
+
+static int fy_path_component_get_text_internal(struct fy_emit_accum *ea, struct fy_path_component *fypc)
+{
+	char *doctxt;
+	const char *text;
+	size_t len;
+
+	switch (fypc->type) {
+	case FYPCT_NONE:
+		abort();
+
+	case FYPCT_MAP:
+
+		/* we don't handle transitionals */
+		if (!fypc->map.has_key || fypc->map.await_key || fypc->map.root)
+			return -1;
+
+		if (!fypc->map.is_complex_key && fypc->map.scalar.key) {
+			text = fy_token_get_text(fypc->map.scalar.key, &len);
+			if (!text)
+				return -1;
+
+			if (fypc->map.scalar.key->type == FYTT_ALIAS)
+				fy_emit_accum_utf8_put_raw(ea, '*');
+			fy_emit_accum_utf8_write_raw(ea, text, len);
+
+		} else if (fypc->map.complex_key) {
+			/* complex key */
+			doctxt = fy_emit_document_to_string(fypc->map.complex_key,
+				FYECF_WIDTH_INF | FYECF_INDENT_DEFAULT |
+				FYECF_MODE_FLOW_ONELINE | FYECF_NO_ENDING_NEWLINE);
+			fy_emit_accum_utf8_write_raw(ea, doctxt, strlen(doctxt));
+			free(doctxt);
+		}
+		break;
+
+	case FYPCT_SEQ:
+
+		/* not started filling yet */
+		if (fypc->seq.idx < 0)
+			return -1;
+
+		fy_emit_accum_utf8_printf_raw(ea, "%d", fypc->seq.idx);
+		break;
+	}
+
+	return 0;
+}
+
+static int fy_path_get_text_internal(struct fy_emit_accum *ea, struct fy_path *fypp)
+{
+	struct fy_path_component *fypc;
+	struct fy_document *fyd;
+	char *doctxt;
+	const char *text;
+	size_t len;
+	bool local_key = false;
+	int rc, count;
+
+	if (fypp->parent) {
+		rc = fy_path_get_text_internal(ea, fypp->parent);
+		assert(!rc);
+		if (rc)
+			return -1;
+	}
+
+	/* OK, we have to iterate and rebuild the paths */
+	for (fypc = fy_path_component_list_head(&fypp->components), count = 0; fypc;
+			fypc = fy_path_component_next(&fypp->components, fypc), count++) {
+
+		fy_emit_accum_utf8_put_raw(ea, '/');
+
+		switch (fypc->type) {
+		case FYPCT_NONE:
+			abort();
+
+		case FYPCT_MAP:
+
+			if (!fypc->map.has_key || fypc->map.root)
+				break;
+
+			/* key reference ? wrap in .key(X)*/
+			local_key = false;
+			if (fypc->map.await_key)
+				local_key = true;
+
+			if (local_key)
+				fy_emit_accum_utf8_write_raw(ea, ".key(", 5);
+
+			if (!fypc->map.is_complex_key) {
+
+				if (fypc->map.scalar.key) {
+					text = fy_token_get_text(fypc->map.scalar.key, &len);
+					assert(text);
+					if (!text)
+						return -1;
+					if (fypc->map.scalar.key->type == FYTT_ALIAS)
+						fy_emit_accum_utf8_put_raw(ea, '*');
+					fy_emit_accum_utf8_write_raw(ea, text, len);
+				} else {
+					fy_emit_accum_utf8_write_raw(ea, ".null()", 7);
+				}
+			} else {
+				if (fypc->map.complex_key)
+					fyd = fypc->map.complex_key;
+				else
+					fyd = fy_document_builder_peek_document(fypp->fydb);
+
+				/* complex key */
+				if (fyd) {
+					doctxt = fy_emit_document_to_string(fyd,
+						FYECF_WIDTH_INF | FYECF_INDENT_DEFAULT |
+						FYECF_MODE_FLOW_ONELINE | FYECF_NO_ENDING_NEWLINE);
+				} else
+					doctxt = NULL;
+
+				if (doctxt) {
+					fy_emit_accum_utf8_write_raw(ea, doctxt, strlen(doctxt));
+					free(doctxt);
+				} else {
+					fy_emit_accum_utf8_write_raw(ea, "<X>", 3);
+				}
+			}
+
+			if (local_key)
+				fy_emit_accum_utf8_put_raw(ea, ')');
+
+			break;
+
+		case FYPCT_SEQ:
+
+			/* not started filling yet */
+			if (fypc->seq.idx < 0)
+				break;
+
+			fy_emit_accum_utf8_printf_raw(ea, "%d", fypc->seq.idx);
+			break;
+		}
+	}
+
+	return 0;
+}
+
+char *fy_path_get_text(struct fy_path *fypp)
+{
+	struct fy_emit_accum ea;	/* use an emit accumulator */
+	char *path = NULL;
+	size_t len;
+	int rc;
+
+	/* no inplace buffer; we will need the malloc'ed contents anyway */
+	fy_emit_accum_init(&ea, NULL, 0, 0, fylb_cr_nl);
+
+	fy_emit_accum_start(&ea, 0, fylb_cr_nl);
+
+	rc = fy_path_get_text_internal(&ea, fypp);
+	if (rc)
+		goto err_out;
+
+	if (fy_emit_accum_empty(&ea))
+		fy_emit_accum_utf8_printf_raw(&ea, "/");
+
+	fy_emit_accum_make_0_terminated(&ea);
+
+	path = fy_emit_accum_steal(&ea, &len);
+
+err_out:
+	fy_emit_accum_cleanup(&ea);
+
+	return path;
+}
+
+char *fy_path_component_get_text(struct fy_path_component *fypc)
+{
+	struct fy_emit_accum ea;	/* use an emit accumulator */
+	char *text = NULL;
+	size_t len;
+	int rc;
+
+	/* no inplace buffer; we will need the malloc'ed contents anyway */
+	fy_emit_accum_init(&ea, NULL, 0, 0, fylb_cr_nl);
+
+	fy_emit_accum_start(&ea, 0, fylb_cr_nl);
+
+	rc = fy_path_component_get_text_internal(&ea, fypc);
+	if (rc)
+		goto err_out;
+
+	fy_emit_accum_make_0_terminated(&ea);
+
+	text = fy_emit_accum_steal(&ea, &len);
+
+err_out:
+	fy_emit_accum_cleanup(&ea);
+
+	return text;
+}
+
+int fy_path_depth(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc;
+	int depth;
+
+	if (!fypp)
+		return 0;
+
+	depth = fy_path_depth(fypp->parent);
+	for (fypc = fy_path_component_list_head(&fypp->components); fypc;
+			fypc = fy_path_component_next(&fypp->components, fypc)) {
+
+		depth++;
+	}
+
+	return depth;
+}
+
+struct fy_path *fy_path_parent(struct fy_path *fypp)
+{
+	if (!fypp)
+		return NULL;
+	return fypp->parent;
+}
+
+struct fy_path_component *
+fy_path_last_component(struct fy_path *fypp)
+{
+	return fy_path_component_list_tail(&fypp->components);
+}
+
+struct fy_path_component *
+fy_path_last_not_collection_root_component(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc_last;
+
+	fypc_last = fy_path_component_list_tail(&fypp->components);
+	if (!fypc_last)
+		return NULL;
+
+	if (!fy_path_component_is_collection_root(fypc_last))
+		return fypc_last;
+
+	fypc_last = fy_path_component_prev(&fypp->components, fypc_last);
+	if (fypc_last)
+		return fypc_last;
+
+	if (fypp->parent)
+		return fy_path_component_list_tail(&fypp->parent->components);
+
+	return NULL;
+}
+
+bool fy_path_in_root(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc_last;
+
+	if (!fypp)
+		return true;
+
+	fypc_last = fy_path_last_not_collection_root_component(fypp);
+	return fypc_last == NULL;
+}
+
+
+bool fy_path_in_mapping(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc_last;
+
+	if (!fypp)
+		return false;
+
+	fypc_last = fy_path_last_not_collection_root_component(fypp);
+	if (!fypc_last)
+		return false;
+
+	return fypc_last->type == FYPCT_MAP;
+}
+
+bool fy_path_in_sequence(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc_last;
+
+	if (!fypp)
+		return false;
+
+	fypc_last = fy_path_last_not_collection_root_component(fypp);
+	if (!fypc_last)
+		return false;
+
+	return fypc_last->type == FYPCT_SEQ;
+}
+
+bool fy_path_in_mapping_key(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc_last;
+
+	if (!fypp)
+		return false;
+
+	fypc_last = fy_path_last_not_collection_root_component(fypp);
+	if (!fypc_last)
+		return false;
+
+	return fypc_last->type == FYPCT_MAP && fypc_last->map.await_key;
+}
+
+bool fy_path_in_mapping_value(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc_last;
+
+	if (!fypp)
+		return false;
+
+	fypc_last = fy_path_last_not_collection_root_component(fypp);
+	if (!fypc_last)
+		return false;
+
+	return fypc_last->type == FYPCT_MAP && !fypc_last->map.await_key;
+}
+
+bool fy_path_in_collection_root(struct fy_path *fypp)
+{
+	struct fy_path_component *fypc_last;
+
+	if (!fypp)
+		return false;
+
+	fypc_last = fy_path_component_list_tail(&fypp->components);
+	if (!fypc_last)
+		return false;
+
+	return fy_path_component_is_collection_root(fypc_last);
+}
+
+void *fy_path_get_root_user_data(struct fy_path *fypp)
+{
+	if (!fypp)
+		return NULL;
+
+	if (!fypp->parent)
+		return fypp->user_data;
+
+	return fy_path_get_root_user_data(fypp->parent);
+}
+
+void fy_path_set_root_user_data(struct fy_path *fypp, void *data)
+{
+	if (!fypp)
+		return;
+
+	if (!fypp->parent) {
+		fypp->user_data = data;
+		return;
+	}
+
+	fy_path_set_root_user_data(fypp->parent, data);
+}
+
+void *fy_path_component_get_mapping_user_data(struct fy_path_component *fypc)
+{
+	return fypc && fypc->type == FYPCT_MAP ? fypc->user_data : NULL;
+}
+
+void *fy_path_component_get_mapping_key_user_data(struct fy_path_component *fypc)
+{
+	return fypc && fypc->type == FYPCT_MAP ? fypc->map.key_user_data : NULL;
+}
+
+void *fy_path_component_get_sequence_user_data(struct fy_path_component *fypc)
+{
+	return fypc && fypc->type == FYPCT_SEQ ? fypc->user_data : NULL;
+}
+
+void fy_path_component_set_mapping_user_data(struct fy_path_component *fypc, void *data)
+{
+	if (!fypc || fypc->type != FYPCT_MAP)
+		return;
+
+	fypc->user_data = data;
+}
+
+void fy_path_component_set_mapping_key_user_data(struct fy_path_component *fypc, void *data)
+{
+	if (!fypc || fypc->type != FYPCT_MAP)
+		return;
+
+	fypc->map.key_user_data = data;
+}
+
+void fy_path_component_set_sequence_user_data(struct fy_path_component *fypc, void *data)
+{
+	if (!fypc || fypc->type != FYPCT_SEQ)
+		return;
+
+	fypc->user_data = data;
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-path.h b/contrib/libs/libfyaml/src/lib/fy-path.h
new file mode 100644
index 0000000000..e551d5a7e4
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-path.h
@@ -0,0 +1,114 @@
+/*
+ * fy-path.h - YAML parser private path definitions
+ *
+ * Copyright (c) 2021 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_PATH_H
+#define FY_PATH_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdbool.h>
+
+#include <libfyaml.h>
+
+#include "fy-list.h"
+#include "fy-typelist.h"
+
+#include "fy-emit-accum.h"
+
+FY_TYPE_FWD_DECL_LIST(path_component);
+
+enum fy_path_component_type {
+	FYPCT_NONE,	/* not yet instantiated */
+	FYPCT_MAP,	/* it's a mapping */
+	FYPCT_SEQ,	/* it's a sequence */
+};
+
+/* fwd declaration */
+struct fy_document;
+struct fy_document_builder;
+
+#define FY_PATH_MAPPING_SHORT_KEY	32
+
+struct fy_path_mapping_state {
+	bool root : 1;		/* no keys, values yet */
+	bool await_key : 1;
+	bool accumulating_complex_key : 1;
+	bool has_key : 1;			/* has a key */
+	bool is_complex_key : 1;
+	bool complex_key_complete : 1;
+	union {
+		struct {
+			struct fy_token *tag;
+			struct fy_token *key;
+		} scalar;
+		struct fy_document *complex_key;
+	};
+	void *key_user_data;
+};
+
+struct fy_path_sequence_state {
+	int idx;
+};
+
+struct fy_path_component {
+	struct fy_list_head node;
+	enum fy_path_component_type type;
+	union {
+		struct fy_path_mapping_state map;
+		struct fy_path_sequence_state seq;
+	};
+	void *user_data;
+};
+FY_TYPE_DECL_LIST(path_component);
+
+static inline bool
+fy_path_component_is_collection_root(struct fy_path_component *fypc)
+{
+	if (!fypc)
+		return false;
+
+	switch (fypc->type) {
+	case FYPCT_NONE:
+		break;
+	case FYPCT_SEQ:
+		return fypc->seq.idx < 0;
+	case FYPCT_MAP:
+		return fypc->map.root;
+	}
+
+	return false;
+}
+
+FY_TYPE_FWD_DECL_LIST(path);
+struct fy_path {
+	struct fy_list_head node;
+	struct fy_path_component_list recycled_component;
+	struct fy_path_component_list components;
+	struct fy_document_builder *fydb;	/* for complex keys */
+	struct fy_path *parent;			/* when we have a parent */
+	void *user_data;
+};
+FY_TYPE_DECL_LIST(path);
+
+struct fy_path *fy_path_create(void);
+void fy_path_destroy(struct fy_path *fypp);
+
+void fy_path_reset(struct fy_path *fypp);
+
+struct fy_path_component *fy_path_component_alloc(struct fy_path *fypp);
+void fy_path_component_cleanup(struct fy_path_component *fypc);
+void fy_path_component_free(struct fy_path_component *fypc);
+void fy_path_component_destroy(struct fy_path_component *fypc);
+void fy_path_component_recycle(struct fy_path *fypp, struct fy_path_component *fypc);
+void fy_path_component_clear_state(struct fy_path_component *fypc);
+
+struct fy_path_component *fy_path_component_create_mapping(struct fy_path *fypp);
+struct fy_path_component *fy_path_component_create_sequence(struct fy_path *fypp);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-token.c b/contrib/libs/libfyaml/src/lib/fy-token.c
new file mode 100644
index 0000000000..91efa89f33
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-token.c
@@ -0,0 +1,1869 @@
+/*
+ * fy-token.c - YAML token methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+
+#include "fy-ctype.h"
+#include "fy-utf8.h"
+#include "fy-emit-accum.h"
+
+#include "fy-walk.h"
+
+#include "fy-token.h"
+
+enum fy_scalar_style fy_token_scalar_style(struct fy_token *fyt)
+{
+	return fy_token_scalar_style_inline(fyt);
+}
+
+enum fy_token_type fy_token_get_type(struct fy_token *fyt)
+{
+	return fy_token_get_type_inline(fyt);
+}
+
+void fy_token_clean_rl(struct fy_token_list *fytl, struct fy_token *fyt)
+{
+	int i;
+
+	if (!fyt)
+		return;
+
+	/* release reference */
+	fy_input_unref(fyt->handle.fyi);
+	fyt->handle.fyi = NULL;
+
+	/* release comment references */
+	if (fyt->comment) {
+		for (i = 0; i < fycp_max; i++)
+			fy_input_unref(fyt->comment[i].fyi);
+		free(fyt->comment);
+		fyt->comment = NULL;
+	}
+
+	switch (fyt->type) {
+	case FYTT_TAG:
+		fy_token_unref(fyt->tag.fyt_td);
+		fyt->tag.fyt_td = NULL;
+		if (fyt->tag.handle0) {
+			free(fyt->tag.handle0);
+			fyt->tag.handle0 = NULL;
+		}
+		if (fyt->tag.suffix0) {
+			free(fyt->tag.suffix0);
+			fyt->tag.suffix0 = NULL;
+		}
+		break;
+
+	case FYTT_TAG_DIRECTIVE:
+		if (fyt->tag_directive.prefix0) {
+			free(fyt->tag_directive.prefix0);
+			fyt->tag_directive.prefix0 = NULL;
+		}
+		if (fyt->tag_directive.handle0) {
+			free(fyt->tag_directive.handle0);
+			fyt->tag_directive.handle0 = NULL;
+		}
+		break;
+
+	case FYTT_PE_MAP_KEY:
+		fy_document_destroy(fyt->map_key.fyd);
+		fyt->map_key.fyd = NULL;
+		break;
+
+	case FYTT_SCALAR:
+		if (fyt->scalar.path_key_storage) {
+			free(fyt->scalar.path_key_storage);
+			fyt->scalar.path_key_storage = NULL;
+		}
+		break;
+
+	case FYTT_ALIAS:
+		if (fyt->alias.expr) {
+			fy_path_expr_free(fyt->alias.expr);
+			fyt->alias.expr = NULL;
+		}
+		break;
+
+	default:
+		break;
+	}
+
+	if (fyt->text0) {
+		free(fyt->text0);
+		fyt->text0 = NULL;
+	}
+
+	fyt->type = FYTT_NONE;
+	fyt->analyze_flags = 0;
+	fyt->text_len = 0;
+	fyt->text = NULL;
+}
+
+void fy_token_list_unref_all_rl(struct fy_token_list *fytl, struct fy_token_list *fytl_tofree)
+{
+	struct fy_token *fyt;
+
+	while ((fyt = fy_token_list_pop(fytl_tofree)) != NULL)
+		fy_token_unref_rl(fytl, fyt);
+}
+
+static bool fy_token_text_needs_rebuild(struct fy_token *fyt)
+{
+	const struct fy_atom *fya;
+
+	if (!fy_token_text_is_direct(fyt))
+		return false;
+
+	fya = fy_token_atom(fyt);
+	if (!fya || !fya->fyi)
+		return false;
+
+	return fya->fyi_generation != fya->fyi->generation;
+}
+
+static int fy_tag_token_format_internal(const struct fy_token *fyt, void *out, size_t *outszp)
+{
+	char *o = NULL, *oe = NULL;
+	size_t outsz;
+	const char *handle, *suffix;
+	size_t handle_size, suffix_size;
+	int len, code_length, rlen;
+	uint8_t code[4];
+	const char *t, *s, *e;
+
+	if (!fyt || fyt->type != FYTT_TAG)
+		return 0;
+
+	if (out && *outszp <= 0)
+		return 0;
+
+	if (out) {
+		outsz = *outszp;
+		o = out;
+		oe = (char *)out + outsz;
+	}
+
+	if (!fyt->tag.fyt_td)
+		return -1;
+
+	handle = fy_tag_directive_token_prefix(fyt->tag.fyt_td, &handle_size);
+	if (!handle)
+		return -1;
+
+	suffix = fy_atom_data(&fyt->handle) + fyt->tag.skip + fyt->tag.handle_length;
+	suffix_size = fyt->tag.suffix_length;
+
+#define O_CPY(_src, _len) \
+	do { \
+		int _l = (_len); \
+		if (o && _l) { \
+			int _cl = _l; \
+			if (_cl > (oe - o)) \
+				_cl = oe - o; \
+			memcpy(o, (_src), _cl); \
+			o += _cl; \
+		} \
+		len += _l; \
+	} while(0)
+
+	len = 0;
+	O_CPY(handle, handle_size);
+
+	/* escape suffix as a URI */
+	s = suffix;
+	e = s + suffix_size;
+	while (s < e) {
+		/* find next escape */
+		t = memchr(s, '%', e - s);
+		rlen = (t ? t : e) - s;
+		O_CPY(s, rlen);
+
+		/* end of string */
+		if (!t)
+			break;
+		s = t;
+
+		code_length = sizeof(code);
+		t = fy_uri_esc(s, e - s, code, &code_length);
+		if (!t)
+			break;
+
+		/* output escaped utf8 */
+		O_CPY(code, code_length);
+		s = t;
+	}
+
+#undef O_CPY
+	return len;
+
+}
+
+int fy_tag_token_format_text_length(const struct fy_token *fyt)
+{
+	return fy_tag_token_format_internal(fyt, NULL, NULL);
+}
+
+const char *fy_tag_token_format_text(const struct fy_token *fyt, char *buf, size_t maxsz)
+{
+	fy_tag_token_format_internal(fyt, buf, &maxsz);
+	return buf;
+}
+
+static int fy_tag_directive_token_format_internal(const struct fy_token *fyt,
+			void *out, size_t *outszp)
+{
+	char *o = NULL, *oe = NULL;
+	size_t outsz;
+	int len;
+	const char *handle, *prefix;
+	size_t handle_size, prefix_size;
+
+	if (!fyt || fyt->type != FYTT_TAG_DIRECTIVE)
+		return 0;
+
+	if (out && *outszp <= 0)
+		return 0;
+
+	if (out) {
+		outsz = *outszp;
+		o = out;
+		oe = (char *)out + outsz;
+	}
+
+#define O_CPY(_src, _len) \
+	do { \
+		int _l = (_len); \
+		if (o && _l) { \
+			int _cl = _l; \
+			if (_cl > (oe - o)) \
+				_cl = oe - o; \
+			memcpy(o, (_src), _cl); \
+			o += _cl; \
+		} \
+		len += _l; \
+	} while(0)
+
+	len = 0;
+
+	handle = fy_atom_data(&fyt->handle);
+	handle_size = fy_atom_size(&fyt->handle);
+
+	prefix = handle + handle_size - fyt->tag_directive.uri_length;
+	prefix_size = fyt->tag_directive.uri_length;
+	handle_size = fyt->tag_directive.tag_length;
+
+	if (handle_size)
+		O_CPY(handle, handle_size);
+	else
+		O_CPY("!<", 2);
+	O_CPY(prefix, prefix_size);
+	if (!handle_size)
+		O_CPY(">", 1);
+
+#undef O_CPY
+	return len;
+
+}
+
+int fy_tag_directive_token_format_text_length(const struct fy_token *fyt)
+{
+	return fy_tag_directive_token_format_internal(fyt, NULL, NULL);
+}
+
+const char *fy_tag_directive_token_format_text(const struct fy_token *fyt, char *buf, size_t maxsz)
+{
+	fy_tag_directive_token_format_internal(fyt, buf, &maxsz);
+	return buf;
+}
+
+const char *fy_tag_directive_token_prefix(struct fy_token *fyt, size_t *lenp)
+{
+	const char *ptr;
+	size_t len;
+
+	if (!fyt || fyt->type != FYTT_TAG_DIRECTIVE) {
+		*lenp = 0;
+		return NULL;
+	}
+	ptr = fy_atom_data(&fyt->handle);
+	len = fy_atom_size(&fyt->handle);
+	ptr = ptr + len - fyt->tag_directive.uri_length;
+	*lenp = fyt->tag_directive.uri_length;
+
+	return ptr;
+}
+
+const char *fy_tag_directive_token_prefix0(struct fy_token *fyt)
+{
+	char *text0;
+	const char *text;
+	size_t len;
+
+	if (!fyt || fyt->type != FYTT_TAG_DIRECTIVE)
+		return NULL;
+
+	/* use the cache if it's there (and doesn't need a rebuild) */
+	if (fyt->tag_directive.prefix0 && !fy_token_text_needs_rebuild(fyt))
+		return fyt->tag_directive.prefix0;
+
+	if (fyt->tag_directive.prefix0) {
+		free(fyt->tag_directive.prefix0);
+		fyt->tag_directive.prefix0 = NULL;
+	}
+
+	text = fy_tag_directive_token_prefix(fyt, &len);
+	if (!text)
+		return NULL;
+
+	text0 = malloc(len + 1);
+	if (!text0)
+		return NULL;
+	memcpy(text0, text, len);
+	text0[len] = '\0';
+
+	fyt->tag_directive.prefix0 = text0;
+
+	return fyt->tag_directive.prefix0;
+}
+
+const char *fy_tag_directive_token_handle(struct fy_token *fyt, size_t *lenp)
+{
+	const char *ptr;
+
+	if (!fyt || fyt->type != FYTT_TAG_DIRECTIVE) {
+		*lenp = 0;
+		return NULL;
+	}
+	ptr = fy_atom_data(&fyt->handle);
+	*lenp = fyt->tag_directive.tag_length;
+	return ptr;
+}
+
+const char *fy_tag_directive_token_handle0(struct fy_token *fyt)
+{
+	char *text0;
+	const char *text;
+	size_t len;
+
+	if (!fyt || fyt->type != FYTT_TAG_DIRECTIVE)
+		return NULL;
+
+	/* use the cache if it's there (and doesn't need a rebuild) */
+	if (fyt->tag_directive.handle0 && !fy_token_text_needs_rebuild(fyt))
+		return fyt->tag_directive.handle0;
+
+	if (fyt->tag_directive.handle0) {
+		free(fyt->tag_directive.handle0);
+		fyt->tag_directive.handle0 = NULL;
+	}
+
+	text = fy_tag_directive_token_handle(fyt, &len);
+	if (!text)
+		return NULL;
+
+	text0 = malloc(len + 1);
+	if (!text0)
+		return NULL;
+	memcpy(text0, text, len);
+	text0[len] = '\0';
+
+	fyt->tag_directive.handle0 = text0;
+
+	return fyt->tag_directive.handle0;
+}
+
+struct fy_token *fy_token_vcreate_rl(struct fy_token_list *fytl, enum fy_token_type type, va_list ap)
+{
+	struct fy_token *fyt = NULL;
+	struct fy_atom *handle;
+	struct fy_token *fyt_td;
+
+	if ((unsigned int)type >= FYTT_COUNT)
+		goto err_out;
+
+	fyt = fy_token_alloc_rl(fytl);
+	if (!fyt)
+		goto err_out;
+	fyt->type = type;
+
+	handle = va_arg(ap, struct fy_atom *);
+	if (handle)
+		fyt->handle = *handle;
+	else
+		fy_atom_reset(&fyt->handle);
+
+	switch (fyt->type) {
+	case FYTT_TAG_DIRECTIVE:
+		fyt->tag_directive.tag_length = va_arg(ap, unsigned int);
+		fyt->tag_directive.uri_length = va_arg(ap, unsigned int);
+		fyt->tag_directive.is_default = va_arg(ap, int) ? true : false;
+		fyt->tag_directive.prefix0 = NULL;
+		fyt->tag_directive.handle0 = NULL;
+		break;
+	case FYTT_SCALAR:
+		fyt->scalar.style = va_arg(ap, enum fy_scalar_style);
+		if (fyt->scalar.style != FYSS_ANY && (unsigned int)fyt->scalar.style >= FYSS_MAX)
+			goto err_out;
+		fyt->scalar.path_key = NULL;
+		fyt->scalar.path_key_len = 0;
+		fyt->scalar.path_key_storage = NULL;
+		break;
+	case FYTT_TAG:
+		fyt->tag.skip = va_arg(ap, unsigned int);
+		fyt->tag.handle_length = va_arg(ap, unsigned int);
+		fyt->tag.suffix_length = va_arg(ap, unsigned int);
+
+		fyt_td = va_arg(ap, struct fy_token *);
+		if (!fyt_td)
+			goto err_out;
+		fyt->tag.fyt_td = fy_token_ref(fyt_td);
+		fyt->tag.handle0 = NULL;
+		fyt->tag.suffix0 = NULL;
+		break;
+
+	case FYTT_VERSION_DIRECTIVE:
+		fyt->version_directive.vers = *va_arg(ap, struct fy_version *);
+		break;
+
+	case FYTT_ALIAS:
+		fyt->alias.expr = va_arg(ap, struct fy_path_expr *);
+		break;
+
+	case FYTT_KEY:
+		fyt->key.flow_level = va_arg(ap, int);
+		break;
+
+	case FYTT_PE_MAP_KEY:
+		fyt->map_key.fyd = va_arg(ap, struct fy_document *);
+		break;
+
+	case FYTT_PE_SEQ_INDEX:
+		fyt->seq_index.index = va_arg(ap, int);
+		break;
+
+	case FYTT_PE_SEQ_SLICE:
+		fyt->seq_slice.start_index = va_arg(ap, int);
+		fyt->seq_slice.end_index = va_arg(ap, int);
+		break;
+
+	case FYTT_NONE:
+		goto err_out;
+
+	default:
+		break;
+	}
+
+	if (fyt->handle.fyi)
+		fy_input_ref(fyt->handle.fyi);
+
+	return fyt;
+
+err_out:
+	fy_token_unref(fyt);
+
+	return NULL;
+}
+
+struct fy_token *fy_token_create_rl(struct fy_token_list *fytl, enum fy_token_type type, ...)
+{
+	struct fy_token *fyt;
+	va_list ap;
+
+	va_start(ap, type);
+	fyt = fy_token_vcreate_rl(fytl, type, ap);
+	va_end(ap);
+
+	return fyt;
+}
+
+struct fy_token *fy_token_vcreate(enum fy_token_type type, va_list ap)
+{
+	return fy_token_vcreate_rl(NULL, type, ap);
+}
+
+struct fy_token *fy_token_create(enum fy_token_type type, ...)
+{
+	struct fy_token *fyt;
+	va_list ap;
+
+	va_start(ap, type);
+	fyt = fy_token_vcreate_rl(NULL, type, ap);
+	va_end(ap);
+
+	return fyt;
+}
+
+struct fy_token *fy_parse_token_create(struct fy_parser *fyp, enum fy_token_type type, ...)
+{
+	struct fy_token *fyt;
+	va_list ap;
+
+	if (!fyp)
+		return NULL;
+
+	va_start(ap, type);
+	fyt = fy_token_vcreate_rl(fyp->recycled_token_list, type, ap);
+	va_end(ap);
+
+	return fyt;
+}
+
+int fy_token_format_text_length(struct fy_token *fyt)
+{
+	int length;
+
+	if (!fyt)
+		return 0;
+
+	switch (fyt->type) {
+
+	case FYTT_TAG:
+		return fy_tag_token_format_text_length(fyt);
+
+	case FYTT_TAG_DIRECTIVE:
+		return fy_tag_directive_token_format_text_length(fyt);
+
+	default:
+		break;
+	}
+
+	length = fy_atom_format_text_length(&fyt->handle);
+
+	return length;
+}
+
+const char *fy_token_format_text(struct fy_token *fyt, char *buf, size_t maxsz)
+{
+	const char *str;
+
+	if (maxsz == 0)
+		return buf;
+
+	if (!fyt) {
+		if (maxsz > 0)
+			buf[0] = '\0';
+		return buf;
+	}
+
+	switch (fyt->type) {
+
+	case FYTT_TAG:
+		return fy_tag_token_format_text(fyt, buf, maxsz);
+
+	case FYTT_TAG_DIRECTIVE:
+		return fy_tag_directive_token_format_text(fyt, buf, maxsz);
+
+	default:
+		break;
+	}
+
+	str = fy_atom_format_text(&fyt->handle, buf, maxsz);
+
+	return str;
+}
+
+int fy_token_format_utf8_length(struct fy_token *fyt)
+{
+	const char *str;
+	size_t len;
+
+	if (!fyt)
+		return 0;
+
+	switch (fyt->type) {
+
+	case FYTT_TAG:
+	case FYTT_TAG_DIRECTIVE:
+		str = fy_token_get_text(fyt, &len);
+		if (!str)
+			return 0;
+		return fy_utf8_count(str, len);
+
+	default:
+		break;
+	}
+
+	return fy_atom_format_utf8_length(&fyt->handle);
+}
+
+
+struct fy_atom *fy_token_atom(struct fy_token *fyt)
+{
+	return fyt ? &fyt->handle : NULL;
+}
+
+const struct fy_mark *fy_token_start_mark(struct fy_token *fyt)
+{
+	const struct fy_atom *atom;
+
+	atom = fy_token_atom(fyt);
+	if (atom)
+		return &atom->start_mark;
+
+	/* something we don't track */
+	return NULL;
+}
+
+const struct fy_mark *fy_token_end_mark(struct fy_token *fyt)
+{
+	const struct fy_atom *atom;
+
+	atom = fy_token_atom(fyt);
+	if (atom)
+		return &atom->end_mark;
+
+	/* something we don't track */
+	return NULL;
+}
+
+int fy_token_text_analyze(struct fy_token *fyt)
+{
+	const char *s, *e;
+	const char *value = NULL;
+	enum fy_atom_style style;
+	int c, w, cn, cp, col;
+	size_t len;
+	int flags;
+
+	if (!fyt)
+		return FYTTAF_CAN_BE_SIMPLE_KEY | FYTTAF_DIRECT_OUTPUT |
+		       FYTTAF_EMPTY | FYTTAF_CAN_BE_DOUBLE_QUOTED;
+
+	if (fyt->analyze_flags)
+		return fyt->analyze_flags;
+
+	/* only tokens that can generate text */
+	if (fyt->type != FYTT_SCALAR &&
+	    fyt->type != FYTT_TAG &&
+	    fyt->type != FYTT_ANCHOR &&
+	    fyt->type != FYTT_ALIAS) {
+		flags = FYTTAF_NO_TEXT_TOKEN;
+		fyt->analyze_flags = flags;
+		return flags;
+	}
+
+	flags = FYTTAF_TEXT_TOKEN;
+
+	style = fy_token_atom_style(fyt);
+
+	/* can this token be a simple key initial condition */
+	if (!fy_atom_style_is_block(style) && style != FYAS_URI)
+		flags |= FYTTAF_CAN_BE_SIMPLE_KEY;
+
+	/* can this token be directly output initial condition */
+	if (!fy_atom_style_is_block(style))
+		flags |= FYTTAF_DIRECT_OUTPUT;
+
+	/* get value */
+	value = fy_token_get_text(fyt, &len);
+	if (!value || len == 0) {
+		flags |= FYTTAF_EMPTY | FYTTAF_CAN_BE_DOUBLE_QUOTED | FYTTAF_CAN_BE_UNQUOTED_PATH_KEY;
+		fyt->analyze_flags = flags;
+		return flags;
+	}
+
+	flags |= FYTTAF_CAN_BE_PLAIN |
+		 FYTTAF_CAN_BE_SINGLE_QUOTED |
+		 FYTTAF_CAN_BE_DOUBLE_QUOTED |
+		 FYTTAF_CAN_BE_LITERAL |
+		 FYTTAF_CAN_BE_LITERAL |
+		 FYTTAF_CAN_BE_FOLDED |
+		 FYTTAF_CAN_BE_PLAIN_FLOW |
+		 FYTTAF_CAN_BE_UNQUOTED_PATH_KEY;
+
+	/* start with document indicators must be quoted at indent 0 */
+	if (len >= 3 && (!memcmp(value, "---", 3) || !memcmp(value, "...", 3)))
+		flags |= FYTTAF_QUOTE_AT_0;
+
+	s = value;
+	e = value + len;
+
+	col = 0;
+
+	/* get first character */
+	cn = fy_utf8_get(s, e - s, &w);
+	s += w;
+	col = fy_token_is_lb(fyt, cn) ? 0 : (col + 1);
+
+	/* disable folded right off the bat, it's a pain */
+	flags &= ~FYTTAF_CAN_BE_FOLDED;
+
+	/* plain scalars can't start with any indicator (or space/lb) */
+	if ((flags & (FYTTAF_CAN_BE_PLAIN | FYTTAF_CAN_BE_PLAIN_FLOW)) &&
+		(fy_is_indicator(cn) || fy_token_is_lb(fyt, cn) || fy_is_ws(cn)))
+		flags &= ~(FYTTAF_CAN_BE_PLAIN |
+			   FYTTAF_CAN_BE_PLAIN_FLOW);
+
+	/* plain scalars in flow mode can't start with a flow indicator */
+	if ((flags & FYTTAF_CAN_BE_PLAIN_FLOW) &&
+		fy_is_flow_indicator(cn))
+		flags &= ~FYTTAF_CAN_BE_PLAIN_FLOW;
+
+	/* plain unquoted path keys can only start with [a-zA-Z_] */
+	if ((flags & FYTTAF_CAN_BE_UNQUOTED_PATH_KEY) &&
+		!fy_is_first_alpha(cn))
+		flags &= ~FYTTAF_CAN_BE_UNQUOTED_PATH_KEY;
+
+	cp = -1;
+	for (c = cn; c >= 0; s += w, cp = c, c = cn) {
+
+		/* can be -1 on end */
+		cn = fy_utf8_get(s, e - s, &w);
+
+		/* zero can't be output, only in double quoted mode */
+		if (c == 0) {
+			flags &= ~(FYTTAF_DIRECT_OUTPUT |
+				   FYTTAF_CAN_BE_PLAIN |
+				   FYTTAF_CAN_BE_SINGLE_QUOTED |
+				   FYTTAF_CAN_BE_LITERAL |
+				   FYTTAF_CAN_BE_FOLDED |
+				   FYTTAF_CAN_BE_PLAIN_FLOW |
+				   FYTTAF_CAN_BE_UNQUOTED_PATH_KEY);
+			flags |= FYTTAF_CAN_BE_DOUBLE_QUOTED;
+
+		} else if (fy_is_ws(c)) {
+
+			flags |= FYTTAF_HAS_WS;
+			if (fy_is_ws(cn))
+				flags |= FYTTAF_HAS_CONSECUTIVE_WS;
+
+		} else if (fy_token_is_lb(fyt, c)) {
+
+			flags |= FYTTAF_HAS_LB;
+			if (fy_token_is_lb(fyt, cn))
+				flags |= FYTTAF_HAS_CONSECUTIVE_LB;
+
+			/* only non linebreaks can be simple keys */
+			flags &= ~FYTTAF_CAN_BE_SIMPLE_KEY;
+
+			/* anything with linebreaks, can't be direct */
+			flags &= ~FYTTAF_DIRECT_OUTPUT;
+		}
+
+		if ((flags & FYTTAF_CAN_BE_UNQUOTED_PATH_KEY) && !fy_is_alnum(c))
+			flags &= ~FYTTAF_CAN_BE_UNQUOTED_PATH_KEY;
+
+		/* illegal plain combination */
+		if ((flags & FYTTAF_CAN_BE_PLAIN) &&
+			((c == ':' && fy_is_blankz_m(cn, fy_token_atom_lb_mode(fyt))) ||
+			 (fy_is_blankz_m(c, fy_token_atom_lb_mode(fyt)) && cn == '#') ||
+			 (cp < 0 && c == '#' && cn < 0) ||
+			 !fy_is_print(c))) {
+			flags &= ~(FYTTAF_CAN_BE_PLAIN |
+				   FYTTAF_CAN_BE_PLAIN_FLOW);
+		}
+
+		/* illegal plain flow combination */
+		if ((flags & FYTTAF_CAN_BE_PLAIN_FLOW) &&
+			(fy_is_flow_indicator(c) || (c == ':' && fy_is_flow_indicator(cn))))
+			flags &= ~FYTTAF_CAN_BE_PLAIN_FLOW;
+
+		/* non printable characters, turn off these styles */
+		if ((flags & (FYTTAF_CAN_BE_SINGLE_QUOTED |
+			      FYTTAF_CAN_BE_LITERAL |
+			      FYTTAF_CAN_BE_FOLDED)) && !fy_is_print(c))
+			flags &= ~(FYTTAF_CAN_BE_SINGLE_QUOTED |
+				   FYTTAF_CAN_BE_LITERAL |
+				   FYTTAF_CAN_BE_FOLDED);
+
+		/* if there's an escape, it can't be direct */
+		if ((flags & FYTTAF_DIRECT_OUTPUT) &&
+		    ((style == FYAS_URI && c == '%') ||
+		     (style == FYAS_SINGLE_QUOTED && c == '\'') ||
+		     (style == FYAS_DOUBLE_QUOTED && c == '\\')))
+			flags &= ~FYTTAF_DIRECT_OUTPUT;
+
+		col = fy_token_is_lb(fyt, c) ? 0 : (col + 1);
+
+		/* last character */
+		if (cn < 0) {
+			/* if ends with whitespace or linebreak, can't be plain */
+			if (fy_is_ws(cn) || fy_token_is_lb(fyt, cn))
+				flags &= ~(FYTTAF_CAN_BE_PLAIN |
+					   FYTTAF_CAN_BE_PLAIN_FLOW);
+		}
+	}
+
+	fyt->analyze_flags = flags;
+	return flags;
+}
+
+const char *fy_tag_token_get_directive_handle(struct fy_token *fyt, size_t *td_handle_sizep)
+{
+	if (!fyt || fyt->type != FYTT_TAG || !fyt->tag.fyt_td)
+		return NULL;
+
+	return fy_tag_directive_token_handle(fyt->tag.fyt_td, td_handle_sizep);
+}
+
+const char *fy_tag_token_get_directive_prefix(struct fy_token *fyt, size_t *td_prefix_sizep)
+{
+	if (!fyt || fyt->type != FYTT_TAG || !fyt->tag.fyt_td)
+		return NULL;
+
+	return fy_tag_directive_token_prefix(fyt->tag.fyt_td, td_prefix_sizep);
+}
+
+const char *fy_token_get_direct_output(struct fy_token *fyt, size_t *sizep)
+{
+	const struct fy_atom *fya;
+
+	fya = fy_token_atom(fyt);
+	if (!fya || !fya->direct_output ||
+	    (fyt->type == FYTT_TAG || fyt->type == FYTT_TAG_DIRECTIVE) ) {
+		*sizep = 0;
+		return NULL;
+	}
+	*sizep = fy_atom_size(fya);
+	return fy_atom_data(fya);
+}
+
+const char *fy_tag_token_handle(struct fy_token *fyt, size_t *lenp)
+{
+	return fy_tag_token_get_directive_handle(fyt, lenp);
+}
+
+const char *fy_tag_token_suffix(struct fy_token *fyt, size_t *lenp)
+{
+	const char *tag, *prefix, *handle, *suffix;
+	size_t tag_len, prefix_len, handle_len, suffix_len;
+
+	if (!fyt || fyt->type != FYTT_TAG) {
+		*lenp = 0;
+		return NULL;
+	}
+
+	tag = fy_token_get_text(fyt, &tag_len);
+	if (!tag)
+		return NULL;
+	prefix = fy_tag_token_get_directive_prefix(fyt, &prefix_len);
+	if (!prefix)
+		return NULL;
+	handle = fy_tag_token_handle(fyt, &handle_len);
+	if (!handle || !handle_len) {
+		suffix = tag;
+		suffix_len = tag_len;
+	} else {
+		assert(prefix_len <= tag_len);
+		assert(tag_len >= prefix_len);
+		suffix = tag + prefix_len;
+		suffix_len = tag_len - prefix_len;
+	}
+	*lenp = suffix_len;
+	return suffix;
+}
+
+const char *fy_tag_token_handle0(struct fy_token *fyt)
+{
+	char *text0;
+	const char *text;
+	size_t len;
+
+	if (!fyt || fyt->type != FYTT_TAG)
+		return NULL;
+
+	/* use the cache if it's there (and doesn't need a rebuild) */
+	if (fyt->tag.handle0 && !fy_token_text_needs_rebuild(fyt))
+		return fyt->tag.handle0;
+
+	if (fyt->tag.handle0) {
+		free(fyt->tag.handle0);
+		fyt->tag.handle0 = NULL;
+	}
+
+	text = fy_tag_token_handle(fyt, &len);
+	if (!text)
+		return NULL;
+
+	text0 = malloc(len + 1);
+	if (!text0)
+		return NULL;
+	memcpy(text0, text, len);
+	text0[len] = '\0';
+
+	fyt->tag.handle0 = text0;
+
+	return fyt->tag.handle0;
+}
+
+const char *fy_tag_token_suffix0(struct fy_token *fyt)
+{
+	char *text0;
+	const char *text;
+	size_t len;
+
+	if (!fyt || fyt->type != FYTT_TAG)
+		return NULL;
+
+	/* use the cache if it's there (and doesn't need a rebuild) */
+	if (fyt->tag.suffix0 && !fy_token_text_needs_rebuild(fyt))
+		return fyt->tag.suffix0;
+
+	if (fyt->tag.suffix0) {
+		free(fyt->tag.suffix0);
+		fyt->tag.suffix0 = NULL;
+	}
+
+	text = fy_tag_token_suffix(fyt, &len);
+	if (!text)
+		return NULL;
+
+	text0 = malloc(len + 1);
+	if (!text0)
+		return NULL;
+	memcpy(text0, text, len);
+	text0[len] = '\0';
+
+	fyt->tag.suffix0 = text0;
+
+	return fyt->tag.suffix0;
+}
+
+const struct fy_version * fy_version_directive_token_version(struct fy_token *fyt)
+{
+	if (!fyt || fyt->type != FYTT_VERSION_DIRECTIVE)
+		return NULL;
+	return &fyt->version_directive.vers;
+}
+
+static void fy_token_prepare_text(struct fy_token *fyt)
+{
+	int ret;
+
+	assert(fyt);
+
+	/* get text length of this token */
+	ret = fy_token_format_text_length(fyt);
+
+	/* no text on this token? */
+	if (ret == -1) {
+		fyt->text_len = 0;
+		fyt->text = fyt->text0 = strdup("");
+		return;
+	}
+
+	fyt->text0 = malloc(ret + 1);
+	if (!fyt->text0) {
+		fyt->text_len = 0;
+		fyt->text = fyt->text0 = strdup("");
+		return;
+	}
+
+	fyt->text0[0] = '\0';
+
+	fyt->text_len = ret;
+
+	fy_token_format_text(fyt, fyt->text0, ret + 1);
+	fyt->text0[ret] = '\0';
+
+	fyt->text_len = ret;
+	fyt->text = fyt->text0;
+}
+
+const char *fy_token_get_text(struct fy_token *fyt, size_t *lenp)
+{
+	/* return empty */
+	if (!fyt) {
+		*lenp = 0;
+		return "";
+	}
+
+	/* already found something */
+	if (fyt->text && !fy_token_text_needs_rebuild(fyt)) {
+		*lenp = fyt->text_len;
+		return fyt->text;
+	}
+
+	/* try direct output first */
+	fyt->text = fy_token_get_direct_output(fyt, &fyt->text_len);
+	if (!fyt->text)
+		fy_token_prepare_text(fyt);
+
+	*lenp = fyt->text_len;
+	return fyt->text;
+}
+
+const char *fy_token_get_text0(struct fy_token *fyt)
+{
+	/* return empty */
+	if (!fyt)
+		return "";
+
+	/* created text is always zero terminated */
+	if (!fyt->text0)
+		fy_token_prepare_text(fyt);
+
+	return fyt->text0;
+}
+
+size_t fy_token_get_text_length(struct fy_token *fyt)
+{
+	return fy_token_format_text_length(fyt);
+}
+
+enum comment_out_state {
+	cos_normal,
+	cos_lastnl,
+	cos_lastnlhash,
+	cos_lastnlhashspc,
+};
+
+const char *fy_token_get_comment(struct fy_token *fyt, char *buf, size_t maxsz,
+	enum fy_comment_placement which)
+{
+	struct fy_atom *handle;
+	struct fy_atom_iter iter;
+	const struct fy_iter_chunk *ic;
+	char *s, *e;
+	const char *ss, *ee;
+	int c, w, ret;
+	enum comment_out_state state;
+	bool output;
+
+	if (!buf || maxsz == 0 || (unsigned int)which >= fycp_max)
+		return NULL;
+
+	/* return empty? */
+	handle = fy_token_comment_handle(fyt, which, false);
+	if (!handle || !fy_atom_is_set(handle))
+		return NULL;
+
+	/* start expecting # */
+	state = cos_lastnl;
+
+	s = buf;
+	e = s + maxsz;
+	fy_atom_iter_start(handle, &iter);
+	ic = NULL;
+	while ((ic = fy_atom_iter_chunk_next(&iter, ic, &ret)) != NULL) {
+		ss = ic->str;
+		ee = ss + ic->len;
+
+		while ((c = fy_utf8_get(ss, ee - ss, &w)) > 0) {
+
+			output = true;
+			switch (state) {
+			case cos_normal:
+				if (fy_is_lb_m(c, handle->lb_mode))
+					state = cos_lastnl;
+				break;
+
+			case cos_lastnl:
+				if (c == '#') {
+					state = cos_lastnlhash;
+					output = false;
+					break;
+				}
+				state = cos_normal;
+				break;
+
+			case cos_lastnlhash:
+				if (c == ' ') {
+					state = cos_lastnlhashspc;
+					output = false;
+					break;
+				}
+				state = cos_normal;
+				break;
+
+			case cos_lastnlhashspc:
+				state = cos_normal;
+				break;
+			}
+
+			if (output) {
+				s = fy_utf8_put(s, (size_t)(e - s), c);
+				if (!s)
+					return NULL;
+			}
+
+			ss += w;
+		}
+	}
+	fy_atom_iter_finish(&iter);
+
+	if (ret != 0 || s >= e)
+		return NULL;
+	*s = '\0';
+
+	return buf;
+}
+
+const char *fy_token_get_scalar_path_key(struct fy_token *fyt, size_t *lenp)
+{
+	struct fy_atom *atom;
+	struct fy_atom_iter iter;
+	struct fy_emit_accum ea;	/* use an emit accumulator */
+	uint8_t non_utf8[4];
+	size_t non_utf8_len, k;
+	int c, i, w, digit;
+	int aflags;
+
+	if (!fyt || fyt->type != FYTT_SCALAR) {
+		*lenp = 0;
+		return NULL;
+	}
+
+	/* was it cached? return */
+	if (fyt->scalar.path_key) {
+		*lenp = fyt->scalar.path_key_len;
+		return fyt->scalar.path_key;
+	}
+
+	/* analyze the token */
+	aflags = fy_token_text_analyze(fyt);
+
+	/* simple one? perfect */
+	if ((aflags & FYTTAF_CAN_BE_UNQUOTED_PATH_KEY) == FYTTAF_CAN_BE_UNQUOTED_PATH_KEY) {
+		fyt->scalar.path_key = fy_token_get_text(fyt, &fyt->scalar.path_key_len);
+		*lenp = fyt->scalar.path_key_len;
+		return fyt->scalar.path_key;
+	}
+
+	/* not possible, need to quote (and escape) */
+
+	/* no atom? i.e. empty */
+	atom = fy_token_atom(fyt);
+	if (!atom) {
+		fyt->scalar.path_key = "";
+		fyt->scalar.path_key_len = 0;
+		*lenp = 0;
+		return fyt->scalar.path_key;
+	}
+
+	/* no inplace buffer; we will need the malloc'ed contents anyway */
+	fy_emit_accum_init(&ea, NULL, 0, 0, fylb_cr_nl);
+
+	fy_atom_iter_start(atom, &iter);
+	fy_emit_accum_start(&ea, 0, fy_token_atom_lb_mode(fyt));
+
+	/* output in quoted form */
+	fy_emit_accum_utf8_put(&ea, '"');
+
+	for (;;) {
+		non_utf8_len = sizeof(non_utf8);
+		c = fy_atom_iter_utf8_quoted_get(&iter, &non_utf8_len, non_utf8);
+		if (c < 0)
+			break;
+
+		if (c == 0 && non_utf8_len > 0) {
+			for (k = 0; k < non_utf8_len; k++) {
+				c = (int)non_utf8[k] & 0xff;
+				fy_emit_accum_utf8_put(&ea, '\\');
+				fy_emit_accum_utf8_put(&ea, 'x');
+				digit = ((unsigned int)c >> 4) & 15;
+				fy_emit_accum_utf8_put(&ea,
+						digit <= 9 ? ('0' + digit) : ('A' + digit - 10));
+				digit = (unsigned int)c & 15;
+				fy_emit_accum_utf8_put(&ea,
+						digit <= 9 ? ('0' + digit) : ('A' + digit - 10));
+			}
+			continue;
+		}
+
+		if (!fy_is_printq(c) || c == '"' || c == '\\') {
+
+			fy_emit_accum_utf8_put(&ea, '\\');
+
+			switch (c) {
+
+			/* common YAML & JSON escapes */
+			case '\b':
+				fy_emit_accum_utf8_put(&ea, 'b');
+				break;
+			case '\f':
+				fy_emit_accum_utf8_put(&ea, 'f');
+				break;
+			case '\n':
+				fy_emit_accum_utf8_put(&ea, 'n');
+				break;
+			case '\r':
+				fy_emit_accum_utf8_put(&ea, 'r');
+				break;
+			case '\t':
+				fy_emit_accum_utf8_put(&ea, 't');
+				break;
+			case '"':
+				fy_emit_accum_utf8_put(&ea, '"');
+				break;
+			case '\\':
+				fy_emit_accum_utf8_put(&ea, '\\');
+				break;
+
+			/* YAML only escapes */
+			case '\0':
+				fy_emit_accum_utf8_put(&ea, '0');
+				break;
+			case '\a':
+				fy_emit_accum_utf8_put(&ea, 'a');
+				break;
+			case '\v':
+				fy_emit_accum_utf8_put(&ea, 'v');
+				break;
+			case '\e':
+				fy_emit_accum_utf8_put(&ea, 'e');
+				break;
+			case 0x85:
+				fy_emit_accum_utf8_put(&ea, 'N');
+				break;
+			case 0xa0:
+				fy_emit_accum_utf8_put(&ea, '_');
+				break;
+			case 0x2028:
+				fy_emit_accum_utf8_put(&ea, 'L');
+				break;
+			case 0x2029:
+				fy_emit_accum_utf8_put(&ea, 'P');
+				break;
+
+			default:
+				/* any kind of binary value */
+				if ((unsigned int)c <= 0xff) {
+					fy_emit_accum_utf8_put(&ea, 'x');
+					w = 2;
+				} else if ((unsigned int)c <= 0xffff) {
+					fy_emit_accum_utf8_put(&ea, 'u');
+					w = 4;
+				} else if ((unsigned int)c <= 0xffffffff) {
+					fy_emit_accum_utf8_put(&ea, 'U');
+					w = 8;
+				}
+
+				for (i = w - 1; i >= 0; i--) {
+					digit = ((unsigned int)c >> (i * 4)) & 15;
+					fy_emit_accum_utf8_put(&ea,
+							digit <= 9 ? ('0' + digit) : ('A' + digit - 10));
+				}
+				break;
+			}
+
+			continue;
+		}
+
+		/* regular character */
+		fy_emit_accum_utf8_put(&ea, c);
+	}
+
+	fy_atom_iter_finish(&iter);
+
+	/* closing quote */
+	fy_emit_accum_utf8_put(&ea, '"');
+
+	fy_emit_accum_make_0_terminated(&ea);
+
+	/* get the output (note it's now NULL terminated) */
+	fyt->scalar.path_key_storage = fy_emit_accum_steal(&ea, &fyt->scalar.path_key_len);
+	fyt->scalar.path_key = fyt->scalar.path_key_storage;
+	fy_emit_accum_cleanup(&ea);
+
+	*lenp = fyt->scalar.path_key_len;
+
+	return fyt->scalar.path_key;
+}
+
+size_t fy_token_get_scalar_path_key_length(struct fy_token *fyt)
+{
+	const char *text;
+	size_t len;
+
+	text = fy_token_get_scalar_path_key(fyt, &len);
+	if (!text)
+		return 0;
+	return len;
+}
+
+const char *fy_token_get_scalar_path_key0(struct fy_token *fyt)
+{
+	const char *text;
+	size_t len;
+
+	if (!fyt || fyt->type != FYTT_SCALAR) {
+		return NULL;
+	}
+
+	/* storage is \0 terminated */
+	if (fyt->scalar.path_key_storage)
+		return fyt->scalar.path_key_storage;
+
+	text = fyt->scalar.path_key;
+	len = fyt->scalar.path_key_len;
+	if (!text)
+		text = fy_token_get_scalar_path_key(fyt, &len);
+
+	/* something is catastrophically wrong */
+	if (!text)
+		return NULL;
+
+	if (fyt->scalar.path_key_storage)
+		return fyt->scalar.path_key_storage;
+
+	fyt->scalar.path_key_storage = malloc(len + 1);
+	if (!fyt->scalar.path_key_storage)
+		return NULL;
+
+	memcpy(fyt->scalar.path_key_storage, text, len);
+	fyt->scalar.path_key_storage[len] = '\0';
+
+	return fyt->scalar.path_key_storage;
+}
+
+unsigned int fy_analyze_scalar_content(const char *data, size_t size,
+		bool json_mode, enum fy_lb_mode lb_mode, enum fy_flow_ws_mode fws_mode)
+{
+	const char *s, *e;
+	int c, lastc, nextc, w, ww, col, break_run;
+	unsigned int flags;
+	bool first;
+
+	flags = FYACF_EMPTY | FYACF_BLOCK_PLAIN | FYACF_FLOW_PLAIN |
+		FYACF_PRINTABLE | FYACF_SINGLE_QUOTED | FYACF_DOUBLE_QUOTED |
+		FYACF_SIZE0 | FYACF_VALID_ANCHOR;
+
+	s = data;
+	e = data + size;
+
+	col = 0;
+	first = true;
+	lastc = -1;
+	break_run = 0;
+	while (s < e && (c = fy_utf8_get(s, e - s, &w)) >= 0) {
+
+		flags &= ~FYACF_SIZE0;
+
+		lastc = c;
+
+		if (first) {
+			if (fy_is_ws(c))
+				flags |= FYACF_STARTS_WITH_WS;
+			else if (fy_is_generic_lb_m(c, lb_mode))
+				flags |= FYACF_STARTS_WITH_LB;
+			/* scalars starting with & or * must be quoted */
+			if (c == '&' || c == '*')
+				flags &= ~(FYACF_BLOCK_PLAIN | FYACF_FLOW_PLAIN);
+			first = false;
+		}
+		nextc = fy_utf8_get(s + w, e - (s + w), &ww);
+
+		/* anything other than white space or linebreak */
+		if ((flags & FYACF_EMPTY) &&
+		    !fy_is_ws(c) && !fy_is_generic_lb_m(c, lb_mode))
+			flags &= ~FYACF_EMPTY;
+
+		if ((flags & FYACF_VALID_ANCHOR) &&
+		    (fy_utf8_strchr(",[]{}&*:", c) || fy_is_ws(c) ||
+		     fy_is_any_lb(c) || fy_is_unicode_control(c) ||
+		     fy_is_unicode_space(c)))
+			flags &= ~FYACF_VALID_ANCHOR;
+
+		/* linebreak */
+		if (fy_is_generic_lb_m(c, lb_mode)) {
+			flags |= FYACF_LB;
+			if (!(flags & FYACF_CONSECUTIVE_LB) &&
+			    fy_is_generic_lb_m(nextc, lb_mode))
+				flags |= FYACF_CONSECUTIVE_LB;
+			break_run++;
+		} else
+			break_run = 0;
+
+		/* white space */
+		if (!(flags & FYACF_WS) && fy_is_ws(c)) {
+			flags |= FYACF_WS;
+			flags &= ~FYACF_VALID_ANCHOR;
+		}
+
+		/* anything not printable (or \r, \n) */
+		if ((flags & FYACF_PRINTABLE) &&
+		    !fy_is_printq(c)) {
+			flags &= ~FYACF_PRINTABLE;
+			flags &= ~(FYACF_BLOCK_PLAIN | FYACF_FLOW_PLAIN |
+				   FYACF_SINGLE_QUOTED | FYACF_VALID_ANCHOR);
+		}
+
+		/* check for document indicators (at column 0) */
+		if (!(flags & FYACF_DOC_IND) &&
+		    ((col == 0 && (e - s) >= 3 &&
+		      (!strncmp(s, "---", 3) || !strncmp(s, "...", 3))))) {
+			flags |= FYACF_DOC_IND;
+			flags &= ~(FYACF_BLOCK_PLAIN | FYACF_FLOW_PLAIN | FYACF_VALID_ANCHOR);
+		}
+
+		/* comment indicator can't be present after a space or lb */
+		/* : followed by blank can't be any plain */
+		if (flags & (FYACF_BLOCK_PLAIN | FYACF_FLOW_PLAIN) &&
+		    (((fy_is_blank(c) || fy_is_generic_lb_m(c, lb_mode)) && nextc == '#') ||
+		     (c == ':' && fy_is_blankz_m(nextc, lb_mode))))
+			flags &= ~(FYACF_BLOCK_PLAIN | FYACF_FLOW_PLAIN);
+
+		/* : followed by flow markers can't be a plain in flow context */
+		if ((flags & FYACF_FLOW_PLAIN) &&
+		    (fy_utf8_strchr(",[]{}", c) || (c == ':' && fy_utf8_strchr(",[]{}", nextc))))
+			flags &= ~FYACF_FLOW_PLAIN;
+
+		if (!(flags & FYACF_JSON_ESCAPE) && !fy_is_json_unescaped(c))
+			flags |= FYACF_JSON_ESCAPE;
+
+		if (fy_is_generic_lb_m(c, lb_mode))
+			col = 0;
+		else
+			col++;
+
+		s += w;
+	}
+
+	/* this contains arbitrary binany values, mark it as such */
+	if (s < e)
+		return FYACF_DOUBLE_QUOTED;
+
+	if (fy_is_ws(lastc))
+		flags |= FYACF_ENDS_WITH_WS;
+	else if (fy_is_generic_lb_m(lastc, lb_mode))
+		flags |= FYACF_ENDS_WITH_LB;
+
+	if (break_run > 1)
+		flags |= FYACF_TRAILING_LB;
+
+	return flags;
+}
+
+char *fy_token_debug_text(struct fy_token *fyt)
+{
+	const char *typetxt;
+	const char *text;
+	char *buf;
+	size_t length;
+	int wlen;
+	int rc __FY_DEBUG_UNUSED__;
+
+	if (!fyt || !fy_token_type_is_valid(fyt->type)) {
+		typetxt = "<NULL>";
+		goto out;
+	}
+	typetxt = fy_token_type_txt[fyt->type];
+
+	/* should never happen really */
+	assert(typetxt);
+
+out:
+	text = fy_token_get_text(fyt, &length);
+
+	wlen = length > 8 ? 8 : length;
+
+	rc = asprintf(&buf, "%s:%.*s%s", typetxt, wlen, text, wlen < (int)length ? "..." : "");
+	assert(rc != -1);
+
+	return buf;
+}
+
+int fy_token_memcmp(struct fy_token *fyt, const void *ptr, size_t len)
+{
+	const char *value = NULL;
+	size_t tlen = 0;
+
+	/* special zero length handling */
+	if (len == 0 && fyt && fy_token_get_text_length(fyt) == 0)
+		return 0;
+
+	/* handle NULL cases */
+	if (!fyt && (!ptr || !len))
+		return 0;
+
+	if (!fyt && (ptr || len))
+		return -1;
+
+	if (fyt && (!ptr || !len))
+		return 1;
+
+	/* those two are special */
+	if (fyt->type == FYTT_TAG || fyt->type == FYTT_TAG_DIRECTIVE) {
+		value = fy_token_get_text(fyt, &tlen);
+		if (!value)
+			return -1;
+		return tlen == len ? memcmp(value, ptr, tlen) : tlen < len ? -1 : 1;
+	}
+
+	return fy_atom_memcmp(fy_token_atom(fyt), ptr, len);
+}
+
+int fy_token_strcmp(struct fy_token *fyt, const char *str)
+{
+	size_t len;
+
+	len = str ? strlen(str) : 0;
+
+	return fy_token_memcmp(fyt, str, len);
+}
+
+int fy_token_cmp(struct fy_token *fyt1, struct fy_token *fyt2)
+{
+	const char *t1, *t2;
+	size_t l1, l2, l;
+	int ret;
+
+	/* handles both NULL */
+	if (fyt1 == fyt2)
+		return 0;
+
+	/* fyt1 is null, 2 wins */
+	if (!fyt1 && fyt2)
+		return -1;
+
+	/* fyt2 is null, 1 wins */
+	if (fyt1 && !fyt2)
+		return 1;
+
+	/* tokens with different types can't be equal */
+	if (fyt1->type != fyt2->type)
+		return fyt2->type > fyt1->type ? -1 : 1;
+
+	/* special case, these can't use the atom comparisons */
+	if (fyt1->type == FYTT_TAG || fyt1->type == FYTT_TAG_DIRECTIVE) {
+		t1 = fy_token_get_text(fyt1, &l1);
+		t2 = fy_token_get_text(fyt2, &l2);
+		l = l1 > l2 ? l2 : l1;
+		ret = memcmp(t1, t2, l);
+		if (ret)
+			return ret;
+		return l1 == l2 ? 0 : l2 > l1 ? -1 : 1;
+	}
+
+	/* just pass it to the atom comparison methods */
+	return fy_atom_cmp(fy_token_atom(fyt1), fy_token_atom(fyt2));
+}
+
+void fy_token_iter_start(struct fy_token *fyt, struct fy_token_iter *iter)
+{
+	if (!iter)
+		return;
+
+	memset(iter, 0, sizeof(*iter));
+
+	iter->unget_c = -1;
+
+	if (!fyt)
+		return;
+
+	iter->fyt = fyt;
+
+	/* TAG or TAG_DIRECTIVE may only work by getting the text */
+	if (fyt->type == FYTT_TAG || fyt->type == FYTT_TAG_DIRECTIVE)
+		iter->ic.str = fy_token_get_text(fyt, &iter->ic.len);
+	else /* try the direct output next  */
+		iter->ic.str = fy_token_get_direct_output(fyt, &iter->ic.len);
+
+	/* got it */
+	if (iter->ic.str) {
+		memset(&iter->atom_iter, 0, sizeof(iter->atom_iter));
+		return;
+	}
+
+	assert(fyt->type != FYTT_TAG && fyt->type != FYTT_TAG_DIRECTIVE);
+
+	/* fall back to the atom iterator */
+	fy_atom_iter_start(fy_token_atom(fyt), &iter->atom_iter);
+}
+
+void fy_token_iter_finish(struct fy_token_iter *iter)
+{
+	if (!iter)
+		return;
+
+	if (!iter->ic.str)
+		fy_atom_iter_finish(&iter->atom_iter);
+}
+
+struct fy_token_iter *
+fy_token_iter_create(struct fy_token *fyt)
+{
+	struct fy_token_iter *iter;
+
+	iter = malloc(sizeof(*iter));
+	if (!iter)
+		return NULL;
+	fy_token_iter_start(fyt, iter);
+	return iter;
+}
+
+void fy_token_iter_destroy(struct fy_token_iter *iter)
+{
+	if (!iter)
+		return;
+
+	fy_token_iter_finish(iter);
+	free(iter);
+}
+
+const struct fy_iter_chunk *fy_token_iter_peek_chunk(struct fy_token_iter *iter)
+{
+	if (!iter)
+		return NULL;
+
+	/* direct mode? */
+	if (iter->ic.str)
+		return &iter->ic;
+
+	/* fallback to the atom iterator */
+	return fy_atom_iter_peek_chunk(&iter->atom_iter);
+}
+
+void fy_token_iter_advance(struct fy_token_iter *iter, size_t len)
+{
+	if (!iter)
+		return;
+
+	/* direct mode? */
+	if (iter->ic.str) {
+		if (len > iter->ic.len)
+			len = iter->ic.len;
+		iter->ic.str += len;
+		iter->ic.len -= len;
+		return;
+	}
+
+	/* fallback to the atom iterator */
+	fy_atom_iter_advance(&iter->atom_iter, len);
+}
+
+const struct fy_iter_chunk *
+fy_token_iter_chunk_next(struct fy_token_iter *iter, const struct fy_iter_chunk *curr, int *errp)
+{
+	if (!iter)
+		return NULL;
+
+	if (errp)
+		*errp = 0;
+
+	/* first time in */
+	if (!curr) {
+		if (iter->ic.str)
+			return iter->ic.len ? &iter->ic : NULL;
+		return fy_atom_iter_chunk_next(&iter->atom_iter, NULL, errp);
+	}
+
+	/* direct, all consumed */
+	if (curr == &iter->ic) {
+		iter->ic.str += iter->ic.len;
+		iter->ic.len = 0;
+		return NULL;
+	}
+
+	/* fallback */
+	return fy_atom_iter_chunk_next(&iter->atom_iter, curr, errp);
+}
+
+ssize_t fy_token_iter_read(struct fy_token_iter *iter, void *buf, size_t count)
+{
+	if (!iter || !buf)
+		return -1;
+
+	/* direct mode */
+	if (iter->ic.str) {
+		if (count > iter->ic.len)
+			count = iter->ic.len;
+		memcpy(buf, iter->ic.str, count);
+		iter->ic.str += count;
+		iter->ic.len -= count;
+		return count;
+	}
+
+	return fy_atom_iter_read(&iter->atom_iter, buf, count);
+}
+
+int fy_token_iter_getc(struct fy_token_iter *iter)
+{
+	int c;
+
+	if (!iter)
+		return -1;
+
+	/* first try the pushed ungetc */
+	if (iter->unget_c != -1) {
+		c = iter->unget_c;
+		iter->unget_c = -1;
+		return c;
+	}
+
+	/* direct mode */
+	if (iter->ic.str) {
+		if (!iter->ic.len)
+			return -1;
+		c = *iter->ic.str++;
+		iter->ic.len--;
+		return c;
+	}
+
+	return fy_atom_iter_getc(&iter->atom_iter);
+}
+
+int fy_token_iter_ungetc(struct fy_token_iter *iter, int c)
+{
+	if (iter->unget_c != -1)
+		return -1;
+	if (c == -1) {
+		iter->unget_c = -1;
+		return 0;
+	}
+	iter->unget_c = c & 0xff;
+	return c & 0xff;
+}
+
+int fy_token_iter_peekc(struct fy_token_iter *iter)
+{
+	int c;
+
+	c = fy_token_iter_getc(iter);
+	if (c == -1)
+		return -1;
+
+	return fy_token_iter_ungetc(iter, c);
+}
+
+int fy_token_iter_utf8_get(struct fy_token_iter *iter)
+{
+	int c, w, w1;
+
+	/* first try the pushed ungetc */
+	if (iter->unget_c != -1) {
+		c = iter->unget_c;
+		iter->unget_c = -1;
+		return c;
+	}
+
+	/* direct */
+	if (iter->ic.str) {
+
+		/* not even 1 octet */
+		if (!iter->ic.len)
+			return -1;
+
+		/* get width by the first octet */
+		w = fy_utf8_width_by_first_octet((uint8_t)*iter->ic.str);
+		if (!w || (unsigned int)w > iter->ic.len)
+			return -1;
+
+		/* get the next character */
+		c = fy_utf8_get(iter->ic.str, w, &w1);
+
+		iter->ic.str += w;
+		iter->ic.len -= w;
+
+		return c;
+	}
+
+	return fy_atom_iter_utf8_get(&iter->atom_iter);
+}
+
+int fy_token_iter_utf8_unget(struct fy_token_iter *iter, int c)
+{
+	if (iter->unget_c != -1)
+		return -1;
+
+	if (c == -1) {
+		iter->unget_c = -1;
+		return 0;
+	}
+
+	iter->unget_c = c;
+	return c;
+}
+
+int fy_token_iter_utf8_peek(struct fy_token_iter *iter)
+{
+	int c;
+
+	c = fy_token_iter_utf8_get(iter);
+	if (c == -1)
+		return -1;
+
+	return fy_token_iter_utf8_unget(iter, c);
+}
+
+enum fy_scalar_style
+fy_scalar_token_get_style(struct fy_token *fyt)
+{
+	if (!fyt || fyt->type != FYTT_SCALAR)
+		return FYSS_ANY;
+	return fyt->scalar.style;
+}
+
+const struct fy_tag *fy_tag_token_tag(struct fy_token *fyt)
+{
+	if (!fyt || fyt->type != FYTT_TAG)
+		return NULL;
+
+	/* always refresh, should be relatively infrequent */
+	fyt->tag.tag.handle = fy_tag_token_handle0(fyt);
+	fyt->tag.tag.prefix = fy_tag_token_suffix0(fyt);
+
+	return &fyt->tag.tag;
+}
+
+const struct fy_tag *
+fy_tag_directive_token_tag(struct fy_token *fyt)
+{
+	if (!fyt || fyt->type != FYTT_TAG_DIRECTIVE)
+		return NULL;
+
+	/* always refresh, should be relatively infrequent */
+	fyt->tag_directive.tag.handle = fy_tag_directive_token_handle0(fyt);
+	fyt->tag_directive.tag.prefix = fy_tag_directive_token_prefix0(fyt);
+
+	return &fyt->tag_directive.tag;
+}
+
+struct fy_atom *fy_token_comment_handle(struct fy_token *fyt, enum fy_comment_placement placement, bool alloc)
+{
+	struct fy_atom *handle;
+	size_t size;
+
+	if (!fyt || (unsigned int)placement >= fycp_max)
+		return NULL;
+
+	if (!fyt->comment) {
+		if (!alloc)
+			return NULL;
+
+		size = sizeof(*fyt->comment) * fycp_max;
+		fyt->comment = malloc(size);
+		if (!fyt->comment)
+			return NULL;
+		memset(fyt->comment, 0, size);
+	}
+	handle = &fyt->comment[placement];
+
+	return handle;
+}
+
+bool fy_token_has_any_comment(struct fy_token *fyt)
+{
+	struct fy_atom *handle;
+	enum fy_comment_placement placement;
+
+	if (!fyt || !fyt->comment)
+		return false;
+
+	for (placement = fycp_top; placement <= fycp_bottom; placement++) {
+		handle = &fyt->comment[placement];
+		if (fy_atom_is_set(handle))
+			return true;
+	}
+	return false;
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-token.h b/contrib/libs/libfyaml/src/lib/fy-token.h
new file mode 100644
index 0000000000..8f904095f5
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-token.h
@@ -0,0 +1,522 @@
+/*
+ * fy-token.h - YAML token methods header
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_TOKEN_H
+#define FY_TOKEN_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include <libfyaml.h>
+
+#include "fy-utils.h"
+#include "fy-atom.h"
+
+extern const char *fy_token_type_txt[FYTT_COUNT];
+
+struct fy_document;
+struct fy_path_expr;
+
+static inline bool fy_token_type_is_sequence_start(enum fy_token_type type)
+{
+	return type == FYTT_BLOCK_SEQUENCE_START || type == FYTT_FLOW_SEQUENCE_START;
+}
+
+static inline bool fy_token_type_is_sequence_end(enum fy_token_type type)
+{
+	return type == FYTT_BLOCK_SEQUENCE_START || type == FYTT_FLOW_SEQUENCE_START;
+}
+
+static inline bool fy_token_type_is_sequence_marker(enum fy_token_type type)
+{
+	return fy_token_type_is_sequence_start(type) || fy_token_type_is_sequence_end(type);
+}
+
+static inline bool fy_token_type_is_mapping_start(enum fy_token_type type)
+{
+	return type == FYTT_BLOCK_MAPPING_START || type == FYTT_FLOW_MAPPING_START;
+}
+
+static inline bool fy_token_type_is_mapping_end(enum fy_token_type type)
+{
+	return type == FYTT_BLOCK_MAPPING_START || type == FYTT_FLOW_MAPPING_START;
+}
+
+static inline bool fy_token_type_is_mapping_marker(enum fy_token_type type)
+{
+	return fy_token_type_is_mapping_start(type) || fy_token_type_is_mapping_end(type);
+}
+
+/* analyze content flags */
+#define FYACF_EMPTY		0x000001	/* is empty (only ws & lb) */
+#define FYACF_LB		0x000002	/* has a linebreak */
+#define FYACF_BLOCK_PLAIN	0x000004	/* can be a plain scalar in block context */
+#define FYACF_FLOW_PLAIN	0x000008	/* can be a plain scalar in flow context */
+#define FYACF_PRINTABLE		0x000010	/* every character is printable */
+#define FYACF_SINGLE_QUOTED	0x000020	/* can be a single quoted scalar */
+#define FYACF_DOUBLE_QUOTED	0x000040	/* can be a double quoted scalar */
+#define FYACF_CONTAINS_ZERO	0x000080	/* contains a zero */
+#define FYACF_DOC_IND		0x000100	/* contains document indicators */
+#define FYACF_CONSECUTIVE_LB 	0x000200	/* has consecutive linebreaks */
+#define FYACF_SIMPLE_KEY	0x000400	/* can be a simple key */
+#define FYACF_WS		0x000800	/* has at least one whitespace */
+#define FYACF_STARTS_WITH_WS	0x001000	/* starts with whitespace */
+#define FYACF_STARTS_WITH_LB	0x002000	/* starts with whitespace */
+#define FYACF_ENDS_WITH_WS	0x004000	/* ends with whitespace */
+#define FYACF_ENDS_WITH_LB	0x008000	/* ends with linebreak */
+#define FYACF_TRAILING_LB	0x010000	/* ends with trailing lb > 1 */
+#define FYACF_SIZE0		0x020000	/* contains absolutely nothing */
+#define FYACF_VALID_ANCHOR	0x040000	/* contains valid anchor (without & prefix) */
+#define FYACF_JSON_ESCAPE	0x080000	/* contains a character that JSON escapes */
+
+FY_TYPE_FWD_DECL_LIST(token);
+struct fy_token {
+	struct fy_list_head node;
+	enum fy_token_type type;
+	int refs;		/* when on document, we switch to reference counting */
+	int analyze_flags;	/* cache of the analysis flags */
+	size_t text_len;
+	const char *text;
+	char *text0;		/* this is allocated */
+	struct fy_atom handle;
+	struct fy_atom *comment;	/* only when enabled */
+	union  {
+		struct {
+			unsigned int tag_length;	/* from start */
+			unsigned int uri_length;	/* from end */
+			char *prefix0;
+			char *handle0;
+			struct fy_tag tag;
+			bool is_default;		/* true when default */
+		} tag_directive;
+		struct {
+			enum fy_scalar_style style;
+			/* path key (if requested only) */
+			const char *path_key;
+			size_t path_key_len;
+			char *path_key_storage;	/* if this is not null, it's \0 terminated */
+		} scalar;
+		struct {
+			unsigned int skip;
+			unsigned int handle_length;
+			unsigned int suffix_length;
+			struct fy_token *fyt_td;
+			char *handle0;	/* zero terminated and allocated, only used by binding */
+			char *suffix0;
+			struct fy_tag tag;	/* prefix is now suffix */
+		} tag;
+		struct {
+			struct fy_version vers;		/* parsed version number */
+		} version_directive;
+		/* path expressions */
+		struct {
+			struct fy_document *fyd;	/* when key is complex */
+		} map_key;
+		struct {
+			int index;
+		} seq_index;
+		struct {
+			int start_index;
+			int end_index;
+		} seq_slice;
+		struct {
+			struct fy_path_expr *expr;
+		} alias;
+		struct {
+			int flow_level;
+		} key;
+	};
+};
+FY_TYPE_DECL_LIST(token);
+
+static inline bool fy_token_text_is_direct(struct fy_token *fyt)
+{
+	if (!fyt || !fyt->text)
+		return false;
+	return fyt->text && fyt->text != fyt->text0;
+}
+
+void fy_token_clean_rl(struct fy_token_list *fytl, struct fy_token *fyt);
+void fy_token_list_unref_all_rl(struct fy_token_list *fytl, struct fy_token_list *fytl_tofree);
+
+static inline FY_ALWAYS_INLINE struct fy_token *
+fy_token_alloc_rl(struct fy_token_list *fytl)
+{
+	struct fy_token *fyt;
+
+	fyt = NULL;
+	if (fytl)
+		fyt = fy_token_list_pop(fytl);
+	if (!fyt) {
+		fyt = malloc(sizeof(*fyt));
+		if (!fyt)
+			return NULL;
+	}
+
+	fyt->type = FYTT_NONE;
+	fyt->refs = 1;
+
+	fyt->analyze_flags = 0;
+	fyt->text_len = 0;
+	fyt->text = NULL;
+	fyt->text0 = NULL;
+	fyt->handle.fyi = NULL;
+	fyt->comment = NULL;
+
+	return fyt;
+}
+
+static inline FY_ALWAYS_INLINE void
+fy_token_free_rl(struct fy_token_list *fytl, struct fy_token *fyt)
+{
+	if (!fyt)
+		return;
+
+	fy_token_clean_rl(fytl, fyt);
+
+	if (fytl)
+		fy_token_list_push(fytl, fyt);
+	else
+		free(fyt);
+}
+
+static inline FY_ALWAYS_INLINE void
+fy_token_unref_rl(struct fy_token_list *fytl, struct fy_token *fyt)
+{
+	if (!fyt)
+		return;
+
+	assert(fyt->refs > 0);
+
+	if (--fyt->refs == 0)
+		fy_token_free_rl(fytl, fyt);
+}
+
+static inline FY_ALWAYS_INLINE struct fy_token *
+fy_token_alloc(void)
+{
+	return fy_token_alloc_rl(NULL);
+}
+
+static inline FY_ALWAYS_INLINE void
+fy_token_clean(struct fy_token *fyt)
+{
+	return fy_token_clean_rl(NULL, fyt);
+}
+
+static inline FY_ALWAYS_INLINE void
+fy_token_free(struct fy_token *fyt)
+{
+	return fy_token_free_rl(NULL, fyt);
+}
+
+static inline FY_ALWAYS_INLINE struct fy_token *
+fy_token_ref(struct fy_token *fyt)
+{
+	/* take care of overflow */
+	if (!fyt)
+		return NULL;
+	assert(fyt->refs + 1 > 0);
+	fyt->refs++;
+
+	return fyt;
+}
+
+static inline FY_ALWAYS_INLINE void
+fy_token_unref(struct fy_token *fyt)
+{
+	return fy_token_unref_rl(NULL, fyt);
+}
+
+static inline void
+fy_token_list_unref_all(struct fy_token_list *fytl_tofree)
+{
+	return fy_token_list_unref_all_rl(NULL, fytl_tofree);
+}
+
+/* recycling aware */
+struct fy_token *fy_token_vcreate_rl(struct fy_token_list *fytl, enum fy_token_type type, va_list ap);
+struct fy_token *fy_token_create_rl(struct fy_token_list *fytl, enum fy_token_type type, ...);
+
+struct fy_token *fy_token_vcreate(enum fy_token_type type, va_list ap);
+struct fy_token *fy_token_create(enum fy_token_type type, ...);
+
+static inline struct fy_token *
+fy_token_list_vqueue(struct fy_token_list *fytl, enum fy_token_type type, va_list ap)
+{
+	struct fy_token *fyt;
+
+	fyt = fy_token_vcreate(type, ap);
+	if (!fyt)
+		return NULL;
+	fy_token_list_add_tail(fytl, fyt);
+	return fyt;
+}
+
+static inline struct fy_token *
+fy_token_list_queue(struct fy_token_list *fytl, enum fy_token_type type, ...)
+{
+	va_list ap;
+	struct fy_token *fyt;
+
+	va_start(ap, type);
+	fyt = fy_token_list_vqueue(fytl, type, ap);
+	va_end(ap);
+
+	return fyt;
+}
+
+int fy_tag_token_format_text_length(const struct fy_token *fyt);
+const char *fy_tag_token_format_text(const struct fy_token *fyt, char *buf, size_t maxsz);
+int fy_token_format_utf8_length(struct fy_token *fyt);
+
+int fy_token_format_text_length(struct fy_token *fyt);
+const char *fy_token_format_text(struct fy_token *fyt, char *buf, size_t maxsz);
+
+/* non-parser token methods */
+struct fy_atom *fy_token_atom(struct fy_token *fyt);
+
+static inline size_t fy_token_start_pos(struct fy_token *fyt)
+{
+	const struct fy_mark *start_mark;
+
+	if (!fyt)
+		return (size_t)-1;
+
+	start_mark = fy_token_start_mark(fyt);
+	return start_mark ? start_mark->input_pos : (size_t)-1;
+}
+
+static inline size_t fy_token_end_pos(struct fy_token *fyt)
+{
+	const struct fy_mark *end_mark;
+
+	if (!fyt)
+		return (size_t)-1;
+
+	end_mark = fy_token_end_mark(fyt);
+	return end_mark ? end_mark->input_pos : (size_t)-1;
+}
+
+static inline int fy_token_start_line(struct fy_token *fyt)
+{
+	const struct fy_mark *start_mark;
+
+	if (!fyt)
+		return -1;
+
+	start_mark = fy_token_start_mark(fyt);
+	return start_mark ? start_mark->line : -1;
+}
+
+static inline int fy_token_start_column(struct fy_token *fyt)
+{
+	const struct fy_mark *start_mark;
+
+	if (!fyt)
+		return -1;
+
+	start_mark = fy_token_start_mark(fyt);
+	return start_mark ? start_mark->column : -1;
+}
+
+static inline int fy_token_end_line(struct fy_token *fyt)
+{
+	const struct fy_mark *end_mark;
+
+	if (!fyt)
+		return -1;
+
+	end_mark = fy_token_end_mark(fyt);
+	return end_mark ? end_mark->line : -1;
+}
+
+static inline int fy_token_end_column(struct fy_token *fyt)
+{
+	const struct fy_mark *end_mark;
+
+	if (!fyt)
+		return -1;
+
+	end_mark = fy_token_end_mark(fyt);
+	return end_mark ? end_mark->column : -1;
+}
+
+static inline bool fy_token_is_multiline(struct fy_token *fyt)
+{
+	const struct fy_mark *start_mark, *end_mark;
+
+	if (!fyt)
+		return false;
+
+	start_mark = fy_token_start_mark(fyt);
+	end_mark = fy_token_end_mark(fyt);
+	return start_mark && end_mark ? end_mark->line > start_mark->line : false;
+}
+
+const char *fy_token_get_direct_output(struct fy_token *fyt, size_t *sizep);
+
+static inline struct fy_input *fy_token_get_input(struct fy_token *fyt)
+{
+	return fyt ? fyt->handle.fyi : NULL;
+}
+
+static inline enum fy_atom_style fy_token_atom_style(struct fy_token *fyt)
+{
+	if (!fyt)
+		return FYAS_PLAIN;
+
+	if (fyt->type == FYTT_TAG)
+		return FYAS_URI;
+
+	return fyt->handle.style;
+}
+
+static inline bool fy_token_atom_json_mode(struct fy_token *fyt)
+{
+	if (!fyt)
+		return false;
+
+	return fy_atom_json_mode(&fyt->handle);
+}
+
+static inline enum fy_lb_mode fy_token_atom_lb_mode(struct fy_token *fyt)
+{
+	if (!fyt)
+		return fylb_cr_nl;
+
+	return fy_atom_lb_mode(&fyt->handle);
+}
+
+static inline enum fy_flow_ws_mode fy_token_atom_flow_ws_mode(struct fy_token *fyt)
+{
+	if (!fyt)
+		return fyfws_space_tab;
+
+	return fy_atom_flow_ws_mode(&fyt->handle);
+}
+
+static inline bool fy_token_is_lb(struct fy_token *fyt, int c)
+{
+	if (!fyt)
+		return false;
+
+	return fy_atom_is_lb(&fyt->handle, c);
+}
+
+static inline bool fy_token_is_flow_ws(struct fy_token *fyt, int c)
+{
+	if (!fyt)
+		return false;
+
+	return fy_atom_is_flow_ws(&fyt->handle, c);
+}
+
+#define FYTTAF_HAS_LB			FY_BIT(0)
+#define FYTTAF_HAS_WS			FY_BIT(1)
+#define FYTTAF_HAS_CONSECUTIVE_LB	FY_BIT(2)
+#define FYTTAF_HAS_CONSECUTIVE_WS	FY_BIT(4)
+#define FYTTAF_EMPTY			FY_BIT(5)
+#define FYTTAF_CAN_BE_SIMPLE_KEY	FY_BIT(6)
+#define FYTTAF_DIRECT_OUTPUT		FY_BIT(7)
+#define FYTTAF_NO_TEXT_TOKEN		FY_BIT(8)
+#define FYTTAF_TEXT_TOKEN		FY_BIT(9)
+#define FYTTAF_CAN_BE_PLAIN		FY_BIT(10)
+#define FYTTAF_CAN_BE_SINGLE_QUOTED	FY_BIT(11)
+#define FYTTAF_CAN_BE_DOUBLE_QUOTED	FY_BIT(12)
+#define FYTTAF_CAN_BE_LITERAL		FY_BIT(13)
+#define FYTTAF_CAN_BE_FOLDED		FY_BIT(14)
+#define FYTTAF_CAN_BE_PLAIN_FLOW	FY_BIT(15)
+#define FYTTAF_QUOTE_AT_0		FY_BIT(16)
+#define FYTTAF_CAN_BE_UNQUOTED_PATH_KEY	FY_BIT(17)
+
+int fy_token_text_analyze(struct fy_token *fyt);
+
+unsigned int fy_analyze_scalar_content(const char *data, size_t size,
+		bool json_mode, enum fy_lb_mode lb_mode, enum fy_flow_ws_mode fws_mode);
+
+/* must be freed */
+char *fy_token_debug_text(struct fy_token *fyt);
+
+#define fy_token_debug_text_a(_fyt, _res) \
+	do { \
+		struct fy_token *__fyt = (_fyt); \
+		char *_buf, *_rbuf = ""; \
+		size_t _len; \
+		_buf = fy_token_debug_text(__fyt); \
+		if (_buf) { \
+			_len = strlen(_buf); \
+			_rbuf = FY_ALLOCA(_len + 1); \
+			memcpy(_rbuf, _buf, _len + 1); \
+			free(_buf); \
+		} \
+		*(_res) = _rbuf; \
+	} while(false)
+
+int fy_token_memcmp(struct fy_token *fyt, const void *ptr, size_t len);
+int fy_token_strcmp(struct fy_token *fyt, const char *str);
+int fy_token_cmp(struct fy_token *fyt1, struct fy_token *fyt2);
+
+struct fy_token_iter {
+	struct fy_token *fyt;
+	struct fy_iter_chunk ic;	/* direct mode */
+	struct fy_atom_iter atom_iter;
+	int unget_c;
+};
+
+void fy_token_iter_start(struct fy_token *fyt, struct fy_token_iter *iter);
+void fy_token_iter_finish(struct fy_token_iter *iter);
+
+const char *fy_tag_token_get_directive_handle(struct fy_token *fyt, size_t *td_handle_sizep);
+const char *fy_tag_token_get_directive_prefix(struct fy_token *fyt, size_t *td_prefix_sizep);
+
+static inline bool fy_token_is_number(struct fy_token *fyt)
+{
+	struct fy_atom *atom;
+
+	if (!fyt || fyt->type != FYTT_SCALAR || fyt->scalar.style != FYSS_PLAIN)
+		return false;
+	atom = fy_token_atom(fyt);
+	if (!atom)
+		return false;
+	return fy_atom_is_number(atom);
+}
+
+struct fy_atom *fy_token_comment_handle(struct fy_token *fyt, enum fy_comment_placement placement, bool alloc);
+bool fy_token_has_any_comment(struct fy_token *fyt);
+
+const char *fy_token_get_scalar_path_key(struct fy_token *fyt, size_t *lenp);
+size_t fy_token_get_scalar_path_key_length(struct fy_token *fyt);
+const char *fy_token_get_scalar_path_key0(struct fy_token *fyt);
+
+struct fy_atom *fy_token_comment_handle(struct fy_token *fyt, enum fy_comment_placement placement, bool alloc);
+
+static inline FY_ALWAYS_INLINE enum fy_scalar_style
+fy_token_scalar_style_inline(struct fy_token *fyt)
+{
+	if (!fyt || fyt->type != FYTT_SCALAR)
+		return FYSS_PLAIN;
+
+	if (fyt->type == FYTT_SCALAR)
+		return fyt->scalar.style;
+
+	return FYSS_PLAIN;
+}
+
+static inline FY_ALWAYS_INLINE enum fy_token_type
+fy_token_get_type_inline(struct fy_token *fyt)
+{
+	return fyt ? fyt->type : FYTT_NONE;
+}
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-typelist.h b/contrib/libs/libfyaml/src/lib/fy-typelist.h
new file mode 100644
index 0000000000..12acd2dee4
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-typelist.h
@@ -0,0 +1,163 @@
+/*
+ * fy-typelist.h - typed list method builders
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_TYPELIST_H
+#define FY_TYPELIST_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include <libfyaml.h>
+
+#include "fy-list.h"
+
+/* declare type methods */
+
+#define FY_TYPE_FWD_DECL_LIST(_type) \
+/* type safe list wrapper */ \
+struct fy_ ## _type ## _list { struct fy_list_head _lh; }; \
+\
+struct __useless_struct_to_allow_semicolon
+
+#define FY_TYPE_DECL_LIST(_type) \
+static inline void fy_ ## _type ## _list_init(struct fy_ ## _type ## _list *_l) \
+{ \
+	fy_list_init_head(&_l->_lh); \
+} \
+static inline void fy_ ## _type ## _list_add(struct fy_ ## _type ## _list *_l, struct fy_ ## _type *_n) \
+{ \
+	if (_l && _n) \
+		fy_list_add_head(&_n->node, &_l->_lh); \
+} \
+static inline void fy_ ## _type ## _list_add_tail(struct fy_ ## _type ## _list *_l, struct fy_ ## _type *_n) \
+{ \
+	if (_l && _n) \
+		fy_list_add_tail(&_n->node, &_l->_lh); \
+} \
+static inline void fy_ ## _type ## _list_push(struct fy_ ## _type ## _list *_l, struct fy_ ## _type *_n) \
+{ \
+	if (_l && _n) \
+		fy_ ## _type ## _list_add(_l, _n); \
+} \
+static inline void fy_ ## _type ## _list_push_tail(struct fy_ ## _type ## _list *_l, struct fy_ ## _type *_n) \
+{ \
+	if (_l && _n) \
+		fy_ ## _type ## _list_add_tail(_l, _n); \
+} \
+static inline bool fy_ ## _type ## _list_empty(struct fy_ ## _type ## _list *_l) \
+{ \
+	return _l ? fy_list_is_empty(&_l->_lh) : true; \
+} \
+static inline bool fy_ ## _type ## _list_is_singular(struct fy_ ## _type ## _list *_l) \
+{ \
+	return _l ? fy_list_is_singular(&_l->_lh) : true; \
+} \
+static inline void fy_ ## _type ## _list_del(struct fy_ ## _type ## _list *_l, struct fy_ ## _type *_n) \
+{ \
+	if (_l && _n) { \
+		fy_list_del(&_n->node); \
+		fy_list_init_head(&_n->node); \
+	} \
+} \
+static inline void fy_ ## _type ## _list_insert_after(struct fy_ ## _type ## _list *_l, \
+		struct fy_ ## _type *_p, struct fy_ ## _type *_n) \
+{ \
+	if (_l && _p && _n) \
+		fy_list_add_head(&_n->node, &_p->node); \
+} \
+static inline void fy_ ## _type ## _list_insert_before(struct fy_ ## _type ## _list *_l, \
+		struct fy_ ## _type *_p, struct fy_ ## _type *_n) \
+{ \
+	if (_l && _p && _n) \
+		fy_list_add_tail(&_n->node, &_p->node); \
+} \
+static inline struct fy_ ## _type *fy_ ## _type ## _list_head(struct fy_ ## _type ## _list *_l) \
+{ \
+	return !fy_ ## _type ## _list_empty(_l) ? fy_container_of(_l->_lh.next, struct fy_ ## _type, node) : NULL; \
+} \
+static inline struct fy_ ## _type *fy_ ## _type ## _list_tail(struct fy_ ## _type ## _list *_l) \
+{ \
+	return !fy_ ## _type ## _list_empty(_l) ? fy_container_of(_l->_lh.prev, struct fy_ ## _type, node) : NULL; \
+} \
+static inline struct fy_ ## _type *fy_ ## _type ## _list_first(struct fy_ ## _type ## _list *_l) \
+{ \
+	return fy_ ## _type ## _list_head(_l); \
+} \
+static inline struct fy_ ## _type *fy_ ## _type ## _list_last(struct fy_ ## _type ## _list *_l) \
+{ \
+	return fy_ ## _type ## _list_tail(_l); \
+} \
+static inline struct fy_ ## _type *fy_ ## _type ## _list_pop(struct fy_ ## _type ## _list *_l) \
+{ \
+	struct fy_ ## _type *_n; \
+	\
+	_n = fy_ ## _type ## _list_head(_l); \
+	if (!_n) \
+		return NULL; \
+	fy_ ## _type ## _list_del(_l, _n); \
+	return _n; \
+} \
+static inline struct fy_ ## _type *fy_ ## _type ## _list_pop_tail(struct fy_ ## _type ## _list *_l) \
+{ \
+	struct fy_ ## _type *_n; \
+	\
+	_n = fy_ ## _type ## _list_tail(_l); \
+	if (!_n) \
+		return NULL; \
+	fy_ ## _type ## _list_del(_l, _n); \
+	return _n; \
+} \
+static inline struct fy_ ## _type *fy_ ## _type ## _next(struct fy_ ## _type ## _list *_l, struct fy_ ## _type *_n) \
+{ \
+	if (!_n || !_l || _n->node.next == &_l->_lh) \
+		return NULL; \
+	return fy_container_of(_n->node.next, struct fy_ ## _type, node); \
+} \
+static inline struct fy_ ## _type *fy_ ## _type ## _prev(struct fy_ ## _type ## _list *_l, struct fy_ ## _type *_n) \
+{ \
+	if (!_n || !_l || _n->node.prev == &_l->_lh) \
+		return NULL; \
+	return fy_container_of(_n->node.prev, struct fy_ ## _type, node); \
+} \
+static inline void fy_ ## _type ## _lists_splice( \
+		struct fy_ ## _type ## _list *_l, \
+		struct fy_ ## _type ## _list *_lfrom) \
+{ \
+	/* check arguments for sanity and lists are not empty */ \
+	if (!_l || !_lfrom || \
+		fy_ ## _type ## _list_empty(_lfrom)) \
+		return; \
+	fy_list_splice(&_lfrom->_lh, &_l->_lh); \
+} \
+static inline void fy_ ## _type ## _list_splice_after( \
+		struct fy_ ## _type ## _list *_l, struct fy_ ## _type *_n, \
+		struct fy_ ## _type ## _list *_lfrom) \
+{ \
+	/* check arguments for sanity and lists are not empty */ \
+	if (!_l || !_n || !_lfrom || \
+		fy_ ## _type ## _list_empty(_lfrom)) \
+		return; \
+	fy_list_splice(&_lfrom->_lh, &_n->node); \
+} \
+static inline void fy_ ## _type ## _list_splice_before( \
+		struct fy_ ## _type ## _list *_l, struct fy_ ## _type *_n, \
+		struct fy_ ## _type ## _list *_lfrom) \
+{ \
+	/* check arguments for sanity and lists are not empty */ \
+	 if (!_l || !_n || !_lfrom || \
+		fy_ ## _type ## _list_empty(_lfrom)) \
+		return; \
+	fy_list_splice(&_lfrom->_lh, _n->node.prev); \
+} \
+struct __useless_struct_to_allow_semicolon
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-types.c b/contrib/libs/libfyaml/src/lib/fy-types.c
new file mode 100644
index 0000000000..5e0da300c6
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-types.c
@@ -0,0 +1,35 @@
+/*
+ * fy-types.c - types definition
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#endif
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <limits.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+
+/* parse only types */
+FY_PARSE_TYPE_DEFINE_SIMPLE(indent);
+FY_PARSE_TYPE_DEFINE_SIMPLE(simple_key);
+FY_PARSE_TYPE_DEFINE_SIMPLE(parse_state_log);
+FY_PARSE_TYPE_DEFINE_SIMPLE(flow);
diff --git a/contrib/libs/libfyaml/src/lib/fy-types.h b/contrib/libs/libfyaml/src/lib/fy-types.h
new file mode 100644
index 0000000000..889f2dcbbc
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-types.h
@@ -0,0 +1,143 @@
+/*
+ * fy-types.h - common types builder
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_TYPES_H
+#define FY_TYPES_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include <libfyaml.h>
+
+#include "fy-list.h"
+
+struct fy_parser;
+
+/* define type methods */
+#define FY_ALLOC_TYPE_DEFINE(_type) \
+\
+struct fy_ ## _type *fy_ ## _type ## _alloc_simple_internal( \
+		struct fy_ ## _type ## _list *_rl) \
+{ \
+	struct fy_ ## _type *_n; \
+	\
+	_n = fy_ ## _type ## _list_pop(_rl); \
+	if (_n) \
+		return _n; \
+	_n = malloc(sizeof(*_n)); \
+	if (_n) \
+        fy_list_init_head(&_n->node); \
+	return _n; \
+} \
+\
+void fy_ ## _type ## _recycle_internal(struct fy_ ## _type ## _list *_rl, \
+		struct fy_ ## _type *_n) \
+{ \
+	if (_n) \
+		fy_ ## _type ## _list_push(_rl, _n); \
+} \
+\
+void fy_ ## _type ## _vacuum_internal(struct fy_ ## _type ## _list *_rl) \
+{ \
+	struct fy_ ## _type *_n; \
+	\
+	while ((_n = fy_ ## _type ## _list_pop(_rl)) != NULL) \
+		free(_n); \
+} \
+\
+struct __useless_struct_to_allow_semicolon
+
+/* declarations for alloc */
+
+#define FY_ALLOC_TYPE_ALLOC(_type) \
+struct fy_ ## _type *fy_ ## _type ## _alloc_simple_internal( \
+		struct fy_ ## _type ## _list *_rl); \
+void fy_ ## _type ## _recycle_internal(struct fy_ ## _type ## _list *_rl, \
+		struct fy_ ## _type *_n); \
+void fy_ ## _type ## _vacuum_internal(struct fy_ ## _type ## _list *_rl); \
+struct __useless_struct_to_allow_semicolon
+
+/* parser type methods */
+#define FY_PARSE_TYPE_DECL_ALLOC(_type) \
+\
+struct fy_ ## _type *fy_parse_ ## _type ## _alloc(struct fy_parser *fyp); \
+void fy_parse_ ## _type ## _vacuum(struct fy_parser *fyp); \
+void fy_parse_ ## _type ## _recycle(struct fy_parser *fyp, struct fy_ ## _type *_n); \
+void fy_parse_ ## _type ## _list_recycle_all(struct fy_parser *fyp, struct fy_ ## _type ## _list *_l); \
+\
+struct __useless_struct_to_allow_semicolon
+
+#define FY_PARSE_TYPE_DECL(_type) \
+FY_TYPE_FWD_DECL_LIST(_type); \
+FY_TYPE_DECL_LIST(_type); \
+FY_PARSE_TYPE_DECL_ALLOC(_type); \
+struct __useless_struct_to_allow_semicolon
+
+#define FY_PARSE_TYPE_DECL_AFTER_FWD(_type) \
+FY_TYPE_DECL_LIST(_type); \
+FY_PARSE_TYPE_DECL_ALLOC(_type); \
+struct __useless_struct_to_allow_semicolon
+
+/* define type methods */
+#define FY_PARSE_TYPE_DEFINE(_type) \
+\
+struct fy_ ## _type *fy_parse_ ## _type ## _alloc_simple(struct fy_parser *fyp) \
+{ \
+	return fy_ ## _type ## _alloc_simple_internal(&fyp->recycled_ ## _type); \
+} \
+\
+void fy_parse_ ## _type ## _vacuum(struct fy_parser *fyp) \
+{ \
+	fy_ ## _type ## _vacuum_internal(&fyp->recycled_ ## _type); \
+} \
+\
+void fy_parse_ ## _type ## _list_recycle_all(struct fy_parser *fyp, struct fy_ ## _type ## _list *_l) \
+{ \
+	struct fy_ ## _type *_n; \
+	\
+	while ((_n = fy_ ## _type ## _list_pop(_l)) != NULL) \
+		fy_parse_ ## _type ## _recycle(fyp, _n); \
+} \
+\
+void fy_parse_ ## _type ## _recycle_simple(struct fy_parser *fyp, struct fy_ ## _type *_n) \
+{ \
+	if (!fyp->suppress_recycling) \
+		fy_ ## _type ## _recycle_internal(&fyp->recycled_ ## _type, _n); \
+	else \
+		free(_n); \
+} \
+\
+struct __useless_struct_to_allow_semicolon
+
+#define FY_PARSE_TYPE_DEFINE_ALLOC_SIMPLE(_type) \
+struct fy_ ## _type *fy_parse_ ## _type ## _alloc(struct fy_parser *_fyp) \
+{ \
+	return fy_parse_ ## _type ## _alloc_simple(_fyp); \
+} \
+\
+void fy_parse_ ## _type ## _recycle(struct fy_parser *_fyp, struct fy_ ## _type *_n) \
+{ \
+	if (_n) \
+		fy_parse_ ## _type ## _recycle_simple(_fyp, _n); \
+} \
+\
+struct __useless_struct_to_allow_semicolon
+
+#define FY_PARSE_TYPE_DEFINE_SIMPLE(_type) \
+\
+FY_ALLOC_TYPE_DEFINE(_type); \
+FY_PARSE_TYPE_DEFINE(_type); \
+FY_PARSE_TYPE_DEFINE_ALLOC_SIMPLE(_type); \
+\
+struct __useless_struct_to_allow_semicolon
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-utf8.c b/contrib/libs/libfyaml/src/lib/fy-utf8.c
new file mode 100644
index 0000000000..8105f71173
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-utf8.c
@@ -0,0 +1,591 @@
+/*
+ * fy-utf8.c - utf8 handling methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include <libfyaml.h>
+
+#include "fy-utf8.h"
+
+const int8_t fy_utf8_width_table[32] = {
+	1, 1, 1, 1, 1, 1, 1, 1,
+	1, 1, 1, 1, 1, 1, 1, 1,
+	0, 0, 0, 0, 0, 0, 0, 0,
+	2, 2, 2, 2, 3, 3, 4, 0,
+};
+
+int fy_utf8_get_generic(const void *ptr, int left, int *widthp)
+{
+	const uint8_t *p = ptr;
+	int i, width, value;
+
+	if (left < 1)
+		return FYUG_EOF;
+
+	/* this is the slow path */
+	width = fy_utf8_width_by_first_octet(p[0]);
+	if (!width)
+		return FYUG_INV;
+	if (width > left)
+		return FYUG_PARTIAL;
+
+	/* initial value */
+	value = *p++ & (0xff >> width);
+	for (i = 1; i < width; i++) {
+		if ((*p & 0xc0) != 0x80)
+			return FYUG_INV;
+		value = (value << 6) | (*p++ & 0x3f);
+	}
+
+	/* check for validity */
+	if ((width == 4 && value < 0x10000) ||
+	    (width == 3 && value <   0x800) ||
+	    (width == 2 && value <    0x80) ||
+	    (value >= 0xd800 && value <= 0xdfff) || value >= 0x110000)
+		return FYUG_INV;
+
+	*widthp = width;
+
+	return value;
+}
+
+int fy_utf8_get_right_generic(const void *ptr, int left, int *widthp)
+{
+	const uint8_t *s, *e;
+	uint8_t v;
+
+	s = ptr;
+	e =  s + left;
+
+	if (left < 1)
+		return FYUG_EOF;
+
+	/* single byte sequence */
+	v = e[-1];
+	if ((v & 0x80) == 0) {
+		if (widthp)
+			*widthp = 1;
+		return (int)v & 0x7f;
+	}
+
+	/* the last byte must be & 0xc0 == 0x80 */
+	if ((v & 0xc0) != 0x80)
+		return FYUG_INV;
+
+	/* at least two byte sequence */
+	if (left < 2)
+		return FYUG_EOF;
+
+	v = e[-2];
+	/* the first byte of the sequence (must be a two byte sequence) */
+	if ((v & 0xc0) != 0x80) {
+		/* two byte start is 110x_xxxx */
+		if ((v & 0xe0) != 0xc0)
+			return FYUG_INV;
+		return fy_utf8_get(e - 2, 2, widthp);
+	}
+
+	/* at least three byte sequence */
+	if (left < 3)
+		return FYUG_EOF;
+
+	v = e[-3];
+	/* the first byte of the sequence (must be a three byte sequence) */
+	if ((v & 0xc0) != 0x80) {
+		/* three byte start is 1110_xxxx */
+		if ((v & 0xf0) != 0xe0)
+			return FYUG_INV;
+		return fy_utf8_get(e - 3, 3, widthp);
+	}
+
+	/* at least four byte sequence */
+	if (left < 4)
+		return FYUG_EOF;
+
+	v = e[-4];
+
+	/* the first byte of the sequence (must be a four byte sequence) */
+	/* four byte start is 1111_0xxx */
+	if ((v & 0xf8) != 0xf0) {
+		return FYUG_INV;
+	}
+	return fy_utf8_get(e - 4, 4, widthp);
+}
+
+struct fy_utf8_fmt_esc_map {
+	const int *ch;
+	const int *map;
+};
+
+static const struct fy_utf8_fmt_esc_map esc_all = {
+	.ch  = (const int []){ '\\', '\0', '\b', '\r', '\t', '\f', '\n', '\v', '\a', '\e', 0x85, 0xa0, 0x2028, 0x2029, -1 },
+	.map = (const int []){ '\\',  '0',  'b',  'r',  't',  'f',  'n',  'v',  'a',  'e',  'N',  '_',    'L',    'P',  0 }
+};
+
+static inline int esc_map(const struct fy_utf8_fmt_esc_map *esc_map, int c)
+{
+	const int *ch;
+	int cc;
+
+	ch = esc_map->ch;
+	while ((cc = *ch++) >= 0) {
+		if (cc == c)
+			return esc_map->map[(ch - esc_map->ch) - 1];
+	}
+	return -1;
+}
+
+static inline int fy_utf8_esc_map(int c, enum fy_utf8_escape esc)
+{
+	if (esc == fyue_none)
+		return -1;
+	if (esc == fyue_singlequote && c == '\'')
+		return '\'';
+	if (fy_utf8_escape_is_any_doublequote(esc) && c == '"')
+		return '"';
+	return esc_map(&esc_all, c);
+}
+
+int fy_utf8_format_text_length(const char *buf, size_t len,
+			       enum fy_utf8_escape esc)
+{
+	int c, w, l;
+	const char *s, *e;
+
+	s = buf;
+	e = buf + len;
+	l = 0;
+	while (s < e) {
+		c = fy_utf8_get(s, e - s, &w);
+		if (!w || c < 0)
+			break;
+		s += w;
+		if (fy_utf8_esc_map(c, esc))
+			w = 2;
+		l += w;
+	}
+	return l + 1;
+}
+
+char *fy_utf8_format_text(const char *buf, size_t len,
+			  char *out, size_t maxsz,
+			  enum fy_utf8_escape esc)
+{
+	int c, w, cc;
+	const char *s, *e;
+	char *os, *oe;
+
+	s = buf;
+	e = buf + len;
+	os = out;
+	oe = out + maxsz - 1;
+	while (s < e) {
+		c = fy_utf8_get(s, e - s, &w);
+		if (!w || c < 0)
+			break;
+		s += w;
+
+		if ((cc = fy_utf8_esc_map(c, esc)) > 0) {
+			if (os + 2 > oe)
+				break;
+			*os++ = '\\';
+			*os++ = cc;
+			continue;
+		}
+
+		if (os + w > oe)
+			break;
+
+		os = fy_utf8_put_unchecked(os, c);
+	}
+	*os++ = '\0';
+	return out;
+}
+
+char *fy_utf8_format(int c, char *buf, enum fy_utf8_escape esc)
+{
+	int cc;
+	char *s;
+
+	if (!fy_utf8_is_valid(c)) {
+		*buf = '\0';
+		return buf;
+	}
+
+	s = buf;
+	if ((cc = fy_utf8_esc_map(c, esc)) > 0) {
+		*s++ = '\\';
+		*s++ = cc;
+	} else
+		s = fy_utf8_put_unchecked(s, c);
+	*s = '\0';
+	return buf;
+}
+
+char *fy_utf8_format_text_alloc(const char *buf, size_t len, enum fy_utf8_escape esc)
+{
+	int outsz;
+	char *out;
+
+	outsz = fy_utf8_format_text_length(buf, len, esc);
+	if (outsz < 0)
+		return NULL;
+	out = malloc(outsz);
+	if (!out)
+		return NULL;
+	fy_utf8_format_text(buf, len, out, outsz, esc);
+
+	return out;
+}
+
+const void *fy_utf8_memchr_generic(const void *s, int c, size_t n)
+{
+	int cc, w;
+	const void *e;
+
+	e = (char*)s + n;
+	while (s < e && (cc = fy_utf8_get(s, (char*)e - (char*)s, &w)) >= 0) {
+		if (c == cc)
+			return s;
+		s = (char*)s + w;
+	}
+
+	return NULL;
+}
+
+/* parse an escape and return utf8 value */
+int fy_utf8_parse_escape(const char **strp, size_t len, enum fy_utf8_escape esc)
+{
+	const char *s, *e;
+	char c;
+	int i, value, code_length, cc, w;
+	unsigned int hi_surrogate, lo_surrogate;
+
+	/* why do you bother us? */
+	if (esc == fyue_none)
+		return -1;
+
+	if (!strp || !*strp || len < 2)
+		return -1;
+
+	value = -1;
+
+	s = *strp;
+	e = s + len;
+
+	c = *s++;
+
+	if (esc == fyue_singlequote) {
+		if (c != '\'')
+			goto out;
+		c = *s++;
+		if (c != '\'')
+			goto out;
+
+		value = '\'';
+		goto out;
+	}
+
+	/* get '\\' */
+	if (c != '\\')
+		goto out;
+
+	c = *s++;
+
+	/* common YAML & JSON escapes */
+	switch (c) {
+	case 'b':
+		value = '\b';
+		break;
+	case 'f':
+		value = '\f';
+		break;
+	case 'n':
+		value = '\n';
+		break;
+	case 'r':
+		value = '\r';
+		break;
+	case 't':
+		value = '\t';
+		break;
+	case '"':
+		value = '"';
+		break;
+	case '/':
+		value = '/';
+		break;
+	case '\\':
+		value = '\\';
+		break;
+	default:
+		break;
+	}
+
+	if (value >= 0)
+		goto out;
+
+	if (esc == fyue_doublequote || esc == fyue_doublequote_yaml_1_1) {
+		switch (c) {
+		case '0':
+			value = '\0';
+			break;
+		case 'a':
+			value = '\a';
+			break;
+		case '\t':
+			value = '\t';
+			break;
+		case 'v':
+			value = '\v';
+			break;
+		case 'e':
+			value = '\e';
+			break;
+		case ' ':
+			value = ' ';
+			break;
+		case 'N':
+			value = 0x85;	/* NEL */
+			break;
+		case '_':
+			value = 0xa0;
+			break;
+		case 'L':
+			value = 0x2028;	/* LS */
+			break;
+		case 'P':	/* PS 0x2029 */
+			value = 0x2029; /* PS */
+			break;
+		default:
+			/* weird unicode escapes */
+			if ((uint8_t)c >= 0x80) {
+				/* in non yaml-1.1 mode we don't allow this craziness */
+				if (esc == fyue_doublequote)
+					goto out;
+
+				cc = fy_utf8_get(s - 1, e - (s - 1), &w);
+				switch (cc) {
+				case 0x2028:
+				case 0x2029:
+				case 0x85:
+				case 0xa0:
+					value = cc;
+					break;
+				default:
+					break;
+				}
+			}
+			break;
+		}
+		if (value >= 0)
+			goto out;
+	}
+
+	/* finally try the unicode escapes */
+	code_length = 0;
+
+	if (esc == fyue_doublequote || esc == fyue_doublequote_yaml_1_1) {
+		switch (c) {
+		case 'x':
+			code_length = 2;
+			break;
+		case 'u':
+			code_length = 4;
+			break;
+		case 'U':
+			code_length = 8;
+			break;
+		default:
+			return -1;
+		}
+	} else if (esc == fyue_doublequote_json && c == 'u')
+		code_length = 4;
+
+	if (!code_length || code_length > (e - s))
+		goto out;
+
+	value = 0;
+	for (i = 0; i < code_length; i++) {
+		c = *s++;
+		value <<= 4;
+		if (c >= '0' && c <= '9')
+			value |= c - '0';
+		else if (c >= 'a' && c <= 'f')
+			value |= 10 + c - 'a';
+		else if (c >= 'A' && c <= 'F')
+			value |= 10 + c - 'A';
+		else
+			goto out;
+	}
+
+	/* hi/lo surrogate pair */
+	if (code_length == 4 && value >= 0xd800 && value <= 0xdbff &&
+		(e - s) >= 6 && s[0] == '\\' && s[1] == 'u') {
+		hi_surrogate = value;
+
+		s += 2;
+
+		value = 0;
+		for (i = 0; i < code_length; i++) {
+			c = *s++;
+			value <<= 4;
+			if (c >= '0' && c <= '9')
+				value |= c - '0';
+			else if (c >= 'a' && c <= 'f')
+				value |= 10 + c - 'a';
+			else if (c >= 'A' && c <= 'F')
+				value |= 10 + c - 'A';
+			else
+				return -1;
+		}
+		lo_surrogate = value;
+		value = 0x10000 + (hi_surrogate - 0xd800) * 0x400 + (lo_surrogate - 0xdc00);
+	}
+
+out:
+	*strp = s;
+
+	return value;
+}
+
+uint8_t fy_utf8_low_ascii_flags[0x80] = {
+	[0x00] = F_NON_PRINT,				// NUL '\0' (null character)
+	[0x01] = F_NON_PRINT, 				// SOH (start of heading)
+	[0x02] = F_NON_PRINT,				// STX (start of text)
+	[0x03] = F_NON_PRINT,				// ETX (end of text)
+	[0x04] = F_NON_PRINT,				// EOT (end of transmission)
+	[0x05] = F_NON_PRINT,				// ENQ (enquiry)
+	[0x06] = F_NON_PRINT,				// ACK (acknowledge)
+	[0x07] = F_NON_PRINT | F_QUOTE_ESC,		// BEL '\a' (bell)
+	[0x08] = F_NON_PRINT | F_QUOTE_ESC,		// BS  '\b' (backspace)
+	[0x09] = F_NON_PRINT | F_QUOTE_ESC | F_WS,	// HT  '\t' (horizontal tab)
+	[0x0A] = F_NON_PRINT | F_QUOTE_ESC | F_LB,	// LF  '\n' (new line)
+	[0x0B] = F_NON_PRINT | F_QUOTE_ESC,		// VT  '\v' (vertical tab)
+	[0x0C] = F_NON_PRINT | F_QUOTE_ESC,		// FF  '\f' (form feed)
+	[0x0D] = F_NON_PRINT | F_QUOTE_ESC | F_LB,	// CR  '\r' (carriage ret)
+	[0x0E] = F_NON_PRINT,				// SO  (shift out)
+	[0x0F] = F_NON_PRINT,				// SI  (shift in)
+	[0x10] = F_NON_PRINT,				// DLE (data link escape)
+	[0x11] = F_NON_PRINT,				// DC1 (device control 1)
+	[0x12] = F_NON_PRINT,				// DC2 (device control 2)
+	[0x13] = F_NON_PRINT,				// DC3 (device control 3)
+	[0x14] = F_NON_PRINT,				// DC4 (device control 4)
+	[0x15] = F_NON_PRINT,				// NAK (negative ack.)
+	[0x16] = F_NON_PRINT,				// SYN (synchronous idle)
+	[0x17] = F_NON_PRINT,				// ETB (end of trans. blk)
+	[0x18] = F_NON_PRINT,				// CAN (cancel)
+	[0x19] = F_NON_PRINT,				// EM  (end of medium)
+	[0x1A] = F_NON_PRINT,				// SUB (substitute)
+	[0x1B] = F_NON_PRINT,				// ESC (escape)
+	[0x1C] = F_NON_PRINT,				// FS  (file separator)
+	[0x1D] = F_NON_PRINT,				// GS  (group separator)
+	[0x1E] = F_NON_PRINT,				// RS  (record separator)
+	[0x1F] = F_NON_PRINT,				// US  (unit separator)
+	[' ']  = F_WS,
+	['!']  = F_PUNCT,
+	['"']  = F_PUNCT,
+	['#']  = F_PUNCT,
+	['$']  = F_PUNCT,
+	['%']  = F_PUNCT,
+	['&']  = F_PUNCT,
+	['\''] = F_PUNCT,
+	['(']  = F_PUNCT,
+	[')']  = F_PUNCT,
+	['*']  = F_PUNCT,
+	['+']  = F_PUNCT,
+	[',']  = F_PUNCT,
+	['-']  = F_PUNCT,
+	['.']  = F_PUNCT,
+	['/']  = F_PUNCT,
+	['0']  = F_DIGIT | F_SIMPLE_SCALAR,
+	['1']  = F_DIGIT | F_SIMPLE_SCALAR,
+	['2']  = F_DIGIT | F_SIMPLE_SCALAR,
+	['3']  = F_DIGIT | F_SIMPLE_SCALAR,
+	['4']  = F_DIGIT | F_SIMPLE_SCALAR,
+	['5']  = F_DIGIT | F_SIMPLE_SCALAR,
+	['6']  = F_DIGIT | F_SIMPLE_SCALAR,
+	['7']  = F_DIGIT | F_SIMPLE_SCALAR,
+	['8']  = F_DIGIT | F_SIMPLE_SCALAR,
+	['9']  = F_DIGIT | F_SIMPLE_SCALAR,
+	[':']  = F_PUNCT,
+	[';']  = F_PUNCT,
+	['<']  = F_PUNCT,
+	['=']  = F_PUNCT,
+	['>']  = F_PUNCT,
+	['?']  = F_PUNCT,
+	['@']  = F_PUNCT,
+	['A']  = F_LETTER | F_SIMPLE_SCALAR,
+	['B']  = F_LETTER | F_SIMPLE_SCALAR,
+	['C']  = F_LETTER | F_SIMPLE_SCALAR,
+	['D']  = F_LETTER | F_SIMPLE_SCALAR,
+	['E']  = F_LETTER | F_SIMPLE_SCALAR,
+	['F']  = F_LETTER | F_SIMPLE_SCALAR,
+	['G']  = F_LETTER | F_SIMPLE_SCALAR,
+	['H']  = F_LETTER | F_SIMPLE_SCALAR,
+	['I']  = F_LETTER | F_SIMPLE_SCALAR,
+	['J']  = F_LETTER | F_SIMPLE_SCALAR,
+	['K']  = F_LETTER | F_SIMPLE_SCALAR,
+	['L']  = F_LETTER | F_SIMPLE_SCALAR,
+	['M']  = F_LETTER | F_SIMPLE_SCALAR,
+	['N']  = F_LETTER | F_SIMPLE_SCALAR,
+	['O']  = F_LETTER | F_SIMPLE_SCALAR,
+	['P']  = F_LETTER | F_SIMPLE_SCALAR,
+	['Q']  = F_LETTER | F_SIMPLE_SCALAR,
+	['R']  = F_LETTER | F_SIMPLE_SCALAR,
+	['S']  = F_LETTER | F_SIMPLE_SCALAR,
+	['T']  = F_LETTER | F_SIMPLE_SCALAR,
+	['U']  = F_LETTER | F_SIMPLE_SCALAR,
+	['V']  = F_LETTER | F_SIMPLE_SCALAR,
+	['W']  = F_LETTER | F_SIMPLE_SCALAR,
+	['X']  = F_LETTER | F_SIMPLE_SCALAR,
+	['Y']  = F_LETTER | F_SIMPLE_SCALAR,
+	['Z']  = F_LETTER | F_SIMPLE_SCALAR,
+	['[']  = F_PUNCT,
+	['\\'] = F_PUNCT,  				// '\\'
+	[']']  = F_PUNCT,
+	['^']  = F_PUNCT,
+	['_']  = F_PUNCT | F_SIMPLE_SCALAR,
+	['`']  = F_PUNCT,
+	['a']  = F_LETTER | F_SIMPLE_SCALAR,
+	['b']  = F_LETTER | F_SIMPLE_SCALAR,
+	['c']  = F_LETTER | F_SIMPLE_SCALAR,
+	['d']  = F_LETTER | F_SIMPLE_SCALAR,
+	['e']  = F_LETTER | F_SIMPLE_SCALAR,
+	['f']  = F_LETTER | F_SIMPLE_SCALAR,
+	['g']  = F_LETTER | F_SIMPLE_SCALAR,
+	['h']  = F_LETTER | F_SIMPLE_SCALAR,
+	['i']  = F_LETTER | F_SIMPLE_SCALAR,
+	['j']  = F_LETTER | F_SIMPLE_SCALAR,
+	['k']  = F_LETTER | F_SIMPLE_SCALAR,
+	['l']  = F_LETTER | F_SIMPLE_SCALAR,
+	['m']  = F_LETTER | F_SIMPLE_SCALAR,
+	['n']  = F_LETTER | F_SIMPLE_SCALAR,
+	['o']  = F_LETTER | F_SIMPLE_SCALAR,
+	['p']  = F_LETTER | F_SIMPLE_SCALAR,
+	['q']  = F_LETTER | F_SIMPLE_SCALAR,
+	['r']  = F_LETTER | F_SIMPLE_SCALAR,
+	['s']  = F_LETTER | F_SIMPLE_SCALAR,
+	['t']  = F_LETTER | F_SIMPLE_SCALAR,
+	['u']  = F_LETTER | F_SIMPLE_SCALAR,
+	['v']  = F_LETTER | F_SIMPLE_SCALAR,
+	['w']  = F_LETTER | F_SIMPLE_SCALAR,
+	['x']  = F_LETTER | F_SIMPLE_SCALAR,
+	['y']  = F_LETTER | F_SIMPLE_SCALAR,
+	['z']  = F_LETTER | F_SIMPLE_SCALAR,
+	['{']  = F_PUNCT,
+	['|']  = F_PUNCT,
+	['}']  = F_PUNCT,
+	['~']  = F_PUNCT,
+	[0x7F] = F_NON_PRINT,				// DEL
+};
diff --git a/contrib/libs/libfyaml/src/lib/fy-utf8.h b/contrib/libs/libfyaml/src/lib/fy-utf8.h
new file mode 100644
index 0000000000..fa4faa1062
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-utf8.h
@@ -0,0 +1,229 @@
+/*
+ * fy-utf8.h - UTF-8 methods
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_UTF8_H
+#define FY_UTF8_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include <libfyaml.h>
+
+#include "fy-utils.h"
+
+extern const int8_t fy_utf8_width_table[32];
+
+static inline int
+fy_utf8_width_by_first_octet_no_table(uint8_t c)
+{
+	return (c & 0x80) == 0x00 ? 1 :
+	       (c & 0xe0) == 0xc0 ? 2 :
+	       (c & 0xf0) == 0xe0 ? 3 :
+	       (c & 0xf8) == 0xf0 ? 4 : 0;
+}
+
+static inline FY_ALWAYS_INLINE int
+fy_utf8_width_by_first_octet(uint8_t c)
+{
+	return fy_utf8_width_table[c >> 3];
+}
+
+/* assumes valid utf8 character */
+static inline size_t
+fy_utf8_width(int c)
+{
+	return c <      0x80 ? 1 :
+	       c <     0x800 ? 2 :
+	       c <   0x10000 ? 3 : 4;
+}
+
+static inline bool
+fy_utf8_is_valid(int c)
+{
+	return c >= 0 && !((c >= 0xd800 && c <= 0xdfff) || c >= 0x110000);
+}
+
+static inline bool
+fy_utf8_is_printable_ascii(int c)
+{
+	return c >= 0x20 && c <= 0x7e;
+}
+
+/* generic utf8 decoder (not inlined) */
+int fy_utf8_get_generic(const void *ptr, int left, int *widthp);
+
+/* -1 for end of input, -2 for invalid character, -3 for partial */
+#define FYUG_EOF	-1
+#define FYUG_INV	-2
+#define FYUG_PARTIAL	-3
+
+static inline int fy_utf8_get(const void *ptr, int left, int *widthp)
+{
+	const uint8_t *p = ptr;
+
+	/* single byte (hot path) */
+	if (left <= 0) {
+		*widthp = 0;
+		return FYUG_EOF;
+	}
+
+	if (!(p[0] & 0x80)) {
+		*widthp = 1;
+		return p[0] & 0x7f;
+	}
+	return fy_utf8_get_generic(ptr, left, widthp);
+}
+
+int fy_utf8_get_right_generic(const void *ptr, int left, int *widthp);
+
+static inline int fy_utf8_get_right(const void *ptr, int left, int *widthp)
+{
+	const uint8_t *p = (const uint8_t*)ptr + left;
+
+	/* single byte (hot path) */
+	if (left > 0 && !(p[-1] & 0x80)) {
+		if (widthp)
+			*widthp = 1;
+		return p[-1] & 0x7f;
+	}
+	return fy_utf8_get_right_generic(ptr, left, widthp);
+}
+
+
+/* for when you _know_ that there's enough room and c is valid */
+static inline void *fy_utf8_put_unchecked(void *ptr, int c)
+{
+	uint8_t *s = ptr;
+
+	assert(c >= 0);
+	if (c < 0x80)
+		*s++ = c;
+	else if (c < 0x800) {
+		*s++ = (c >> 6) | 0xc0;
+		*s++ = (c & 0x3f) | 0x80;
+	} else if (c < 0x10000) {
+		*s++ = (c >> 12) | 0xe0;
+		*s++ = ((c >> 6) & 0x3f) | 0x80;
+		*s++ = (c & 0x3f) | 0x80;
+	} else {
+		*s++ = (c >> 18) | 0xf0;
+		*s++ = ((c >> 12) & 0x3f) | 0x80;
+		*s++ = ((c >> 6) & 0x3f) | 0x80;
+		*s++ = (c & 0x3f) | 0x80;
+	}
+	return s;
+}
+
+static inline void *fy_utf8_put(void *ptr, size_t left, int c)
+{
+	if (!fy_utf8_is_valid(c) || fy_utf8_width(c) > left)
+		return NULL;
+
+	return fy_utf8_put_unchecked(ptr, c);
+}
+
+/* buffer must contain at least 5 characters */
+#define FY_UTF8_FORMAT_BUFMIN	5
+enum fy_utf8_escape {
+	fyue_none,
+	fyue_singlequote,
+	fyue_doublequote,
+	fyue_doublequote_json,
+	fyue_doublequote_yaml_1_1,
+};
+
+static inline bool fy_utf8_escape_is_any_doublequote(enum fy_utf8_escape esc)
+{
+	return esc >= fyue_doublequote && esc <= fyue_doublequote_yaml_1_1;
+}
+
+char *fy_utf8_format(int c, char *buf, enum fy_utf8_escape esc);
+
+#define fy_utf8_format_a(_c, _esc, _res) \
+	do { \
+	 	char *_buf = FY_ALLOCA(FY_UTF8_FORMAT_BUFMIN); \
+	 	*(_res) = fy_utf8_format((_c), _buf, _esc); \
+	} while(false)
+
+int fy_utf8_format_text_length(const char *buf, size_t len,
+			       enum fy_utf8_escape esc);
+char *fy_utf8_format_text(const char *buf, size_t len,
+			  char *out, size_t maxsz,
+			  enum fy_utf8_escape esc);
+
+#define fy_utf8_format_text_a(_buf, _len, _esc, _res) \
+	do { \
+		const char *__buf = (_buf); \
+		size_t __len = (_len); \
+		enum fy_utf8_escape __esc = (_esc); \
+		size_t _outsz = fy_utf8_format_text_length(__buf, __len, __esc); \
+		char *_out = FY_ALLOCA(_outsz + 1); \
+		*(_res) = fy_utf8_format_text(__buf, __len, _out, _outsz, __esc); \
+	} while(false)
+
+char *fy_utf8_format_text_alloc(const char *buf, size_t len, enum fy_utf8_escape esc);
+
+const void *fy_utf8_memchr_generic(const void *s, int c, size_t n);
+
+static inline const void *fy_utf8_memchr(const void *s, int c, size_t n)
+{
+	if (c < 0 || !n)
+		return NULL;
+	if (c < 0x80)
+		return memchr(s, c, n);
+	return fy_utf8_memchr_generic(s, c, n);
+}
+
+static inline const void *fy_utf8_strchr(const void *s, int c)
+{
+	if (c < 0)
+		return NULL;
+	if (c < 0x80)
+		return strchr(s, c);
+	return fy_utf8_memchr_generic(s, c, strlen(s));
+}
+
+static inline int fy_utf8_count(const void *ptr, size_t len)
+{
+	const uint8_t *s = ptr, *e = (const uint8_t *)ptr + len;
+	int w, count;
+
+	count = 0;
+	while (s < e) {
+		w = fy_utf8_width_by_first_octet(*s);
+
+		/* malformed? */
+		if (!w || s + w > e)
+			break;
+		s += w;
+
+		count++;
+	}
+
+	return count;
+}
+
+int fy_utf8_parse_escape(const char **strp, size_t len, enum fy_utf8_escape esc);
+
+#define F_NONE			0
+#define F_NON_PRINT		FY_BIT(0)	/* non printable */
+#define F_SIMPLE_SCALAR		FY_BIT(1)	/* part of simple scalar */
+#define F_QUOTE_ESC		FY_BIT(2)	/* escape form, i.e \n */
+#define F_LB			FY_BIT(3)	/* is a linebreak */
+#define F_WS			FY_BIT(4)	/* is a whitespace */
+#define F_PUNCT			FY_BIT(5)	/* is a punctuation mark */
+#define F_LETTER		FY_BIT(6)	/* is a letter a..z A..Z */
+#define F_DIGIT			FY_BIT(7)	/* is a digit 0..9 */
+
+extern uint8_t fy_utf8_low_ascii_flags[0x80];
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-utils.c b/contrib/libs/libfyaml/src/lib/fy-utils.c
new file mode 100644
index 0000000000..8f87ae77d2
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-utils.c
@@ -0,0 +1,721 @@
+/*
+ * fy-utils.c - Generic utilities for functionality that's missing
+ *              from platforms.
+ *
+ * For now only used to implement memstream for Apple platforms.
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <termios.h>
+#include <unistd.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#elif defined(_MSC_VER)
+#include <windows.h>
+#endif
+
+#include "fy-utf8.h"
+#include "fy-ctype.h"
+#include "fy-utils.h"
+
+int fy_get_pagesize() {
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+       return sysconf(_SC_PAGESIZE);
+#elif defined (_MSC_VER)
+    SYSTEM_INFO si;
+    GetSystemInfo(&si);
+       return si.dwPageSize;
+#endif
+}
+
+#if defined(_MSC_VER)
+#ifndef VA_COPY
+# ifdef HAVE_VA_COPY
+#  define VA_COPY(dest, src) va_copy(dest, src)
+# else
+#  ifdef HAVE___VA_COPY
+#   define VA_COPY(dest, src) __va_copy(dest, src)
+#  else
+#   define VA_COPY(dest, src) (dest) = (src)
+#  endif
+# endif
+#endif
+
+#define INIT_SZ 128
+
+int
+vasprintf(char **str, const char *fmt, va_list ap)
+{
+    int ret;
+    va_list ap2;
+    char *string, *newstr;
+    size_t len;
+
+    if ((string = malloc(INIT_SZ)) == NULL)
+        goto fail;
+
+    VA_COPY(ap2, ap);
+    ret = vsnprintf(string, INIT_SZ, fmt, ap2);
+    va_end(ap2);
+    if (ret >= 0 && ret < INIT_SZ) { /* succeeded with initial alloc */
+        *str = string;
+    } else if (ret == INT_MAX || ret < 0) { /* Bad length */
+        free(string);
+        goto fail;
+    } else {    /* bigger than initial, realloc allowing for nul */
+        len = (size_t)ret + 1;
+        if ((newstr = realloc(string, len)) == NULL) {
+            free(string);
+            goto fail;
+        }
+        VA_COPY(ap2, ap);
+        ret = vsnprintf(newstr, len, fmt, ap2);
+        va_end(ap2);
+        if (ret < 0 || (size_t)ret >= len) { /* failed with realloc'ed string */
+            free(newstr);
+            goto fail;
+        }
+        *str = newstr;
+    }
+    return (ret);
+
+fail:
+    *str = NULL;
+    errno = ENOMEM;
+    return (-1);
+}
+
+int asprintf(char **str, const char *fmt, ...)
+{
+    va_list ap;
+    int ret;
+
+    *str = NULL;
+    va_start(ap, fmt);
+    ret = vasprintf(str, fmt, ap);
+    va_end(ap);
+
+    return ret;
+}
+#endif
+
+#if defined(__APPLE__) && (_POSIX_C_SOURCE < 200809L)
+
+/*
+ * adapted from http://piumarta.com/software/memstream/
+ *
+ * Under the MIT license.
+ */
+
+/*
+ * ----------------------------------------------------------------------------
+ *
+ * OPEN_MEMSTREAM(3)      BSD and Linux Library Functions     OPEN_MEMSTREAM(3)
+ *
+ * SYNOPSIS
+ *     #include "memstream.h"
+ *
+ *     FILE *open_memstream(char **bufp, size_t *sizep);
+ *
+ * DESCRIPTION
+ *     The open_memstream()  function opens a  stream for writing to  a buffer.
+ *     The   buffer  is   dynamically  allocated   (as  with   malloc(3)),  and
+ *     automatically grows  as required.  After closing the  stream, the caller
+ *     should free(3) this buffer.
+ *
+ *     When  the  stream is  closed  (fclose(3))  or  flushed (fflush(3)),  the
+ *     locations  pointed  to  by  bufp  and  sizep  are  updated  to  contain,
+ *     respectively,  a pointer  to  the buffer  and  the current  size of  the
+ *     buffer.  These values  remain valid only as long  as the caller performs
+ *     no further output  on the stream.  If further  output is performed, then
+ *     the  stream  must  again  be  flushed  before  trying  to  access  these
+ *     variables.
+ *
+ *     A null byte  is maintained at the  end of the buffer.  This  byte is not
+ *     included in the size value stored at sizep.
+ *
+ *     The stream's  file position can  be changed with fseek(3)  or fseeko(3).
+ *     Moving the file position past the  end of the data already written fills
+ *     the intervening space with zeros.
+ *
+ * RETURN VALUE
+ *     Upon  successful  completion open_memstream()  returns  a FILE  pointer.
+ *     Otherwise, NULL is returned and errno is set to indicate the error.
+ *
+ * CONFORMING TO
+ *     POSIX.1-2008
+ *
+ * ----------------------------------------------------------------------------
+ */
+
+#ifndef min
+#define min(X, Y) (((X) < (Y)) ? (X) : (Y))
+#endif
+
+struct memstream {
+	size_t position;
+	size_t size;
+	size_t capacity;
+	char *contents;
+	char **ptr;
+	size_t *sizeloc;
+};
+
+static int memstream_grow(struct memstream *ms, size_t minsize)
+{
+	size_t newcap;
+	char *newcontents;
+
+	newcap = ms->capacity * 2;
+	while (newcap <= minsize + 1)
+		newcap *= 2;
+	newcontents = realloc(ms->contents, newcap);
+	if (!newcontents)
+		return -1;
+	ms->contents = newcontents;
+	memset(ms->contents + ms->capacity, 0, newcap - ms->capacity);
+	ms->capacity = newcap;
+	*ms->ptr = ms->contents;
+	return 0;
+}
+
+static int memstream_read(void *cookie, char *buf, int count)
+{
+	struct memstream *ms = cookie;
+	size_t n;
+
+	n = min(ms->size - ms->position, (size_t)count);
+	if (n < 1)
+		return 0;
+	memcpy(buf, ms->contents, n);
+	ms->position += n;
+	return n;
+}
+
+static int memstream_write(void *cookie, const char *buf, int count)
+{
+	struct memstream *ms = cookie;
+
+	if (ms->capacity <= ms->position + (size_t)count &&
+	    memstream_grow(ms, ms->position + (size_t)count) < 0)
+		return -1;
+	memcpy(ms->contents + ms->position, buf, count);
+	ms->position += count;
+	ms->contents[ms->position] = '\0';
+	if (ms->size < ms->position)
+		*ms->sizeloc = ms->size = ms->position;
+
+	return count;
+}
+
+static fpos_t memstream_seek(void *cookie, fpos_t offset, int whence)
+{
+	struct memstream *ms = cookie;
+	fpos_t pos= 0;
+
+	switch (whence) {
+	case SEEK_SET:
+		pos = offset;
+		break;
+	case SEEK_CUR:
+		pos = ms->position + offset;
+		break;
+	case SEEK_END:
+		pos = ms->size + offset;
+		break;
+	default:
+		errno= EINVAL;
+		return -1;
+	}
+	if (pos >= (fpos_t)ms->capacity && memstream_grow(ms, pos) < 0)
+		return -1;
+	ms->position = pos;
+	if (ms->size < ms->position)
+		*ms->sizeloc = ms->size = ms->position;
+	return pos;
+}
+
+static int memstream_close(void *cookie)
+{
+	struct memstream *ms = cookie;
+
+	ms->size = min(ms->size, ms->position);
+	*ms->ptr = ms->contents;
+	*ms->sizeloc = ms->size;
+	ms->contents[ms->size]= 0;
+	/* ms->contents is what's returned */
+	free(ms);
+	return 0;
+}
+
+FILE *open_memstream(char **ptr, size_t *sizeloc)
+{
+	struct memstream *ms;
+	FILE *fp;
+
+	if (!ptr || !sizeloc) {
+		errno= EINVAL;
+		goto err_out;
+	}
+
+	ms = calloc(1, sizeof(struct memstream));
+	if (!ms)
+		goto err_out;
+
+	ms->position = ms->size= 0;
+	ms->capacity = 4096;
+	ms->contents = calloc(ms->capacity, 1);
+	if (!ms->contents)
+		goto err_free_ms;
+	ms->ptr = ptr;
+	ms->sizeloc = sizeloc;
+	fp= funopen(ms, memstream_read, memstream_write,
+			memstream_seek, memstream_close);
+	if (!fp)
+		goto err_free_all;
+	*ptr = ms->contents;
+	*sizeloc = ms->size;
+	return fp;
+
+err_free_all:
+	free(ms->contents);
+err_free_ms:
+	free(ms);
+err_out:
+	return NULL;
+}
+
+#endif /* __APPLE__ && _POSIX_C_SOURCE < 200809L */
+
+bool fy_tag_uri_is_valid(const char *data, size_t len)
+{
+	const char *s, *e;
+	int w, j, k, width, c;
+	uint8_t octet, esc_octets[4];
+
+	s = data;
+	e = s + len;
+
+	while ((c = fy_utf8_get(s, e - s, &w)) >= 0) {
+		if (c != '%') {
+			s += w;
+			continue;
+		}
+
+		width = 0;
+		k = 0;
+		do {
+			/* short URI escape */
+			if ((e - s) < 3)
+				return false;
+
+			if (width > 0) {
+				c = fy_utf8_get(s, e - s, &w);
+				if (c != '%')
+					return false;
+			}
+
+			s += w;
+
+			octet = 0;
+
+			for (j = 0; j < 2; j++) {
+				c = fy_utf8_get(s, e - s, &w);
+				if (!fy_is_hex(c))
+					return false;
+				s += w;
+
+				octet <<= 4;
+				if (c >= '0' && c <= '9')
+					octet |= c - '0';
+				else if (c >= 'a' && c <= 'f')
+					octet |= 10 + c - 'a';
+				else
+					octet |= 10 + c - 'A';
+			}
+			if (!width) {
+				width = fy_utf8_width_by_first_octet(octet);
+
+				if (width < 1 || width > 4)
+					return false;
+				k = 0;
+			}
+			esc_octets[k++] = octet;
+
+		} while (--width > 0);
+
+		/* now convert to utf8 */
+		c = fy_utf8_get(esc_octets, k, &w);
+
+		if (c < 0)
+			return false;
+	}
+
+	return true;
+}
+
+int fy_tag_handle_length(const char *data, size_t len)
+{
+	const char *s, *e;
+	int c, w;
+
+	s = data;
+	e = s + len;
+
+	c = fy_utf8_get(s, e - s, &w);
+	if (c != '!')
+		return -1;
+	s += w;
+
+	c = fy_utf8_get(s, e - s, &w);
+	if (fy_is_ws(c))
+		return s - data;
+	/* if first character is !, empty handle */
+	if (c == '!') {
+		s += w;
+		return s - data;
+	}
+	if (!fy_is_first_alpha(c))
+		return -1;
+	s += w;
+	while (fy_is_alnum(c = fy_utf8_get(s, e - s, &w)))
+		s += w;
+	if (c == '!')
+		s += w;
+
+	return s - data;
+}
+
+int fy_tag_uri_length(const char *data, size_t len)
+{
+	const char *s, *e;
+	int c, w, cn, wn, uri_length;
+
+	s = data;
+	e = s + len;
+
+	while (fy_is_uri(c = fy_utf8_get(s, e - s, &w))) {
+		cn = fy_utf8_get(s + w, e - (s + w), &wn);
+		if ((fy_is_z(cn) || fy_is_blank(cn) || fy_is_any_lb(cn)) && fy_utf8_strchr(",}]", c))
+			break;
+		s += w;
+	}
+	uri_length = s - data;
+
+	if (!fy_tag_uri_is_valid(data, uri_length))
+		return -1;
+
+	return uri_length;
+}
+
+int fy_tag_scan(const char *data, size_t len, struct fy_tag_scan_info *info)
+{
+	const char *s, *e;
+	int total_length, handle_length, uri_length, prefix_length, suffix_length;
+	int c, cn, w, wn;
+
+	s = data;
+	e = s + len;
+
+	prefix_length = 0;
+
+	/* it must start with '!' */
+	c = fy_utf8_get(s, e - s, &w);
+	if (c != '!')
+		return -1;
+	cn = fy_utf8_get(s + w, e - (s + w), &wn);
+	if (cn == '<') {
+		prefix_length = 2;
+		suffix_length = 1;
+	} else
+		prefix_length = suffix_length = 0;
+
+	if (prefix_length) {
+		handle_length = 0; /* set the handle to '' */
+		s += prefix_length;
+	} else {
+		/* either !suffix or !handle!suffix */
+		/* we scan back to back, and split handle/suffix */
+		handle_length = fy_tag_handle_length(s, e - s);
+		if (handle_length <= 0)
+			return -1;
+		s += handle_length;
+	}
+
+	uri_length = fy_tag_uri_length(s, e - s);
+	if (uri_length < 0)
+		return -1;
+
+	/* a handle? */
+	if (!prefix_length && (handle_length == 0 || data[handle_length - 1] != '!')) {
+		/* special case, '!', handle set to '' and suffix to '!' */
+		if (handle_length == 1 && uri_length == 0) {
+			handle_length = 0;
+			uri_length = 1;
+		} else {
+			uri_length = handle_length - 1 + uri_length;
+			handle_length = 1;
+		}
+	}
+	total_length = prefix_length + handle_length + uri_length + suffix_length;
+
+	if (total_length != (int)len)
+		return -1;
+
+	info->total_length = total_length;
+	info->handle_length = handle_length;
+	info->uri_length = uri_length;
+	info->prefix_length = prefix_length;
+	info->suffix_length = suffix_length;
+
+	return 0;
+}
+
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+/* simple terminal methods; mainly for getting size of terminal */
+int fy_term_set_raw(int fd, struct termios *oldt)
+{
+	struct termios newt, t;
+	int ret;
+
+	/* must be a terminal */
+	if (!isatty(fd))
+		return -1;
+
+	ret = tcgetattr(fd, &t);
+	if (ret != 0)
+		return ret;
+
+	newt = t;
+
+	cfmakeraw(&newt);
+    
+	ret = tcsetattr(fd, TCSANOW, &newt);
+	if (ret != 0)
+		return ret;
+
+	if (oldt)
+		*oldt = t;
+
+	return 0;
+}
+
+int fy_term_restore(int fd, const struct termios *oldt)
+{
+	/* must be a terminal */
+	if (!isatty(fd))
+		return -1;
+
+	return tcsetattr(fd, TCSANOW, oldt);
+}
+
+ssize_t fy_term_write(int fd, const void *data, size_t count)
+{
+	ssize_t wrn, r;
+
+	if (!isatty(fd))
+		return -1;
+	r = 0;
+	wrn = 0;
+	while (count > 0) {
+		do {
+			r = write(fd, data, count);
+		} while (r == -1 && errno == EAGAIN);
+		if (r < 0)
+			break;
+		wrn += r;
+		data += r;
+		count -= r;
+	}
+
+	/* return the amount written, or the last error code */
+	return wrn > 0 ? wrn : r;
+}
+
+int fy_term_safe_write(int fd, const void *data, size_t count)
+{
+	if (!isatty(fd))
+		return -1;
+
+	return fy_term_write(fd, data, count) == (ssize_t)count ? 0 : -1;
+}
+
+ssize_t fy_term_read(int fd, void *data, size_t count, int timeout_us)
+{
+	ssize_t rdn, r;
+	struct timeval tv, tvto, *tvp;
+	fd_set rdfds;
+
+	if (!isatty(fd))
+		return -1;
+
+	FD_ZERO(&rdfds);
+
+	memset(&tvto, 0, sizeof(tvto));
+	memset(&tv, 0, sizeof(tv));
+
+	if (timeout_us >= 0) {
+		tvto.tv_sec = timeout_us / 1000000;
+		tvto.tv_usec = timeout_us % 1000000;
+		tvp = &tv;
+	} else {
+		tvp = NULL;
+	}
+
+	r = 0;
+	rdn = 0;
+	while (count > 0) {
+		do {
+			FD_SET(fd, &rdfds);
+			if (tvp)
+				*tvp = tvto;
+			r = select(fd + 1, &rdfds, NULL, NULL, tvp);
+		} while (r == -1 && errno == EAGAIN);
+
+		/* select ends, or something weird */
+		if (r <= 0 || !FD_ISSET(fd, &rdfds))
+			break;
+
+		/* now read */
+		do {
+			r = read(fd, data, count);
+		} while (r == -1 && errno == EAGAIN);
+		if (r < 0)
+			break;
+
+		rdn += r;
+		data += r;
+		count -= r;
+	}
+
+	/* return the amount written, or the last error code */
+	return rdn > 0 ? rdn : r;
+}
+
+ssize_t fy_term_read_escape(int fd, void *buf, size_t count)
+{
+	char *p;
+	int r, rdn;
+	char c;
+
+	/* at least 3 characters */
+	if (count < 3)
+		return -1;
+
+	p = buf;
+	rdn = 0;
+
+	/* ESC */
+	r = fy_term_read(fd, &c, 1, 100 * 1000);
+	if (r != 1 || c != '\x1b')
+		return -1;
+	*p++ = c;
+	count--;
+	rdn++;
+
+	/* [ */
+	r = fy_term_read(fd, &c, 1, 100 * 1000);
+	if (r != 1 || c != '[')
+		return rdn;
+	*p++ = c;
+	count--;
+	rdn++;
+
+	/* read until error, out of buffer, or < 0x40 || > 0x7e */
+	r = -1;
+	while (count > 0) {
+		r = fy_term_read(fd, &c, 1, 100 * 1000);
+		if (r != 1)
+			r = -1;
+		if (r != 1)
+			break;
+		*p++ = c;
+		count--;
+		rdn++;
+
+		/* end of escape */
+		if (c >= 0x40 && c <= 0x7e)
+			break;
+	}
+
+	return rdn;
+}
+
+int fy_term_query_size_raw(int fd, int *rows, int *cols)
+{
+	char buf[32];
+	char *s, *e;
+	ssize_t r;
+
+	/* must be a terminal */
+	if (!isatty(fd))
+		return -1;
+
+	*rows = *cols = 0;
+
+	/* query text area */
+	r = fy_term_safe_write(fd, "\x1b[18t", 5);
+	if (r != 0)
+		return r;
+
+	/* read a character */
+	r = fy_term_read_escape(fd, buf, sizeof(buf));
+
+	/* return must be ESC[8;<height>;<width>;t */
+
+	if (r < 8 || r >= (int)sizeof(buf) - 2)	/* minimum ESC[8;1;1t */
+		return -1;
+
+	s = buf;
+	e = s + r;
+
+	/* correct response? starts with ESC[8; */
+	if (s[0] != '\x1b' || s[1] != '[' || s[2] != '8' || s[3] != ';')
+		return -1;
+	s += 4;
+
+	/* must end with t */
+	if (e[-1] != 't')
+		return -1;
+	*--e = '\0';	/* remove trailing t, and zero terminate */
+
+	/* scan two ints separated by ; */
+	r = sscanf(s, "%d;%d", rows, cols);
+	if (r != 2)
+		return -1;
+
+	return 0;
+}
+
+int fy_term_query_size(int fd, int *rows, int *cols)
+{
+	struct termios old_term;
+	int ret, r;
+
+	if (!isatty(fd))
+		return -1;
+
+	r = fy_term_set_raw(fd, &old_term);
+	if (r != 0)
+		return -1;
+
+	ret = fy_term_query_size_raw(fd, rows, cols);
+
+	r = fy_term_restore(fd, &old_term);
+	if (r != 0)
+		return -1;
+
+	return ret;
+}
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-utils.h b/contrib/libs/libfyaml/src/lib/fy-utils.h
new file mode 100644
index 0000000000..dd99125e5e
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-utils.h
@@ -0,0 +1,77 @@
+/*
+ * fy-utils.h - internal utilities header file
+ *
+ * Copyright (c) 2019 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef FY_UTILS_H
+#define FY_UTILS_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <stdbool.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <unistd.h>
+#include <termios.h>
+#endif
+
+#if defined(__APPLE__) && (_POSIX_C_SOURCE < 200809L)
+FILE *open_memstream(char **ptr, size_t *sizeloc);
+#endif
+
+int fy_get_pagesize();
+
+#if defined(_MSC_VER)
+int vasprintf(char **strp, const char *fmt, va_list ap);
+int asprintf(char **strp, const char *fmt, ...);
+#endif
+
+int fy_tag_handle_length(const char *data, size_t len);
+bool fy_tag_uri_is_valid(const char *data, size_t len);
+int fy_tag_uri_length(const char *data, size_t len);
+
+struct fy_tag_scan_info {
+	int total_length;
+	int handle_length;
+	int uri_length;
+	int prefix_length;
+	int suffix_length;
+};
+
+int fy_tag_scan(const char *data, size_t len, struct fy_tag_scan_info *info);
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) ((sizeof(x)/sizeof((x)[0])))
+#endif
+
+#if !defined(NDEBUG) && (defined(__GNUC__) && __GNUC__ >= 4)
+#define FY_ALWAYS_INLINE __attribute__((always_inline))
+#else
+#define FY_ALWAYS_INLINE /* nothing */
+#endif
+
+#if defined(__GNUC__) && __GNUC__ >= 4
+#define FY_UNUSED __attribute__((unused))
+#else
+#define FY_UNUSED /* nothing */
+#endif
+
+int fy_term_set_raw(int fd, struct termios *oldt);
+int fy_term_restore(int fd, const struct termios *oldt);
+ssize_t fy_term_write(int fd, const void *data, size_t count);
+int fy_term_safe_write(int fd, const void *data, size_t count);
+ssize_t fy_term_read(int fd, void *data, size_t count, int timeout_us);
+ssize_t fy_term_read_escape(int fd, void *buf, size_t count);
+
+/* the raw methods require the terminal to be in raw mode */
+int fy_term_query_size_raw(int fd, int *rows, int *cols);
+
+/* the non raw methods will set the terminal to raw and then restore */
+int fy_term_query_size(int fd, int *rows, int *cols);
+
+#endif
diff --git a/contrib/libs/libfyaml/src/lib/fy-walk.c b/contrib/libs/libfyaml/src/lib/fy-walk.c
new file mode 100644
index 0000000000..d76125071e
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-walk.c
@@ -0,0 +1,5236 @@
+/*
+ * fy-walk.c - path walker
+ *
+ * Copyright (c) 2021 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+#if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
+#include <unistd.h>
+#endif
+#include <math.h>
+#include <limits.h>
+
+#include <libfyaml.h>
+
+#include "fy-parse.h"
+#include "fy-doc.h"
+#include "fy-walk.h"
+
+#include "fy-utils.h"
+
+#undef DEBUG_EXPR
+// #define DEBUG_EXPR
+
+const char *fy_walk_result_type_txt[FWRT_COUNT] = {
+	[fwrt_none]	= "none",
+	[fwrt_node_ref]	= "node-ref",
+	[fwrt_number]	= "number",
+	[fwrt_string]	= "string",
+	[fwrt_doc]	= "doc",
+	[fwrt_refs]	= "refs",
+};
+
+void fy_walk_result_dump(struct fy_walk_result *fwr, struct fy_diag *diag, enum fy_error_type errlevel, int level,
+		const char *fmt, ...);
+
+void fy_walk_result_vdump(struct fy_walk_result *fwr, struct fy_diag *diag, enum fy_error_type errlevel, int level,
+		const char *fmt, va_list ap)
+{
+	struct fy_walk_result *fwr2;
+	char *banner;
+	char *texta = NULL;
+	const char *text = "";
+	size_t len;
+	bool save_on_error;
+	char buf[30];
+	int rc __FY_DEBUG_UNUSED__;
+
+	if (!diag)
+		return;
+
+	if (errlevel < diag->cfg.level)
+		return;
+
+	save_on_error = diag->on_error;
+	diag->on_error = true;
+
+	if (fmt) {
+		banner = NULL;
+		rc = vasprintf(&banner, fmt, ap);
+		assert(rc != -1);
+		assert(banner);
+		fy_diag_diag(diag, errlevel, "%-*s%s", level*2, "", banner);
+		free(banner);
+	}
+	if (!fwr)
+		goto out;
+
+	switch (fwr->type) {
+	case fwrt_none:
+		text="";
+		break;
+	case fwrt_node_ref:
+		texta = fy_node_get_path(fwr->fyn);
+		assert(texta);
+		text = texta;
+		break;
+	case fwrt_number:
+		snprintf(buf, sizeof(buf), "%f", fwr->number);
+		text = buf;
+		break;
+	case fwrt_string:
+		text = fwr->string;
+		break;
+	case fwrt_doc:
+		texta = fy_emit_document_to_string(fwr->fyd, FYECF_WIDTH_INF | FYECF_INDENT_DEFAULT | FYECF_MODE_FLOW_ONELINE);
+		assert(texta);
+		text = texta;
+		break;
+	case fwrt_refs:
+		text="";
+		break;
+	}
+
+	len = strlen(text);
+
+	fy_diag_diag(diag, errlevel, "%-*s%s%s%.*s",
+			(level + 1) * 2, "",
+			fy_walk_result_type_txt[fwr->type],
+			len ? " " : "",
+			(int)len, text);
+
+	if (texta)
+		free(texta);
+
+	if (fwr->type == fwrt_refs) {
+		for (fwr2 = fy_walk_result_list_head(&fwr->refs); fwr2; fwr2 = fy_walk_result_next(&fwr->refs, fwr2))
+			fy_walk_result_dump(fwr2, diag, errlevel, level + 1, NULL);
+	}
+out:
+	diag->on_error = save_on_error;
+}
+
+void fy_walk_result_dump(struct fy_walk_result *fwr, struct fy_diag *diag, enum fy_error_type errlevel, int level,
+		const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fy_walk_result_vdump(fwr, diag, errlevel, level, fmt, ap);
+	va_end(ap);
+}
+
+/* NOTE that walk results do not take references and it is invalid to
+ * use _any_ call that modifies the document structure
+ */
+struct fy_walk_result *fy_walk_result_alloc_rl(struct fy_walk_result_list *fwrl)
+{
+	struct fy_walk_result *fwr = NULL;
+
+	if (fwrl)
+		fwr = fy_walk_result_list_pop(fwrl);
+
+	if (!fwr) {
+		fwr = malloc(sizeof(*fwr));
+		if (!fwr)
+			return NULL;
+		memset(fwr, 0, sizeof(*fwr));
+	}
+	fwr->type = fwrt_none;
+	return fwr;
+}
+
+struct fy_walk_result *fy_walk_result_clone_rl(struct fy_walk_result_list *fwrl, struct fy_walk_result *fwr)
+{
+	struct fy_walk_result *fwrn = NULL, *fwrn2 = NULL, *fwrn3;
+
+	if (!fwr)
+		return NULL;
+
+	fwrn = fy_walk_result_alloc_rl(fwrl);
+	if (!fwrn)
+		return NULL;
+
+	fwrn->type = fwr->type;
+	switch (fwr->type) {
+	case fwrt_none:
+		break;
+	case fwrt_node_ref:
+		fwrn->fyn = fwr->fyn;
+		break;
+	case fwrt_number:
+		fwrn->number = fwr->number;
+		break;
+	case fwrt_string:
+		fwrn->string = strdup(fwr->string);
+		if (!fwrn->string)
+			goto err_out;
+		break;
+	case fwrt_doc:
+		fwrn->fyd = fy_document_clone(fwr->fyd);
+		if (!fwrn->fyd)
+			goto err_out;
+		break;
+	case fwrt_refs:
+
+		fy_walk_result_list_init(&fwrn->refs);
+
+		for (fwrn2 = fy_walk_result_list_head(&fwr->refs); fwrn2;
+			fwrn2 = fy_walk_result_next(&fwr->refs, fwrn2)) {
+
+			fwrn3 = fy_walk_result_clone_rl(fwrl, fwrn2);
+			if (!fwrn3)
+				goto err_out;
+
+			fy_walk_result_list_add_tail(&fwrn->refs, fwrn3);
+		}
+		break;
+	}
+	return fwrn;
+err_out:
+	if (fwrn)
+		fy_walk_result_free_rl(fwrl, fwrn);
+	return NULL;
+}
+
+struct fy_walk_result *fy_walk_result_clone(struct fy_walk_result *fwr)
+{
+	struct fy_walk_result_list *fwrl;
+
+	if (!fwr)
+		return NULL;
+
+	fwrl = fy_path_exec_walk_result_rl(fwr->fypx);
+	return fy_walk_result_clone_rl(fwrl, fwr);
+}
+
+void fy_walk_result_clean_rl(struct fy_walk_result_list *fwrl, struct fy_walk_result *fwr)
+{
+	struct fy_walk_result *fwrn;
+
+	if (!fwr)
+		return;
+
+	switch (fwr->type) {
+	case fwrt_none:
+		break;
+	case fwrt_node_ref:
+	case fwrt_number:
+		break;
+	case fwrt_string:
+		if (fwr->string)
+			free(fwr->string);
+		break;
+	case fwrt_doc:
+		if (fwr->fyd)
+			fy_document_destroy(fwr->fyd);
+		break;
+	case fwrt_refs:
+		while ((fwrn = fy_walk_result_list_pop(&fwr->refs)) != NULL)
+			fy_walk_result_free_rl(fwrl, fwrn);
+		break;
+	}
+
+	fwr->type = fwrt_none;
+}
+
+void fy_walk_result_clean(struct fy_walk_result *fwr)
+{
+	struct fy_walk_result_list *fwrl;
+
+	if (!fwr)
+		return;
+
+	fwrl = fy_path_exec_walk_result_rl(fwr->fypx);
+	fy_walk_result_clean_rl(fwrl, fwr);
+}
+
+void fy_walk_result_free_rl(struct fy_walk_result_list *fwrl, struct fy_walk_result *fwr)
+{
+	struct fy_path_exec *fypx;
+
+	if (!fwr)
+		return;
+
+	fypx = fwr->fypx;
+
+	fy_walk_result_clean_rl(fwrl, fwr);
+
+	if (fwrl)
+		fy_walk_result_list_push(fwrl, fwr);
+	else
+		free(fwr);
+
+	fy_path_exec_unref(fypx);	/* NULL is OK */
+}
+
+void fy_walk_result_free(struct fy_walk_result *fwr)
+{
+	struct fy_walk_result_list *fwrl;
+
+	if (!fwr)
+		return;
+
+	fwrl = fy_path_exec_walk_result_rl(fwr->fypx);
+	fy_walk_result_free_rl(fwrl, fwr);
+}
+
+void fy_walk_result_list_free_rl(struct fy_walk_result_list *fwrl, struct fy_walk_result_list *results)
+{
+	struct fy_walk_result *fwr;
+
+	while ((fwr = fy_walk_result_list_pop(results)) != NULL)
+		fy_walk_result_free_rl(fwrl, fwr);
+}
+
+struct fy_walk_result *fy_walk_result_vcreate_rl(struct fy_walk_result_list *fwrl, enum fy_walk_result_type type, va_list ap)
+{
+	struct fy_walk_result *fwr = NULL;
+
+	if ((unsigned int)type >= FWRT_COUNT)
+		goto err_out;
+
+	fwr = fy_walk_result_alloc_rl(fwrl);
+	if (!fwr)
+		goto err_out;
+
+	fwr->type = type;
+
+	switch (fwr->type) {
+	case fwrt_none:
+		break;
+	case fwrt_node_ref:
+		fwr->fyn = va_arg(ap, struct fy_node *);
+		break;
+	case fwrt_number:
+		fwr->number = va_arg(ap, double);
+		break;
+	case fwrt_string:
+		fwr->string = strdup(va_arg(ap, const char *));
+		if (!fwr->string)
+			goto err_out;
+		break;
+	case fwrt_doc:
+		fwr->fyd = va_arg(ap, struct fy_document *);
+		break;
+	case fwrt_refs:
+		fy_walk_result_list_init(&fwr->refs);
+		break;
+	}
+
+	return fwr;
+
+err_out:
+	fy_walk_result_free_rl(fwrl, fwr);
+
+	return NULL;
+}
+
+struct fy_walk_result *fy_walk_result_create_rl(struct fy_walk_result_list *fwrl, enum fy_walk_result_type type, ...)
+{
+	struct fy_walk_result *fwr;
+	va_list ap;
+
+	va_start(ap, type);
+	fwr = fy_walk_result_vcreate_rl(fwrl, type, ap);
+	va_end(ap);
+
+	return fwr;
+}
+
+void fy_walk_result_flatten_internal(struct fy_walk_result *fwr, struct fy_walk_result *fwrf)
+{
+	struct fy_walk_result *fwr2, *fwr2n;
+
+	if (!fwr || !fwrf || fwr->type != fwrt_refs)
+		return;
+
+	for (fwr2 = fy_walk_result_list_head(&fwr->refs); fwr2; fwr2 = fwr2n) {
+
+		fwr2n = fy_walk_result_next(&fwr->refs, fwr2);
+
+		if (fwr2->type != fwrt_refs) {
+			fy_walk_result_list_del(&fwr->refs, fwr2);
+			fy_walk_result_list_add_tail(&fwrf->refs, fwr2);
+			continue;
+		}
+		fy_walk_result_flatten_internal(fwr2, fwrf);
+	}
+}
+
+bool fy_walk_result_has_leaves_only(struct fy_walk_result *fwr)
+{
+	struct fy_walk_result *fwrn;
+
+	if (!fwr || fwr->type != fwrt_refs)
+		return false;
+
+	if (fy_walk_result_list_empty(&fwr->refs))
+		return false;
+
+	for (fwrn = fy_walk_result_list_head(&fwr->refs); fwrn;
+			fwrn = fy_walk_result_next(&fwr->refs, fwrn)) {
+
+		if (fwrn->type == fwrt_refs)
+			return false;
+	}
+
+	return true;
+}
+
+struct fy_walk_result *
+fy_walk_result_flatten_rl(struct fy_walk_result_list *fwrl, struct fy_walk_result *fwr)
+{
+	struct fy_walk_result *fwrf;
+
+	if (!fwr)
+		return NULL;
+
+	fwrf = fy_walk_result_create_rl(fwrl, fwrt_refs);
+	assert(fwrf);
+
+	fy_walk_result_flatten_internal(fwr, fwrf);
+	fy_walk_result_free_rl(fwrl, fwr);
+	return fwrf;
+}
+
+struct fy_walk_result *
+fy_walk_result_flatten(struct fy_walk_result *fwr)
+{
+	struct fy_walk_result_list *fwrl;
+
+	if (!fwr)
+		return NULL;
+
+	fwrl = fy_path_exec_walk_result_rl(fwr->fypx);
+	return fy_walk_result_flatten_rl(fwrl, fwr);
+}
+
+struct fy_node *
+fy_walk_result_node_iterate(struct fy_walk_result *fwr, void **prevp)
+{
+	struct fy_walk_result *fwrn;
+
+	if (!fwr || !prevp)
+		return NULL;
+
+	switch (fwr->type) {
+	case fwrt_node_ref:
+		if (!*prevp) {
+			*prevp = fwr;
+			return fwr->fyn;
+		}
+		*prevp = NULL;
+		return NULL;
+
+	case fwrt_refs:
+		if (!*prevp)
+			fwrn = fy_walk_result_list_head(&fwr->refs);
+		else
+			fwrn = fy_walk_result_next(&fwr->refs, *prevp);
+
+		/* skip over any non node refs */
+		while (fwrn && fwrn->type != fwrt_node_ref)
+			fwrn = fy_walk_result_next(&fwr->refs, fwrn);
+		*prevp = fwrn;
+		return fwrn ? fwrn->fyn : NULL;
+
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+const char *fy_path_expr_type_txt[FPET_COUNT] = {
+	[fpet_none]			= "none",
+	/* */
+	[fpet_root]			= "root",
+	[fpet_this]			= "this",
+	[fpet_parent]			= "parent",
+	[fpet_every_child]		= "every-child",
+	[fpet_every_child_r]		= "every-child-recursive",
+	[fpet_filter_collection]	= "filter-collection",
+	[fpet_filter_scalar]		= "filter-scalar",
+	[fpet_filter_sequence]		= "filter-sequence",
+	[fpet_filter_mapping]		= "filter-mapping",
+	[fpet_filter_unique]		= "filter-unique",
+	[fpet_seq_index]		= "seq-index",
+	[fpet_seq_slice]		= "seq-slice",
+	[fpet_alias]			= "alias",
+
+	[fpet_map_key]			= "map-key",
+
+	[fpet_multi]			= "multi",
+	[fpet_chain]			= "chain",
+	[fpet_logical_or]		= "logical-or",
+	[fpet_logical_and]		= "logical-and",
+
+	[fpet_eq]			= "equals",
+	[fpet_neq]			= "not-equals",
+	[fpet_lt]			= "less-than",
+	[fpet_gt]			= "greater-than",
+	[fpet_lte]			= "less-or-equal-than",
+	[fpet_gte]			= "greater-or-equal-than",
+
+	[fpet_scalar]			= "scalar",
+
+	[fpet_plus]			= "plus",
+	[fpet_minus]			= "minus",
+	[fpet_mult]			= "multiply",
+	[fpet_div]			= "divide",
+
+	[fpet_lparen]			= "left-parentheses",
+	[fpet_rparen]			= "right-parentheses",
+	[fpet_method]			= "method",
+
+	[fpet_scalar_expr]		= "scalar-expression",
+	[fpet_path_expr]		= "path-expression",
+	[fpet_arg_separator]		= "argument-separator",
+};
+
+struct fy_path_expr *fy_path_expr_alloc(void)
+{
+	struct fy_path_expr *expr = NULL;
+
+	expr = malloc(sizeof(*expr));
+	if (!expr)
+		return NULL;
+	memset(expr, 0, sizeof(*expr));
+	fy_path_expr_list_init(&expr->children);
+
+	return expr;
+}
+
+void fy_path_expr_free(struct fy_path_expr *expr)
+{
+	struct fy_path_expr *exprn;
+
+	if (!expr)
+		return;
+
+	while ((exprn = fy_path_expr_list_pop(&expr->children)) != NULL)
+		fy_path_expr_free(exprn);
+
+	fy_token_unref(expr->fyt);
+
+	free(expr);
+}
+
+struct fy_path_expr *fy_path_expr_alloc_recycle(struct fy_path_parser *fypp)
+{
+	struct fy_path_expr *expr = NULL;
+
+	if (!fypp || fypp->suppress_recycling)
+		expr = fy_path_expr_alloc();
+
+	if (!expr) {
+		expr = fy_path_expr_list_pop(&fypp->expr_recycle);
+		if (expr) {
+			memset(expr, 0, sizeof(*expr));
+			fy_path_expr_list_init(&expr->children);
+		} else
+			expr = fy_path_expr_alloc();
+	}
+
+	if (!expr)
+		return NULL;
+
+	expr->expr_mode = fypp->expr_mode;
+
+	return expr;
+}
+
+void fy_path_expr_free_recycle(struct fy_path_parser *fypp, struct fy_path_expr *expr)
+{
+	struct fy_path_expr *exprn;
+
+	if (!fypp || fypp->suppress_recycling) {
+		fy_path_expr_free(expr);
+		return;
+	}
+
+	while ((exprn = fy_path_expr_list_pop(&expr->children)) != NULL)
+		fy_path_expr_free_recycle(fypp, exprn);
+
+	if (expr->fyt) {
+		fy_token_unref(expr->fyt);
+		expr->fyt = NULL;
+	}
+	fy_path_expr_list_add_tail(&fypp->expr_recycle, expr);
+}
+
+void fy_expr_stack_setup(struct fy_expr_stack *stack)
+{
+	if (!stack)
+		return;
+
+	memset(stack, 0, sizeof(*stack));
+	stack->items = stack->items_static;
+	stack->alloc = ARRAY_SIZE(stack->items_static);
+}
+
+void fy_expr_stack_cleanup(struct fy_expr_stack *stack)
+{
+	if (!stack)
+		return;
+
+	while (stack->top > 0)
+		fy_path_expr_free(stack->items[--stack->top]);
+
+	if (stack->items != stack->items_static)
+		free(stack->items);
+	stack->items = stack->items_static;
+	stack->alloc = ARRAY_SIZE(stack->items_static);
+}
+
+void fy_expr_stack_dump(struct fy_diag *diag, struct fy_expr_stack *stack)
+{
+	struct fy_path_expr *expr;
+	unsigned int i;
+
+	if (!stack)
+		return;
+
+	if (!stack->top)
+		return;
+
+	i = stack->top;
+	do {
+		expr = stack->items[--i];
+		fy_path_expr_dump(expr, diag, FYET_NOTICE, 0, NULL);
+	} while (i > 0);
+}
+
+int fy_expr_stack_size(struct fy_expr_stack *stack)
+{
+	if (!stack || stack->top >= (unsigned int)INT_MAX)
+		return -1;
+	return (int)stack->top;
+}
+
+int fy_expr_stack_push(struct fy_expr_stack *stack, struct fy_path_expr *expr)
+{
+	struct fy_path_expr **items_new;
+	unsigned int alloc;
+	size_t size;
+
+	if (!stack || !expr)
+		return -1;
+
+	assert(stack->items);
+	assert(stack->alloc > 0);
+
+	assert(expr->fyt);
+
+	/* grow the stack if required */
+	if (stack->top >= stack->alloc) {
+		alloc = stack->alloc;
+		size = alloc * sizeof(*items_new);
+
+		if (stack->items == stack->items_static) {
+			items_new = malloc(size * 2);
+			if (items_new)
+				memcpy(items_new, stack->items_static, size);
+		} else
+			items_new = realloc(stack->items, size * 2);
+
+		if (!items_new)
+			return -1;
+
+		stack->alloc = alloc * 2;
+		stack->items = items_new;
+	}
+
+	stack->items[stack->top++] = expr;
+
+	return 0;
+}
+
+struct fy_path_expr *fy_expr_stack_peek_at(struct fy_expr_stack *stack, unsigned int pos)
+{
+	if (!stack || stack->top <= pos)
+		return NULL;
+	return stack->items[stack->top - 1 - pos];
+}
+
+struct fy_path_expr *fy_expr_stack_peek(struct fy_expr_stack *stack)
+{
+	return fy_expr_stack_peek_at(stack, 0);
+}
+
+struct fy_path_expr *fy_expr_stack_pop(struct fy_expr_stack *stack)
+{
+	if (!stack || !stack->top)
+		return NULL;
+
+	return stack->items[--stack->top];
+}
+
+bool fy_token_type_can_be_path_expr(enum fy_token_type type)
+{
+	return type == FYTT_NONE ||
+	       type == FYTT_PE_LPAREN ||
+	       type == FYTT_PE_RPAREN ||
+	       type == FYTT_PE_EQEQ ||
+	       type == FYTT_PE_NOTEQ ||
+	       type == FYTT_PE_GT ||
+	       type == FYTT_PE_LT ||
+	       type == FYTT_PE_GTE ||
+	       type == FYTT_PE_LTE ||
+	       type == FYTT_PE_METHOD;
+}
+
+bool fy_token_type_can_be_before_negative_number(enum fy_token_type type)
+{
+	return type == FYTT_NONE ||
+	       type == FYTT_PE_LPAREN ||
+	       type == FYTT_PE_RPAREN ||
+	       type == FYTT_PE_EQEQ ||
+	       type == FYTT_PE_NOTEQ ||
+	       type == FYTT_PE_GT ||
+	       type == FYTT_PE_LT ||
+	       type == FYTT_PE_GTE ||
+	       type == FYTT_PE_LTE ||
+	       type == FYTT_SE_PLUS ||
+	       type == FYTT_SE_MINUS ||
+	       type == FYTT_SE_MULT ||
+	       type == FYTT_SE_DIV ||
+
+	       type == FYTT_SE_METHOD;
+}
+
+const char *fy_expr_mode_txt[FYEM_COUNT] = {
+	[fyem_none]	= "none",
+	[fyem_path]	= "path",
+	[fyem_scalar]	= "scalar",
+};
+
+static struct fy_diag *fy_path_parser_reader_get_diag(struct fy_reader *fyr)
+{
+	struct fy_path_parser *fypp = fy_container_of(fyr, struct fy_path_parser, reader);
+	return fypp->cfg.diag;
+}
+
+static const struct fy_reader_ops fy_path_parser_reader_ops = {
+	.get_diag = fy_path_parser_reader_get_diag,
+};
+
+void fy_path_parser_setup(struct fy_path_parser *fypp, const struct fy_path_parse_cfg *pcfg)
+{
+	if (!fypp)
+		return;
+
+	memset(fypp, 0, sizeof(*fypp));
+	if (pcfg)
+		fypp->cfg = *pcfg;
+	fy_reader_setup(&fypp->reader, &fy_path_parser_reader_ops);
+	fy_token_list_init(&fypp->queued_tokens);
+	fypp->last_queued_token_type = FYTT_NONE;
+
+	fy_expr_stack_setup(&fypp->operators);
+	fy_expr_stack_setup(&fypp->operands);
+
+	fy_path_expr_list_init(&fypp->expr_recycle);
+	fypp->suppress_recycling = (fypp->cfg.flags & FYPPCF_DISABLE_RECYCLING) || getenv("FY_VALGRIND");
+
+	fypp->expr_mode = fyem_path;
+	fypp->paren_nest_level = 0;
+}
+
+void fy_path_parser_cleanup(struct fy_path_parser *fypp)
+{
+	struct fy_path_expr *expr;
+
+	if (!fypp)
+		return;
+
+	fy_expr_stack_cleanup(&fypp->operands);
+	fy_expr_stack_cleanup(&fypp->operators);
+
+	fy_reader_cleanup(&fypp->reader);
+	fy_token_list_unref_all(&fypp->queued_tokens);
+
+	while ((expr = fy_path_expr_list_pop(&fypp->expr_recycle)) != NULL)
+		fy_path_expr_free(expr);
+
+	fypp->last_queued_token_type = FYTT_NONE;
+	fypp->stream_start_produced = false;
+	fypp->stream_end_produced = false;
+	fypp->stream_error = false;
+	fypp->token_activity_counter = 0;
+	fypp->paren_nest_level = 0;
+}
+
+int fy_path_parser_open(struct fy_path_parser *fypp,
+			struct fy_input *fyi, const struct fy_reader_input_cfg *icfg)
+{
+	int ret;
+	if (!fypp)
+		return -1;
+
+	ret = fy_reader_input_open(&fypp->reader, fyi, icfg);
+	if (ret)
+		return ret;
+	/* take a reference to the input */
+	fypp->fyi = fy_input_ref(fyi);
+	return 0;
+}
+
+void fy_path_parser_close(struct fy_path_parser *fypp)
+{
+	if (!fypp)
+		return;
+
+	fy_input_unref(fypp->fyi);
+
+	fy_reader_input_done(&fypp->reader);
+}
+
+struct fy_token *fy_path_token_vqueue(struct fy_path_parser *fypp, enum fy_token_type type, va_list ap)
+{
+	struct fy_token *fyt;
+
+	fyt = fy_token_list_vqueue(&fypp->queued_tokens, type, ap);
+	if (fyt) {
+		fypp->token_activity_counter++;
+		fypp->last_queued_token_type = type;
+	}
+	return fyt;
+}
+
+struct fy_token *fy_path_token_queue(struct fy_path_parser *fypp, enum fy_token_type type, ...)
+{
+	va_list ap;
+	struct fy_token *fyt;
+
+	va_start(ap, type);
+	fyt = fy_path_token_vqueue(fypp, type, ap);
+	va_end(ap);
+
+	return fyt;
+}
+
+int fy_path_fetch_seq_index_or_slice(struct fy_path_parser *fypp, int c)
+{
+	struct fy_reader *fyr;
+	struct fy_token *fyt;
+	bool neg;
+	int i, j, val, nval, digits, indices[2];
+
+	fyr = &fypp->reader;
+
+	/* verify that the called context is correct */
+	assert(fy_is_num(c) || (c == '-' && fy_is_num(fy_reader_peek_at(fyr, 1))));
+
+	i = 0;
+	indices[0] = indices[1] = -1;
+
+	j = 0;
+	while (j < 2) {
+
+		neg = false;
+		if (c == '-') {
+			neg = true;
+			i++;
+		}
+
+		digits = 0;
+		val = 0;
+		while (fy_is_num((c = fy_reader_peek_at(fyr, i)))) {
+			nval = (val * 10) | (c - '0');
+			FYR_PARSE_ERROR_CHECK(fyr, 0, i, FYEM_SCAN,
+					nval >= val && nval >= 0, err_out,
+					"illegal sequence index (overflow)");
+			val = nval;
+			i++;
+			digits++;
+		}
+		FYR_PARSE_ERROR_CHECK(fyr, 0, i, FYEM_SCAN,
+				(val == 0 && digits == 1) || (val > 0), err_out,
+				"bad number");
+		if (neg)
+			val = -val;
+
+		indices[j] = val;
+
+		/* continue only on slice : */
+		if (c == ':') {
+			c = fy_reader_peek_at(fyr, i + 1);
+			if (fy_is_num(c) || (c == '-' && fy_is_num(fy_reader_peek_at(fyr, i + 2)))) {
+				i++;
+				j++;
+				continue;
+			}
+		}
+
+		break;
+	}
+
+	if (j >= 1)
+		fyt = fy_path_token_queue(fypp, FYTT_PE_SEQ_SLICE, fy_reader_fill_atom_a(fyr, i), indices[0], indices[1]);
+	else
+		fyt = fy_path_token_queue(fypp, FYTT_PE_SEQ_INDEX, fy_reader_fill_atom_a(fyr, i), indices[0]);
+
+	fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+
+	return 0;
+
+err_out:
+	fypp->stream_error = true;
+	return -1;
+}
+
+int fy_path_fetch_plain_or_method(struct fy_path_parser *fypp, int c,
+				  enum fy_token_type fytt_plain,
+				  enum fy_token_type fytt_method)
+{
+	struct fy_reader *fyr;
+	struct fy_token *fyt;
+	struct fy_atom *handlep;
+	int i;
+	enum fy_token_type type;
+
+	fyr = &fypp->reader;
+
+	assert(fy_is_first_alpha(c));
+
+	type = fytt_plain;
+
+	i = 1;
+	while (fy_is_alnum(fy_reader_peek_at(fyr, i)))
+		i++;
+
+	if (fy_reader_peek_at(fyr, i) == '(')
+		type = fytt_method;
+
+	handlep = fy_reader_fill_atom_a(fyr, i);
+	if (type == FYTT_SCALAR) {
+		fyt = fy_path_token_queue(fypp, FYTT_SCALAR, handlep, FYSS_PLAIN, NULL);
+		fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+	} else {
+		fyt = fy_path_token_queue(fypp, type, handlep, NULL);
+		fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+	}
+
+	return 0;
+
+err_out:
+	fypp->stream_error = true;
+	return -1;
+}
+
+int fy_path_fetch_dot_method(struct fy_path_parser *fypp, int c, enum fy_token_type fytt)
+{
+	struct fy_reader *fyr;
+	struct fy_token *fyt;
+	struct fy_atom *handlep;
+	int i;
+
+	fyr = &fypp->reader;
+
+	assert(c == '.');
+	fy_reader_advance(fyr, c);
+	c = fy_reader_peek(fyr);
+	assert(fy_is_first_alpha(c));
+
+	/* verify that the called context is correct */
+	i = 1;
+	while (fy_is_alnum(fy_reader_peek_at(fyr, i)))
+		i++;
+
+	handlep = fy_reader_fill_atom_a(fyr, i);
+
+	fyt = fy_path_token_queue(fypp, fytt, handlep, NULL);
+	fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+
+	return 0;
+
+err_out:
+	fypp->stream_error = true;
+	return -1;
+}
+
+int fy_path_fetch_flow_document(struct fy_path_parser *fypp, int c, enum fy_token_type fytt)
+{
+	struct fy_reader *fyr;
+	struct fy_token *fyt;
+	struct fy_document *fyd;
+	struct fy_atom handle;
+	struct fy_parser fyp_data, *fyp = &fyp_data;
+	struct fy_parse_cfg cfg_data, *cfg = NULL;
+	int rc;
+
+	fyr = &fypp->reader;
+
+	/* verify that the called context is correct */
+	assert(fy_is_path_flow_key_start(c));
+
+	fy_reader_fill_atom_start(fyr, &handle);
+
+	cfg = &cfg_data;
+	memset(cfg, 0, sizeof(*cfg));
+	cfg->flags = FYPCF_DEFAULT_PARSE;
+	cfg->diag = fypp->cfg.diag;
+
+	rc = fy_parse_setup(fyp, cfg);
+	fyr_error_check(fyr, !rc, err_out, "fy_parse_setup() failed\n");
+
+	/* associate with reader and set flow mode */
+	fy_parser_set_reader(fyp, fyr);
+	fy_parser_set_flow_only_mode(fyp, true);
+
+	fyd = fy_parse_load_document(fyp);
+
+	/* cleanup the parser no matter what */
+	fy_parse_cleanup(fyp);
+
+	fyr_error_check(fyr, fyd, err_out, "fy_parse_load_document() failed\n");
+
+	fy_reader_fill_atom_end(fyr, &handle);
+
+	/* document is NULL, is a simple key */
+	fyt = fy_path_token_queue(fypp, fytt, &handle, fyd);
+	fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+
+	return 0;
+
+err_out:
+	fypp->stream_error = true;
+	return -1;
+}
+
+int fy_path_fetch_flow_map_key(struct fy_path_parser *fypp, int c)
+{
+	return fy_path_fetch_flow_document(fypp, c, FYTT_PE_MAP_KEY);
+}
+
+int fy_path_fetch_flow_scalar(struct fy_path_parser *fypp, int c)
+{
+	struct fy_reader *fyr;
+	struct fy_token *fyt;
+	struct fy_atom handle;
+	bool is_single;
+	int rc = -1;
+
+	fyr = &fypp->reader;
+
+	/* verify that the called context is correct */
+	assert(fy_is_path_flow_scalar_start(c));
+
+	is_single = c == '\'';
+
+	rc = fy_reader_fetch_flow_scalar_handle(fyr, c, 0, &handle, false);
+	if (rc)
+		goto err_out_rc;
+
+	/* document is NULL, is a simple key */
+	fyt = fy_path_token_queue(fypp, FYTT_SCALAR, &handle, is_single ? FYSS_SINGLE_QUOTED : FYSS_DOUBLE_QUOTED);
+	fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+
+	return 0;
+
+err_out:
+	rc = -1;
+err_out_rc:
+	fypp->stream_error = true;
+	return rc;
+}
+
+int fy_path_fetch_number(struct fy_path_parser *fypp, int c)
+{
+	struct fy_reader *fyr;
+	struct fy_token *fyt;
+	int i, digits;
+
+	fyr = &fypp->reader;
+
+	/* verify that the called context is correct */
+	assert(fy_is_num(c) || (c == '-' && fy_is_num(fy_reader_peek_at(fyr, 1))));
+
+	i = 0;
+	if (c == '-')
+		i++;
+
+	digits = 0;
+	while (fy_is_num((c = fy_reader_peek_at(fyr, i)))) {
+		i++;
+		digits++;
+	}
+	FYR_PARSE_ERROR_CHECK(fyr, 0, i, FYEM_SCAN,
+			digits > 0, err_out,
+			"bad number");
+
+	fyt = fy_path_token_queue(fypp, FYTT_SCALAR, fy_reader_fill_atom_a(fyr, i), FYSS_PLAIN);
+	fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+
+	return 0;
+
+err_out:
+	fypp->stream_error = true;
+	return -1;
+}
+
+int fy_path_fetch_tokens(struct fy_path_parser *fypp)
+{
+	enum fy_token_type type;
+	struct fy_token *fyt;
+	struct fy_reader *fyr;
+	int c, cn, rc, simple_token_count;
+
+	fyr = &fypp->reader;
+	if (!fypp->stream_start_produced) {
+
+		fyt = fy_path_token_queue(fypp, FYTT_STREAM_START, fy_reader_fill_atom_a(fyr, 0));
+		fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+
+		fypp->stream_start_produced = true;
+		return 0;
+	}
+
+	/* XXX scan to next token? */
+
+	c = fy_reader_peek(fyr);
+
+	if (fy_is_z(c)) {
+
+		if (c >= 0)
+			fy_reader_advance(fyr, c);
+
+		/* produce stream end continuously */
+		fyt = fy_path_token_queue(fypp, FYTT_STREAM_END, fy_reader_fill_atom_a(fyr, 0));
+		fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+
+		return 0;
+	}
+
+	fyt = NULL;
+	type = FYTT_NONE;
+	simple_token_count = 0;
+
+	/* first do the common tokens */
+	switch (c) {
+	case ',':
+		type = FYTT_PE_COMMA;
+		simple_token_count = 1;
+		break;
+
+	case '|':
+		if (fy_reader_peek_at(fyr, 1) == '|') {
+			type = FYTT_PE_BARBAR;
+			simple_token_count = 2;
+			break;
+		}
+		break;
+
+	case '&':
+		if (fy_reader_peek_at(fyr, 1) == '&') {
+			type = FYTT_PE_AMPAMP;
+			simple_token_count = 2;
+			break;
+		}
+		break;
+
+	case '(':
+		type = FYTT_PE_LPAREN;
+		simple_token_count = 1;
+		break;
+
+	case ')':
+		type = FYTT_PE_RPAREN;
+		simple_token_count = 1;
+		break;
+
+	case '=':
+		cn = fy_reader_peek_at(fyr, 1);
+		if (cn == '=') {
+			type = FYTT_PE_EQEQ;
+			simple_token_count = 2;
+			break;
+		}
+		break;
+
+	case '>':
+		cn = fy_reader_peek_at(fyr, 1);
+		if (cn == '=') {
+			type = FYTT_PE_GTE;
+			simple_token_count = 2;
+			break;
+		}
+		type = FYTT_PE_GT;
+		simple_token_count = 1;
+		break;
+
+	case '<':
+		cn = fy_reader_peek_at(fyr, 1);
+		if (cn == '=') {
+			type = FYTT_PE_LTE;
+			simple_token_count = 2;
+			break;
+		}
+		type = FYTT_PE_LT;
+		simple_token_count = 1;
+		break;
+
+	case '!':
+		cn = fy_reader_peek_at(fyr, 1);
+		if (cn == '=') {
+			type = FYTT_PE_NOTEQ;
+			simple_token_count = 2;
+			break;
+		}
+		/* may still be something else */
+		break;
+
+	default:
+		break;
+	}
+
+	if (type != FYTT_NONE)
+		goto do_token;
+
+again:
+
+	switch (fypp->expr_mode) {
+	case fyem_none:
+		assert(0);	/* should never happen */
+		break;
+
+	case fyem_path:
+
+		switch (c) {
+		case '/':
+			type = FYTT_PE_SLASH;
+			simple_token_count = 1;
+			break;
+
+		case '^':
+			type = FYTT_PE_ROOT;
+			simple_token_count = 1;
+			break;
+
+		case ':':
+			type = FYTT_PE_SIBLING;
+			simple_token_count = 1;
+			break;
+
+		case '$':
+			type = FYTT_PE_SCALAR_FILTER;
+			simple_token_count = 1;
+			break;
+
+		case '%':
+			type = FYTT_PE_COLLECTION_FILTER;
+			simple_token_count = 1;
+			break;
+
+		case '[':
+			if (fy_reader_peek_at(fyr, 1) == ']') {
+				type = FYTT_PE_SEQ_FILTER;
+				simple_token_count = 2;
+			}
+			break;
+
+		case '{':
+			if (fy_reader_peek_at(fyr, 1) == '}') {
+				type = FYTT_PE_MAP_FILTER;
+				simple_token_count = 2;
+			}
+			break;
+
+
+		case '.':
+			cn = fy_reader_peek_at(fyr, 1);
+			if (cn == '.') {
+				type = FYTT_PE_PARENT;
+				simple_token_count = 2;
+			} else if (!fy_is_first_alpha(cn)) {
+				type = FYTT_PE_THIS;
+				simple_token_count = 1;
+			}
+			break;
+
+		case '*':
+			if (fy_reader_peek_at(fyr, 1) == '*') {
+				type = FYTT_PE_EVERY_CHILD_R;
+				simple_token_count = 2;
+			} else if (!fy_is_first_alpha(fy_reader_peek_at(fyr, 1))) {
+				type = FYTT_PE_EVERY_CHILD;
+				simple_token_count = 1;
+			} else {
+				type = FYTT_PE_ALIAS;
+				simple_token_count = 2;
+				while (fy_is_alnum(fy_reader_peek_at(fyr, simple_token_count)))
+					simple_token_count++;
+			}
+			break;
+
+		case '!':
+			cn = fy_reader_peek_at(fyr, 1);
+			if (cn == '=') {
+				type = FYTT_PE_NOTEQ;
+				simple_token_count = 2;
+				break;
+			}
+			type = FYTT_PE_UNIQUE_FILTER;
+			simple_token_count = 1;
+			break;
+
+		default:
+			break;
+		}
+		break;
+
+	case fyem_scalar:
+
+
+		/* it is possible for the expression to be a path
+		 * we only detect a few cases (doing all too complex)
+		 * (/ , (./ , (*
+		 */
+		if (fy_token_type_can_be_path_expr(fypp->last_queued_token_type)) {
+			cn = fy_reader_peek_at(fyr, 1);
+			if (c == '/' ||
+			    (c == '.' && (cn == '/' || cn == ')' || cn == '>' || cn == '<' || cn == '!' || cn == '='))) {
+				fypp->expr_mode = fyem_path;
+#ifdef DEBUG_EXPR
+				fyr_notice(fyr, "switching to path expr\n");
+#endif
+				goto again;
+			}
+		}
+
+		switch (c) {
+		case '+':
+			type = FYTT_SE_PLUS;
+			simple_token_count = 1;
+			break;
+
+		case '-':
+			cn = fy_reader_peek_at(fyr, 1);
+			if (fy_is_num(cn) &&
+			    fy_token_type_can_be_before_negative_number(fypp->last_queued_token_type))
+				break;
+
+			type = FYTT_SE_MINUS;
+			simple_token_count = 1;
+			break;
+
+		case '*':
+			type = FYTT_SE_MULT;
+			simple_token_count = 1;
+			break;
+
+		case '/':
+			type = FYTT_SE_DIV;
+			simple_token_count = 1;
+			break;
+
+		default:
+			break;
+		}
+		break;
+	}
+
+do_token:
+	/* simple tokens */
+	if (simple_token_count > 0) {
+		fyt = fy_path_token_queue(fypp, type, fy_reader_fill_atom_a(fyr, simple_token_count));
+		fyr_error_check(fyr, fyt, err_out, "fy_path_token_queue() failed\n");
+
+		return 0;
+	}
+
+	switch (fypp->expr_mode) {
+	case fyem_none:
+		assert(0);	/* should never happen */
+		break;
+
+	case fyem_path:
+		if (fy_is_first_alpha(c))
+			return fy_path_fetch_plain_or_method(fypp, c, FYTT_PE_MAP_KEY, FYTT_PE_METHOD);
+
+		if (fy_is_path_flow_key_start(c))
+			return fy_path_fetch_flow_map_key(fypp, c);
+
+		if (fy_is_num(c) || (c == '-' && fy_is_num(fy_reader_peek_at(fyr, 1))))
+			return fy_path_fetch_seq_index_or_slice(fypp, c);
+
+		if (c == '.' && fy_is_first_alpha(fy_reader_peek_at(fyr, 1)))
+			return fy_path_fetch_dot_method(fypp, c, FYTT_PE_METHOD);
+
+		break;
+
+	case fyem_scalar:
+
+		if (fy_is_first_alpha(c))
+			return fy_path_fetch_plain_or_method(fypp, c, FYTT_SCALAR, FYTT_SE_METHOD);
+
+		if (fy_is_path_flow_scalar_start(c))
+			return fy_path_fetch_flow_scalar(fypp, c);
+
+		if (fy_is_num(c) || (c == '-' && fy_is_num(fy_reader_peek_at(fyr, 1))))
+			return fy_path_fetch_number(fypp, c);
+
+#if 0
+		if (c == '.' && fy_is_first_alpha(fy_reader_peek_at(fyr, 1)))
+			return fy_path_fetch_dot_method(fypp, c, FYTT_SE_METHOD);
+#endif
+
+		break;
+	}
+
+	FYR_PARSE_ERROR(fyr, 0, 1, FYEM_SCAN, "bad path expression starts here c=%d", c);
+
+err_out:
+	fypp->stream_error = true;
+	rc = -1;
+	return rc;
+}
+
+struct fy_token *fy_path_scan_peek(struct fy_path_parser *fypp, struct fy_token *fyt_prev)
+{
+	struct fy_token *fyt;
+	struct fy_reader *fyr;
+	int rc, last_token_activity_counter;
+
+	fyr = &fypp->reader;
+
+	/* nothing if stream end produced (and no stream end token in queue) */
+	if (!fyt_prev && fypp->stream_end_produced && fy_token_list_empty(&fypp->queued_tokens)) {
+
+		fyt = fy_token_list_head(&fypp->queued_tokens);
+		if (fyt && fyt->type == FYTT_STREAM_END)
+			return fyt;
+
+		return NULL;
+	}
+
+	for (;;) {
+		if (!fyt_prev)
+			fyt = fy_token_list_head(&fypp->queued_tokens);
+		else
+			fyt = fy_token_next(&fypp->queued_tokens, fyt_prev);
+		if (fyt)
+			break;
+
+		/* on stream error we're done */
+		if (fypp->stream_error)
+			return NULL;
+
+		/* keep track of token activity, if it didn't change
+		* after the fetch tokens call, the state machine is stuck
+		*/
+		last_token_activity_counter = fypp->token_activity_counter;
+
+		/* fetch more then */
+		rc = fy_path_fetch_tokens(fypp);
+		if (rc) {
+			fy_error(fypp->cfg.diag, "fy_path_fetch_tokens() failed\n");
+			goto err_out;
+		}
+		if (last_token_activity_counter == fypp->token_activity_counter) {
+			fy_error(fypp->cfg.diag, "out of tokens and failed to produce anymore");
+			goto err_out;
+		}
+	}
+
+	switch (fyt->type) {
+	case FYTT_STREAM_START:
+		fypp->stream_start_produced = true;
+		break;
+	case FYTT_STREAM_END:
+		fypp->stream_end_produced = true;
+
+		rc = fy_reader_input_done(fyr);
+		if (rc) {
+			fy_error(fypp->cfg.diag, "fy_parse_input_done() failed");
+			goto err_out;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return fyt;
+
+err_out:
+	fypp->stream_error = true;
+	return NULL;
+}
+
+struct fy_token *fy_path_scan_remove(struct fy_path_parser *fypp, struct fy_token *fyt)
+{
+	if (!fypp || !fyt)
+		return NULL;
+
+	fy_token_list_del(&fypp->queued_tokens, fyt);
+
+	return fyt;
+}
+
+struct fy_token *fy_path_scan_remove_peek(struct fy_path_parser *fypp, struct fy_token *fyt)
+{
+	fy_token_unref(fy_path_scan_remove(fypp, fyt));
+
+	return fy_path_scan_peek(fypp, NULL);
+}
+
+struct fy_token *fy_path_scan(struct fy_path_parser *fypp)
+{
+	return fy_path_scan_remove(fypp, fy_path_scan_peek(fypp, NULL));
+}
+
+void fy_path_expr_dump(struct fy_path_expr *expr, struct fy_diag *diag, enum fy_error_type errlevel, int level, const char *banner)
+{
+	struct fy_path_expr *expr2;
+	const char *style = "";
+	const char *text;
+	size_t len;
+	bool save_on_error;
+
+	if (errlevel < diag->cfg.level)
+		return;
+
+	save_on_error = diag->on_error;
+	diag->on_error = true;
+
+	if (banner)
+		fy_diag_diag(diag, errlevel, "%-*s%s", level*2, "", banner);
+
+	text = fy_token_get_text(expr->fyt, &len);
+
+	style = "";
+	if (expr->type == fpet_scalar) {
+		switch (fy_scalar_token_get_style(expr->fyt)) {
+		case FYSS_SINGLE_QUOTED:
+			style = "'";
+			break;
+		case FYSS_DOUBLE_QUOTED:
+			style = "\"";
+			break;
+		default:
+			style = "";
+			break;
+		}
+	}
+
+	fy_diag_diag(diag, errlevel, "> %-*s%s:%s %s%.*s%s",
+			level*2, "",
+			fy_path_expr_type_txt[expr->type],
+			fy_expr_mode_txt[expr->expr_mode],
+			style, (int)len, text, style);
+
+	for (expr2 = fy_path_expr_list_head(&expr->children); expr2; expr2 = fy_path_expr_next(&expr->children, expr2))
+		fy_path_expr_dump(expr2, diag, errlevel, level + 1, NULL);
+
+	diag->on_error = save_on_error;
+}
+
+static struct fy_node *
+fy_path_expr_to_node_internal(struct fy_document *fyd, struct fy_path_expr *expr)
+{
+	struct fy_path_expr *expr2;
+	const char *style = "";
+	const char *text;
+	size_t len;
+	struct fy_node *fyn = NULL, *fyn2, *fyn_seq = NULL;
+	int rc;
+
+	text = fy_token_get_text(expr->fyt, &len);
+
+	/* by default use double quoted style */
+	style = "\"";
+	switch (expr->type) {
+	case fpet_scalar:
+		switch (fy_scalar_token_get_style(expr->fyt)) {
+		case FYSS_SINGLE_QUOTED:
+			style = "'";
+			break;
+		case FYSS_DOUBLE_QUOTED:
+			style = "\"";
+			break;
+		default:
+			style = "";
+			break;
+		}
+		break;
+
+	case fpet_map_key:
+		/* no styles for complex map keys */
+		if (expr->fyt->map_key.fyd)
+			style = "";
+		break;
+
+	default:
+		break;
+	}
+
+	/* list is empty this is a terminal */
+	if (fy_path_expr_list_empty(&expr->children) &&
+	    expr->type != fpet_method) {
+
+		fyn = fy_node_buildf(fyd, "%s: %s%.*s%s",
+			fy_path_expr_type_txt[expr->type],
+			style, (int)len, text, style);
+		if (!fyn)
+			return NULL;
+
+		return fyn;
+	}
+
+	fyn = fy_node_create_mapping(fyd);
+	if (!fyn)
+		goto err_out;
+
+	fyn_seq = fy_node_create_sequence(fyd);
+	if (!fyn_seq)
+		goto err_out;
+
+	for (expr2 = fy_path_expr_list_head(&expr->children); expr2; expr2 = fy_path_expr_next(&expr->children, expr2)) {
+		fyn2 = fy_path_expr_to_node_internal(fyd, expr2);
+		if (!fyn2)
+			goto err_out;
+		rc = fy_node_sequence_append(fyn_seq, fyn2);
+		if (rc)
+			goto err_out;
+	}
+
+	if (expr->type != fpet_method) {
+		rc = fy_node_mapping_append(fyn,
+				fy_node_create_scalar(fyd, fy_path_expr_type_txt[expr->type], FY_NT),
+				fyn_seq);
+	} else {
+		rc = fy_node_mapping_append(fyn,
+				fy_node_create_scalarf(fyd, "%s()", expr->fym->name),
+				fyn_seq);
+	}
+	if (rc)
+		goto err_out;
+
+	return fyn;
+
+err_out:
+	fy_node_free(fyn_seq);
+	fy_node_free(fyn);
+	return NULL;
+}
+
+struct fy_document *fy_path_expr_to_document(struct fy_path_expr *expr)
+{
+	struct fy_document *fyd = NULL;
+
+	if (!expr)
+		return NULL;
+
+	fyd = fy_document_create(NULL);
+	if (!fyd)
+		return NULL;
+
+	fyd->root = fy_path_expr_to_node_internal(fyd, expr);
+	if (!fyd->root)
+		goto err_out;
+
+	return fyd;
+
+err_out:
+	fy_document_destroy(fyd);
+	return NULL;
+}
+
+enum fy_path_expr_type fy_map_token_to_path_expr_type(enum fy_token_type type, enum fy_expr_mode mode)
+{
+	switch (type) {
+	case FYTT_PE_ROOT:
+		return fpet_root;
+	case FYTT_PE_THIS:
+		return fpet_this;
+	case FYTT_PE_PARENT:
+	case FYTT_PE_SIBLING:	/* sibling maps to a chain of fpet_parent */
+		return fpet_parent;
+	case FYTT_PE_MAP_KEY:
+		return fpet_map_key;
+	case FYTT_PE_SEQ_INDEX:
+		return fpet_seq_index;
+	case FYTT_PE_SEQ_SLICE:
+		return fpet_seq_slice;
+	case FYTT_PE_EVERY_CHILD:
+		return fpet_every_child;
+	case FYTT_PE_EVERY_CHILD_R:
+		return fpet_every_child_r;
+	case FYTT_PE_ALIAS:
+		return fpet_alias;
+	case FYTT_PE_SCALAR_FILTER:
+		return fpet_filter_scalar;
+	case FYTT_PE_COLLECTION_FILTER:
+		return fpet_filter_collection;
+	case FYTT_PE_SEQ_FILTER:
+		return fpet_filter_sequence;
+	case FYTT_PE_MAP_FILTER:
+		return fpet_filter_mapping;
+	case FYTT_PE_UNIQUE_FILTER:
+		return fpet_filter_unique;
+	case FYTT_PE_COMMA:
+		return mode == fyem_path ? fpet_multi : fpet_arg_separator;
+	case FYTT_PE_SLASH:
+		return fpet_chain;
+	case FYTT_PE_BARBAR:
+		return fpet_logical_or;
+	case FYTT_PE_AMPAMP:
+		return fpet_logical_and;
+
+	case FYTT_PE_EQEQ:
+		return fpet_eq;
+	case FYTT_PE_NOTEQ:
+		return fpet_neq;
+	case FYTT_PE_LT:
+		return fpet_lt;
+	case FYTT_PE_GT:
+		return fpet_gt;
+	case FYTT_PE_LTE:
+		return fpet_lte;
+	case FYTT_PE_GTE:
+		return fpet_gte;
+
+	case FYTT_SCALAR:
+		return fpet_scalar;
+
+	case FYTT_SE_PLUS:
+		return fpet_plus;
+	case FYTT_SE_MINUS:
+		return fpet_minus;
+	case FYTT_SE_MULT:
+		return fpet_mult;
+	case FYTT_SE_DIV:
+		return fpet_div;
+
+	case FYTT_PE_LPAREN:
+		return fpet_lparen;
+	case FYTT_PE_RPAREN:
+		return fpet_rparen;
+
+	case FYTT_SE_METHOD:
+	case FYTT_PE_METHOD:
+		return fpet_method;
+
+	default:
+		/* note parentheses do not have an expression */
+		assert(0);
+		break;
+	}
+	return fpet_none;
+}
+
+bool fy_token_type_is_operand(enum fy_token_type type)
+{
+	return type == FYTT_PE_ROOT ||
+	       type == FYTT_PE_THIS ||
+	       type == FYTT_PE_PARENT ||
+	       type == FYTT_PE_MAP_KEY ||
+	       type == FYTT_PE_SEQ_INDEX ||
+	       type == FYTT_PE_SEQ_SLICE ||
+	       type == FYTT_PE_EVERY_CHILD ||
+	       type == FYTT_PE_EVERY_CHILD_R ||
+	       type == FYTT_PE_ALIAS ||
+
+	       type == FYTT_SCALAR;
+}
+
+bool fy_token_type_is_operator(enum fy_token_type type)
+{
+	return type == FYTT_PE_SLASH ||
+	       type == FYTT_PE_SCALAR_FILTER ||
+	       type == FYTT_PE_COLLECTION_FILTER ||
+	       type == FYTT_PE_SEQ_FILTER ||
+	       type == FYTT_PE_MAP_FILTER ||
+	       type == FYTT_PE_UNIQUE_FILTER ||
+	       type == FYTT_PE_SIBLING ||
+	       type == FYTT_PE_COMMA ||
+	       type == FYTT_PE_BARBAR ||
+	       type == FYTT_PE_AMPAMP ||
+	       type == FYTT_PE_LPAREN ||
+	       type == FYTT_PE_RPAREN ||
+
+	       type == FYTT_PE_EQEQ ||
+	       type == FYTT_PE_NOTEQ ||
+	       type == FYTT_PE_LT ||
+	       type == FYTT_PE_GT ||
+	       type == FYTT_PE_LTE ||
+	       type == FYTT_PE_GTE ||
+
+	       type == FYTT_SE_PLUS ||
+	       type == FYTT_SE_MINUS ||
+	       type == FYTT_SE_MULT ||
+	       type == FYTT_SE_DIV;
+}
+
+bool fy_token_type_is_operand_or_operator(enum fy_token_type type)
+{
+	return fy_token_type_is_operand(type) ||
+	       fy_token_type_is_operator(type);
+}
+
+int fy_path_expr_type_prec(enum fy_path_expr_type type)
+{
+	switch (type) {
+	default:
+		return -1;	/* terminals */
+	case fpet_filter_collection:
+	case fpet_filter_scalar:
+	case fpet_filter_sequence:
+	case fpet_filter_mapping:
+	case fpet_filter_unique:
+		return 5;
+	case fpet_logical_or:
+	case fpet_logical_and:
+		return 4;
+	case fpet_multi:
+		return 11;
+	case fpet_eq:
+	case fpet_neq:
+	case fpet_lt:
+	case fpet_gt:
+	case fpet_lte:
+	case fpet_gte:
+		return 7;
+	case fpet_mult:
+	case fpet_div:
+		return 9;
+	case fpet_plus:
+	case fpet_minus:
+		return 8;
+	case fpet_chain:
+		return 10;
+	case fpet_lparen:
+	case fpet_rparen:
+	case fpet_method:
+		return 1000;
+	case fpet_arg_separator:
+		return 1;	/* lowest */
+	}
+	return -1;
+}
+
+static inline FY_UNUSED void
+dump_operand_stack(struct fy_path_parser *fypp)
+{
+	return fy_expr_stack_dump(fypp->cfg.diag, &fypp->operands);
+}
+
+static inline int
+push_operand(struct fy_path_parser *fypp, struct fy_path_expr *expr)
+{
+	return fy_expr_stack_push(&fypp->operands, expr);
+}
+
+static inline FY_UNUSED struct fy_path_expr *
+peek_operand_at(struct fy_path_parser *fypp, unsigned int pos)
+{
+	return fy_expr_stack_peek_at(&fypp->operands, pos);
+}
+
+static inline FY_UNUSED struct fy_path_expr *
+peek_operand(struct fy_path_parser *fypp)
+{
+	return fy_expr_stack_peek(&fypp->operands);
+}
+
+static inline FY_UNUSED struct fy_path_expr *
+pop_operand(struct fy_path_parser *fypp)
+{
+	return fy_expr_stack_pop(&fypp->operands);
+}
+
+#define PREFIX	0
+#define INFIX	1
+#define SUFFIX	2
+
+int fy_token_type_operator_placement(enum fy_token_type type)
+{
+	switch (type) {
+	case FYTT_PE_SLASH:	/* SLASH is special at the start of the expression */
+	case FYTT_PE_COMMA:
+	case FYTT_PE_BARBAR:
+	case FYTT_PE_AMPAMP:
+	case FYTT_PE_EQEQ:
+	case FYTT_PE_NOTEQ:
+	case FYTT_PE_LT:
+	case FYTT_PE_GT:
+	case FYTT_PE_LTE:
+	case FYTT_PE_GTE:
+	case FYTT_SE_PLUS:
+	case FYTT_SE_MINUS:
+	case FYTT_SE_MULT:
+	case FYTT_SE_DIV:
+		return INFIX;
+	case FYTT_PE_SCALAR_FILTER:
+	case FYTT_PE_COLLECTION_FILTER:
+	case FYTT_PE_SEQ_FILTER:
+	case FYTT_PE_MAP_FILTER:
+	case FYTT_PE_UNIQUE_FILTER:
+		return SUFFIX;
+	case FYTT_PE_SIBLING:
+		return PREFIX;
+	default:
+		break;
+	}
+	return -1;
+}
+
+const struct fy_mark *fy_path_expr_start_mark(struct fy_path_expr *expr)
+{
+	if (!expr)
+		return NULL;
+
+	return fy_token_start_mark(expr->fyt);
+}
+
+const struct fy_mark *fy_path_expr_end_mark(struct fy_path_expr *expr)
+{
+	if (!expr)
+		return NULL;
+
+	return fy_token_end_mark(expr->fyt);
+}
+
+struct fy_token *
+expr_to_token_mark(struct fy_path_expr *expr, struct fy_input *fyi)
+{
+	const struct fy_mark *ms, *me;
+	struct fy_atom handle;
+
+	if (!expr || !fyi)
+		return NULL;
+
+	ms = fy_path_expr_start_mark(expr);
+	assert(ms);
+	me = fy_path_expr_end_mark(expr);
+	assert(me);
+
+	memset(&handle, 0, sizeof(handle));
+	handle.start_mark = *ms;
+	handle.end_mark = *me;
+	handle.fyi = fyi;
+	handle.style = FYAS_PLAIN;
+	handle.chomp = FYAC_CLIP;
+
+	return fy_token_create(FYTT_INPUT_MARKER, &handle);
+}
+
+struct fy_token *
+expr_lr_to_token_mark(struct fy_path_expr *exprl, struct fy_path_expr *exprr, struct fy_input *fyi)
+{
+	const struct fy_mark *ms, *me;
+	struct fy_atom handle;
+
+	if (!exprl || !exprr || !fyi)
+		return NULL;
+
+	ms = fy_path_expr_start_mark(exprl);
+	assert(ms);
+	me = fy_path_expr_end_mark(exprr);
+	assert(me);
+
+	memset(&handle, 0, sizeof(handle));
+	handle.start_mark = *ms;
+	handle.end_mark = *me;
+	handle.fyi = fyi;
+	handle.style = FYAS_PLAIN;
+	handle.chomp = FYAC_CLIP;
+
+	return fy_token_create(FYTT_INPUT_MARKER, &handle);
+}
+
+int
+fy_path_expr_order(struct fy_path_expr *expr1, struct fy_path_expr *expr2)
+{
+	const struct fy_mark *m1 = NULL, *m2 = NULL;
+
+	if (expr1)
+		m1 = fy_path_expr_start_mark(expr1);
+
+	if (expr2)
+		m2 = fy_path_expr_start_mark(expr2);
+
+	if (m1 == m2)
+		return 0;
+
+	if (!m1)
+		return -1;
+
+	if (!m2)
+		return 1;
+
+	return m1->input_pos == m2->input_pos ? 0 :
+	       m1->input_pos  < m2->input_pos ? -1 : 1;
+}
+
+int push_operand_lr(struct fy_path_parser *fypp,
+		    enum fy_path_expr_type type,
+		    struct fy_path_expr *exprl, struct fy_path_expr *exprr,
+		    bool optimize)
+{
+	struct fy_reader *fyr;
+	struct fy_path_expr *expr = NULL, *exprt;
+	const struct fy_mark *ms = NULL, *me = NULL;
+	struct fy_atom handle;
+	int ret;
+
+	optimize = false;
+	assert(exprl || exprr);
+
+	fyr = &fypp->reader;
+
+#if 0
+	fyr_notice(fyr, ">>> %s <%s> l=<%s> r=<%s>\n", __func__,
+			fy_path_expr_type_txt[type],
+			exprl ?fy_path_expr_type_txt[exprl->type] : "NULL",
+			exprr ?fy_path_expr_type_txt[exprr->type] : "NULL");
+#endif
+
+	expr = fy_path_expr_alloc_recycle(fypp);
+	fyr_error_check(fyr, expr, err_out,
+			"fy_path_expr_alloc_recycle() failed\n");
+
+	expr->type = type;
+	expr->fyt = NULL;
+
+	if (exprl) {
+		assert(exprl->fyt);
+		ms = fy_token_start_mark(exprl->fyt);
+		assert(ms);
+	} else {
+		ms = fy_token_start_mark(exprr->fyt);
+		assert(ms);
+	}
+
+	if (exprr) {
+		assert(exprr->fyt);
+		me = fy_token_end_mark(exprr->fyt);
+		assert(me);
+	} else {
+		me = fy_token_end_mark(exprr->fyt);
+		assert(me);
+	}
+
+	assert(ms && me);
+
+	memset(&handle, 0, sizeof(handle));
+	handle.start_mark = *ms;
+	handle.end_mark = *me;
+	handle.fyi = fypp->fyi;
+	handle.style = FYAS_PLAIN;
+	handle.chomp = FYAC_CLIP;
+
+	if (exprl) {
+		if (type == exprl->type && fy_path_expr_type_is_mergeable(type)) {
+			while ((exprt = fy_path_expr_list_pop(&exprl->children)) != NULL) {
+				fy_path_expr_list_add_tail(&expr->children, exprt);
+				exprt->parent = expr;
+			}
+			fy_path_expr_free_recycle(fypp, exprl);
+		} else {
+			fy_path_expr_list_add_tail(&expr->children, exprl);
+			exprl->parent = expr;
+		}
+		exprl = NULL;
+	}
+
+	if (exprr) {
+		if (type == exprr->type && fy_path_expr_type_is_mergeable(type)) {
+			while ((exprt = fy_path_expr_list_pop(&exprr->children)) != NULL) {
+				fy_path_expr_list_add_tail(&expr->children, exprt);
+				exprt->parent = expr;
+			}
+			fy_path_expr_free_recycle(fypp, exprr);
+		} else {
+			fy_path_expr_list_add_tail(&expr->children, exprr);
+			exprr->parent = expr;
+		}
+		exprr = NULL;
+	}
+
+	expr->fyt = fy_token_create(FYTT_INPUT_MARKER, &handle);
+	fyr_error_check(fyr, expr->fyt, err_out,
+			"expr_to_token_mark() failed\n");
+
+	ret = push_operand(fypp, expr);
+	fyr_error_check(fyr, !ret, err_out,
+			"push_operand() failed\n");
+
+#ifdef DEBUG_EXPR
+	FYR_TOKEN_DIAG(fyr, expr->fyt,
+		FYDF_NOTICE, FYEM_PARSE, "pushed operand lr");
+#endif
+
+	return 0;
+err_out:
+	fy_path_expr_free(expr);
+	fy_path_expr_free(exprl);
+	fy_path_expr_free(exprr);
+	return -1;
+}
+
+enum fy_method_idx {
+	fymi_test,
+	fymi_sum,
+	fymi_this,
+	fymi_parent,
+	fymi_root,
+	fymi_any,
+	fymi_all,
+	fymi_select,
+	fymi_key,
+	fymi_value,
+	fymi_index,
+	fymi_null,
+};
+
+static struct fy_walk_result *
+common_builtin_ref_exec(const struct fy_method *fym,
+	struct fy_path_exec *fypx, int level,
+	struct fy_path_expr *expr,
+	struct fy_walk_result *input,
+	struct fy_walk_result **args, int nargs);
+
+static struct fy_walk_result *
+common_builtin_collection_exec(const struct fy_method *fym,
+	struct fy_path_exec *fypx, int level,
+	struct fy_path_expr *expr,
+	struct fy_walk_result *input,
+	struct fy_walk_result **args, int nargs);
+
+
+static struct fy_walk_result *
+test_exec(const struct fy_method *fym,
+	  struct fy_path_exec *fypx, int level,
+	  struct fy_path_expr *expr,
+	  struct fy_walk_result *input,
+	  struct fy_walk_result **args, int nargs);
+
+static struct fy_walk_result *
+sum_exec(const struct fy_method *fym,
+	 struct fy_path_exec *fypx, int level,
+	 struct fy_path_expr *expr,
+	 struct fy_walk_result *input,
+	 struct fy_walk_result **args, int nargs);
+
+static const struct fy_method fy_methods[] = {
+	[fymi_test] = {
+		.name	= "test",
+		.len    = 4,
+		.mode	= fyem_scalar,
+		.nargs	= 1,
+		.exec	= test_exec,
+	},
+	[fymi_sum] = {
+		.name	= "sum",
+		.len    = 3,
+		.mode	= fyem_scalar,
+		.nargs	= 2,
+		.exec	= sum_exec,
+	},
+	[fymi_this] = {
+		.name	= "this",
+		.len    = 4,
+		.mode	= fyem_path,
+		.nargs	= 0,
+		.exec	= common_builtin_ref_exec,
+	},
+	[fymi_parent] = {
+		.name	= "parent",
+		.len    = 6,
+		.mode	= fyem_path,
+		.nargs	= 0,
+		.exec	= common_builtin_ref_exec,
+	},
+	[fymi_root] = {
+		.name	= "root",
+		.len    = 4,
+		.mode	= fyem_path,
+		.nargs	= 0,
+		.exec	= common_builtin_ref_exec,
+	},
+	[fymi_any] = {
+		.name	= "any",
+		.len    = 3,
+		.mode	= fyem_path,
+		.nargs	= 1,
+		.exec	= common_builtin_collection_exec,
+	},
+	[fymi_all] = {
+		.name	= "all",
+		.len    = 3,
+		.mode	= fyem_path,
+		.nargs	= 1,
+		.exec	= common_builtin_collection_exec,
+	},
+	[fymi_select] = {
+		.name	= "select",
+		.len    = 6,
+		.mode	= fyem_path,
+		.nargs	= 1,
+		.exec	= common_builtin_collection_exec,
+	},
+	[fymi_key] = {
+		.name	= "key",
+		.len    = 3,
+		.mode	= fyem_path,
+		.nargs	= 1,
+		.exec	= common_builtin_ref_exec,
+	},
+	[fymi_value] = {
+		.name	= "value",
+		.len    = 5,
+		.mode	= fyem_path,
+		.nargs	= 1,
+		.exec	= common_builtin_ref_exec,
+	},
+	[fymi_index] = {
+		.name	= "index",
+		.len    = 5,
+		.mode	= fyem_path,
+		.nargs	= 1,
+		.exec	= common_builtin_ref_exec,
+	},
+	[fymi_null] = {
+		.name	= "null",
+		.len    = 4,
+		.mode	= fyem_path,
+		.nargs	= 0,
+		.exec	= common_builtin_ref_exec,
+	},
+};
+
+static inline int fy_method_to_builtin_idx(const struct fy_method *fym)
+{
+	if (!fym || fym < fy_methods || fym >= &fy_methods[ARRAY_SIZE(fy_methods)])
+		return -1;
+	return fym - fy_methods;
+}
+
+static struct fy_walk_result *
+common_builtin_ref_exec(const struct fy_method *fym,
+	    struct fy_path_exec *fypx, int level,
+            struct fy_path_expr *expr,
+	    struct fy_walk_result *input,
+	    struct fy_walk_result **args, int nargs)
+{
+	enum fy_method_idx midx;
+	struct fy_walk_result *output = NULL;
+	struct fy_walk_result *fwr, *fwrn;
+	struct fy_node *fyn, *fynt;
+	int i;
+
+	if (!fypx || !input)
+		goto out;
+
+	i = fy_method_to_builtin_idx(fym);
+	if (i < 0)
+		goto out;
+	midx = (enum fy_method_idx)i;
+
+	switch (midx) {
+	case fymi_key:
+	case fymi_value:
+		if (!args || nargs != 1 || !args[0] || args[0]->type != fwrt_string)
+			goto out;
+		break;
+	case fymi_index:
+		if (!args || nargs != 1 || !args[0] || args[0]->type != fwrt_number)
+			goto out;
+		break;
+	case fymi_root:
+	case fymi_parent:
+	case fymi_this:
+	case fymi_null:
+		if (nargs != 0)
+			goto out;
+		break;
+	default:
+		goto out;
+	}
+
+	output = fy_path_exec_walk_result_create(fypx, fwrt_refs);
+	assert(output);
+
+	for (fwr = fy_walk_result_iter_start(input); fwr;
+			fwr = fy_walk_result_iter_next(input, fwr)) {
+
+		if (fwr->type != fwrt_node_ref || !fwr->fyn)
+			continue;
+
+		fynt = fwr->fyn;
+
+		switch (midx) {
+		case fymi_key:
+		case fymi_value:
+		case fymi_index:
+		case fymi_this:
+		case fymi_null:
+			/* dereference alias */
+			if (fy_node_is_alias(fynt)) {
+				// fprintf(stderr, "%s: %s calling fy_node_alias_resolve_by_ypath()\n", __func__, fy_node_get_path_alloca(fyn));
+				fynt = fy_node_alias_resolve_by_ypath(fynt);
+			}
+			break;
+		default:
+			break;
+		}
+
+		fyn = NULL;
+		switch (midx) {
+		case fymi_key:
+			if (!fy_node_is_mapping(fynt))
+				break;
+			fyn = fy_node_mapping_lookup_key_by_string(fynt, args[0]->string, FY_NT);
+			break;
+
+		case fymi_value:
+			if (!fy_node_is_mapping(fynt))
+				break;
+			fyn = fy_node_mapping_lookup_by_string(fynt, args[0]->string, FY_NT);
+			break;
+
+		case fymi_index:
+			if (!fy_node_is_sequence(fynt))
+				break;
+			fyn = fy_node_sequence_get_by_index(fynt, (int)args[0]->number);
+			break;
+
+		case fymi_root:
+			fyn = fy_document_root(fy_node_document(fynt));
+			break;
+
+		case fymi_parent:
+			fyn = fy_node_get_parent(fynt);
+			break;
+
+		case fymi_null:
+			if (!fy_node_is_mapping(fynt))
+				break;
+			fyn = fy_node_mapping_lookup_value_by_null_key(fynt);
+			break;
+
+		case fymi_this:
+			fyn = fynt;
+			break;
+
+		default:
+			break;
+		}
+
+		if (!fyn)
+			continue;
+
+		fwrn = fy_path_exec_walk_result_create(fypx, fwrt_node_ref, fyn);
+		assert(fwrn);
+
+		fy_walk_result_list_add_tail(&output->refs, fwrn);
+	}
+
+	/* output convert zero to NULL, singular to node_ref */
+	if (output && output->type == fwrt_refs) {
+		if (fy_walk_result_list_empty(&output->refs)) {
+			fy_walk_result_free(output);
+			output = NULL;
+		} else if (fy_walk_result_list_is_singular(&output->refs)) {
+			fwr = fy_walk_result_list_pop(&output->refs);
+			assert(fwr);
+			fy_walk_result_free(output);
+			output = fwr;
+		}
+	}
+
+out:
+	fy_walk_result_free(input);
+	if (args) {
+		for (i = 0; i < nargs; i++)
+			fy_walk_result_free(args[i]);
+	}
+	return output;
+}
+
+static struct fy_walk_result *
+common_builtin_collection_exec(const struct fy_method *fym,
+	 struct fy_path_exec *fypx, int level,
+	 struct fy_path_expr *expr,
+	 struct fy_walk_result *input,
+	 struct fy_walk_result **args, int nargs)
+{
+	enum fy_method_idx midx;
+	struct fy_walk_result *output = NULL;
+	struct fy_walk_result *fwr, *fwrn, *fwrt;
+	struct fy_path_expr *expr_arg;
+	bool match, done;
+	int input_count, match_count;
+	int i;
+
+	if (!fypx || !input)
+		goto out;
+
+	i = fy_method_to_builtin_idx(fym);
+	if (i < 0)
+		goto out;
+	midx = (enum fy_method_idx)i;
+
+	switch (midx) {
+	case fymi_any:
+	case fymi_all:
+	case fymi_select:
+		if (!args || nargs != 1 || !args[0])
+			goto out;
+		break;
+	default:
+		goto out;
+	}
+
+	expr_arg = fy_path_expr_list_head(&expr->children);
+	assert(expr_arg);
+
+	/* only handle inputs of node and refs */
+	if (input->type != fwrt_node_ref && input->type != fwrt_refs)
+		goto out;
+
+	output = NULL;
+
+	switch (midx) {
+	case fymi_select:
+		output = fy_path_exec_walk_result_create(fypx, fwrt_refs);
+		assert(output);
+		break;
+	default:
+		break;
+	}
+
+
+	done = false;
+	match_count = input_count = 0;
+	for (fwr = fy_walk_result_iter_start(input); fwr && !done; fwr = fy_walk_result_iter_next(input, fwr)) {
+
+		input_count++;
+
+		fwrt = fy_walk_result_clone(fwr);
+		assert(fwrt);
+
+		fwrn = fy_path_expr_execute(fypx, level + 1, expr_arg, fwrt, expr->type);
+
+		match = fwrn != NULL;
+		if (match)
+			match_count++;
+
+		switch (midx) {
+		case fymi_any:
+			/* on any match, we're done */
+			if (match)
+				done = true;
+			break;
+
+		case fymi_all:
+			/* on any non match, we're done */
+			if (!match)
+				done = true;
+			break;
+
+		case fymi_select:
+			/* select only works on node refs */
+			if (fwr->type != fwrt_node_ref)
+				break;
+			if (match) {
+				fwrt = fy_walk_result_clone(fwr);
+				assert(fwrt);
+				fy_walk_result_list_add_tail(&output->refs, fwrt);
+			}
+			break;
+
+		default:
+			break;
+		}
+
+		if (fwrn)
+			fy_walk_result_free(fwrn);
+	}
+
+	switch (midx) {
+	case fymi_any:
+		if (input_count > 0 && match_count <= input_count) {
+			output = input;
+			input = NULL;
+		}
+		break;
+	case fymi_all:
+		if (input_count > 0 && match_count == input_count) {
+			output = input;
+			input = NULL;
+		}
+		break;
+
+	default:
+		break;
+	}
+
+	/* output convert zero to NULL, singular to node_ref */
+	if (output && output->type == fwrt_refs) {
+		if (fy_walk_result_list_empty(&output->refs)) {
+			fy_walk_result_free(output);
+			output = NULL;
+		} else if (fy_walk_result_list_is_singular(&output->refs)) {
+			fwr = fy_walk_result_list_pop(&output->refs);
+			assert(fwr);
+			fy_walk_result_free(output);
+			output = fwr;
+		}
+	}
+
+out:
+	if (input)
+		fy_walk_result_free(input);
+	if (args) {
+		for (i = 0; i < nargs; i++)
+			fy_walk_result_free(args[i]);
+	}
+
+	return output;
+}
+
+static struct fy_walk_result *
+test_exec(const struct fy_method *fym,
+	  struct fy_path_exec *fypx, int level,
+	  struct fy_path_expr *expr,
+	  struct fy_walk_result *input,
+	  struct fy_walk_result **args, int nargs)
+{
+	int i;
+	struct fy_walk_result *output = NULL;
+
+	if (!fypx || !args || nargs != 1)
+		goto out;
+
+	/* require a single number argument */
+	if (!args[0] || args[0]->type != fwrt_number)
+		goto out;
+
+	/* reuse argument */
+	output = args[0];
+	args[0] = NULL;
+
+	/* add 1 to the number */
+	output->number += 1;
+
+out:
+	fy_walk_result_free(input);
+	if (args) {
+		for (i = 0; i < nargs; i++)
+			fy_walk_result_free(args[i]);
+	}
+	return output;
+}
+
+static struct fy_walk_result *
+sum_exec(const struct fy_method *fym,
+	 struct fy_path_exec *fypx, int level,
+         struct fy_path_expr *expr,
+	 struct fy_walk_result *input,
+	 struct fy_walk_result **args, int nargs)
+{
+	int i;
+	struct fy_walk_result *output = NULL;
+
+	if (!fypx || !args || nargs != 2)
+		goto out;
+
+	/* require two number argument */
+	if (!args[0] || args[0]->type != fwrt_number ||
+	    !args[1] || args[1]->type != fwrt_number)
+		goto out;
+
+	/* reuse argument */
+	output = args[0];
+	args[0] = NULL;
+
+	/* add 1 to the number */
+	output->number += args[1]->number;
+
+out:
+	fy_walk_result_free(input);
+	if (args) {
+		for (i = 0; i < nargs; i++)
+			fy_walk_result_free(args[i]);
+	}
+	return output;
+}
+
+int evaluate_method(struct fy_path_parser *fypp, struct fy_path_expr *exprm,
+		    struct fy_path_expr *exprl, struct fy_path_expr *exprr)
+{
+	struct fy_reader *fyr;
+	struct fy_path_expr *exprt;
+	struct fy_token *fyt;
+	const char *text;
+	size_t len;
+	const struct fy_method *fym;
+	unsigned int i, count;
+	int ret;
+
+	fyr = &fypp->reader;
+
+#ifdef DEBUG_EXPR
+	FYR_TOKEN_DIAG(fyr, exprm->fyt,
+		FYDF_NOTICE, FYEM_PARSE, "evaluating method");
+#endif
+
+	text = fy_token_get_text(exprm->fyt, &len);
+	fyr_error_check(fyr, text, err_out,
+			"fy_token_get_text() failed\n");
+
+	for (i = 0, fym = fy_methods; i < ARRAY_SIZE(fy_methods); i++, fym++) {
+		if (fym->len == len && !memcmp(text, fym->name, len))
+			break;
+	}
+
+	FYR_TOKEN_ERROR_CHECK(fyr, exprm->fyt, FYEM_PARSE,
+			i < ARRAY_SIZE(fy_methods), err_out,
+			"invalid method %.*s\n", (int)len, text);
+
+	/* reuse exprm */
+	count = 0;
+	while ((exprt = fy_expr_stack_peek(&fypp->operands)) != NULL &&
+		fy_path_expr_order(exprm, exprt) < 0) {
+
+		exprt = fy_expr_stack_pop(&fypp->operands);
+		assert(exprt);
+
+#ifdef DEBUG_EXPR
+		FYR_TOKEN_DIAG(fyr, exprt->fyt,
+			FYDF_NOTICE, FYEM_PARSE, "poped argument %d", count);
+#endif
+
+		/* add in reverse order */
+		fy_path_expr_list_add(&exprm->children, exprt);
+		exprt->parent = exprm;
+		count++;
+
+	}
+
+	if (exprr) {
+		fyt = expr_lr_to_token_mark(exprm, exprr, fypp->fyi);
+		fyr_error_check(fyr, fyt, err_out,
+				"expr_lr_to_token_mark() failed\n");
+
+		fy_token_unref(exprm->fyt);
+		exprm->fyt = fyt;
+	}
+
+	FYR_TOKEN_ERROR_CHECK(fyr, exprm->fyt, FYEM_PARSE,
+			fym->nargs == count, err_out,
+			"too %s argument for method %s, expected %d, got %d\n",
+			fym->nargs < count ? "many" : "few",
+			fym->name, fym->nargs, count);
+
+	exprm->fym = fym;
+
+	if (exprl)
+		fy_path_expr_free_recycle(fypp, exprl);
+	if (exprr)
+		fy_path_expr_free_recycle(fypp, exprr);
+
+	/* and push as an operand */
+	ret = push_operand(fypp, exprm);
+	fyr_error_check(fyr, !ret, err_out,
+			"push_operand() failed\n");
+
+#ifdef DEBUG_EXPR
+	FYR_TOKEN_DIAG(fyr, exprm->fyt,
+		FYDF_NOTICE, FYEM_PARSE, "pushed operand evaluate_method");
+#endif
+	return 0;
+
+err_out:
+	/* we don't need the parentheses operators */
+	fy_path_expr_free_recycle(fypp, exprm);
+	if (exprl)
+		fy_path_expr_free_recycle(fypp, exprl);
+	if (exprr)
+		fy_path_expr_free_recycle(fypp, exprr);
+
+	return -1;
+}
+
+int evaluate_new(struct fy_path_parser *fypp)
+{
+	struct fy_reader *fyr;
+	struct fy_path_expr *expr = NULL, *expr_peek, *exprt;
+	struct fy_path_expr *exprl = NULL, *exprr = NULL, *chain = NULL, *exprm = NULL;
+	struct fy_path_expr *parent = NULL;
+	struct fy_token *fyt;
+	enum fy_path_expr_type type, etype;
+	int ret;
+
+	fyr = &fypp->reader;
+
+	expr = fy_expr_stack_pop(&fypp->operators);
+	fyr_error_check(fyr, expr, err_out,
+			"pop_operator() failed to find token operator to evaluate\n");
+
+	assert(expr->fyt);
+
+#ifdef DEBUG_EXPR
+	FYR_TOKEN_DIAG(fyr, expr->fyt,
+		FYDF_NOTICE, FYEM_PARSE, "poped operator expression");
+#endif
+
+	exprl = NULL;
+	exprr = NULL;
+	type = expr->type;
+	switch (type) {
+
+	case fpet_chain:
+
+		/* dump_operand_stack(fypp); */
+		/* dump_operator_stack(fypp); */
+
+		/* peek the next operator */
+		expr_peek = fy_expr_stack_peek(&fypp->operators);
+
+		/* pop the top in either case */
+		exprr = fy_expr_stack_pop(&fypp->operands);
+		if (!exprr) {
+			// fyr_notice(fyr, "ROOT value (with no arguments)\n");
+
+			/* conver to root and push to operands */
+			expr->type = fpet_root;
+
+			ret = push_operand(fypp, expr);
+			fyr_error_check(fyr, !ret, err_out,
+					"push_operand() failed\n");
+			return 0;
+		}
+
+#ifdef DEBUG_EXPR
+		FYR_TOKEN_DIAG(fyr, exprr->fyt,
+			FYDF_NOTICE, FYEM_PARSE, "exprr");
+#endif
+
+		/* expression is to the left, that means it's a root chain */
+		if (fy_path_expr_order(expr, exprr) < 0 &&
+		    (!(exprl = fy_expr_stack_peek(&fypp->operands)) ||
+		     (expr_peek && fy_path_expr_order(exprl, expr_peek) <= 0))) {
+
+			// fyr_notice(fyr, "ROOT operator (with arguments)\n");
+
+			exprl = fy_path_expr_alloc_recycle(fypp);
+			fyr_error_check(fyr, exprl, err_out,
+					"fy_path_expr_alloc_recycle() failed\n");
+			exprl->type = fpet_root;
+
+			/* move token to the root */
+			exprl->fyt = expr->fyt;
+			expr->fyt = NULL;
+
+		} else if (!(exprl = fy_expr_stack_pop(&fypp->operands))) {
+
+			// fyr_notice(fyr, "COLLECTION operator\n");
+
+			exprl = exprr;
+
+			exprr = fy_path_expr_alloc_recycle(fypp);
+			fyr_error_check(fyr, exprr, err_out,
+					"fy_path_expr_alloc_recycle() failed\n");
+			exprr->type = fpet_filter_collection;
+
+			/* move token to the filter collection */
+			exprr->fyt = expr->fyt;
+			expr->fyt = NULL;
+
+		} else {
+			assert(exprr && exprl);
+
+			// fyr_notice(fyr, "CHAIN operator\n");
+		}
+
+		/* we don't need the chain operator now */
+		fy_path_expr_free_recycle(fypp, expr);
+		expr = NULL;
+
+		ret = push_operand_lr(fypp, fpet_chain, exprl, exprr, true);
+		fyr_error_check(fyr, !ret, err_out,
+				"push_operand_lr() failed\n");
+		return 0;
+
+	case fpet_multi:
+	case fpet_logical_or:
+	case fpet_logical_and:
+
+	case fpet_eq:
+	case fpet_neq:
+	case fpet_lt:
+	case fpet_gt:
+	case fpet_lte:
+	case fpet_gte:
+
+	case fpet_plus:
+	case fpet_minus:
+	case fpet_mult:
+	case fpet_div:
+
+		exprl = NULL;
+		exprr = NULL;
+		exprt = fy_expr_stack_peek(&fypp->operators);
+
+		// fyr_error(fyr, "mode=%s top-mode=%s\n",
+		//		fy_expr_mode_txt[fypp->expr_mode],
+		//		exprt ? fy_expr_mode_txt[exprt->expr_mode] : "");
+
+#if 0
+		exprr = fy_expr_stack_peek(&fypp->operands);
+		if (exprr && exprt && fy_path_expr_order(exprr, exprt) <= 0)
+			exprr = NULL;
+		else
+#endif
+			exprr = fy_expr_stack_pop(&fypp->operands);
+		fyr_error_check(fyr, exprr, err_out,
+				"fy_expr_stack_pop() failed for exprr\n");
+
+#if 0
+		exprl = fy_expr_stack_peek_at(&fypp->operands, 1);
+		if (exprl && exprt && fy_path_expr_order(exprl, exprt) <= 0)
+			exprl = NULL;
+		else
+#endif
+			exprl = fy_expr_stack_pop(&fypp->operands);
+		fyr_error_check(fyr, exprl, err_out,
+				"fy_expr_stack_pop() failed for exprl\n");
+
+		/* we don't need the operator now */
+		fy_path_expr_free_recycle(fypp, expr);
+		expr = NULL;
+
+		ret = push_operand_lr(fypp, type, exprl, exprr, true);
+		fyr_error_check(fyr, !ret, err_out,
+				"push_operand_lr() failed\n");
+
+		break;
+
+	case fpet_filter_collection:
+	case fpet_filter_scalar:
+	case fpet_filter_sequence:
+	case fpet_filter_mapping:
+	case fpet_filter_unique:
+
+		exprl = fy_expr_stack_pop(&fypp->operands);
+		FYR_TOKEN_ERROR_CHECK(fyr, expr->fyt, FYEM_PARSE,
+				exprl, err_out,
+				"filter operator without argument");
+
+		exprr = fy_path_expr_alloc_recycle(fypp);
+		fyr_error_check(fyr, exprr, err_out,
+				"fy_path_expr_alloc_recycle() failed\n");
+		exprr->type = type;
+
+		/* move token to the filter collection */
+		exprr->fyt = expr->fyt;
+		expr->fyt = NULL;
+
+		/* we don't need the operator now */
+		fy_path_expr_free_recycle(fypp, expr);
+		expr = NULL;
+
+		/* push as a chain */
+		ret = push_operand_lr(fypp, fpet_chain, exprl, exprr, true);
+		fyr_error_check(fyr, !ret, err_out,
+				"push_operand_lr() failed\n");
+
+		break;
+
+	case fpet_lparen:
+		abort();
+		assert(0);
+
+#ifdef DEBUG_EXPR
+		FYR_TOKEN_DIAG(fyr, expr->fyt,
+			FYDF_NOTICE, FYEM_PARSE, "(");
+#endif
+
+		return 0;
+
+	case fpet_arg_separator:
+
+		/* separator is right hand side of the expression now */
+		exprr = expr;
+		expr = NULL;
+
+		/* evaluate until we hit a match to the rparen */
+		exprl = fy_expr_stack_peek(&fypp->operators);
+
+		if (!fy_path_expr_type_is_lparen(exprl->type)) {
+			ret = evaluate_new(fypp);
+			if (ret)
+				goto err_out;
+		}
+		exprl = NULL;
+
+		fy_path_expr_free_recycle(fypp, exprr);
+		exprr = NULL;
+
+		break;
+
+	case fpet_rparen:
+
+		/* rparen is right hand side of the expression now */
+		exprr = expr;
+		expr = NULL;
+
+		/* evaluate until we hit a match to the rparen */
+		while ((exprl = fy_expr_stack_peek(&fypp->operators)) != NULL) {
+
+			if (fy_path_expr_type_is_lparen(exprl->type))
+				break;
+
+			ret = evaluate_new(fypp);
+			if (ret)
+				goto err_out;
+		}
+
+		FYR_TOKEN_ERROR_CHECK(fyr, exprr->fyt, FYEM_PARSE,
+				exprl, err_out,
+				"missing matching left parentheses");
+
+		exprl = fy_expr_stack_pop(&fypp->operators);
+		assert(exprl);
+
+		exprt = fy_expr_stack_peek(&fypp->operands);
+
+		etype = exprl->expr_mode == fyem_scalar ? fpet_scalar_expr : fpet_path_expr;
+
+		/* already is an expression, reuse */
+		if (exprt && exprt->type == etype) {
+
+			fyt = expr_lr_to_token_mark(exprl, exprr, fypp->fyi);
+			fyr_error_check(fyr, fyt, err_out,
+					"expr_lr_to_token_mark() failed\n");
+			fy_token_unref(exprt->fyt);
+			exprt->fyt = fyt;
+			exprt->expr_mode = exprl->expr_mode;
+
+			/* we don't need the parentheses operators */
+			fy_path_expr_free_recycle(fypp, exprl);
+			exprl = NULL;
+			fy_path_expr_free_recycle(fypp, exprr);
+			exprr = NULL;
+
+			return 0;
+		}
+
+		/* if it's method, evaluate */
+		exprm = fy_expr_stack_peek(&fypp->operators);
+		if (exprm && exprm->type == fpet_method) {
+
+			exprm = fy_expr_stack_pop(&fypp->operators);
+			assert(exprm);
+
+			return evaluate_method(fypp, exprm, exprl, exprr);
+		}
+
+		expr = fy_path_expr_alloc_recycle(fypp);
+		fyr_error_check(fyr, expr, err_out,
+				"fy_path_expr_alloc_recycle() failed\n");
+		expr->type = etype;
+		expr->expr_mode = exprl->expr_mode;
+
+		expr->fyt = expr_lr_to_token_mark(exprl, exprr, fypp->fyi);
+
+		exprt = fy_expr_stack_pop(&fypp->operands);
+
+		FYR_TOKEN_ERROR_CHECK(fyr, exprr->fyt, FYEM_PARSE,
+				exprt, err_out,
+				"empty expression in parentheses");
+
+		fy_path_expr_list_add_tail(&expr->children, exprt);
+		exprt->parent = expr;
+
+		/* pop all operands that after exprl */
+		while ((exprt = fy_expr_stack_peek(&fypp->operands)) != NULL &&
+			fy_path_expr_order(exprt, exprl) >= 0) {
+#ifdef DEBUG_EXPR
+			FYR_TOKEN_DIAG(fyr, exprt->fyt,
+				FYDF_NOTICE, FYEM_PARSE, "discarding argument");
+#endif
+			fy_path_expr_free_recycle(fypp, fy_expr_stack_pop(&fypp->operands));
+		}
+
+		if (exprl->expr_mode != fyem_none) {
+			fypp->expr_mode = exprl->expr_mode;
+#ifdef DEBUG_EXPR
+			fyr_notice(fyr, "poping expr_mode %s\n", fy_expr_mode_txt[fypp->expr_mode]);
+#endif
+		}
+
+		/* we don't need the parentheses operators */
+		fy_path_expr_free_recycle(fypp, exprl);
+		exprl = NULL;
+		fy_path_expr_free_recycle(fypp, exprr);
+		exprr = NULL;
+
+		ret = push_operand(fypp, expr);
+		fyr_error_check(fyr, !ret, err_out,
+				"push_operand() failed\n");
+
+#ifdef DEBUG_EXPR
+		FYR_TOKEN_DIAG(fyr, expr->fyt,
+			FYDF_NOTICE, FYEM_PARSE, "pushed operand evaluate_new");
+#endif
+		return 0;
+
+	case fpet_method:
+		return evaluate_method(fypp, expr, NULL, NULL);
+
+		/* shoud never */
+	case fpet_scalar_expr:
+	case fpet_path_expr:
+		assert(0);
+		abort();
+
+	default:
+		fyr_error(fyr, "Unknown expression %s\n", fy_path_expr_type_txt[expr->type]);
+		goto err_out;
+	}
+
+	return 0;
+
+err_out:
+
+#ifdef DEBUG_EXPR
+	if (expr)
+		fy_path_expr_dump(expr, fypp->cfg.diag, FYET_NOTICE, 0, "expr:");
+	if (exprl)
+		fy_path_expr_dump(exprl, fypp->cfg.diag, FYET_NOTICE, 0, "exprl:");
+	if (exprr)
+		fy_path_expr_dump(exprr, fypp->cfg.diag, FYET_NOTICE, 0, "exprr:");
+	if (chain)
+		fy_path_expr_dump(chain, fypp->cfg.diag, FYET_NOTICE, 0, "chain:");
+	if (parent)
+		fy_path_expr_dump(parent, fypp->cfg.diag, FYET_NOTICE, 0, "parent:");
+
+	fy_notice(fypp->cfg.diag, "operator stack\n");
+	fy_expr_stack_dump(fypp->cfg.diag, &fypp->operators);
+	fy_notice(fypp->cfg.diag, "operand stack\n");
+	fy_expr_stack_dump(fypp->cfg.diag, &fypp->operands);
+#endif
+
+	fy_path_expr_free(expr);
+	fy_path_expr_free(exprl);
+	fy_path_expr_free(exprr);
+	fy_path_expr_free(chain);
+	fy_path_expr_free(parent);
+
+	return -1;
+}
+
+int fy_path_check_expression_alias(struct fy_path_parser *fypp, struct fy_path_expr *expr)
+{
+	struct fy_reader *fyr;
+	struct fy_path_expr *exprn;
+	int rc;
+
+	if (!expr)
+		return 0;
+
+	fyr = &fypp->reader;
+
+	/* an alias with a parent.. must be the first one */
+	if (expr->type == fpet_alias && expr->parent) {
+
+		exprn = fy_path_expr_list_head(&expr->parent->children);
+
+		/* an alias may only be the first of a path expression */
+		FYR_TOKEN_ERROR_CHECK(fyr, expr->fyt, FYEM_PARSE,
+				expr == exprn, err_out,
+				"alias is not first in the path expresion");
+	}
+
+	for (exprn = fy_path_expr_list_head(&expr->children); exprn;
+		exprn = fy_path_expr_next(&expr->children, exprn)) {
+
+		rc = fy_path_check_expression_alias(fypp, exprn);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+
+err_out:
+	return -1;
+}
+
+/* check expression for validity */
+int fy_path_check_expression(struct fy_path_parser *fypp, struct fy_path_expr *expr)
+{
+	int rc;
+
+	rc = fy_path_check_expression_alias(fypp, expr);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+struct fy_path_expr *
+fy_path_parse_expression(struct fy_path_parser *fypp)
+{
+	struct fy_reader *fyr;
+	struct fy_token *fyt = NULL;
+	enum fy_token_type fytt;
+	struct fy_path_expr *expr, *expr_top, *exprt;
+	enum fy_expr_mode old_scan_mode, prev_scan_mode;
+	int ret, rc;
+#ifdef DEBUG_EXPR
+    char *dbg;
+#endif
+
+	/* the parser must be in the correct state */
+	if (!fypp || fy_expr_stack_size(&fypp->operators) > 0 || fy_expr_stack_size(&fypp->operands) > 0)
+		return NULL;
+
+	fyr = &fypp->reader;
+
+	/* find stream start */
+	fyt = fy_path_scan_peek(fypp, NULL);
+	FYR_PARSE_ERROR_CHECK(fyr, 0, 1, FYEM_PARSE,
+			fyt && fyt->type == FYTT_STREAM_START, err_out,
+			"no tokens available or start without stream start");
+
+	/* remove stream start */
+	fy_token_unref(fy_path_scan_remove(fypp, fyt));
+	fyt = NULL;
+
+	prev_scan_mode = fypp->expr_mode;
+
+	while ((fyt = fy_path_scan_peek(fypp, NULL)) != NULL) {
+
+		if (fyt->type == FYTT_STREAM_END)
+			break;
+
+#ifdef DEBUG_EXPR
+        fy_token_debug_text_a(fyt, &dbg);
+		FYR_TOKEN_DIAG(fyr, fyt, FYET_NOTICE, FYEM_PARSE, "next token %s", dbg);
+#endif
+		fytt = fyt->type;
+
+		/* create an expression in either operator/operand case */
+		expr = fy_path_expr_alloc_recycle(fypp);
+		fyr_error_check(fyr, expr, err_out,
+				"fy_path_expr_alloc_recycle() failed\n");
+
+		expr->fyt = fy_path_scan_remove(fypp, fyt);
+		/* this it the first attempt, it might not be the final one */
+		expr->type = fy_map_token_to_path_expr_type(fyt->type, fypp->expr_mode);
+		fyt = NULL;
+
+#ifdef DEBUG_EXPR
+		fy_path_expr_dump(expr, fypp->cfg.diag, FYET_NOTICE, 0, "-> expr");
+#endif
+
+		if (prev_scan_mode != fypp->expr_mode) {
+#ifdef DEBUG_EXPR
+			fyr_warning(fyr, "switched expr_mode %s -> %s\n",
+					fy_expr_mode_txt[prev_scan_mode],
+					fy_expr_mode_txt[fypp->expr_mode]);
+#endif
+			expr_top = fy_expr_stack_peek(&fypp->operators);
+
+#ifdef DEBUG_EXPR
+			if (expr_top)
+				fy_path_expr_dump(expr_top, fypp->cfg.diag, FYET_NOTICE, 0, NULL);
+#endif
+
+			if (expr_top && fy_path_expr_type_is_lparen(expr_top->type) &&
+					expr_top->expr_mode != fypp->expr_mode) {
+#ifdef DEBUG_EXPR
+				fyr_warning(fyr, "switched top lparen expr_mode %s -> %s\n",
+						fy_expr_mode_txt[expr_top->expr_mode],
+						fy_expr_mode_txt[fypp->expr_mode]);
+				expr_top->expr_mode = fypp->expr_mode;
+#endif
+			}
+		}
+
+		prev_scan_mode = fypp->expr_mode;
+
+		/* if it's an operand convert it to expression and push */
+		if (fy_token_type_is_operand(fytt)) {
+
+			ret = fy_expr_stack_push(&fypp->operands, expr);
+			fyr_error_check(fyr, !ret, err_out, "push_operand() failed\n");
+			expr = NULL;
+
+			continue;
+		}
+
+		/* specials for SLASH */
+
+		if (expr->fyt->type == FYTT_PE_SLASH) {
+
+			/* try to get next token */
+			fyt = fy_path_scan_peek(fypp, NULL);
+			if (!fyt) {
+				if (!fypp->stream_error) {
+					(void)fy_path_fetch_tokens(fypp);
+					fyt = fy_path_scan_peek(fypp, NULL);
+				}
+			}
+
+			/* last token, it means it's a collection filter (or a root) */
+			if (!fyt || fyt->type == FYTT_STREAM_END || fyt->type == FYTT_PE_RPAREN) {
+
+				exprt = fy_expr_stack_peek(&fypp->operands);
+
+				/* if no argument exists it's a root */
+				if (!exprt) {
+					expr->type = fpet_root;
+
+					ret = fy_expr_stack_push(&fypp->operands, expr);
+					fyr_error_check(fyr, !ret, err_out, "push_operand() failed\n");
+					expr = NULL;
+					continue;
+				}
+
+				expr->type = fpet_filter_collection;
+			}
+		}
+
+#ifdef DEBUG_EXPR
+		fy_notice(fypp->cfg.diag, "operator stack (before)\n");
+		fy_expr_stack_dump(fypp->cfg.diag, &fypp->operators);
+		fy_notice(fypp->cfg.diag, "operand stack (before)\n");
+		fy_expr_stack_dump(fypp->cfg.diag, &fypp->operands);
+#endif
+
+		old_scan_mode = fypp->expr_mode;
+
+		/* for rparen, need to push before */
+		if (expr->type == fpet_rparen) {
+
+			FYR_TOKEN_ERROR_CHECK(fyr, expr->fyt, FYEM_PARSE,
+					fypp->paren_nest_level > 0, err_out,
+					"Mismatched right parentheses");
+
+			fypp->paren_nest_level--;
+
+			ret = fy_expr_stack_push(&fypp->operators, expr);
+			fyr_error_check(fyr, !ret, err_out, "push_operator() failed\n");
+			expr = NULL;
+
+			ret = evaluate_new(fypp);
+			/* evaluate will print diagnostic on error */
+			if (ret < 0)
+				goto err_out;
+
+		} else if (fy_path_expr_type_is_lparen(expr->type)) {
+
+			expr->expr_mode = fypp->expr_mode;
+			fypp->expr_mode = fyem_scalar;
+
+			fypp->paren_nest_level++;
+
+			/* push the operator */
+			ret = fy_expr_stack_push(&fypp->operators, expr);
+			fyr_error_check(fyr, !ret, err_out, "push_operator() failed\n");
+			expr = NULL;
+
+#ifdef DEBUG_EXPR
+			if (old_scan_mode != fypp->expr_mode)
+				fyr_notice(fyr, "expr_mode %s -> %s\n",
+						fy_expr_mode_txt[old_scan_mode],
+						fy_expr_mode_txt[fypp->expr_mode]);
+#endif
+		} else {
+			switch (fypp->expr_mode) {
+			case fyem_none:
+				assert(0);	/* should never happen */
+				break;
+
+			case fyem_path:
+				if (fy_path_expr_type_is_conditional(expr->type)) {
+					/* switch to scalar mode */
+					fypp->expr_mode = fyem_scalar;
+					break;
+				}
+				break;
+			case fyem_scalar:
+				if (expr->type == fpet_root) {
+					fypp->expr_mode = fyem_path;
+					break;
+				}
+
+				/* div out of parentheses, it's a chain */
+				if (expr->type == fpet_div && fypp->paren_nest_level == 0) {
+					expr->type = fpet_chain;
+					fypp->expr_mode = fyem_path;
+
+					/* mode change means evaluate */
+					ret = evaluate_new(fypp);
+					/* evaluate will print diagnostic on error */
+					if (ret < 0)
+						goto err_out;
+
+					break;
+				}
+				break;
+			}
+
+			if (old_scan_mode != fypp->expr_mode) {
+#ifdef DEBUG_EXPR
+				fyr_notice(fyr, "expr_mode %s -> %s\n",
+						fy_expr_mode_txt[old_scan_mode],
+						fy_expr_mode_txt[fypp->expr_mode]);
+#endif
+			}
+
+			ret = -1;
+			while ((expr_top = fy_expr_stack_peek(&fypp->operators)) != NULL &&
+				fy_path_expr_type_prec(expr->type) <= fy_path_expr_type_prec(expr_top->type) &&
+				!fy_path_expr_type_is_lparen(expr_top->type)) {
+
+				ret = evaluate_new(fypp);
+				/* evaluate will print diagnostic on error */
+				if (ret < 0)
+					goto err_out;
+			}
+
+			/* push the operator */
+			ret = fy_expr_stack_push(&fypp->operators, expr);
+			fyr_error_check(fyr, !ret, err_out, "push_operator() failed\n");
+			expr = NULL;
+		}
+
+#ifdef DEBUG_EXPR
+		fy_notice(fypp->cfg.diag, "operator stack (after)\n");
+		fy_expr_stack_dump(fypp->cfg.diag, &fypp->operators);
+		fy_notice(fypp->cfg.diag, "operand stack (after)\n");
+		fy_expr_stack_dump(fypp->cfg.diag, &fypp->operands);
+#endif
+
+		prev_scan_mode = fypp->expr_mode;
+	}
+
+	if (fypp->stream_error)
+		goto err_out;
+
+	FYR_PARSE_ERROR_CHECK(fyr, 0, 1, FYEM_PARSE,
+			fypp->stream_error || (fyt && fyt->type == FYTT_STREAM_END), err_out,
+			"stream ended without STREAM_END");
+
+	/* remove stream end */
+	fy_token_unref(fy_path_scan_remove(fypp, fyt));
+	fyt = NULL;
+
+#if 0
+	FYR_PARSE_ERROR_CHECK(fyr, 0, 1, FYEM_PARSE,
+			fypp->paren_nest_level == 0, err_out,
+			"Missing right parenthesis");
+#endif
+
+	/* drain */
+	while ((expr_top = fy_expr_stack_peek(&fypp->operators)) != NULL &&
+		!fy_path_expr_type_is_lparen(expr_top->type)) {
+
+		ret = evaluate_new(fypp);
+		/* evaluate will print diagnostic on error */
+		if (ret < 0)
+			goto err_out;
+
+	}
+
+#ifdef DEBUG_EXPR
+	expr_top = fy_expr_stack_peek(&fypp->operators);
+	if (expr_top)
+		fy_path_expr_dump(expr_top, fypp->cfg.diag, FYET_NOTICE, 0, "operator top left");
+#endif
+
+	expr = fy_expr_stack_pop(&fypp->operands);
+
+	FYR_PARSE_ERROR_CHECK(fyr, 0, 1, FYEM_PARSE,
+			expr != NULL, err_out,
+			"No operands left on operand stack");
+
+	FYR_TOKEN_ERROR_CHECK(fyr, expr->fyt, FYEM_PARSE,
+			fy_expr_stack_size(&fypp->operands) == 0, err_out,
+			"Operand stack contains more than 1 value at end");
+
+	/* check the expression for validity */
+	rc = fy_path_check_expression(fypp, expr);
+	if (rc) {
+		fy_path_expr_free(expr);
+		expr = NULL;
+	}
+
+	return expr;
+
+err_out:
+#ifdef DEBUG_EXPR
+	fy_notice(fypp->cfg.diag, "operator stack (error)\n");
+	fy_expr_stack_dump(fypp->cfg.diag, &fypp->operators);
+	fy_notice(fypp->cfg.diag, "operand stack (error)\n");
+	fy_expr_stack_dump(fypp->cfg.diag, &fypp->operands);
+#endif
+	fypp->stream_error = true;
+	return NULL;
+}
+
+static struct fy_node *
+fy_path_expr_execute_single_result(struct fy_diag *diag, struct fy_path_expr *expr, struct fy_node *fyn)
+{
+	struct fy_token *fyt;
+	struct fy_anchor *fya;
+	const char *text;
+	size_t len;
+
+	assert(expr);
+
+	switch (expr->type) {
+	case fpet_root:
+		return fyn->fyd->root;
+
+	case fpet_this:
+		if (fy_node_is_alias(fyn)) {
+			// fprintf(stderr, "%s:%d %s calling fy_node_alias_resolve_by_ypath()\n", __func__, __LINE__, fy_node_get_path_alloca(fyn));
+			fyn = fy_node_alias_resolve_by_ypath(fyn);
+		}
+
+		return fyn;
+
+	case fpet_parent:
+		return fy_node_get_parent(fyn);
+
+	case fpet_alias:
+		fyt = expr->fyt;
+		assert(fyt);
+		assert(fyt->type == FYTT_PE_ALIAS);
+
+		text = fy_token_get_text(fyt, &len);
+		if (!text || len < 1)
+			break;
+
+		if (*text == '*') {
+			text++;
+			len--;
+		}
+		fya = fy_document_lookup_anchor(fyn->fyd, text, len);
+		if (!fya)
+			break;
+		return fya->fyn;
+
+	case fpet_seq_index:
+		fyt = expr->fyt;
+		assert(fyt);
+		assert(fyt->type == FYTT_PE_SEQ_INDEX);
+
+		if (fy_node_is_alias(fyn)) {
+			// fprintf(stderr, "%s:%d %s calling fy_node_alias_resolve_by_ypath()\n", __func__, __LINE__, fy_node_get_path_alloca(fyn));
+			fyn = fy_node_alias_resolve_by_ypath(fyn);
+		}
+
+		/* only on sequence */
+		if (!fy_node_is_sequence(fyn))
+			break;
+
+		return fy_node_sequence_get_by_index(fyn, fyt->seq_index.index);
+
+	case fpet_map_key:
+		fyt = expr->fyt;
+		assert(fyt);
+		assert(fyt->type == FYTT_PE_MAP_KEY);
+
+		if (fy_node_is_alias(fyn)) {
+			// fprintf(stderr, "%s:%d %s calling fy_node_alias_resolve_by_ypath()\n", __func__, __LINE__, fy_node_get_path_alloca(fyn));
+			fyn = fy_node_alias_resolve_by_ypath(fyn);
+		}
+
+		if (!fy_node_is_mapping(fyn))
+			break;
+
+		if (!fyt->map_key.fyd) {
+			/* simple key */
+			text = fy_token_get_text(fyt, &len);
+			if (!text || len < 1)
+				break;
+			return fy_node_mapping_lookup_value_by_simple_key(fyn, text, len);
+		}
+
+		return fy_node_mapping_lookup_value_by_key(fyn, fyt->map_key.fyd->root);
+
+	case fpet_filter_scalar:
+		if (!(fy_node_is_scalar(fyn) || fy_node_is_alias(fyn)))
+			break;
+		return fyn;
+
+	case fpet_filter_collection:
+
+		if (fy_node_is_alias(fyn)) {
+			// fprintf(stderr, "%s:%d %s calling fy_node_alias_resolve_by_ypath()\n", __func__, __LINE__, fy_node_get_path_alloca(fyn));
+			fyn = fy_node_alias_resolve_by_ypath(fyn);
+		}
+
+		if (!(fy_node_is_mapping(fyn) || fy_node_is_sequence(fyn)))
+			break;
+		return fyn;
+
+	case fpet_filter_sequence:
+
+		if (fy_node_is_alias(fyn)) {
+			// fprintf(stderr, "%s:%d %s calling fy_node_alias_resolve_by_ypath()\n", __func__, __LINE__, fy_node_get_path_alloca(fyn));
+			fyn = fy_node_alias_resolve_by_ypath(fyn);
+		}
+
+		if (!fy_node_is_sequence(fyn))
+			break;
+		return fyn;
+
+	case fpet_filter_mapping:
+
+		if (fy_node_is_alias(fyn)) {
+			// fprintf(stderr, "%s:%d %s calling fy_node_alias_resolve_by_ypath()\n", __func__, __LINE__, fy_node_get_path_alloca(fyn));
+			fyn = fy_node_alias_resolve_by_ypath(fyn);
+		}
+
+		if (!fy_node_is_mapping(fyn))
+			break;
+		return fyn;
+
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+static double
+token_number(struct fy_token *fyt)
+{
+	const char *value;
+
+	if (!fyt || fyt->type != FYTT_SCALAR || (value = fy_token_get_text0(fyt)) == NULL)
+		return NAN;
+	return strtod(value, NULL);
+}
+
+void fy_path_exec_cleanup(struct fy_path_exec *fypx)
+{
+	if (!fypx)
+		return;
+
+	fy_walk_result_free(fypx->result);
+	fypx->result = NULL;
+	fypx->fyn_start = NULL;
+}
+
+/* publicly exported methods */
+struct fy_path_parser *fy_path_parser_create(const struct fy_path_parse_cfg *pcfg)
+{
+	struct fy_path_parser *fypp;
+
+	fypp = malloc(sizeof(*fypp));
+	if (!fypp)
+		return NULL;
+	fy_path_parser_setup(fypp, pcfg);
+	return fypp;
+}
+
+void fy_path_parser_destroy(struct fy_path_parser *fypp)
+{
+	if (!fypp)
+		return;
+	fy_path_parser_cleanup(fypp);
+	free(fypp);
+}
+
+int fy_path_parser_reset(struct fy_path_parser *fypp)
+{
+	if (!fypp)
+		return -1;
+	fy_path_parser_cleanup(fypp);
+	return 0;
+}
+
+struct fy_path_expr *
+fy_path_parse_expr_from_string(struct fy_path_parser *fypp,
+			       const char *str, size_t len)
+{
+	struct fy_path_expr *expr = NULL;
+	struct fy_input *fyi = NULL;
+	int rc;
+
+	if (!fypp || !str || !len)
+		return NULL;
+
+	fy_path_parser_reset(fypp);
+
+	fyi = fy_input_from_data(str, len, NULL, false);
+	if (!fyi) {
+		fy_error(fypp->cfg.diag, "failed to create ypath input from %.*s\n",
+				(int)len, str);
+		goto err_out;
+	}
+
+	rc = fy_path_parser_open(fypp, fyi, NULL);
+	if (rc) {
+		fy_error(fypp->cfg.diag, "failed to open path parser input from %.*s\n",
+				(int)len, str);
+		goto err_out;
+	}
+
+	expr = fy_path_parse_expression(fypp);
+	if (!expr) {
+		fy_error(fypp->cfg.diag, "failed to parse path expression %.*s\n",
+				(int)len, str);
+		goto err_out;
+	}
+
+	fy_path_parser_close(fypp);
+
+	fy_input_unref(fyi);
+
+	return expr;
+
+err_out:
+	fy_path_expr_free(expr);
+	fy_path_parser_close(fypp);
+	fy_input_unref(fyi);
+	return NULL;
+}
+
+struct fy_path_expr *
+fy_path_expr_build_from_string(const struct fy_path_parse_cfg *pcfg,
+			       const char *str, size_t len)
+{
+	struct fy_path_parser fypp_data, *fypp = &fypp_data;
+	struct fy_path_expr *expr = NULL;
+
+	if (!str)
+		return NULL;
+
+	fy_path_parser_setup(fypp, pcfg);
+	expr = fy_path_parse_expr_from_string(fypp, str, len);
+	fy_path_parser_cleanup(fypp);
+
+	return expr;
+}
+
+struct fy_path_exec *fy_path_exec_create(const struct fy_path_exec_cfg *xcfg)
+{
+	struct fy_path_exec *fypx;
+
+	fypx = malloc(sizeof(*fypx));
+	if (!fypx)
+		return NULL;
+
+	memset(fypx, 0, sizeof(*fypx));
+	if (xcfg)
+		fypx->cfg = *xcfg;
+	fypx->fwr_recycle = NULL;	/* initially no recycling list */
+	fypx->refs = 1;
+
+	fypx->supress_recycling = !!(fypx->cfg.flags & FYPXCF_DISABLE_RECYCLING) ||
+		                  (getenv("FY_VALGRIND") &&
+				   !getenv("FY_VALGRIND_RECYCLING"));
+	return fypx;
+}
+
+struct fy_path_exec *fy_path_exec_create_on_document(struct fy_document *fyd)
+{
+	struct fy_path_exec_cfg xcfg_local, *xcfg = &xcfg_local;
+	struct fy_path_exec *fypx;
+
+	memset(xcfg, 0, sizeof(*xcfg));
+	xcfg->diag = fyd ? fyd->diag : NULL;
+
+	xcfg->flags = (fyd->parse_cfg.flags & FYPCF_DISABLE_RECYCLING) ?
+			FYPXCF_DISABLE_RECYCLING : 0;
+
+	fypx = fy_path_exec_create(xcfg);
+	if (!fypx)
+		return NULL;
+	return fypx;
+}
+
+void fy_path_exec_destroy(struct fy_path_exec *fypx)
+{
+	if (!fypx)
+		return;
+	fy_path_exec_cleanup(fypx);
+	free(fypx);
+}
+
+int fy_path_exec_reset(struct fy_path_exec *fypx)
+{
+	if (!fypx)
+		return -1;
+	fy_path_exec_cleanup(fypx);
+	return 0;
+}
+
+struct fy_walk_result *fy_walk_result_simplify(struct fy_walk_result *fwr)
+{
+	struct fy_walk_result *fwr2;
+#if 0
+	struct fy_walk_result *fwrf;
+	bool recursive;
+#endif
+
+	/* no fwr */
+	if (!fwr)
+		return NULL;
+
+	/* non recursive */
+	if (fwr->type != fwrt_refs)
+		return fwr;
+
+	/* refs, if empty, return NULL */
+	if (fy_walk_result_list_empty(&fwr->refs)) {
+		fy_walk_result_free(fwr);
+		return NULL;
+	}
+
+	/* single element, switch it out */
+	if (fy_walk_result_list_is_singular(&fwr->refs)) {
+		fwr2 = fy_walk_result_list_pop(&fwr->refs);
+		assert(fwr2);
+
+		fy_walk_result_free(fwr);
+		fwr = fwr2;
+	}
+
+	return fwr;
+#if 0
+	/* non recursive return immediately */
+	if (fwr->type != fwrt_refs)
+		return fwr;
+
+	/* flatten if recursive */
+	recursive = false;
+	for (fwr2 = fy_walk_result_list_head(&fwr->refs); fwr2;
+		fwr2 = fy_walk_result_next(&fwr->refs, fwr2)) {
+
+		/* refs, recursive */
+		if (fwr2->type == fwrt_refs) {
+			recursive = true;
+			break;
+		}
+	}
+
+	if (!recursive)
+		return fwr;
+
+	fwrf = fy_path_exec_walk_result_create(fypx, fwrt_refs);
+	assert(fwrf);
+
+	fy_walk_result_flatten_internal(fwr, fwrf);
+
+	fy_walk_result_free(fwr);
+	return fwrf;
+#endif
+
+}
+
+int fy_walk_result_all_children_recursive_internal(struct fy_path_exec *fypx, struct fy_node *fyn, struct fy_walk_result *output)
+{
+	struct fy_node *fyni;
+	struct fy_walk_result *fwr;
+	void *prevp;
+	int ret;
+
+	if (!fyn)
+		return 0;
+
+	assert(output);
+	assert(output->type == fwrt_refs);
+
+	/* this node */
+	fwr = fy_path_exec_walk_result_create(fypx, fwrt_node_ref, fyn);
+	if (!fwr)
+		return -1;
+	fy_walk_result_list_add_tail(&output->refs, fwr);
+
+	if (fy_node_is_scalar(fyn))
+		return 0;
+
+	prevp = NULL;
+	while ((fyni = fy_node_collection_iterate(fyn, &prevp)) != NULL) {
+		ret = fy_walk_result_all_children_recursive_internal(fypx, fyni, output);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+bool
+fy_walk_result_compare_simple(struct fy_path_exec *fypx, enum fy_path_expr_type type,
+			      struct fy_walk_result *fwrl, struct fy_walk_result *fwrr)
+{
+	struct fy_token *fyt;
+	struct fy_walk_result *fwrt;
+	const char *str;
+	bool match;
+
+	/* both NULL */
+	if (!fwrl && !fwrr) {
+		switch (type) {
+		case fpet_eq:
+			return true;
+		default:
+			break;
+		}
+		return false;
+	}
+
+	/* any NULL */
+	if (!fwrl || !fwrr) {
+		switch (type) {
+		case fpet_neq:
+			return true;
+		default:
+			break;
+		}
+		return false;
+	}
+
+	/* both are non NULL */
+
+	/* none should be multiple */
+	assert(fwrl->type != fwrt_refs && fwrr->type != fwrt_refs);
+
+	/* both are the same type */
+	if (fwrl->type == fwrr->type) {
+
+		switch (fwrl->type) {
+		case fwrt_none:
+			abort();	/* should never happen */
+			break;
+
+		case fwrt_node_ref:
+			switch (type) {
+			case fpet_eq:
+				/* simple and fast direct node comparison */
+				if (fwrl->fyn == fwrr->fyn)
+					return true;
+				return fy_node_compare(fwrl->fyn, fwrr->fyn);
+			case fpet_neq:
+				/* simple and fast direct node comparison */
+				if (fwrl->fyn != fwrr->fyn)
+					return true;
+				return !fy_node_compare(fwrl->fyn, fwrr->fyn);
+			default:
+				break;
+			}
+			break;
+
+		case fwrt_refs:
+			assert(0);	/* should not get here */
+			break;
+
+		case fwrt_doc:
+			switch (type) {
+			case fpet_eq:
+			case fpet_neq:
+				match = false;
+				if (fwrl->fyd == fwrr->fyd)
+					match = true;
+				else if (!fwrl->fyd || !fwrr->fyd)
+					match = false;
+				else
+					match = fy_node_compare(fwrl->fyd->root, fwrr->fyd->root);
+				if (type == fpet_neq)
+					match = !match;
+				return match;
+			default:
+				break;
+			}
+			break;
+
+		case fwrt_number:
+			switch (type) {
+			case fpet_eq:
+				return fwrl->number == fwrr->number;
+			case fpet_neq:
+				return fwrl->number != fwrr->number;
+			case fpet_lt:
+				return fwrl->number < fwrr->number;
+			case fpet_gt:
+				return fwrl->number > fwrr->number;
+			case fpet_lte:
+				return fwrl->number <= fwrr->number;
+			case fpet_gte:
+				return fwrl->number >= fwrr->number;
+			default:
+				break;
+			}
+			break;
+
+		case fwrt_string:
+			switch (type) {
+			case fpet_eq:
+				return strcmp(fwrl->string, fwrr->string) == 0;
+			case fpet_neq:
+				return strcmp(fwrl->string, fwrr->string) != 0;
+			case fpet_lt:
+				return strcmp(fwrl->string, fwrr->string) < 0;
+			case fpet_gt:
+				return strcmp(fwrl->string, fwrr->string) > 0;
+			case fpet_lte:
+				return strcmp(fwrl->string, fwrr->string) <= 0;
+			case fpet_gte:
+				return strcmp(fwrl->string, fwrr->string) >= 0;
+			default:
+				break;
+			}
+			break;
+		}
+		return false;
+	}
+
+	/* only handle the node refs at the left */
+	if (fwrr->type == fwrt_node_ref) {
+		switch (type) {
+		case fpet_lt:
+			type = fpet_gte;
+			break;
+		case fpet_gt:
+			type = fpet_lte;
+			break;
+		case fpet_lte:
+			type = fpet_gt;
+			break;
+		case fpet_gte:
+			type = fpet_lt;
+			break;
+		default:
+			break;
+		}
+
+		/* swap left with right */
+		return fy_walk_result_compare_simple(fypx, type, fwrr, fwrl);
+	}
+
+	switch (fwrl->type) {
+	case fwrt_node_ref:
+
+		/* non scalar mode, only returns true for non-eq */
+		if (!fy_node_is_scalar(fwrl->fyn)) {
+			/* XXX case of rhs being a document not handled */
+			return type == fpet_neq;
+		}
+
+		fyt = fy_node_get_scalar_token(fwrl->fyn);
+		assert(fyt);
+
+		str = fy_token_get_text0(fyt);
+		assert(str);
+
+		fwrt = NULL;
+		/* node ref against */
+		switch (fwrr->type) {
+		case fwrt_string:
+			/* create a new temporary walk result */
+			fwrt = fy_path_exec_walk_result_create(fypx, fwrt_string, str);
+			assert(fwrt);
+
+			break;
+
+		case fwrt_number:
+			/* if it's not a number return true only for non-eq */
+			if (!fy_token_is_number(fyt))
+				return type == fpet_neq;
+
+			/* create a new temporary walk result */
+			fwrt = fy_path_exec_walk_result_create(fypx, fwrt_number, strtod(str, NULL));
+			assert(fwrt);
+			break;
+
+		default:
+			break;
+		}
+
+		if (!fwrt)
+			return false;
+
+		match = fy_walk_result_compare_simple(fypx, type, fwrt, fwrr);
+
+		/* free the temporary result */
+		fy_walk_result_free(fwrt);
+
+		return match;
+
+	default:
+		break;
+	}
+
+	return false;
+}
+
+struct fy_walk_result *
+fy_walk_result_arithmetic_simple(struct fy_path_exec *fypx,
+				 struct fy_path_expr *expr,
+				 struct fy_path_expr *exprl, struct fy_walk_result *fwrl,
+				 struct fy_path_expr *exprr, struct fy_walk_result *fwrr)
+{
+	struct fy_diag *diag;
+	struct fy_walk_result *output = NULL;
+	char *str;
+	size_t len, len1, len2;
+
+	if (!fwrl || !fwrr)
+		goto out;
+
+	diag = fypx->cfg.diag;
+
+	/* node refs are not handled yet */
+	if (fwrl->type == fwrt_node_ref || fwrr->type == fwrt_node_ref)
+		goto out;
+
+	/* same type */
+	if (fwrl->type == fwrr->type) {
+
+		switch (fwrl->type) {
+
+		case fwrt_string:
+			/* for strings, only concatenation */
+			if (expr->type != fpet_plus)
+				break;
+			len1 = strlen(fwrl->string);
+			len2 = strlen(fwrr->string);
+			len = len1 + len2;
+			str = malloc(len + 1);
+			assert(str);
+			memcpy(str, fwrl->string, len1);
+			memcpy(str + len1, fwrr->string, len2);
+			str[len] = '\0';
+
+			free(fwrl->string);
+			fwrl->string = str;
+
+			/* reuse */
+			output = fwrl;
+			fwrl = NULL;
+
+			break;
+
+		case fwrt_number:
+			/* reuse fwrl */
+			output = fwrl;
+			switch (expr->type) {
+			case fpet_plus:
+				output->number = fwrl->number + fwrr->number;
+				break;
+			case fpet_minus:
+				output->number = fwrl->number - fwrr->number;
+				break;
+			case fpet_mult:
+				output->number = fwrl->number * fwrr->number;
+				break;
+			case fpet_div:
+				output->number = fwrr->number ? (fwrl->number / fwrr->number) : INFINITY;
+				break;
+			default:
+				assert(0);
+				break;
+			}
+			fwrl = NULL;
+			break;
+
+		default:
+			fy_error(diag, "fwrl->type=%s\n", fy_walk_result_type_txt[fwrl->type]);
+			assert(0);
+			break;
+		}
+	}
+
+out:
+	fy_walk_result_free(fwrl);
+	fy_walk_result_free(fwrr);
+	return output;
+}
+
+struct fy_walk_result *
+fy_walk_result_conditional_simple(struct fy_path_exec *fypx,
+				  struct fy_path_expr *expr,
+				  struct fy_path_expr *exprl, struct fy_walk_result *fwrl,
+				  struct fy_path_expr *exprr, struct fy_walk_result *fwrr)
+{
+	bool match;
+
+	match = fy_walk_result_compare_simple(fypx, expr->type, fwrl, fwrr);
+
+	if (!match) {
+		fy_walk_result_free(fwrl);
+		fy_walk_result_free(fwrr);
+		return NULL;
+	}
+
+	/* path expr, return left hand side result */
+	fy_walk_result_free(fwrr);
+	return fwrl;
+}
+
+struct fy_walk_result *
+fy_walk_result_lhs_rhs(struct fy_path_exec *fypx,
+		       struct fy_path_expr *expr,
+		       struct fy_path_expr *exprl, struct fy_walk_result *fwrl,
+		       struct fy_path_expr *exprr, struct fy_walk_result *fwrr)
+{
+	struct fy_walk_result *output = NULL, *fwr, *fwrrt, *fwrlt, *fwrlc, *fwrrc;
+	struct fy_walk_result *outputl = NULL, *outputr = NULL;
+
+	assert(expr);
+	assert(exprl);
+	assert(exprr);
+
+	/* only supports those */
+	if (!fy_path_expr_type_is_conditional(expr->type) &&
+	    !fy_path_expr_type_is_arithmetic(expr->type))
+		goto out;
+
+	/* both NULL */
+	if (!fwrl && !fwrr)
+		goto out;
+
+	/* any NULL */
+	if (!fwrl || !fwrr) {
+		if (expr->type == fpet_neq) {
+			output = fwrl;
+			fwrl = NULL;
+		}
+		goto out;
+	}
+
+	output = fy_path_exec_walk_result_create(fypx, fwrt_refs);
+	assert(output);
+
+	for (fwrlt = fy_walk_result_iter_start(fwrl); fwrlt;
+			fwrlt = fy_walk_result_iter_next(fwrl, fwrlt)) {
+
+		/* for recursive ones */
+		if (fwrlt->type == fwrt_refs) {
+
+			fwrlc = fy_walk_result_clone(fwrlt);
+			assert(fwrlc);
+			fwrrc = fy_walk_result_clone(fwrr);
+			assert(fwrrc);
+
+			outputl = fy_walk_result_lhs_rhs(fypx, expr, exprl, fwrlc, exprr, fwrrc);
+			if (outputl)
+				fy_walk_result_list_add_tail(&output->refs, outputl);
+			else
+				fy_walk_result_free(outputl);
+			continue;
+		}
+
+		/* non-recursive case */
+		for (fwrrt = fy_walk_result_iter_start(fwrr); fwrrt;
+				fwrrt = fy_walk_result_iter_next(fwrr, fwrrt)) {
+
+			/* for recursive ones */
+			if (fwrrt->type == fwrt_refs) {
+
+				fwrlc = fy_walk_result_clone(fwrlt);
+				assert(fwrlc);
+				fwrrc = fy_walk_result_clone(fwrrt);
+				assert(fwrrc);
+
+				outputr = fy_walk_result_lhs_rhs(fypx, expr, exprl, fwrlc, exprr, fwrrc);
+				if (outputr)
+					fy_walk_result_list_add_tail(&output->refs, outputr);
+				else
+					fy_walk_result_free(outputr);
+				continue;
+			}
+
+
+			fwrlc = fy_walk_result_clone(fwrlt);
+			assert(fwrlc);
+			fwrrc = fy_walk_result_clone(fwrrt);
+			assert(fwrrc);
+
+			fwr = NULL;
+
+			if (fy_path_expr_type_is_conditional(expr->type))
+				fwr = fy_walk_result_conditional_simple(fypx, expr, exprl, fwrlc, exprr, fwrrc);
+			else if (fy_path_expr_type_is_arithmetic(expr->type))
+				fwr = fy_walk_result_arithmetic_simple(fypx, expr, exprl, fwrlc, exprr, fwrrc);
+			else {
+				assert(0);
+			}
+
+			fwrlc = NULL;
+			fwrrc = NULL;
+
+			if (fwr)
+				fy_walk_result_list_add_tail(&output->refs, fwr);
+		}
+	}
+
+out:
+	fy_walk_result_free(fwrl);
+	fy_walk_result_free(fwrr);
+
+	return fy_walk_result_simplify(output);
+}
+
+struct fy_path_expr *
+fy_scalar_walk_result_to_expr(struct fy_path_exec *fypx, struct fy_walk_result *fwr, enum fy_path_expr_type ptype)
+{
+	struct fy_input *fyit = NULL;
+	struct fy_path_expr *exprt = NULL;
+	struct fy_atom handle;
+	bool collection_addressing;
+	char *buf;
+	int rc __FY_DEBUG_UNUSED__;
+
+	exprt = NULL;
+
+	if (!fwr)
+		return NULL;
+
+	collection_addressing = ptype == fpet_chain || ptype == fpet_multi;
+
+	switch (fwr->type) {
+	case fwrt_string:
+		fyit = fy_input_from_malloc_data(fwr->string, FY_NT, &handle, true);
+		assert(fyit);
+
+		fwr->string = NULL;
+		fy_walk_result_free(fwr);
+		fwr = NULL;
+
+		exprt = fy_path_expr_alloc();
+		assert(exprt);
+		if (collection_addressing) {
+			exprt->type = fpet_map_key;
+			exprt->fyt = fy_token_create(FYTT_PE_MAP_KEY, &handle, NULL);
+			assert(exprt->fyt);
+		} else {
+			exprt->type = fpet_scalar;
+			exprt->fyt = fy_token_create(FYTT_SCALAR, &handle, FYSS_PLAIN, NULL);
+			assert(exprt->fyt);
+		}
+		break;
+
+	case fwrt_number:
+
+		rc = asprintf(&buf, "%d", (int)fwr->number);
+		assert(rc != -1);
+
+		fyit = fy_input_from_malloc_data(buf, FY_NT, &handle, true);
+		assert(fyit);
+
+		exprt = fy_path_expr_alloc();
+		assert(exprt);
+		if (collection_addressing) {
+			exprt->type = fpet_seq_index;
+			exprt->fyt = fy_token_create(FYTT_PE_SEQ_INDEX, &handle, (int)fwr->number);
+			assert(exprt->fyt);
+		} else {
+			exprt->type = fpet_scalar;
+			exprt->fyt = fy_token_create(FYTT_SCALAR, &handle, FYSS_PLAIN, NULL);
+			assert(exprt->fyt);
+		}
+
+		break;
+
+	default:
+		break;
+	}
+
+	fy_walk_result_free(fwr);
+	fy_input_unref(fyit);
+
+	return exprt;
+}
+
+struct fy_walk_result *
+fy_path_expr_execute(struct fy_path_exec *fypx, int level, struct fy_path_expr *expr,
+		     struct fy_walk_result *input, enum fy_path_expr_type ptype)
+{
+	struct fy_diag *diag;
+	struct fy_walk_result *fwr, *fwrn, *fwrt, *fwrtn;
+	struct fy_walk_result *output = NULL, *input1, *output1, *input2, *output2;
+	struct fy_path_expr *exprn, *exprl, *exprr;
+	struct fy_node *fyn, *fynn, *fyni;
+	struct fy_token *fyt;
+	int start, end, count, i;
+	bool match;
+	struct fy_path_expr *exprt;
+	unsigned int nargs;
+	struct fy_walk_result **fwr_args;
+	void *prevp;
+	int rc __FY_DEBUG_UNUSED__;
+
+	/* error */
+	if (!fypx || !expr)
+		goto out;
+
+	diag = fypx->cfg.diag;
+
+#ifdef DEBUG_EXPR
+	if (input)
+		fy_walk_result_dump(input, diag, FYET_NOTICE, level, "input %s\n", fy_path_expr_type_txt[expr->type]);
+#endif
+
+	/* recursive */
+	if (input && input->type == fwrt_refs && !fy_path_expr_type_handles_refs(expr->type)) {
+
+		output = fy_path_exec_walk_result_create(fypx, fwrt_refs);
+		assert(output);
+
+		while ((fwr = fy_walk_result_list_pop(&input->refs)) != NULL) {
+
+			fwrn = fy_path_expr_execute(fypx, level + 1, expr, fwr, ptype);
+			if (fwrn)
+				fy_walk_result_list_add_tail(&output->refs, fwrn);
+		}
+		fy_walk_result_free(input);
+		input = NULL;
+		goto out;
+	}
+
+
+	/* single result case is common enough to optimize */
+	if (fy_path_expr_type_is_single_result(expr->type)) {
+
+		if (input && input->type == fwrt_node_ref) {
+
+			fynn = fy_path_expr_execute_single_result(diag, expr, input->fyn);
+			if (!fynn)
+				goto out;
+
+			fy_walk_result_clean(input);
+			output = input;
+			output->type = fwrt_node_ref;
+			output->fyn = fynn;
+			input = NULL;
+		}
+
+		goto out;
+	}
+
+	/* handle the remaining multi result cases */
+	switch (expr->type) {
+
+	case fpet_chain:
+
+		if (!input)
+			goto out;
+
+		/* iterate over each chain item */
+		output = input;
+		input = NULL;
+		for (exprn = fy_path_expr_list_head(&expr->children); exprn;
+			exprn = fy_path_expr_next(&expr->children, exprn)) {
+
+			output = fy_path_expr_execute(fypx, level + 1, exprn, output, expr->type);
+			if (!output)
+				break;
+		}
+
+		break;
+
+	case fpet_multi:
+
+		if (!input)
+			goto out;
+
+		/* allocate a refs output result */
+		output = fy_path_exec_walk_result_create(fypx, fwrt_refs);
+		assert(output);
+
+		/* iterate over each multi item */
+		for (exprn = fy_path_expr_list_head(&expr->children); exprn;
+			exprn = fy_path_expr_next(&expr->children, exprn)) {
+
+			input2 = fy_walk_result_clone(input);
+			assert(input2);
+
+			output2 = fy_path_expr_execute(fypx, level + 1, exprn, input2, expr->type);
+			if (!output2)
+				continue;
+
+			fy_walk_result_list_add_tail(&output->refs, output2);
+		}
+		fy_walk_result_free(input);
+		input = NULL;
+		break;
+
+	case fpet_every_child:
+
+		if (!input)
+			goto out;
+
+		/* only valid for node ref */
+		if (input->type != fwrt_node_ref)
+			break;
+
+		fyn = input->fyn;
+
+		/* every scalar/alias is a single result (although it should not happen) */
+		if (fy_node_is_scalar(fyn) || fy_node_is_alias(fyn)) {
+			output = input;
+			input = NULL;
+			break;
+
+		}
+
+		/* re-use input for output root */
+		fy_walk_result_clean(input);
+		output = input;
+		input = NULL;
+
+		output->type = fwrt_refs;
+		fy_walk_result_list_init(&output->refs);
+
+		prevp = NULL;
+		while ((fyni = fy_node_collection_iterate(fyn, &prevp)) != NULL) {
+			fwr = fy_path_exec_walk_result_create(fypx, fwrt_node_ref, fyni);
+			assert(fwr);
+
+			fy_walk_result_list_add_tail(&output->refs, fwr);
+		}
+
+		break;
+
+	case fpet_every_child_r:
+
+		if (!input)
+			goto out;
+
+		/* only valid for node ref */
+		if (input->type != fwrt_node_ref)
+			break;
+
+		fyn = input->fyn;
+
+		/* re-use input for output root */
+		fy_walk_result_clean(input);
+		output = input;
+		input = NULL;
+
+		output->type = fwrt_refs;
+		fy_walk_result_list_init(&output->refs);
+
+		rc = fy_walk_result_all_children_recursive_internal(fypx, fyn, output);
+		assert(!rc);
+
+		break;
+
+	case fpet_seq_slice:
+
+		if (!input)
+			goto out;
+
+		/* only valid for node ref on a sequence */
+		if (input->type != fwrt_node_ref || !fy_node_is_sequence(input->fyn)) {
+			break;
+		}
+		fyn = input->fyn;
+
+		fyt = expr->fyt;
+		assert(fyt);
+		assert(fyt->type == FYTT_PE_SEQ_SLICE);
+
+		start = fyt->seq_slice.start_index;
+		end = fyt->seq_slice.end_index;
+		count = fy_node_sequence_item_count(fyn);
+
+		/* don't handle negative slices yet */
+		if (start < 0 || end < 1 || start >= end)
+			break;
+
+		if (count < end)
+			end = count;
+
+		/* re-use input for output root */
+		fy_walk_result_clean(input);
+		output = input;
+		input = NULL;
+
+		output->type = fwrt_refs;
+		fy_walk_result_list_init(&output->refs);
+
+		for (i = start; i < end; i++) {
+
+			fynn = fy_node_sequence_get_by_index(fyn, i);
+			if (!fynn)
+				continue;
+
+			fwr = fy_path_exec_walk_result_create(fypx, fwrt_node_ref, fynn);
+			assert(fwr);
+
+			fy_walk_result_list_add_tail(&output->refs, fwr);
+		}
+
+		break;
+
+	case fpet_eq:
+	case fpet_neq:
+	case fpet_lt:
+	case fpet_gt:
+	case fpet_lte:
+	case fpet_gte:
+	case fpet_plus:
+	case fpet_minus:
+	case fpet_mult:
+	case fpet_div:
+
+		exprl = fy_path_expr_lhs(expr);
+		assert(exprl);
+
+		exprr = fy_path_expr_rhs(expr);
+		assert(exprr);
+
+		if (input) {
+			input1 = fy_walk_result_clone(input);
+			assert(input1);
+
+			input2 = input;
+			input = NULL;
+
+		} else {
+			input1 = NULL;
+			input2 = NULL;
+		}
+
+		/* execute LHS and RHS */
+		output1 = fy_path_expr_execute(fypx, level + 1, exprl, input1, expr->type);
+		output2 = fy_path_expr_execute(fypx, level + 1, exprr, input2, expr->type);
+
+		output = fy_walk_result_lhs_rhs(fypx, expr, exprl, output1, exprr, output2);
+
+		break;
+
+	case fpet_scalar:
+
+		/* duck typing! */
+		if (fy_token_is_number(expr->fyt)) {
+			output = fy_path_exec_walk_result_create(fypx, fwrt_number, token_number(expr->fyt));
+			assert(output);
+		} else {
+			output = fy_path_exec_walk_result_create(fypx, fwrt_string, fy_token_get_text0(expr->fyt));
+			assert(output);
+		}
+
+		fy_walk_result_free(input);
+		input = NULL;
+
+		break;
+
+	case fpet_logical_or:
+
+		/* return the first that is not NULL */
+		for (exprn = fy_path_expr_list_head(&expr->children); exprn;
+			exprn = fy_path_expr_next(&expr->children, exprn)) {
+
+			if (input) {
+				input1 = fy_walk_result_clone(input);
+				assert(input1);
+			} else {
+				input1 = NULL;
+			}
+
+			output = fy_path_expr_execute(fypx, level + 1, exprn, input1, expr->type);
+			if (output)
+				break;
+		}
+		break;
+
+	case fpet_logical_and:
+		output = NULL;
+
+		/* return the last that was not NULL */
+		for (exprn = fy_path_expr_list_head(&expr->children); exprn;
+			exprn = fy_path_expr_next(&expr->children, exprn)) {
+
+			if (input) {
+				input1 = fy_walk_result_clone(input);
+				assert(input1);
+			} else {
+				input1 = NULL;
+			}
+
+			output1 = fy_path_expr_execute(fypx, level + 1, exprn, input1, expr->type);
+			if (output1) {
+				fy_walk_result_free(output);
+				output = output1;
+			} else
+				break;
+		}
+		break;
+
+	case fpet_filter_unique:
+
+		if (!input)
+			goto out;
+
+		/* flatten input */
+		input = fy_walk_result_flatten(input);
+		assert(input);	/* must work */
+
+		/* for non refs, return input */
+		if (input->type != fwrt_refs) {
+			output = input;
+			input = NULL;
+			break;
+		}
+
+		/* remove duplicates filter */
+		for (fwr = fy_walk_result_list_head(&input->refs); fwr;
+				fwr = fy_walk_result_next(&input->refs, fwr)) {
+
+			/* do not check recursively */
+			if (fwr->type == fwrt_refs)
+				continue;
+
+			/* check the entries from this point forward */
+			for (fwrt = fy_walk_result_next(&input->refs, fwr); fwrt; fwrt = fwrtn) {
+
+				fwrtn = fy_walk_result_next(&input->refs, fwrt);
+
+				/* do not check recursively (or the same result) */
+				if (fwrt->type == fwrt_refs)
+					continue;
+
+				assert(fwrt != fwr);
+
+				match = fy_walk_result_compare_simple(fypx, fpet_eq, fwr, fwrt);
+
+				if (match) {
+					fy_walk_result_list_del(&input->refs, fwrt);
+					fy_walk_result_free(fwrt);
+				}
+			}
+		}
+		output = input;
+		input = NULL;
+
+		break;
+
+	case fpet_scalar_expr:
+
+		exprl = fy_path_expr_list_head(&expr->children);
+		if (!exprl) {
+			fy_warning(diag, "%s:%d\n", __FILE__, __LINE__);
+			goto out;
+		}
+
+		output = fy_path_expr_execute(fypx, level + 1, exprl, NULL, ptype);
+		if (!output) {
+			fy_warning(diag, "%s:%d\n", __FILE__, __LINE__);
+			goto out;
+		}
+
+		exprt = fy_scalar_walk_result_to_expr(fypx, output, ptype);
+		output = NULL;
+		if (!exprt) {
+			fy_warning(diag, "%s:%d\n", __FILE__, __LINE__);
+			break;
+		}
+
+		output = fy_path_expr_execute(fypx, level + 1, exprt, input, ptype);
+		if (!output) {
+			fy_warning(diag, "%s:%d\n", __FILE__, __LINE__);
+		}
+		input = NULL;
+
+		fy_path_expr_free(exprt);
+		break;
+
+	case fpet_path_expr:
+		exprl = fy_path_expr_list_head(&expr->children);
+		if (!exprl)
+			goto out;
+
+		output = fy_path_expr_execute(fypx, level + 1, exprl, input, ptype);
+		input = NULL;
+		break;
+
+	case fpet_method:
+
+		assert(expr->fym);
+
+		/* execute the arguments */
+		nargs = expr->fym->nargs;
+		if (nargs > 0) {
+			fwr_args = FY_ALLOCA(sizeof(*fwr_args) * nargs);
+			memset(fwr_args, 0, sizeof(*fwr_args) * nargs);
+			for (i = 0, exprt = fy_path_expr_list_head(&expr->children); exprt;
+					exprt = fy_path_expr_next(&expr->children, exprt), i++) {
+
+				if (input) {
+					input1 = fy_walk_result_clone(input);
+					assert(input1);
+				} else
+					input1 = NULL;
+
+				fwr_args[i] = fy_path_expr_execute(fypx, level + 1, exprt, input1, expr->type);
+			}
+		} else
+			fwr_args = NULL;
+
+		output = expr->fym->exec(expr->fym, fypx, level + 1, expr, input, fwr_args, nargs);
+		input = NULL;
+
+		break;
+
+	default:
+		fy_error(diag, "%s\n", fy_path_expr_type_txt[expr->type]);
+		assert(0);
+		break;
+	}
+
+out:
+	fy_walk_result_free(input);
+	output = fy_walk_result_simplify(output);
+
+#ifdef DEBUG_EXPR
+	if (output)
+		fy_walk_result_dump(output, diag, FYET_NOTICE, level, "output %s\n", fy_path_expr_type_txt[expr->type]);
+#endif
+	return output;
+}
+
+static int fy_path_exec_execute_internal(struct fy_path_exec *fypx,
+		struct fy_path_expr *expr, struct fy_node *fyn_start)
+{
+	struct fy_walk_result *fwr;
+
+	if (!fypx || !expr || !fyn_start)
+		return -1;
+
+	fy_walk_result_free(fypx->result);
+	fypx->result = NULL;
+
+	fwr = fy_path_exec_walk_result_create(fypx, fwrt_node_ref, fyn_start);
+	assert(fwr);
+
+	fwr = fy_path_expr_execute(fypx, 0, expr, fwr, fpet_none);
+	if (!fwr)
+		return 0;
+
+	/* flatten results */
+	if (fwr->type == fwrt_refs) {
+		fwr = fy_walk_result_flatten(fwr);
+		if (!fwr)
+			return -1;
+	}
+	fypx->result = fwr;
+
+	return 0;
+}
+
+int fy_path_exec_execute(struct fy_path_exec *fypx, struct fy_path_expr *expr, struct fy_node *fyn_start)
+{
+	if (!fypx || !expr || !fyn_start)
+		return -1;
+
+	fypx->fyn_start = fyn_start;
+	return fy_path_exec_execute_internal(fypx, expr, fypx->fyn_start);
+}
+
+struct fy_node *
+fy_path_exec_results_iterate(struct fy_path_exec *fypx, void **prevp)
+{
+	struct fy_walk_result *fwr;
+
+	if (!fypx || !prevp)
+		return NULL;
+
+	if (!fypx->result)
+		return NULL;
+
+	if (fypx->result->type != fwrt_refs) {
+		fwr = fypx->result;
+
+		if (fwr->type != fwrt_node_ref)
+			return NULL;
+
+		if (!*prevp) {
+			*prevp = fwr;
+			return fwr->fyn;
+		}
+		*prevp = NULL;
+		return NULL;
+	}
+
+	/* loop over non node refs for now */
+	do {
+		if (!*prevp)
+			fwr = fy_walk_result_list_head(&fypx->result->refs);
+		else
+			fwr = fy_walk_result_next(&fypx->result->refs, *prevp);
+		*prevp = fwr;
+	} while (fwr && fwr->type != fwrt_node_ref);
+
+	return fwr ? fwr->fyn : NULL;
+}
+
+struct fy_walk_result *
+fy_path_exec_take_results(struct fy_path_exec *fypx)
+{
+	struct fy_walk_result *fwr;
+
+	if (!fypx || !fypx->result)
+		return NULL;
+	fwr = fypx->result;
+	fypx->result = NULL;
+	return fwr;
+}
+
+struct fy_walk_result *
+fy_path_exec_walk_result_vcreate(struct fy_path_exec *fypx, enum fy_walk_result_type type, va_list ap)
+{
+	struct fy_walk_result_list *fwrl;
+
+	if (!fypx)
+		return NULL;
+
+	fwrl = fy_path_exec_walk_result_rl(fypx);
+	return fy_walk_result_vcreate_rl(fwrl, type, ap);
+}
+
+struct fy_walk_result *
+fy_path_exec_walk_result_create(struct fy_path_exec *fypx, enum fy_walk_result_type type, ...)
+{
+	struct fy_walk_result_list *fwrl;
+	struct fy_walk_result *fwr;
+	va_list ap;
+
+	if (!fypx)
+		return NULL;
+
+	fwrl = fy_path_exec_walk_result_rl(fypx);
+
+	va_start(ap, type);
+	fwr = fy_walk_result_vcreate_rl(fwrl, type, ap);
+	va_end(ap);
+
+	if (!fwr)
+		return NULL;
+
+	fwr->fypx = fy_path_exec_ref(fypx);
+
+	return fwr;
+}
+
+void
+fy_path_exec_walk_result_free(struct fy_path_exec *fypx, struct fy_walk_result *fwr)
+{
+	struct fy_walk_result_list *fwrl;
+
+	fwrl = fypx ? fy_path_exec_walk_result_rl(fypx) : NULL;
+	fy_walk_result_free_rl(fwrl, fwr);
+}
+
+int fy_document_setup_path_expr_data(struct fy_document *fyd)
+{
+	struct fy_path_parse_cfg pcfg_local, *pcfg = &pcfg_local;
+	struct fy_path_expr_document_data *pxdd;
+
+	if (!fyd || fyd->pxdd)
+		return 0;
+
+	pxdd = malloc(sizeof(*pxdd));
+	if (!pxdd)
+		goto err_no_mem;
+
+	memset(pxdd, 0, sizeof(*pxdd));
+
+	fy_walk_result_list_init(&pxdd->fwr_recycle);
+
+	memset(pcfg, 0, sizeof(*pcfg));
+	pcfg->diag = fyd->diag;
+	pxdd->fypp = fy_path_parser_create(pcfg);
+	if (!pxdd->fypp)
+		goto err_no_fypp;
+
+	fyd->pxdd = pxdd;
+
+	return 0;
+
+err_no_fypp:
+	free(pxdd);
+err_no_mem:
+	return -1;
+}
+
+void fy_document_cleanup_path_expr_data(struct fy_document *fyd)
+{
+	struct fy_path_expr_document_data *pxdd;
+	struct fy_walk_result *fwr;
+
+	if (!fyd || !fyd->pxdd)
+		return;
+
+	pxdd = fyd->pxdd;
+
+	fy_path_parser_destroy(pxdd->fypp);
+
+	while ((fwr = fy_walk_result_list_pop(&pxdd->fwr_recycle)) != NULL)
+		free(fwr);
+
+	free(fyd->pxdd);
+	fyd->pxdd = NULL;
+}
+
+int fy_node_setup_path_expr_data(struct fy_node *fyn)
+{
+	struct fy_path_expr_document_data *pxdd;
+	struct fy_path_expr_node_data *pxnd;
+	const char *text;
+	size_t len;
+	char *alloc = NULL;
+	int rc;
+
+	if (!fyn || fyn->pxnd)
+		return 0;
+
+	/* only on alias nodes */
+	if (!fy_node_is_alias(fyn))
+		return 0;
+
+	/* a document must exist */
+	if (!fyn->fyd)
+		return -1;
+
+	if (!fyn->fyd->pxdd) {
+		rc = fy_document_setup_path_expr_data(fyn->fyd);
+		if (rc)
+			return rc;
+	}
+	pxdd = fyn->fyd->pxdd;
+	assert(pxdd);
+
+	pxnd = malloc(sizeof(*pxnd));
+	if (!pxnd)
+		goto err_no_mem;
+	memset(pxnd, 0, sizeof(*pxnd));
+
+	text = fy_token_get_text(fyn->scalar, &len);
+	if (!text)
+		goto err_no_text;
+
+	if (!fy_is_first_alpha(*text)) {
+		pxnd->fyi = fy_input_from_data(text, len, NULL, false);
+		if (!pxnd->fyi)
+			goto err_no_input;
+	} else {
+		alloc = malloc(len + 2);
+		if (!alloc)
+			goto err_no_input;
+		alloc[0] = '*';
+		memcpy(alloc + 1, text, len);
+		alloc[len + 1] = '\0';
+
+		pxnd->fyi = fy_input_from_malloc_data(alloc, len + 1, NULL, false);
+		if (!pxnd->fyi)
+			goto err_no_input;
+	}
+
+	fy_path_parser_reset(pxdd->fypp);
+
+	rc = fy_path_parser_open(pxdd->fypp, pxnd->fyi, NULL);
+	if (rc)
+		goto err_no_open;
+
+	pxnd->expr = fy_path_parse_expression(pxdd->fypp);
+	if (!pxnd->expr)
+		goto err_parse;
+
+	fy_path_parser_close(pxdd->fypp);
+
+	fyn->pxnd = pxnd;
+
+	return 0;
+err_parse:
+	fy_path_parser_close(pxdd->fypp);
+err_no_open:
+	fy_input_unref(pxnd->fyi);
+err_no_input:
+	if (alloc)
+		free(alloc);
+err_no_text:
+	free(pxnd);
+err_no_mem:
+	return -1;
+}
+
+void fy_node_cleanup_path_expr_data(struct fy_node *fyn)
+{
+	struct fy_path_expr_node_data *pxnd;
+
+	if (!fyn || !fyn->pxnd)
+		return;
+
+	pxnd = fyn->pxnd;
+
+	if (pxnd->expr)
+		fy_path_expr_free(pxnd->expr);
+
+	if (pxnd->fyi)
+		fy_input_unref(pxnd->fyi);
+
+	free(pxnd);
+	fyn->pxnd = NULL;
+}
+
+struct fy_walk_result *
+fy_node_alias_resolve_by_ypath_result(struct fy_node *fyn)
+{
+	struct fy_document *fyd;
+	struct fy_path_expr_document_data *pxdd = NULL;
+	struct fy_path_expr_node_data *pxnd = NULL;
+	struct fy_walk_result *fwr;
+	struct fy_anchor *fya;
+	struct fy_path_exec *fypx = NULL;
+	int rc;
+	char* path;
+
+	if (!fyn || !fy_node_is_alias(fyn))
+		return NULL;
+
+	fyd = fyn->fyd;
+	if (!fyd)
+		return NULL;
+
+	/* simple */
+	fya = fy_document_lookup_anchor_by_token(fyd, fyn->scalar);
+	if (fya) {
+
+		fwr = fy_path_exec_walk_result_create(fypx, fwrt_node_ref, fya->fyn);
+		fyd_error_check(fyd, fwr, err_out,
+				"fy_walk_result_alloc_rl() failed");
+
+		return fwr;
+	}
+
+	/* ok, complex, setup the node data */
+	rc = fy_node_setup_path_expr_data(fyn);
+	fyd_error_check(fyd, !rc, err_out,
+			"fy_node_setup_path_expr_data() failed");
+
+	pxnd = fyn->pxnd;
+	assert(pxnd);
+
+	pxdd = fyd->pxdd;
+	assert(pxdd);
+
+	if (pxnd->traversals++ > 0) {
+        fy_node_get_path_alloca(fyn, &path);
+		FYD_NODE_ERROR(fyd, fyn, FYEM_DOC,
+				"recursive reference detected at %s\n",
+				path);
+		pxnd->traversals--;
+		return NULL;
+	}
+
+	fypx = fy_path_exec_create_on_document(fyd);
+	fyd_error_check(fyd, !rc, err_out,
+			"fy_path_exec_create_on_document() failed");
+
+	fy_path_exec_set_result_recycle_list(fypx, &pxdd->fwr_recycle);
+
+#if 0
+	{
+		struct fy_document *fyd_pe;
+		const char *text;
+		size_t len;
+
+		text = fy_token_get_text(fyn->scalar, &len);
+		if (text) {
+			fyd_pe = fy_path_expr_to_document(pxnd->expr);
+			if (fyd_pe) {
+				fprintf(stderr, "%s: %.*s\n", __func__, (int)len, text);
+				fy_document_default_emit_to_fp(fyd_pe, stderr);
+				fy_document_destroy(fyd_pe);
+			}
+		}
+	}
+#endif
+
+	// fprintf(stderr, "%s: %s 2\n", __func__, fy_node_get_path_alloca(fyn));
+
+	/* execute, starting at this */
+	rc = fy_path_exec_execute(fypx, pxnd->expr, fyn);
+	fyd_error_check(fyd, !rc, err_out,
+			"fy_path_exec_execute() failed");
+
+	// fprintf(stderr, "%s: %s 3\n", __func__, fy_node_get_path_alloca(fyn));
+
+	fwr = fy_path_exec_take_results(fypx);
+
+	fy_path_exec_unref(fypx);
+
+	pxnd->traversals--;
+
+	if (!fwr)
+		return NULL;
+
+	// fprintf(stderr, "%s: %s 4\n", __func__, fy_node_get_path_alloca(fyn));
+
+	return fwr;
+
+err_out:
+	if (pxnd)
+		pxnd->traversals--;
+	fy_path_exec_unref(fypx);	/* NULL OK */
+	return NULL;
+}
+
+struct fy_node *fy_node_alias_resolve_by_ypath(struct fy_node *fyn)
+{
+	struct fy_anchor *fya;
+	struct fy_walk_result *fwr;
+	void *iterp;
+
+	if (!fyn || !fy_node_is_alias(fyn))
+		return NULL;
+
+	/* simple and common enough to do it now */
+	fya = fy_document_lookup_anchor_by_token(fyn->fyd, fyn->scalar);
+	if (fya)
+		return fya->fyn;
+
+	fwr = fy_node_alias_resolve_by_ypath_result(fyn);
+	if (!fwr)
+		return NULL;
+
+	iterp = NULL;
+	fyn = fy_walk_result_node_iterate(fwr, &iterp);
+
+	fy_walk_result_free(fwr);
+
+	return fyn;
+}
+
+struct fy_walk_result *
+fy_node_by_ypath_result(struct fy_node *fyn, const char *path, size_t len)
+{
+	struct fy_path_expr_document_data *pxdd;
+	struct fy_document *fyd;
+	struct fy_walk_result *fwr;
+	struct fy_anchor *fya;
+	struct fy_input *fyi;
+	struct fy_path_expr *expr;
+	struct fy_path_exec *fypx = NULL;
+	int rc;
+
+	if (!fyn || !path || !len)
+		return NULL;
+
+	fyd = fyn->fyd;
+	if (!fyd)
+		return NULL;
+
+	if (len == FY_NT)
+		len = strlen(path);
+
+	/* simple */
+	fya = fy_document_lookup_anchor(fyn->fyd, path, len);
+	if (fya) {
+		fwr = fy_path_exec_walk_result_create(fypx, fwrt_node_ref, fya->fyn);
+		fyd_error_check(fyd, fwr, err_out,
+				"fy_walk_result_alloc_rl() failed");
+		return fwr;
+	}
+
+	/* ok, complex, setup the document data */
+	rc = fy_document_setup_path_expr_data(fyd);
+	fyd_error_check(fyd, !rc, err_setup,
+			"fy_node_setup_path_expr_data() failed");
+
+	pxdd = fyd->pxdd;
+	assert(pxdd);
+
+	fyi = fy_input_from_data(path, len, NULL, false);
+	fyd_error_check(fyd, fyi, err_no_input,
+			"fy_input_from_data() failed");
+
+	fy_path_parser_reset(pxdd->fypp);
+
+	rc = fy_path_parser_open(pxdd->fypp, fyi, NULL);
+	fyd_error_check(fyd, !rc, err_no_open,
+			"fy_path_parser_open() failed");
+
+	expr = fy_path_parse_expression(pxdd->fypp);
+	fyd_error_check(fyd, expr, err_parse,
+			"fy_path_parse_expression() failed");
+
+	fy_path_parser_close(pxdd->fypp);
+
+	fypx = fy_path_exec_create_on_document(fyd);
+	fyd_error_check(fyd, !rc, err_no_fypx,
+			"fy_path_exec_create_on_document() failed");
+
+	/* execute, starting at this */
+	rc = fy_path_exec_execute(fypx, expr, fyn);
+	fyd_error_check(fyd, !rc, err_exec,
+			"fy_path_parse_expression() failed");
+
+	fwr = fy_path_exec_take_results(fypx);
+
+	fy_path_exec_unref(fypx);
+
+	fy_path_expr_free(expr);
+	fy_input_unref(fyi);
+
+	return fwr;
+
+err_exec:
+	fy_path_expr_free(expr);
+err_no_fypx:
+	fy_path_exec_unref(fypx);
+err_parse:
+	fy_path_parser_close(pxdd->fypp);
+
+err_no_open:
+	fy_input_unref(fyi);
+
+err_no_input:
+err_setup:
+err_out:
+	return NULL;
+}
+
+struct fy_node *fy_node_by_ypath(struct fy_node *fyn, const char *path, size_t len)
+{
+	struct fy_walk_result *fwr;
+	struct fy_anchor *fya;
+	void *iterp;
+
+	if (!fyn || !path || !len)
+		return NULL;
+
+	/* simple */
+	fya = fy_document_lookup_anchor(fyn->fyd, path, len);
+	if (fya)
+		return fya->fyn;
+
+	fwr = fy_node_by_ypath_result(fyn, path, len);
+	if (!fwr)
+		return NULL;
+
+	iterp = NULL;
+	fyn = fy_walk_result_node_iterate(fwr, &iterp);
+
+	fy_walk_result_free(fwr);
+
+	return fyn;
+}
diff --git a/contrib/libs/libfyaml/src/lib/fy-walk.h b/contrib/libs/libfyaml/src/lib/fy-walk.h
new file mode 100644
index 0000000000..bc200f66eb
--- /dev/null
+++ b/contrib/libs/libfyaml/src/lib/fy-walk.h
@@ -0,0 +1,438 @@
+/*
+ * fy-walk.h - walker  internal header file
+ *
+ * Copyright (c) 2021 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#ifndef FY_WALK_H
+#define FY_WALK_H
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <assert.h>
+
+#include <libfyaml.h>
+
+#include "fy-ctype.h"
+#include "fy-utf8.h"
+#include "fy-list.h"
+#include "fy-typelist.h"
+#include "fy-types.h"
+#include "fy-diag.h"
+#include "fy-dump.h"
+#include "fy-docstate.h"
+#include "fy-accel.h"
+#include "fy-token.h"
+
+struct fy_document;
+
+enum fy_walk_result_type {
+	fwrt_none,
+	fwrt_node_ref,
+	fwrt_number,
+	fwrt_string,
+	fwrt_doc,
+	fwrt_refs,
+};
+
+#define FWRT_COUNT (fwrt_refs + 1)
+extern const char *fy_walk_result_type_txt[FWRT_COUNT];
+
+struct fy_path_exec;
+
+FY_TYPE_FWD_DECL_LIST(walk_result);
+struct fy_walk_result {
+	struct fy_list_head node;
+	struct fy_path_exec *fypx;
+	enum fy_walk_result_type type;
+	union {
+		struct fy_node *fyn;
+		double number;
+		char *string;
+		struct fy_walk_result_list refs;
+		struct fy_document *fyd;
+	};
+};
+FY_TYPE_DECL_LIST(walk_result);
+
+struct fy_walk_result *fy_walk_result_alloc_rl(struct fy_walk_result_list *fwrl);
+void fy_walk_result_free_rl(struct fy_walk_result_list *fwrl, struct fy_walk_result *fwr);
+void fy_walk_result_list_free_rl(struct fy_walk_result_list *fwrl, struct fy_walk_result_list *results);
+
+void fy_walk_result_free(struct fy_walk_result *fwr);
+
+struct fy_walk_result *fy_walk_result_vcreate_rl(struct fy_walk_result_list *fwrl, enum fy_walk_result_type type, va_list ap);
+struct fy_walk_result *fy_walk_result_create_rl(struct fy_walk_result_list *fwrl, enum fy_walk_result_type type, ...);
+
+static inline struct fy_walk_result *
+fy_walk_result_iter_start(struct fy_walk_result *fwr)
+{
+	struct fy_walk_result *fwri;
+
+	if (!fwr)
+		return NULL;
+	if (fwr->type != fwrt_refs)
+		return fwr;
+	fwri = fy_walk_result_list_head(&fwr->refs);
+	if (!fwri)
+		return NULL;
+	return fwri;
+}
+
+static inline struct fy_walk_result *
+fy_walk_result_iter_next(struct fy_walk_result *fwr, struct fy_walk_result *fwri)
+{
+	if (!fwr || !fwri || fwr->type != fwrt_refs)
+		return NULL;
+	fwri = fy_walk_result_next(&fwr->refs, fwri);
+	if (!fwri)
+		return NULL;
+	return fwri;
+}
+
+struct fy_node *
+fy_walk_result_node_iterate(struct fy_walk_result *fwr, void **prevp);
+
+enum fy_path_expr_type {
+	fpet_none,
+	/* ypath */
+	fpet_root,		/* /^ or / at the beginning of the expr */
+	fpet_this,		/* /. */
+	fpet_parent,		/* /.. */
+	fpet_every_child,	// /* every immediate child
+	fpet_every_child_r,	// /** every recursive child
+	fpet_filter_collection,	/* match only collection (at the end only) */
+	fpet_filter_scalar,	/* match only scalars (leaves) */
+	fpet_filter_sequence,	/* match only sequences */
+	fpet_filter_mapping,	/* match only mappings */
+	fpet_filter_unique,	/* removes duplicates */
+	fpet_seq_index,
+	fpet_map_key,		/* complex map key (quoted, flow seq or map) */
+	fpet_seq_slice,
+	fpet_alias,
+
+	fpet_multi,		/* merge results of children */
+	fpet_chain,		/* children move in sequence */
+	fpet_logical_or,	/* first non null result set */
+	fpet_logical_and,	/* the last non null result set */
+
+	fpet_eq,		/* equal expression */
+	fpet_neq,		/* not equal */
+	fpet_lt,		/* less than */
+	fpet_gt,		/* greater than */
+	fpet_lte,		/* less or equal than */
+	fpet_gte,		/* greater or equal than */
+
+	fpet_scalar,		/* scalar */
+
+	fpet_plus,		/* add */
+	fpet_minus,		/* subtract */
+	fpet_mult,		/* multiply */
+	fpet_div,		/* divide */
+
+	fpet_lparen,		/* left paren (they do not appear in final expression) */
+	fpet_rparen,		/* right parent */
+	fpet_method,		/* method (or parentheses) */
+
+	fpet_scalar_expr,	/* non-eval phase scalar expression  */
+	fpet_path_expr,		/* non-eval phase path expression */
+	fpet_arg_separator,	/* argument separator (comma in scalar mode) */
+};
+
+#define FPET_COUNT (fpet_arg_separator + 1)
+
+extern const char *path_expr_type_txt[FPET_COUNT];
+
+static inline bool fy_path_expr_type_is_valid(enum fy_path_expr_type type)
+{
+	return type >= fpet_root && type < FPET_COUNT;
+}
+
+static inline bool fy_path_expr_type_is_single_result(enum fy_path_expr_type type)
+{
+	return type == fpet_root ||
+	       type == fpet_this ||
+	       type == fpet_parent ||
+	       type == fpet_map_key ||
+	       type == fpet_seq_index ||
+	       type == fpet_alias ||
+	       type == fpet_filter_collection ||
+	       type == fpet_filter_scalar ||
+	       type == fpet_filter_sequence ||
+	       type == fpet_filter_mapping;
+}
+
+static inline bool fy_path_expr_type_is_parent(enum fy_path_expr_type type)
+{
+	return type == fpet_multi ||
+	       type == fpet_chain ||
+	       type == fpet_logical_or ||
+	       type == fpet_logical_and ||
+	       type == fpet_eq ||
+	       type == fpet_method ||
+	       type == fpet_scalar_expr ||
+	       type == fpet_path_expr;
+}
+
+static inline bool fy_path_expr_type_is_mergeable(enum fy_path_expr_type type)
+{
+	return type == fpet_multi ||
+	       type == fpet_chain ||
+	       type == fpet_logical_or ||
+	       type == fpet_logical_and;
+}
+
+/* type handles refs by itself */
+static inline bool fy_path_expr_type_handles_refs(enum fy_path_expr_type type)
+{
+	return type == fpet_filter_unique ||
+	       type == fpet_method;
+}
+
+static inline bool fy_path_expr_type_is_parent_lhs_rhs(enum fy_path_expr_type type)
+{
+	return type == fpet_eq ||
+	       type == fpet_neq ||
+	       type == fpet_lt ||
+	       type == fpet_gt ||
+	       type == fpet_lte ||
+	       type == fpet_gte ||
+
+	       type == fpet_plus ||
+	       type == fpet_minus ||
+	       type == fpet_mult ||
+	       type == fpet_div;
+}
+
+static inline bool
+fy_path_expr_type_is_conditional(enum fy_path_expr_type type)
+{
+	return type == fpet_eq ||
+	       type == fpet_neq ||
+	       type == fpet_lt ||
+	       type == fpet_gt ||
+	       type == fpet_lte ||
+	       type == fpet_gte;
+}
+
+static inline bool
+fy_path_expr_type_is_arithmetic(enum fy_path_expr_type type)
+{
+	return type == fpet_plus ||
+	       type == fpet_minus ||
+	       type == fpet_mult ||
+	       type == fpet_div;
+}
+
+static inline bool
+fy_path_expr_type_is_lparen(enum fy_path_expr_type type)
+{
+	return type == fpet_lparen /* ||
+	       type == fpet_method */ ;
+}
+
+enum fy_expr_mode {
+	fyem_none,	/* invalid mode */
+	fyem_path,	/* expression is path */
+	fyem_scalar,	/* expression is scalar */
+};
+
+#define FYEM_COUNT (fyem_scalar + 1)
+
+extern const char *fy_expr_mode_txt[FYEM_COUNT];
+
+struct fy_path_expr;
+
+struct fy_method {
+	const char *name;
+	size_t len;
+	enum fy_expr_mode mode;
+	unsigned int nargs;
+	struct fy_walk_result *(*exec)(const struct fy_method *fym,
+		struct fy_path_exec *fypx, int level,
+		struct fy_path_expr *expr,
+		struct fy_walk_result *input,
+		struct fy_walk_result **args, int nargs);
+};
+
+FY_TYPE_FWD_DECL_LIST(path_expr);
+struct fy_path_expr {
+	struct fy_list_head node;
+	struct fy_path_expr *parent;
+	enum fy_path_expr_type type;
+	struct fy_token *fyt;
+	struct fy_path_expr_list children;
+	enum fy_expr_mode expr_mode;	/* for parens */
+	const struct fy_method *fym;
+};
+FY_TYPE_DECL_LIST(path_expr);
+
+static inline struct fy_path_expr *
+fy_path_expr_lhs(struct fy_path_expr *expr)
+{
+	if (!expr || !fy_path_expr_type_is_parent_lhs_rhs(expr->type))
+		return NULL;
+	return fy_path_expr_list_head(&expr->children);
+}
+
+static inline struct fy_path_expr *
+fy_path_expr_rhs(struct fy_path_expr *expr)
+{
+	if (!expr || !fy_path_expr_type_is_parent_lhs_rhs(expr->type))
+		return NULL;
+	return fy_path_expr_list_tail(&expr->children);
+}
+
+const struct fy_mark *fy_path_expr_start_mark(struct fy_path_expr *expr);
+const struct fy_mark *fy_path_expr_end_mark(struct fy_path_expr *expr);
+
+struct fy_expr_stack {
+	unsigned int top;
+	unsigned int alloc;
+	struct fy_path_expr **items;
+	struct fy_path_expr *items_static[32];
+};
+
+void fy_expr_stack_setup(struct fy_expr_stack *stack);
+void fy_expr_stack_cleanup(struct fy_expr_stack *stack);
+void fy_expr_stack_dump(struct fy_diag *diag, struct fy_expr_stack *stack);
+int fy_expr_stack_push(struct fy_expr_stack *stack, struct fy_path_expr *expr);
+struct fy_path_expr *fy_expr_stack_peek_at(struct fy_expr_stack *stack, unsigned int pos);
+struct fy_path_expr *fy_expr_stack_peek(struct fy_expr_stack *stack);
+struct fy_path_expr *fy_expr_stack_pop(struct fy_expr_stack *stack);
+
+struct fy_path_parser {
+	struct fy_path_parse_cfg cfg;
+	struct fy_reader reader;
+	struct fy_token_list queued_tokens;
+	enum fy_token_type last_queued_token_type;
+	bool stream_start_produced;
+	bool stream_end_produced;
+	bool stream_error;
+	int token_activity_counter;
+
+	struct fy_input *fyi;
+	struct fy_expr_stack operators;
+	struct fy_expr_stack operands;
+
+	/* to avoid allocating */
+	struct fy_path_expr_list expr_recycle;
+	bool suppress_recycling;
+
+	enum fy_expr_mode expr_mode;
+	int paren_nest_level;
+
+};
+
+struct fy_path_expr *fy_path_expr_alloc(void);
+/* fy_path_expr_free is declared in libfyaml.h */
+// void fy_path_expr_free(struct fy_path_expr *expr);
+
+void fy_path_parser_setup(struct fy_path_parser *fypp, const struct fy_path_parse_cfg *pcfg);
+void fy_path_parser_cleanup(struct fy_path_parser *fypp);
+int fy_path_parser_open(struct fy_path_parser *fypp,
+			struct fy_input *fyi, const struct fy_reader_input_cfg *icfg);
+void fy_path_parser_close(struct fy_path_parser *fypp);
+
+struct fy_token *fy_path_scan(struct fy_path_parser *fypp);
+
+struct fy_path_expr *fy_path_parse_expression(struct fy_path_parser *fypp);
+
+void fy_path_expr_dump(struct fy_path_expr *expr, struct fy_diag *diag, enum fy_error_type errlevel, int level, const char *banner);
+
+struct fy_path_exec {
+	struct fy_path_exec_cfg cfg;
+	struct fy_node *fyn_start;
+	struct fy_walk_result *result;
+	struct fy_walk_result_list *fwr_recycle;
+	int refs;
+	bool supress_recycling;
+};
+
+struct fy_path_exec *fy_path_exec_create(const struct fy_path_exec_cfg *xcfg);
+struct fy_path_exec *fy_path_exec_create_on_document(struct fy_document *fyd);
+void fy_path_exec_destroy(struct fy_path_exec *fypx);
+void fy_path_exec_cleanup(struct fy_path_exec *fypx);
+
+static inline struct fy_path_exec *
+fy_path_exec_ref(struct fy_path_exec *fypx)
+{
+	/* take care of overflow */
+	if (!fypx)
+		return NULL;
+	assert(fypx->refs + 1 > 0);
+	fypx->refs++;
+
+	return fypx;
+}
+
+static inline void
+fy_path_exec_unref(struct fy_path_exec *fypx)
+{
+	if (!fypx)
+		return;
+
+	assert(fypx->refs > 0);
+
+	if (--fypx->refs == 0)
+		fy_path_exec_destroy(fypx);
+}
+
+struct fy_walk_result *
+fy_path_expr_execute(struct fy_path_exec *fypx, int level, struct fy_path_expr *expr,
+		     struct fy_walk_result *input, enum fy_path_expr_type ptype);
+
+static inline struct fy_walk_result_list *
+fy_path_exec_walk_result_rl(struct fy_path_exec *fypx)
+{
+	return fypx && !fypx->supress_recycling ? fypx->fwr_recycle : NULL;
+}
+
+static inline void
+fy_path_exec_set_result_recycle_list(struct fy_path_exec *fypx,
+				     struct fy_walk_result_list *fwrl)
+{
+	if (!fypx)
+		return;
+	fypx->fwr_recycle = fwrl;
+}
+
+struct fy_walk_result *
+fy_path_exec_walk_result_create(struct fy_path_exec *fypx, enum fy_walk_result_type type, ...);
+
+void
+fy_path_exec_walk_result_free(struct fy_path_exec *fypx, struct fy_walk_result *fwr);
+
+struct fy_path_expr_document_data {
+	struct fy_path_parser *fypp;
+	struct fy_walk_result_list fwr_recycle;
+};
+
+struct fy_path_expr_node_data {
+	struct fy_input *fyi;
+	struct fy_path_expr *expr;
+	struct fy_node *fyn_target;
+	int traversals;
+};
+
+int fy_document_setup_path_expr_data(struct fy_document *fyd);
+void fy_document_cleanup_path_expr_data(struct fy_document *fyd);
+int fy_node_setup_path_expr_data(struct fy_node *fyn);
+void fy_node_cleanup_path_expr_data(struct fy_node *fyn);
+
+struct fy_walk_result *
+fy_node_alias_resolve_by_ypath_result(struct fy_node *fyn);
+struct fy_node *fy_node_alias_resolve_by_ypath(struct fy_node *fyn);
+
+struct fy_walk_result *
+fy_node_by_ypath_result(struct fy_node *fyn, const char *path, size_t len);
+struct fy_node *fy_node_by_ypath(struct fy_node *fyn, const char *path, size_t len);
+
+#endif
diff --git a/library/cpp/yaml/CMakeLists.txt b/library/cpp/yaml/CMakeLists.txt
index 0d9d53cb1c..8d31aa7dec 100644
--- a/library/cpp/yaml/CMakeLists.txt
+++ b/library/cpp/yaml/CMakeLists.txt
@@ -7,3 +7,4 @@
 
 
 add_subdirectory(as)
+add_subdirectory(fyamlcpp)
diff --git a/library/cpp/yaml/fyamlcpp/CMakeLists.darwin.txt b/library/cpp/yaml/fyamlcpp/CMakeLists.darwin.txt
new file mode 100644
index 0000000000..ed89c6d02d
--- /dev/null
+++ b/library/cpp/yaml/fyamlcpp/CMakeLists.darwin.txt
@@ -0,0 +1,18 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_library(cpp-yaml-fyamlcpp)
+target_link_libraries(cpp-yaml-fyamlcpp PUBLIC
+  contrib-libs-cxxsupp
+  yutil
+  contrib-libs-libfyaml
+)
+target_sources(cpp-yaml-fyamlcpp PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/yaml/fyamlcpp/fyamlcpp.cpp
+)
diff --git a/library/cpp/yaml/fyamlcpp/CMakeLists.linux-aarch64.txt b/library/cpp/yaml/fyamlcpp/CMakeLists.linux-aarch64.txt
new file mode 100644
index 0000000000..e96ca3e0ec
--- /dev/null
+++ b/library/cpp/yaml/fyamlcpp/CMakeLists.linux-aarch64.txt
@@ -0,0 +1,19 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_library(cpp-yaml-fyamlcpp)
+target_link_libraries(cpp-yaml-fyamlcpp PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  contrib-libs-libfyaml
+)
+target_sources(cpp-yaml-fyamlcpp PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/yaml/fyamlcpp/fyamlcpp.cpp
+)
diff --git a/library/cpp/yaml/fyamlcpp/CMakeLists.linux.txt b/library/cpp/yaml/fyamlcpp/CMakeLists.linux.txt
new file mode 100644
index 0000000000..e96ca3e0ec
--- /dev/null
+++ b/library/cpp/yaml/fyamlcpp/CMakeLists.linux.txt
@@ -0,0 +1,19 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_library(cpp-yaml-fyamlcpp)
+target_link_libraries(cpp-yaml-fyamlcpp PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  contrib-libs-libfyaml
+)
+target_sources(cpp-yaml-fyamlcpp PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/yaml/fyamlcpp/fyamlcpp.cpp
+)
diff --git a/library/cpp/yaml/fyamlcpp/CMakeLists.txt b/library/cpp/yaml/fyamlcpp/CMakeLists.txt
new file mode 100644
index 0000000000..5bb4faffb4
--- /dev/null
+++ b/library/cpp/yaml/fyamlcpp/CMakeLists.txt
@@ -0,0 +1,15 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+if (CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux-aarch64.txt)
+elseif (APPLE AND CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
+  include(CMakeLists.darwin.txt)
+elseif (CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux.txt)
+endif()
diff --git a/library/cpp/yaml/fyamlcpp/fyamlcpp.cpp b/library/cpp/yaml/fyamlcpp/fyamlcpp.cpp
new file mode 100644
index 0000000000..42ee6b830d
--- /dev/null
+++ b/library/cpp/yaml/fyamlcpp/fyamlcpp.cpp
@@ -0,0 +1,872 @@
+#include "fyamlcpp.h"
+
+#include <contrib/libs/libfyaml/include/libfyaml.h>
+
+namespace NFyaml {
+
+#define ENSURE_NODE_NOT_EMPTY(NODE) Y_ENSURE_EX(NODE, TFyamlEx() << "Expected non-empty Node")
+#define ENSURE_DOCUMENT_NOT_EMPTY(NODE) Y_ENSURE_EX(NODE, TFyamlEx() << "Expected non-empty Document")
+
+enum class EErrorType {
+    Debug = FYET_DEBUG,
+    Info = FYET_INFO,
+    Notice = FYET_NOTICE,
+    Warning = FYET_WARNING,
+    Error = FYET_ERROR,
+    Max = FYET_MAX,
+};
+
+enum class EErrorModule {
+    Unknown = FYEM_UNKNOWN,
+    Atom = FYEM_ATOM,
+    Scan = FYEM_SCAN,
+    Parse = FYEM_PARSE,
+    Doc = FYEM_DOC,
+    Build = FYEM_BUILD,
+    Internal = FYEM_INTERNAL,
+    System = FYEM_SYSTEM,
+    Max = FYEM_MAX,
+};
+
+enum class EParseCfgFlags {
+    Quiet = FYPCF_QUIET,
+    CollectDiag = FYPCF_COLLECT_DIAG,
+    ResolveDocument = FYPCF_RESOLVE_DOCUMENT,
+    DisableMmapOpt = FYPCF_DISABLE_MMAP_OPT,
+    DisableRecycling = FYPCF_DISABLE_RECYCLING,
+    ParseComments = FYPCF_PARSE_COMMENTS,
+    DisableDepth_limit = FYPCF_DISABLE_DEPTH_LIMIT,
+    DisableAccelerators = FYPCF_DISABLE_ACCELERATORS,
+    DisableBuffering = FYPCF_DISABLE_BUFFERING,
+    DefaultVersionAuto = FYPCF_DEFAULT_VERSION_AUTO,
+    DefaultVersion1_1 = FYPCF_DEFAULT_VERSION_1_1,
+    DefaultVersion1_2 = FYPCF_DEFAULT_VERSION_1_2,
+    DefaultVersion1_3 = FYPCF_DEFAULT_VERSION_1_3,
+    SloppyFlowIndentation = FYPCF_SLOPPY_FLOW_INDENTATION,
+    PreferRecursive = FYPCF_PREFER_RECURSIVE,
+    JsonAuto = FYPCF_JSON_AUTO,
+    JsonNone = FYPCF_JSON_NONE,
+    JsonForce = FYPCF_JSON_FORCE,
+    YpathAliases = FYPCF_YPATH_ALIASES,
+    AllowDuplicateKeys = FYPCF_ALLOW_DUPLICATE_KEYS,
+};
+
+enum class EEventType {
+    None = FYET_NONE,
+    StreamStart = FYET_STREAM_START,
+    StreamEnd = FYET_STREAM_END,
+    DocumentStart = FYET_DOCUMENT_START,
+    DocumentEnd = FYET_DOCUMENT_END,
+    MappingStart = FYET_MAPPING_START,
+    MappingEnd = FYET_MAPPING_END,
+    SequenceStart = FYET_SEQUENCE_START,
+    SequenceEnd = FYET_SEQUENCE_END,
+    Scalar = FYET_SCALAR,
+    Alias = FYET_ALIAS,
+};
+
+enum class EScalarStyle {
+    Any = FYSS_ANY,
+    Plain = FYSS_PLAIN,
+    SingleQuoted = FYSS_SINGLE_QUOTED,
+    DoubleQuoted = FYSS_DOUBLE_QUOTED,
+    Literal = FYSS_LITERAL,
+    Folded = FYSS_FOLDED,
+    Max = FYSS_MAX,
+};
+
+enum class EEmitterWriteType {
+    DocumentIndicator = fyewt_document_indicator,
+    TagDirective = fyewt_tag_directive,
+    VersionDirective = fyewt_version_directive,
+    Indent = fyewt_indent,
+    Indicator = fyewt_indicator,
+    Whitespace = fyewt_whitespace,
+    PlainScalar = fyewt_plain_scalar,
+    SingleQuotedScalar = fyewt_single_quoted_scalar,
+    DoubleQuotedScalar = fyewt_double_quoted_scalar,
+    LiteralScalar = fyewt_literal_scalar,
+    FoldedScalar = fyewt_folded_scalar,
+    Anchor = fyewt_anchor,
+    Tag = fyewt_tag,
+    Linebreak = fyewt_linebreak,
+    Alias = fyewt_alias,
+    TerminatingZero = fyewt_terminating_zero,
+    PlainScalarKey = fyewt_plain_scalar_key,
+    SingleQuotedScalarKey = fyewt_single_quoted_scalar_key,
+    DoubleQuotedScalarKey = fyewt_double_quoted_scalar_key,
+    Comment = fyewt_comment,
+};
+
+enum class ECommentPlacement {
+    Top = fycp_top,
+    Right = fycp_right,
+    Bottom = fycp_bottom,
+};
+
+enum EEmitterCfgFlags {
+    SortKeys = FYECF_SORT_KEYS,
+    OutputComments = FYECF_OUTPUT_COMMENTS,
+    StripLabels = FYECF_STRIP_LABELS,
+    StripTags = FYECF_STRIP_TAGS,
+    StripDoc = FYECF_STRIP_DOC,
+    NoEndingNewline = FYECF_NO_ENDING_NEWLINE,
+    StripEmptyKv = FYECF_STRIP_EMPTY_KV,
+    IndentDefault = FYECF_INDENT_DEFAULT,
+    Indent1 = FYECF_INDENT_1,
+    Indent2 = FYECF_INDENT_2,
+    Indent3 = FYECF_INDENT_3,
+    Indent4 = FYECF_INDENT_4,
+    Indent5 = FYECF_INDENT_5,
+    Indent6 = FYECF_INDENT_6,
+    Indent7 = FYECF_INDENT_7,
+    Indent8 = FYECF_INDENT_8,
+    Indent9 = FYECF_INDENT_9,
+    WidthDefault = FYECF_WIDTH_DEFAULT,
+    Width80 = FYECF_WIDTH_80,
+    Width132 = FYECF_WIDTH_132,
+    WidthInf = FYECF_WIDTH_INF,
+    ModeOriginal = FYECF_MODE_ORIGINAL,
+    ModeBlock = FYECF_MODE_BLOCK,
+    ModeFlow = FYECF_MODE_FLOW,
+    ModeFlowOneline = FYECF_MODE_FLOW_ONELINE,
+    ModeJson = FYECF_MODE_JSON,
+    ModeJsonTp = FYECF_MODE_JSON_TP,
+    ModeJsonOneline = FYECF_MODE_JSON_ONELINE,
+    ModeDejson = FYECF_MODE_DEJSON,
+    ModePretty = FYECF_MODE_PRETTY,
+    DocStartMarkAuto = FYECF_DOC_START_MARK_AUTO,
+    DocStartMarkOff = FYECF_DOC_START_MARK_OFF,
+    DocStartMarkOn = FYECF_DOC_START_MARK_ON,
+    DocEndMarkAuto = FYECF_DOC_END_MARK_AUTO,
+    DocEndMarkOff = FYECF_DOC_END_MARK_OFF,
+    DocEndMarkOn = FYECF_DOC_END_MARK_ON,
+    VersionDirAuto = FYECF_VERSION_DIR_AUTO,
+    VersionDirOff = FYECF_VERSION_DIR_OFF,
+    VersionDirOn = FYECF_VERSION_DIR_ON,
+    TagDirAuto = FYECF_TAG_DIR_AUTO,
+    TagDirOff = FYECF_TAG_DIR_OFF,
+    TagDirOn = FYECF_TAG_DIR_ON,
+
+    Default = FYECF_DEFAULT,
+};
+
+enum class ENodeStyle {
+    Any = FYNS_ANY,
+    Flow = FYNS_FLOW,
+    Block = FYNS_BLOCK,
+    Plain = FYNS_PLAIN,
+    SingleQuoted = FYNS_SINGLE_QUOTED,
+    DoubleQuoted = FYNS_DOUBLE_QUOTED,
+    Literal = FYNS_LITERAL,
+    Folded = FYNS_FOLDED,
+    Alias = FYNS_ALIAS,
+};
+
+enum class ENodeWalkFlags {
+    DontFollow = FYNWF_DONT_FOLLOW,
+    Follow = FYNWF_FOLLOW,
+    PtrYaml = FYNWF_PTR_YAML,
+    PtrJson = FYNWF_PTR_JSON,
+    PtrReljson = FYNWF_PTR_RELJSON,
+    PtrYpath = FYNWF_PTR_YPATH,
+    UriEncoded = FYNWF_URI_ENCODED,
+    MaxdepthDefault = FYNWF_MAXDEPTH_DEFAULT,
+    MarkerDefault = FYNWF_MARKER_DEFAULT,
+    PtrDefault = FYNWF_PTR_DEFAULT,
+};
+
+enum class EPathParseCfgFlags {
+    Quiet = FYPPCF_QUIET,
+    DisableRecycling = FYPPCF_DISABLE_RECYCLING,
+    DisableAccelerators = FYPPCF_DISABLE_ACCELERATORS,
+};
+
+enum class EPathExecCfgFlags {
+    Quiet = FYPXCF_QUIET,
+    DisableRecycling = FYPXCF_DISABLE_RECYCLING,
+    DisableAccelerators = FYPXCF_DISABLE_ACCELERATORS,
+};
+
+enum class ETokenType {
+    /* non-content token types */
+    None = FYTT_NONE,
+    StreamStart = FYTT_STREAM_START,
+    StreamEnd = FYTT_STREAM_END,
+    VersionDirective = FYTT_VERSION_DIRECTIVE,
+    TagDirective = FYTT_TAG_DIRECTIVE,
+    DocumentStart = FYTT_DOCUMENT_START,
+    DocumentEnd = FYTT_DOCUMENT_END,
+    /* content token types */
+    BlockSequenceStart = FYTT_BLOCK_SEQUENCE_START,
+    BlockMappingStart = FYTT_BLOCK_MAPPING_START,
+    BlockEnd = FYTT_BLOCK_END,
+    FlowSequenceStart = FYTT_FLOW_SEQUENCE_START,
+    FlowSequenceEnd = FYTT_FLOW_SEQUENCE_END,
+    FlowMappingStart = FYTT_FLOW_MAPPING_START,
+    FlowMappingEnd = FYTT_FLOW_MAPPING_END,
+    BlockEntry = FYTT_BLOCK_ENTRY,
+    FlowEntry = FYTT_FLOW_ENTRY,
+    Key = FYTT_KEY,
+    Value = FYTT_VALUE,
+    Alias = FYTT_ALIAS,
+    Anchor = FYTT_ANCHOR,
+    Tag = FYTT_TAG,
+    Scalar = FYTT_SCALAR,
+
+    /* special error reporting */
+    Input_marker = FYTT_INPUT_MARKER,
+
+    /* path expression tokens */
+    PeSlash = FYTT_PE_SLASH,
+    PeRoot = FYTT_PE_ROOT,
+    PeThis = FYTT_PE_THIS,
+    PeParent = FYTT_PE_PARENT,
+    PeMapKey = FYTT_PE_MAP_KEY,
+    PeSeqIndex = FYTT_PE_SEQ_INDEX,
+    PeSeqSlice = FYTT_PE_SEQ_SLICE,
+    PeScalarFilter = FYTT_PE_SCALAR_FILTER,
+    PeCollectionFilter = FYTT_PE_COLLECTION_FILTER,
+    PeSeqFilter = FYTT_PE_SEQ_FILTER,
+    PeMapFilter = FYTT_PE_MAP_FILTER,
+    PeUniqueFilter = FYTT_PE_UNIQUE_FILTER,
+    PeEveryChild = FYTT_PE_EVERY_CHILD,
+    PeEveryChildR = FYTT_PE_EVERY_CHILD_R,
+    PeAlias = FYTT_PE_ALIAS,
+    PeSibling = FYTT_PE_SIBLING,
+    PeComma = FYTT_PE_COMMA,
+    PeBarbar = FYTT_PE_BARBAR,
+    PeAmpamp = FYTT_PE_AMPAMP,
+    PeLparen = FYTT_PE_LPAREN,
+    PeRparen = FYTT_PE_RPAREN,
+
+    /* comparison operators */
+    PeEqeq = FYTT_PE_EQEQ,
+    PeNoteq = FYTT_PE_NOTEQ,
+    PeLt = FYTT_PE_LT,
+    PeGt = FYTT_PE_GT,
+    PeLte = FYTT_PE_LTE,
+    PeGte = FYTT_PE_GTE,
+
+    /* scalar expression tokens */
+    SePlus = FYTT_SE_PLUS,
+    SeMinus = FYTT_SE_MINUS,
+    SeMult = FYTT_SE_MULT,
+    SeDiv = FYTT_SE_DIV,
+
+    PeMethod = FYTT_PE_METHOD,
+    SeMethod = FYTT_SE_METHOD,
+};
+
+enum class EComposerReturn {
+    OkContinue = FYCR_OK_CONTINUE,
+    OkStop = FYCR_OK_STOP,
+    OkStartSkip = FYCR_OK_START_SKIP,
+    OkStopSkip = FYCR_OK_STOP_SKIP,
+    Error = FYCR_ERROR,
+};
+
+TDocumentIterator::TDocumentIterator(fy_document_iterator* iterator)
+    : Iterator_(iterator, fy_document_iterator_destroy)
+{}
+
+TNode TNodeRef::CreateReference() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return TNode(fy_node_create_reference(Node_));
+}
+
+TNode TNodeRef::Copy() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return TNode(fy_node_copy(fy_node_document(Node_), Node_));
+}
+
+TString TNodeRef::Path() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    char* path = fy_node_get_path(Node_);
+
+    if (path) {
+        TString str(path);
+        free(path);
+        return str;
+    }
+
+    return {};
+}
+
+ENodeType TNodeRef::Type() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return static_cast<ENodeType>(fy_node_get_type(Node_));
+}
+
+bool TNodeRef::IsAlias() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return fy_node_is_alias(Node_);
+}
+
+TNodeRef TNodeRef::ResolveAlias() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    Y_VERIFY_DEBUG(IsAlias());
+    return TNodeRef(fy_node_resolve_alias(Node_));
+}
+
+TString TNodeRef::Scalar() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    Y_ENSURE_EX(fy_node_is_scalar(Node_), TFyamlEx() << "Node is not Scalar: " << Path());
+    size_t size;
+    const char* text = fy_node_get_scalar(Node_, &size);
+    return TString(text, size);
+}
+
+TMapping TNodeRef::Map() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    Y_ENSURE_EX(fy_node_is_mapping(Node_), TFyamlEx() << "Node is not Mapping: " << Path());
+    return TMapping(*this);
+}
+
+TSequence TNodeRef::Sequence() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    Y_ENSURE_EX(fy_node_is_sequence(Node_), TFyamlEx() << "Node is not Sequence: " << Path());
+    return TSequence(*this);
+}
+
+void TNodeRef::Insert(const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    NDetail::RethrowOnError(fy_node_insert(Node_, node.Node_), Node_);
+}
+
+std::optional<TString> TNodeRef::Tag() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    size_t len = 0;
+    const char* tag = fy_node_get_tag(Node_, &len);
+
+    if (tag) {
+        return TString(tag, len);
+    }
+
+    return std::nullopt;
+}
+
+void TNodeRef::SetTag(const TString& tag) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    auto* str = new TString(std::move(tag));
+    auto* data = new NDetail::TUserDataHolder(UserData(), str);
+    SetUserData(data);
+    NDetail::RethrowOnError(fy_node_set_tag(Node_, str->c_str(), str->length()), Node_);
+}
+
+bool TNodeRef::RemoveTag() {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    bool ret = fy_node_remove_tag(Node_);
+    ClearUserData();
+    return ret;
+}
+
+bool TNodeRef::HasAnchor() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return fy_node_get_anchor(Node_) != nullptr;
+}
+
+void TNodeRef::SetAnchor(const TString& anchor) {
+    auto* str = new TString(anchor);
+    auto* data = new NDetail::TUserDataHolder(UserData(), str);
+    SetUserData(data);
+    NDetail::RethrowOnError(fy_node_set_anchor(Node_, str->c_str(), str->length()), Node_);
+}
+
+bool TNodeRef::DeepEqual(const TNodeRef& other) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(other.Node_);
+    return fy_node_compare(Node_, other.Node_);
+}
+
+std::unique_ptr<char, void(*)(char*)> TNodeRef::EmitToCharArray() const {
+    std::unique_ptr<char, void(*)(char*)> res(
+        fy_emit_node_to_string(
+            Node_,
+            (fy_emitter_cfg_flags)(FYECF_DEFAULT)), &NDetail::FreeChar);
+    return res;
+}
+
+void TNodeRef::SetUserData(NDetail::IBasicUserData* data) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    fy_node_set_meta(Node_, data);
+}
+
+NDetail::IBasicUserData* TNodeRef::UserData() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return reinterpret_cast<NDetail::IBasicUserData* >(fy_node_get_meta(Node_));
+}
+
+void TNodeRef::ClearUserData() {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    fy_node_clear_meta(Node_);
+}
+
+TNode& TNode::operator=(fy_node* node) {
+    Node_.reset(node, fy_node_free);
+    return *this;
+}
+
+TNode::TNode(fy_node* node)
+    : Node_(node, fy_node_free)
+{}
+
+TNodeRef TNodePairRef::Key() const {
+    ENSURE_NODE_NOT_EMPTY(Pair_);
+    return TNodeRef(fy_node_pair_key(Pair_));
+}
+
+void TNodePairRef::SetKey(const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Pair_);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_pair_set_key(Pair_, node.Node_), Pair_);
+}
+
+TNodeRef TNodePairRef::Value() const {
+    ENSURE_NODE_NOT_EMPTY(Pair_);
+    return TNodeRef(fy_node_pair_value(Pair_));
+}
+
+void TNodePairRef::SetValue(const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Pair_);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_pair_set_value(Pair_, node.Node_), Pair_);
+}
+
+TMappingIterator::TMappingIterator(const TNodeRef& node, bool end)
+    : Node_(node)
+{
+    if (!end) {
+        NodePair_ = TNodePairRef(fy_node_mapping_iterate(Node_.Node_, reinterpret_cast<void**>(&NodePair_.Pair_)));
+    }
+}
+
+TMappingIterator& TMappingIterator::operator++() {
+    NodePair_ = TNodePairRef(fy_node_mapping_iterate(Node_.Node_, reinterpret_cast<void**>(&NodePair_.Pair_)));
+    return *this;
+}
+
+TReverseMappingIterator::TReverseMappingIterator(const TNodeRef& node, bool end)
+    : Node_(node)
+{
+    if (!end) {
+        NodePair_ = TNodePairRef(fy_node_mapping_reverse_iterate(Node_.Node_, reinterpret_cast<void**>(&NodePair_.Pair_)));
+    }
+}
+
+TReverseMappingIterator& TReverseMappingIterator::operator++() {
+    NodePair_ = TNodePairRef(fy_node_mapping_reverse_iterate(Node_.Node_, reinterpret_cast<void**>(&NodePair_.Pair_)));
+    return *this;
+}
+
+size_t TMapping::size() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return fy_node_mapping_item_count(Node_);
+}
+
+size_t TMapping::empty() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return fy_node_mapping_is_empty(Node_);
+}
+
+TNodePairRef TMapping::at(int index) const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    auto res = fy_node_mapping_get_by_index(Node_, index);
+    Y_ENSURE_EX(res, TFyamlEx() << "No such child: " << Path() << "/" << index);
+    return TNodePairRef(res);
+}
+
+TNodePairRef TMapping::operator[](int index) const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return TNodePairRef(fy_node_mapping_get_by_index(Node_, index));
+}
+
+TNodeRef TMapping::at(const TString& index) const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    auto res = fy_node_mapping_lookup_by_string(Node_, index.data(), index.size());
+    Y_ENSURE_EX(res, TFyamlEx() << "No such child: " << Path() << "/" << index);
+    return TNodeRef(res);
+}
+
+TNodePairRef TMapping::pair_at(const TString& index) const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    auto res = fy_node_mapping_lookup_pair_by_string(Node_, index.data(), index.size());
+    Y_ENSURE_EX(res, TFyamlEx() << "No such child: " << Path() << "/" << index);
+    return TNodePairRef(res);
+}
+
+TNodePairRef TMapping::pair_at_opt(const TString& index) const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return TNodePairRef(fy_node_mapping_lookup_pair_by_string(Node_, index.data(), index.size()));
+}
+
+TNodeRef TMapping::operator[](const TString& index) const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return TNodeRef(fy_node_mapping_lookup_by_string(Node_, index.data(), index.size()));
+}
+
+TNodeRef TMapping::operator[](const char* str) const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    TString index(str);
+    return TNodeRef(fy_node_mapping_lookup_by_string(Node_, index.data(), index.size()));
+}
+
+void TMapping::Append(const TNodeRef& key, const TNodeRef& value) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(key);
+    ENSURE_NODE_NOT_EMPTY(value);
+    NDetail::RethrowOnError(fy_node_mapping_append(Node_, key.Node_, value.Node_), Node_);
+}
+
+void TMapping::Prepend(const TNodeRef& key, const TNodeRef& value) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(key);
+    ENSURE_NODE_NOT_EMPTY(value);
+    NDetail::RethrowOnError(fy_node_mapping_prepend(Node_, key.Node_, value.Node_), Node_);
+}
+
+void TMapping::Remove(const TNodePairRef& toRemove) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(toRemove);
+    NDetail::RethrowOnError(fy_node_mapping_remove(Node_, toRemove.Pair_), Node_);
+}
+
+TMappingIterator TMapping::Remove(const TMappingIterator& toRemove) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    Y_VERIFY_DEBUG(Node_ == toRemove.Node_);
+    TMappingIterator ret = toRemove;
+    ++ret;
+    fy_node_mapping_remove(Node_, toRemove.NodePair_.Pair_);
+    return ret;
+}
+
+void TMapping::Remove(const TNodeRef& key) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    fy_node_free(fy_node_mapping_remove_by_key(Node_, key.Node_));
+}
+
+TSequenceIterator::TSequenceIterator(const TNodeRef& node, bool end)
+    : Node_(node)
+{
+    if (!end) {
+        IterNode_ = TNodeRef(fy_node_sequence_iterate(Node_.Node_, &Iter_));
+    }
+}
+
+TSequenceIterator& TSequenceIterator::operator++() {
+    IterNode_ = TNodeRef(fy_node_sequence_iterate(Node_.Node_, &Iter_));
+    return *this;
+}
+
+void TSequenceIterator::InsertBefore(const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(IterNode_);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_sequence_insert_before(Node_.Node_, IterNode_.Node_, node.Node_), Node_.Node_);
+}
+
+void TSequenceIterator::InsertAfter(const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(IterNode_);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_sequence_insert_after(Node_.Node_, IterNode_.Node_, node.Node_), Node_.Node_);
+}
+
+TReverseSequenceIterator::TReverseSequenceIterator(const TNodeRef& node, bool end)
+    : Node_(node)
+{
+    if (!end) {
+        IterNode_ = TNodeRef(fy_node_sequence_reverse_iterate(Node_.Node_, &Iter_));
+    }
+}
+
+TReverseSequenceIterator& TReverseSequenceIterator::operator++() {
+    IterNode_ = TNodeRef(fy_node_sequence_reverse_iterate(Node_.Node_, &Iter_));
+    return *this;
+}
+
+void TReverseSequenceIterator::InsertBefore(const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(IterNode_);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_sequence_insert_after(Node_.Node_, IterNode_.Node_, node.Node_), Node_.Node_);
+}
+
+void TReverseSequenceIterator::InsertAfter(const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(IterNode_);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_sequence_insert_before(Node_.Node_, IterNode_.Node_, node.Node_), Node_.Node_);
+}
+
+size_t TSequence::size() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return fy_node_sequence_item_count(Node_);
+}
+
+size_t TSequence::empty() const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return fy_node_sequence_is_empty(Node_);
+}
+
+TNodeRef TSequence::at(int index) const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    auto res = fy_node_sequence_get_by_index(Node_, index);
+    Y_ENSURE_EX(res, TFyamlEx() << "No such index: " << Path() << "/" << index);
+    return TNodeRef(res);
+}
+
+TNodeRef TSequence::operator[](int index) const {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    return TNodeRef(fy_node_sequence_get_by_index(Node_, index));
+}
+
+void TSequence::Append(const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_sequence_append(Node_, node.Node_), Node_);
+}
+
+void TSequence::Prepend(const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_sequence_prepend(Node_, node.Node_), Node_);
+}
+
+void TSequence::InsertBefore(const TNodeRef& mark, const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(mark);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_sequence_insert_before(Node_, mark.Node_, node.Node_), Node_);
+}
+
+void TSequence::InsertAfter(const TNodeRef& mark, const TNodeRef& node) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(mark);
+    ENSURE_NODE_NOT_EMPTY(node);
+    NDetail::RethrowOnError(fy_node_sequence_insert_after(Node_, mark.Node_, node.Node_), Node_);
+}
+
+TNode TSequence::Remove(const TNodeRef& toRemove) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    ENSURE_NODE_NOT_EMPTY(toRemove.Node_);
+    return TNode(fy_node_sequence_remove(Node_, toRemove.Node_));
+}
+
+TSequenceIterator TSequence::Remove(const TSequenceIterator& toRemove) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    Y_VERIFY_DEBUG(Node_ == toRemove.Node_);
+    ENSURE_NODE_NOT_EMPTY(toRemove.IterNode_);
+    TSequenceIterator ret = toRemove;
+    ++ret;
+    fy_node_sequence_remove(Node_, toRemove.IterNode_.Node_);
+    fy_node_free(toRemove.IterNode_.Node_); // TODO add extract
+    return ret;
+}
+
+TReverseSequenceIterator TSequence::Remove(const TReverseSequenceIterator& toRemove) {
+    ENSURE_NODE_NOT_EMPTY(Node_);
+    Y_VERIFY_DEBUG(Node_ == toRemove.Node_);
+    ENSURE_NODE_NOT_EMPTY(toRemove.IterNode_);
+    TReverseSequenceIterator ret = toRemove;
+    ++ret;
+    fy_node_sequence_remove(Node_, toRemove.IterNode_.Node_);
+    fy_node_free(toRemove.IterNode_.Node_); // TODO add extract
+    return ret;
+}
+
+TDocumentNodeIterator::TDocumentNodeIterator(TNodeRef&& node)
+    : Node_(node)
+{
+    if (node) {
+        Iterator_ = {fy_document_iterator_create(), fy_document_iterator_destroy};
+        fy_document_iterator_node_start(Iterator_.get(), node.Node_);
+    }
+}
+
+TDocumentNodeIterator& TDocumentNodeIterator::operator++() {
+    Node_ = fy_document_iterator_node_next(Iterator_.get());
+    return *this;
+}
+
+TDocument::TDocument(fy_document* doc, fy_diag* diag)
+    : Document_(doc, fy_document_destroy)
+    , Diag_(diag, fy_diag_destroy)
+{
+    RegisterUserDataCleanup();
+}
+
+TDocument TDocument::Parse(const char* cstr) {
+    fy_diag_cfg dcfg;
+    fy_diag_cfg_default(&dcfg);
+    std::unique_ptr<fy_diag, void(*)(fy_diag*)> diag(fy_diag_create(&dcfg), fy_diag_destroy);
+    fy_diag_set_collect_errors(diag.get(), true);
+    fy_parse_cfg cfg{
+        "",
+        // FYPCF_PARSE_COMMENTS,
+        FYPCF_QUIET,
+        nullptr,
+        diag.get()
+    };
+    fy_document* doc = fy_document_build_from_string(&cfg, cstr, FY_NT);
+    if (!doc) {
+        fy_diag_error* err;
+        void *iter = nullptr;
+        while ((err = fy_diag_errors_iterate(diag.get(), &iter)) != nullptr) {
+            ythrow yexception() << err->file << ":" << err->line << ":" << err->column << " " << err->msg;
+        }
+    }
+    return TDocument(doc, diag.release());
+}
+
+TDocument TDocument::Clone() const {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    fy_document* doc = fy_document_clone(Document_.get());
+    return TDocument(doc, fy_document_get_diag(doc));
+}
+
+void TDocument::InsertAt(const char* path, const TNodeRef& node) {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    NDetail::RethrowOnError(fy_document_insert_at(Document_.get(), path, FY_NT, node.Node_), Diag_.get());
+}
+
+TNodeRef TDocument::Buildf(const char* content) {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    return fy_node_build_from_string(Document_.get(), content, strlen(content));
+}
+
+void TDocument::Resolve() {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    if (fy_document_resolve(Document_.get()) != 0) {
+        fy_diag_error* err;
+        void *iter = nullptr;
+        while ((err = fy_diag_errors_iterate(Diag_.get(), &iter)) != nullptr) {
+            ythrow yexception() << err->line << ":" << err->column << " " << err->msg;
+        }
+    }
+}
+
+bool TDocument::HasDirectives() {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    return fy_document_has_directives(Document_.get());
+}
+
+bool TDocument::HasExplicitDocumentStart() {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    return fy_document_has_explicit_document_start(Document_.get());
+}
+
+bool TDocument::HasExplicitDocumentEnd() {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    return fy_document_has_explicit_document_end(Document_.get());
+}
+
+void TDocument::SetParent(const TDocument& doc) {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    ENSURE_DOCUMENT_NOT_EMPTY(doc.Document_);
+    NDetail::RethrowOnError(fy_document_set_parent(doc.Document_.get(), Document_.release()), Diag_.get());
+}
+
+TNodeRef TDocument::Root() {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    return fy_document_root(Document_.get());
+}
+
+void TDocument::SetRoot(const TNodeRef& node) {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    ENSURE_NODE_NOT_EMPTY(node.Node_);
+    NDetail::RethrowOnError(fy_document_set_root(Document_.get(), node.Node_), Diag_.get());
+}
+
+TNodeRef TDocument::CreateAlias(const TString& name) {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    return TNodeRef(fy_node_create_alias_copy(Document_.get(), name.c_str(), name.length()));
+}
+
+std::unique_ptr<char, void(*)(char*)> TDocument::EmitToCharArray() const {
+    std::unique_ptr<char, void(*)(char*)> res(
+        fy_emit_document_to_string(
+            Document_.get(),
+            (fy_emitter_cfg_flags)(FYECF_DEFAULT | FYECF_OUTPUT_COMMENTS)), &NDetail::FreeChar);
+    return res;
+}
+
+bool TDocument::RegisterUserDataCleanup() {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    return fy_document_register_meta(Document_.get(), &DestroyUserData, nullptr) == 0;
+}
+
+void TDocument::UnregisterUserDataCleanup() {
+    ENSURE_DOCUMENT_NOT_EMPTY(Document_);
+    fy_document_unregister_meta(Document_.get());
+}
+
+std::unique_ptr<char, void(*)(char*)> TJsonEmitter::EmitToCharArray() const {
+    std::unique_ptr<char, void(*)(char*)> res(
+        fy_emit_document_to_string(
+            Document_.Document_.get(),
+            (fy_emitter_cfg_flags)(FYECF_DEFAULT | FYECF_SORT_KEYS | FYECF_MODE_JSON_TP)), &NDetail::FreeChar);
+    return res;
+}
+
+namespace NDetail {
+
+void RethrowError(fy_diag* diag) {
+    void *iter = nullptr;
+    fy_diag_error* err;
+    TStringStream ss;
+    while ((err = fy_diag_errors_iterate(diag, &iter)) != nullptr) {
+        ss << err->line << ":" << err->column << " " << err->msg << "\n";
+    }
+    ythrow yexception() << ss.Str();
+}
+
+void RethrowOnError(bool isError, fy_node* node) {
+    if (!isError) {
+        return;
+    }
+
+    std::unique_ptr<fy_diag, void(*)(fy_diag*)> diag(fy_document_get_diag(fy_node_document(node)), fy_diag_unref);
+    RethrowError(diag.get());
+}
+
+void RethrowOnError(bool isError, fy_node_pair* pair) {
+    if (!isError) {
+        return;
+    }
+
+    std::unique_ptr<fy_diag, void(*)(fy_diag*)> diag(fy_document_get_diag(fy_node_document(fy_node_pair_key(pair))), fy_diag_unref);
+    RethrowError(diag.get());
+}
+
+void RethrowOnError(bool isError, fy_diag* diag) {
+    if (!isError) {
+        return;
+    }
+
+    RethrowError(diag);
+}
+
+
+void FreeChar(char* mem) {
+    free(mem);
+}
+
+} // namespace NDetail
+
+} // namespace NFyaml
+
+template <>
+void Out<NFyaml::TDocument>(IOutputStream& out, const NFyaml::TDocument& value) {
+    out << value.EmitToCharArray().get();
+}
+
+template <>
+void Out<NFyaml::TNodeRef>(IOutputStream& out, const NFyaml::TNodeRef& value) {
+    out << value.EmitToCharArray().get();
+}
+
+template <>
+void Out<NFyaml::TJsonEmitter>(IOutputStream& out, const NFyaml::TJsonEmitter& value) {
+    out << value.EmitToCharArray().get();
+}
diff --git a/library/cpp/yaml/fyamlcpp/fyamlcpp.h b/library/cpp/yaml/fyamlcpp/fyamlcpp.h
new file mode 100644
index 0000000000..7437b74ef7
--- /dev/null
+++ b/library/cpp/yaml/fyamlcpp/fyamlcpp.h
@@ -0,0 +1,593 @@
+#pragma once
+
+#include <util/generic/yexception.h>
+#include <util/system/compiler.h>
+#include <util/system/yassert.h>
+#include <util/stream/str.h>
+
+#include <memory>
+#include <optional>
+
+struct fy_node;
+struct fy_document;
+struct fy_diag;
+struct fy_document_iterator;
+struct fy_node_pair;
+
+namespace NFyaml {
+
+struct TFyamlEx : public yexception {};
+
+enum class ENodeType {
+    Scalar,
+    Sequence,
+    Mapping,
+};
+
+namespace NDetail {
+
+class IBasicUserData {
+public:
+    virtual ~IBasicUserData() = default;
+};
+
+template <class T>
+class TUserDataHolder : public IBasicUserData {
+public:
+    TUserDataHolder(IBasicUserData* next, T* data)
+        : Next_(next)
+        , Data_(data)
+    {}
+
+private:
+    std::unique_ptr<IBasicUserData> Next_ = nullptr;
+    std::unique_ptr<T> Data_ = nullptr;
+};
+
+void RethrowError(fy_diag* diag);
+
+void RethrowOnError(bool isError, fy_node* node);
+
+void RethrowOnError(bool isError, fy_node_pair* pair);
+
+void RethrowOnError(bool isError, fy_diag* diag);
+
+void FreeChar(char* mem);
+
+} // namespace NDetail
+
+class TNodeRef;
+class TDocumentIterator;
+class TDocument;
+class TNode;
+class TMappingIterator;
+class TReverseMappingIterator;
+class TMapping;
+class TSequenceIterator;
+class TReverseSequenceIterator;
+class TSequence;
+class TJsonEmitter;
+
+class TDocumentIterator {
+    friend class TDocument;
+public:
+    TDocumentIterator(fy_document_iterator* iterator = nullptr);
+
+protected:
+    std::unique_ptr<fy_document_iterator, void(*)(fy_document_iterator*)> Iterator_;
+};
+
+class TNodeRef {
+    friend class TDocument;
+    friend class TDocumentNodeIterator;
+    friend class TNode;
+    friend class TMapping;
+    friend class TMappingIterator;
+    friend class TReverseMappingIterator;
+    friend class TNodePairRef;
+    friend class TSequence;
+    friend class TSequenceIterator;
+    friend class TReverseSequenceIterator;
+
+    TNodeRef(fy_node* node)
+        : Node_(node)
+    {}
+
+public:
+    TNodeRef() {};
+
+    TNodeRef(const TNodeRef& other) { Node_ = other.Node_; }
+
+    TNodeRef& operator=(const TNodeRef& other) { Node_ = other.Node_; return *this; }
+
+    TNodeRef& operator=(fy_node* node) { Node_ = node; return *this; }
+
+    bool operator==(const TNodeRef& other) const { return Node_ == other.Node_; }
+
+    explicit operator bool() const { return Node_ != nullptr; }
+
+    TString Path() const;
+
+    ENodeType Type() const;
+
+    TNode Copy() const;
+
+    bool IsAlias() const;
+
+    TNodeRef ResolveAlias() const;
+
+    TNode CreateReference() const;
+
+    TSequence Sequence() const;
+
+    TMapping Map() const;
+
+    TString Scalar() const;
+
+    void Insert(const TNodeRef& node);
+
+    bool Empty() const { return Node_ == nullptr; }
+
+    std::optional<TString> Tag() const;
+
+    void SetTag(const TString& tag);
+
+    bool RemoveTag();
+
+    bool HasAnchor() const;
+
+    void SetAnchor(const TString& anchor);
+
+    bool DeepEqual(const TNodeRef& other);
+
+    std::unique_ptr<char, void(*)(char*)> EmitToCharArray() const;
+
+protected:
+    fy_node* Node_ = nullptr;
+
+    void SetUserData(NDetail::IBasicUserData* data);
+    NDetail::IBasicUserData* UserData() const;
+    void ClearUserData();
+};
+
+class TNode {
+    friend class TDocument;
+    friend class TDocumentNodeIterator;
+    friend class TNodeRef;
+    friend class TSequence;
+
+    TNode& operator=(fy_node* node);
+public:
+    TNode(fy_node* node = nullptr);
+
+    bool operator==(const TNode& other) const { return Node_ == other.Node_; }
+
+    explicit operator bool() { return Node_ != nullptr; }
+
+    TNodeRef Ref() { return TNodeRef(Node_.get()); }
+
+private:
+    std::shared_ptr<fy_node> Node_;
+};
+
+class TNodePairRef {
+    friend class TMappingIterator;
+    friend class TReverseMappingIterator;
+    friend class TMapping;
+public:
+    TNodePairRef(fy_node_pair* pair = nullptr)
+        : Pair_(pair)
+    {}
+
+    bool operator==(const TNodePairRef& other) const { return Pair_ == other.Pair_; }
+
+    explicit operator bool() const { return Pair_ != nullptr; }
+
+    TNodeRef Key() const;
+
+    void SetKey(const TNodeRef& node);
+
+    TNodeRef Value() const;
+
+    void SetValue(const TNodeRef& node);
+
+private:
+    fy_node_pair* Pair_ = nullptr;
+};
+
+class TMappingIterator {
+    friend class TMapping;
+public:
+    TMappingIterator(const TNodeRef& node, bool end = false);
+
+    TMappingIterator(const TMappingIterator& other) {
+        Node_ = other.Node_;
+        NodePair_ = other.NodePair_;
+    }
+
+    TMappingIterator& operator=(const TMappingIterator& other) {
+        Node_ = other.Node_;
+        NodePair_ = other.NodePair_;
+        return *this;
+    }
+
+    TMappingIterator& operator++();
+
+    const TNodePairRef* operator->() const { return &NodePair_; }
+
+    TMappingIterator operator++(int) {
+        TMappingIterator retval = *this;
+        ++(*this);
+        return retval;
+    }
+
+    bool operator==(TMappingIterator other) const { return Node_ == other.Node_ && NodePair_ == other.NodePair_; }
+
+    const TNodePairRef& operator*() const { return NodePair_; }
+
+private:
+    TNodeRef Node_;
+    TNodePairRef NodePair_;
+};
+
+class TReverseMappingIterator {
+    friend class TMapping;
+public:
+    TReverseMappingIterator(const TNodeRef& node, bool end = false);
+
+    TReverseMappingIterator(const TReverseMappingIterator& other) {
+        Node_ = other.Node_;
+        NodePair_ = other.NodePair_;
+    }
+
+    TReverseMappingIterator& operator=(const TReverseMappingIterator& other) {
+        Node_ = other.Node_;
+        NodePair_ = other.NodePair_;
+        return *this;
+    }
+
+    TReverseMappingIterator& operator++();
+
+    const TNodePairRef* operator->() const { return &NodePair_; }
+
+    TReverseMappingIterator operator++(int) {
+        TReverseMappingIterator retval = *this;
+        ++(*this);
+        return retval;
+    }
+
+    bool operator==(TReverseMappingIterator other) const { return Node_ == other.Node_ && NodePair_ == other.NodePair_; }
+
+    bool operator!=(TReverseMappingIterator other) const { return !(*this == other); }
+
+    const TNodePairRef& operator*() const { return NodePair_; }
+
+private:
+    TNodeRef Node_;
+    TNodePairRef NodePair_;
+};
+
+class TMapping : public TNodeRef {
+public:
+    explicit TMapping(const TNodeRef& node)
+        : TNodeRef(node)
+    {
+        Y_VERIFY_DEBUG(Type() == ENodeType::Mapping);
+    }
+
+    TMappingIterator begin() const {
+        return TMappingIterator(Node_);
+    }
+
+    TMappingIterator end() const {
+        return TMappingIterator(Node_, true);
+    }
+
+    TReverseMappingIterator rbegin() const {
+        return TReverseMappingIterator(Node_);
+    }
+
+    TReverseMappingIterator rend() const {
+        return TReverseMappingIterator(Node_, true);
+    }
+
+    size_t size() const;
+
+    size_t empty() const;
+
+    TNodePairRef at(int index) const;
+
+    TNodePairRef operator[](int index) const;
+
+    TNodeRef at(const TString& index) const;
+
+    TNodePairRef pair_at(const TString& index) const;
+
+    TNodePairRef pair_at_opt(const TString& index) const;
+
+    TNodeRef operator[](const TString& index) const;
+
+    TNodeRef operator[](const char* str) const;
+
+    void Append(const TNodeRef& key, const TNodeRef& value);
+
+    void Prepend(const TNodeRef& key, const TNodeRef& value);
+
+    void Remove(const TNodePairRef& toRemove);
+
+    TMappingIterator Remove(const TMappingIterator& toRemove);
+
+    void Remove(const TNodeRef& key);
+};
+
+class TSequenceIterator {
+    friend class TSequence;
+public:
+    TSequenceIterator(const TNodeRef& node, bool end = false);
+
+    TSequenceIterator(const TSequenceIterator& other) {
+        Node_ = other.Node_;
+        IterNode_ = other.IterNode_;
+        Iter_ = other.Iter_;
+    }
+
+    TSequenceIterator& operator=(const TSequenceIterator& other) {
+        Node_ = other.Node_;
+        IterNode_ = other.IterNode_;
+        Iter_ = other.Iter_;
+        return *this;
+    }
+
+    TSequenceIterator& operator++();
+
+    const TNodeRef* operator->() const {
+        return &IterNode_;
+    }
+
+    TSequenceIterator operator++(int) {
+        TSequenceIterator retval = *this;
+        ++(*this);
+        return retval;
+    }
+
+    bool operator==(TSequenceIterator other) const { return Node_ == other.Node_ && Iter_ == other.Iter_; }
+
+    bool operator!=(TSequenceIterator other) const { return !(*this == other); }
+
+    const TNodeRef& operator*() const { return IterNode_; }
+
+    void InsertBefore(const TNodeRef& node);
+
+    void InsertAfter(const TNodeRef& node);
+
+private:
+    TNodeRef Node_;
+    TNodeRef IterNode_;
+    void* Iter_ = nullptr;
+};
+
+class TReverseSequenceIterator {
+    friend class TSequence;
+public:
+    TReverseSequenceIterator(const TNodeRef& node, bool end = false);
+
+    TReverseSequenceIterator(const TReverseSequenceIterator& other) {
+        Node_ = other.Node_;
+        IterNode_ = other.IterNode_;
+        Iter_ = other.Iter_;
+    }
+
+    TReverseSequenceIterator& operator=(const TReverseSequenceIterator& other) {
+        Node_ = other.Node_;
+        IterNode_ = other.IterNode_;
+        Iter_ = other.Iter_;
+        return *this;
+    }
+
+    TReverseSequenceIterator& operator++();
+
+    const TNodeRef* operator->() const {
+        return &IterNode_;
+    }
+
+    TReverseSequenceIterator operator++(int) {
+        TReverseSequenceIterator retval = *this;
+        ++(*this);
+        return retval;
+    }
+
+    bool operator==(TReverseSequenceIterator other) const { return Node_ == other.Node_ && Iter_ == other.Iter_; }
+
+    bool operator!=(TReverseSequenceIterator other) const { return !(*this == other); }
+
+    const TNodeRef& operator*() const { return IterNode_; }
+
+    void InsertBefore(const TNodeRef& node);
+
+    void InsertAfter(const TNodeRef& node);
+
+private:
+    TNodeRef Node_;
+    TNodeRef IterNode_;
+    void* Iter_ = nullptr;
+};
+
+class TSequence : public TNodeRef {
+public:
+    explicit TSequence(const TNodeRef& node)
+        : TNodeRef(node)
+    {
+        Y_VERIFY_DEBUG(Type() == ENodeType::Sequence);
+    }
+
+    TSequenceIterator begin() const {
+        return TSequenceIterator(Node_);
+    }
+
+    TSequenceIterator end() const {
+        return TSequenceIterator(Node_, true);
+    }
+
+    TReverseSequenceIterator rbegin() const {
+        return TReverseSequenceIterator(Node_);
+    }
+
+    TReverseSequenceIterator rend() const {
+        return TReverseSequenceIterator(Node_, true);
+    }
+
+    size_t size() const;
+
+    size_t empty() const;
+
+    TNodeRef at(int index) const;
+
+    TNodeRef operator[](int index) const;
+
+    void Append(const TNodeRef& node);
+
+    void Prepend(const TNodeRef& node);
+
+    void InsertBefore(const TNodeRef& mark, const TNodeRef& node);
+
+    void InsertAfter(const TNodeRef& mark, const TNodeRef& node);
+
+    TNode Remove(const TNodeRef& toRemove);
+
+    TSequenceIterator Remove(const TSequenceIterator& toRemove);
+
+    TReverseSequenceIterator Remove(const TReverseSequenceIterator& toRemove);
+};
+
+class TDocumentNodeIterator
+    : public TDocumentIterator
+{
+public:
+    TDocumentNodeIterator(TNodeRef&& node);
+
+    TDocumentNodeIterator(const TDocumentNodeIterator& other)
+        : TDocumentIterator(other.Iterator_.get())
+        , Node_(other.Node_)
+    {}
+
+    TDocumentNodeIterator& operator=(const TDocumentNodeIterator& other) {
+        Iterator_.reset(other.Iterator_.get());
+        Node_ = other.Node_;
+        return *this;
+    }
+
+    TDocumentNodeIterator& operator++();
+
+    TNodeRef* operator->() {
+        return &Node_;
+    }
+
+    TDocumentNodeIterator operator++(int) {
+        TDocumentNodeIterator retval = *this;
+        ++(*this);
+        return retval;
+    }
+
+    bool operator==(TDocumentNodeIterator other) const { return Node_ == other.Node_; }
+
+    bool operator!=(TDocumentNodeIterator other) const { return !(*this == other); }
+
+    TNodeRef& operator*() { return Node_; }
+
+private:
+    TNodeRef Node_;
+};
+
+class TDocument {
+    friend class TNode;
+    friend class TJsonEmitter;
+
+    TDocument(fy_document* doc = nullptr, fy_diag* diag = nullptr);
+
+public:
+    TDocument(TDocument&& other)
+        : Document_(std::move(other.Document_))
+        , Diag_(std::move(other.Diag_))
+    {}
+
+    static TDocument Parse(const char* cstr);
+
+    TDocument Clone() const;
+
+    template <class... Args>
+    size_t Scanf(const char* fmt, Args&& ...args) {
+        Y_VERIFY_DEBUG(Document_);
+        return fy_document_scanf(Document_.get(), fmt, std::forward<Args>(args)...);
+    }
+
+    void InsertAt(const char* path, const TNodeRef& node);
+
+    template <class... Args>
+    TNodeRef Buildf(const char* fmt, Args&& ...args) {
+        Y_VERIFY_DEBUG(Document_);
+        return fy_node_buildf(Document_.get(), fmt, std::forward<Args>(args)...);
+    }
+
+    TNodeRef Buildf(const char* content);
+
+    void Resolve();
+
+    bool HasDirectives();
+
+    bool HasExplicitDocumentStart();
+
+    bool HasExplicitDocumentEnd();
+
+    void SetParent(const TDocument& doc);
+
+    TNodeRef Root();
+
+    void SetRoot(const TNodeRef& node);
+
+    TDocumentNodeIterator begin() {
+        auto it = TDocumentNodeIterator(Root());
+        ++it;
+        return it;
+    }
+
+
+    TDocumentNodeIterator end() {
+        return TDocumentNodeIterator(TNodeRef(nullptr));
+    }
+
+    TNodeRef CreateAlias(const TString& name);
+
+    std::unique_ptr<char, void(*)(char*)> EmitToCharArray() const;
+
+private:
+    std::unique_ptr<fy_document, void(*)(fy_document*)> Document_;
+    std::unique_ptr<fy_diag, void(*)(fy_diag*)> Diag_;
+
+    static void DestroyUserData(fy_node *fyn, void *meta, void *user) {
+        Y_UNUSED(fyn);
+        Y_UNUSED(user);
+        if (meta) {
+            auto* data = reinterpret_cast<NDetail::IBasicUserData*>(meta);
+            delete data;
+        }
+    }
+
+    bool RegisterUserDataCleanup();
+    void UnregisterUserDataCleanup();
+};
+
+class TJsonEmitter {
+public:
+    TJsonEmitter(const TDocument& doc) : Document_(doc) {}
+
+    std::unique_ptr<char, void(*)(char*)> EmitToCharArray() const;
+
+private:
+    const TDocument& Document_;
+
+    fy_document* Document() const {
+        return Document_.Document_.get();
+    }
+};
+
+} // namesapce NFyaml
diff --git a/library/cpp/yaml/fyamlcpp/fyamlcpp_ut.cpp b/library/cpp/yaml/fyamlcpp/fyamlcpp_ut.cpp
new file mode 100644
index 0000000000..f9aab7b011
--- /dev/null
+++ b/library/cpp/yaml/fyamlcpp/fyamlcpp_ut.cpp
@@ -0,0 +1,53 @@
+#include "fyamlcpp.h"
+
+#include <contrib/libs/libfyaml/include/libfyaml.h>
+
+#include <library/cpp/testing/unittest/registar.h>
+
+#include <util/stream/str.h>
+
+Y_UNIT_TEST_SUITE(FYamlCpp) {
+    Y_UNIT_TEST(EnumEquals) {
+        UNIT_ASSERT_EQUAL((int)NFyaml::ENodeType::Scalar, FYNT_SCALAR);
+        UNIT_ASSERT_EQUAL((int)NFyaml::ENodeType::Sequence, FYNT_SEQUENCE);
+        UNIT_ASSERT_EQUAL((int)NFyaml::ENodeType::Mapping, FYNT_MAPPING);
+    }
+
+    Y_UNIT_TEST(ErrorHandling) {
+        {
+            const char *yaml = R"(
+config: a
+config: b
+)";
+            UNIT_ASSERT_EXCEPTION_CONTAINS(
+                NFyaml::TDocument::Parse(yaml),
+                yexception,
+                "3:1 duplicate key");
+        }
+
+        {
+            const char *yaml = R"(
+anchor: *does_not_exists
+)";
+            auto doc = NFyaml::TDocument::Parse(yaml);
+            UNIT_ASSERT_EXCEPTION_CONTAINS(
+                doc.Resolve(),
+                yexception,
+                "2:10 invalid alias");
+        }
+    }
+
+    Y_UNIT_TEST(Out) {
+        const char *yaml = R"(
+test: output
+)";
+
+        auto doc = NFyaml::TDocument::Parse(yaml);
+
+        TStringStream ss;
+
+        ss << doc;
+
+        UNIT_ASSERT_VALUES_EQUAL(ss.Str(), "test: output\n");
+    }
+}
diff --git a/library/cpp/yaml/fyamlcpp/libfyaml_ut.cpp b/library/cpp/yaml/fyamlcpp/libfyaml_ut.cpp
new file mode 100644
index 0000000000..d5e28cf98e
--- /dev/null
+++ b/library/cpp/yaml/fyamlcpp/libfyaml_ut.cpp
@@ -0,0 +1,1838 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <limits.h>
+
+#include <span>
+
+#include <contrib/libs/libfyaml/include/libfyaml.h>
+#include <library/cpp/testing/unittest/registar.h>
+
+/*
+These tests are ported from https://github.com/pantoniou/libfyaml/blob/master/test/libfyaml-test-core.c
+To check windows compatibility and avoid possible internal patch issues
+*/
+
+Y_UNIT_TEST_SUITE(LibFyamlCore) {
+
+Y_UNIT_TEST(doc_build_simple) {
+    struct fy_document *fyd;
+
+    /* setup */
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* cleanup */
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_build_parse_check) {
+    struct fy_document *fyd;
+    char *buf;
+
+    /* build document (with comments, newlines etc) */
+    fyd = fy_document_build_from_string(NULL, "#comment\n[ 42,  \n  12 ] # comment\n", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* convert to string */
+    buf = fy_emit_document_to_string(fyd, FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* compare with expected result */
+    UNIT_ASSERT_VALUES_EQUAL(buf, TString("[42, 12]\n"));
+
+    free(buf);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_build_scalar) {
+    struct fy_document *fyd;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL, "plain scalar # comment", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* compare with expected result */
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_document_root(fyd)), TString("plain scalar"));
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_build_sequence) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    int count;
+    void *iter;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL, "[ 10, 11, foo ] # comment", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* check for correct count value */
+    count = fy_node_sequence_item_count(fy_document_root(fyd));
+    UNIT_ASSERT_EQUAL(count, 3);
+
+    /* try forward iterator first */
+    iter = NULL;
+
+    /* 0 */
+    fyn = fy_node_sequence_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("10"));
+
+    /* 1 */
+    fyn = fy_node_sequence_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("11"));
+
+    /* 2 */
+    fyn = fy_node_sequence_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("foo"));
+
+    /* final, iterator must return NULL */
+    fyn = fy_node_sequence_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_EQUAL(fyn, NULL);
+
+    /* reverse iterator */
+    iter = NULL;
+
+    /* 2 */
+    fyn = fy_node_sequence_reverse_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("foo"));
+
+    /* 1 */
+    fyn = fy_node_sequence_reverse_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("11"));
+
+    /* 0 */
+    fyn = fy_node_sequence_reverse_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("10"));
+
+    /* final, iterator must return NULL */
+    fyn = fy_node_sequence_reverse_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_EQUAL(fyn, NULL);
+
+    /* do forward index based accesses */
+
+    /* 0 */
+    fyn = fy_node_sequence_get_by_index(fy_document_root(fyd), 0);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("10"));
+
+    /* 1 */
+    fyn = fy_node_sequence_get_by_index(fy_document_root(fyd), 1);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("11"));
+
+    /* 2 */
+    fyn = fy_node_sequence_get_by_index(fy_document_root(fyd), 2);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("foo"));
+
+    /* 3, it must not exist */
+    fyn = fy_node_sequence_get_by_index(fy_document_root(fyd), 3);
+    UNIT_ASSERT_EQUAL(fyn, NULL);
+
+    /* do backward index based accesses */
+
+    /* 2 */
+    fyn = fy_node_sequence_get_by_index(fy_document_root(fyd), -1);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("foo"));
+
+    /* 1 */
+    fyn = fy_node_sequence_get_by_index(fy_document_root(fyd), -2);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("11"));
+
+    /* 0 */
+    fyn = fy_node_sequence_get_by_index(fy_document_root(fyd), -3);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn), TString("10"));
+
+    /* -1, it must not exist */
+    fyn = fy_node_sequence_get_by_index(fy_document_root(fyd), -4);
+    UNIT_ASSERT_EQUAL(fyn, NULL);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_build_mapping) {
+    struct fy_document *fyd;
+    struct fy_node_pair *fynp;
+    int count;
+    void *iter;
+
+    fyd = fy_document_build_from_string(NULL, "{ foo: 10, bar : 20, baz: [100, 101], [frob, 1]: boo }", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* check for correct count value */
+    count = fy_node_mapping_item_count(fy_document_root(fyd));
+    UNIT_ASSERT_EQUAL(count, 4);
+
+    /* forward iterator first */
+    iter = NULL;
+
+    /* 0 */
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_key(fynp)), TString("foo"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), TString("10"));
+
+    /* 1 */
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_key(fynp)), TString("bar"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), TString("20"));
+
+    /* 2 */
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_key(fynp)), TString("baz"));
+    UNIT_ASSERT_EQUAL(fy_node_sequence_item_count(fy_node_pair_value(fynp)), 2);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_sequence_get_by_index(fy_node_pair_value(fynp), 0)), TString("100"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_sequence_get_by_index(fy_node_pair_value(fynp), 1)), TString("101"));
+
+    /* 3 */
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_EQUAL(fy_node_sequence_item_count(fy_node_pair_key(fynp)), 2);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_sequence_get_by_index(fy_node_pair_key(fynp), 0)), TString("frob"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_sequence_get_by_index(fy_node_pair_key(fynp), 1)), TString("1"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), TString("boo"));
+
+    /* 4, it must not exist */
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_EQUAL(fynp, NULL);
+
+    /* reverse iterator */
+    iter = NULL;
+
+    /* 3 */
+    fynp = fy_node_mapping_reverse_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_EQUAL(fy_node_sequence_item_count(fy_node_pair_key(fynp)), 2);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_sequence_get_by_index(fy_node_pair_key(fynp), 0)), TString("frob"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_sequence_get_by_index(fy_node_pair_key(fynp), 1)), TString("1"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), TString("boo"));
+
+    /* 2 */
+    fynp = fy_node_mapping_reverse_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_key(fynp)), TString("baz"));
+    UNIT_ASSERT_EQUAL(fy_node_sequence_item_count(fy_node_pair_value(fynp)), 2);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_sequence_get_by_index(fy_node_pair_value(fynp), 0)), TString("100"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_sequence_get_by_index(fy_node_pair_value(fynp), 1)), TString("101"));
+
+    /* 1 */
+    fynp = fy_node_mapping_reverse_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_key(fynp)), TString("bar"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), TString("20"));
+
+    /* 0 */
+    fynp = fy_node_mapping_reverse_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_key(fynp)), TString("foo"));
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), TString("10"));
+
+    /* -1, it must not exist */
+    fynp = fy_node_mapping_reverse_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_EQUAL(fynp, NULL);
+
+    /* key lookups (note how only the contents are compared) */
+    UNIT_ASSERT(fy_node_compare_string(fy_node_mapping_lookup_by_string(fy_document_root(fyd), "foo", FY_NT), "10", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_mapping_lookup_by_string(fy_document_root(fyd), "bar", FY_NT), "20", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_mapping_lookup_by_string(fy_document_root(fyd), "baz", FY_NT), "- 100\n- 101", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_mapping_lookup_by_string(fy_document_root(fyd), "- 'frob'\n- \"\x31\"", FY_NT), "boo", FY_NT) == true);
+
+    fy_document_destroy(fyd);
+    fyd = NULL;
+}
+
+Y_UNIT_TEST(doc_path_access) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL, "{ "
+        "foo: 10, bar : 20, baz:{ frob: boo }, "
+        "frooz: [ seq1, { key: value} ], \"zero\\0zero\" : 0, "
+        "{ key2: value2 }: { key3: value3 } "
+        "}", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* check that getting root node works */
+    fyn = fy_node_by_path(fy_document_root(fyd), "/", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fy_document_root(fyd));
+
+    /* check access to scalars */
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/foo", FY_NT, FYNWF_DONT_FOLLOW), "10", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "bar", FY_NT, FYNWF_DONT_FOLLOW), "20", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "baz/frob", FY_NT, FYNWF_DONT_FOLLOW), "boo", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/frooz/0", FY_NT, FYNWF_DONT_FOLLOW), "seq1", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/frooz/1/key", FY_NT, FYNWF_DONT_FOLLOW), "value", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "\"zero\\0zero\"", FY_NT, FYNWF_DONT_FOLLOW), "0", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/{ key2: value2 }/key3", FY_NT, FYNWF_DONT_FOLLOW), "value3", FY_NT) == true);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_path_node) {
+    struct fy_document *fyd;
+    char *path;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL, "{ "
+        "foo: 10, bar : 20, baz:{ frob: boo }, "
+        "frooz: [ seq1, { key: value} ], \"zero\\0zero\" : 0, "
+        "{ key2: value2 }: { key3: value3 } "
+        "}", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    path = fy_node_get_path(fy_node_by_path(fy_document_root(fyd), "/", FY_NT, FYNWF_DONT_FOLLOW));
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("/"));
+    free(path);
+
+    path = fy_node_get_path(fy_node_by_path(fy_document_root(fyd), "/frooz", FY_NT, FYNWF_DONT_FOLLOW));
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("/frooz"));
+    free(path);
+
+    path = fy_node_get_path(fy_node_by_path(fy_document_root(fyd), "/frooz/0", FY_NT, FYNWF_DONT_FOLLOW));
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("/frooz/0"));
+    free(path);
+
+    path = fy_node_get_path(fy_node_by_path(fy_document_root(fyd), "/{ key2: value2 }/key3", FY_NT, FYNWF_DONT_FOLLOW));
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("/{key2: value2}/key3"));
+    free(path);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_path_parent) {
+    struct fy_document *fyd;
+    struct fy_node *fyn_root, *fyn_foo, *fyn_bar, *fyn_baz, *fyn_frob, *fyn_ten;
+    struct fy_node *fyn_deep, *fyn_deeper;
+    char *path;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL, "{ "
+        "foo: 10, bar : [ ten, 20 ], baz:{ frob: boo, deep: { deeper: yet } }, "
+        "}", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn_root = fy_document_root(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_root, NULL);
+
+    fyn_foo = fy_node_by_path(fyn_root, "/foo", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_foo, NULL);
+
+    fyn_bar = fy_node_by_path(fyn_root, "/bar", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_bar, NULL);
+
+    fyn_baz = fy_node_by_path(fyn_root, "/baz", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_baz, NULL);
+
+    fyn_frob = fy_node_by_path(fyn_root, "/baz/frob", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_frob, NULL);
+
+    fyn_ten = fy_node_by_path(fyn_root, "/bar/0", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_ten, NULL);
+
+    fyn_deep = fy_node_by_path(fyn_root, "/baz/deep", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_deep, NULL);
+
+    fyn_deeper = fy_node_by_path(fyn_root, "/baz/deep/deeper", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_deeper, NULL);
+
+    /* check parent paths of foo, frob, ten */
+    path = fy_node_get_parent_address(fyn_foo);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("foo"));
+    free(path);
+
+    path = fy_node_get_parent_address(fyn_frob);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("frob"));
+    free(path);
+
+    path = fy_node_get_parent_address(fyn_ten);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("0"));
+    free(path);
+
+    /* check relative paths to root */
+    path = fy_node_get_path_relative_to(NULL, fyn_foo);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("foo"));
+    free(path);
+
+    path = fy_node_get_path_relative_to(fyn_root, fyn_foo);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("foo"));
+    free(path);
+
+    path = fy_node_get_path_relative_to(fyn_root, fyn_frob);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("baz/frob"));
+    free(path);
+
+    path = fy_node_get_path_relative_to(fyn_root, fyn_ten);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("bar/0"));
+    free(path);
+
+    /* check relative paths to other parents */
+    path = fy_node_get_path_relative_to(fyn_baz, fyn_frob);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("frob"));
+    free(path);
+
+    path = fy_node_get_path_relative_to(fyn_bar, fyn_ten);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("0"));
+    free(path);
+
+    path = fy_node_get_path_relative_to(fyn_baz, fyn_deeper);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("deep/deeper"));
+    free(path);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_short_path) {
+    struct fy_document *fyd;
+    struct fy_node *fyn_root, *fyn_foo, *fyn_notfoo, *fyn_bar, *fyn_baz;
+    const char *str;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL,
+        "--- &r\n"
+        "  foo: &f\n"
+        "    bar: [ 0, two, baz: what ]\n"
+        "    frob: true\n"
+        "  notfoo: false\n"
+        , FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn_root = fy_document_root(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_root, NULL);
+
+    fyn_foo = fy_node_by_path(fyn_root, "/foo", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_foo, NULL);
+
+    fyn_notfoo = fy_node_by_path(fyn_root, "/notfoo", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_notfoo, NULL);
+
+    fyn_bar = fy_node_by_path(fyn_root, "/foo/bar", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_bar, NULL);
+
+    fyn_baz = fy_node_by_path(fyn_root, "/foo/bar/2/baz", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_baz, NULL);
+
+    str = fy_node_get_short_path(fyn_root);
+    UNIT_ASSERT_UNEQUAL(str, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(str, "*r");
+    UNIT_ASSERT_EQUAL(fy_node_by_path(fy_document_root(fyd), str, FY_NT, FYNWF_FOLLOW), fyn_root);
+    free((void*)str);
+
+    str = fy_node_get_short_path(fyn_foo);
+    UNIT_ASSERT_UNEQUAL(str, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(str, "*f");
+    UNIT_ASSERT_EQUAL(fy_node_by_path(fy_document_root(fyd), str, FY_NT, FYNWF_FOLLOW), fyn_foo);
+    free((void*)str);
+
+    str = fy_node_get_short_path(fyn_notfoo);
+    UNIT_ASSERT_UNEQUAL(str, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(str, "*r/notfoo");
+    UNIT_ASSERT_EQUAL(fy_node_by_path(fy_document_root(fyd), str, FY_NT, FYNWF_FOLLOW), fyn_notfoo);
+    free((void*)str);
+
+    str = fy_node_get_short_path(fyn_bar);
+    UNIT_ASSERT_UNEQUAL(str, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(str, "*f/bar");
+    UNIT_ASSERT_EQUAL(fy_node_by_path(fy_document_root(fyd), str, FY_NT, FYNWF_FOLLOW), fyn_bar);
+    free((void*)str);
+
+    str = fy_node_get_short_path(fyn_baz);
+    UNIT_ASSERT_UNEQUAL(str, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(str, "*f/bar/2/baz");
+    UNIT_ASSERT_EQUAL(fy_node_by_path(fy_document_root(fyd), str, FY_NT, FYNWF_FOLLOW), fyn_baz);
+    free((void*)str);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_scalar_path) {
+    struct fy_document *fyd;
+    struct fy_node *fyn_root, *fyn_foo;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL, "--- foo\n", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn_root = fy_document_root(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_root, NULL);
+
+    /* get the scalar root and verify */
+    fyn_foo = fy_node_by_path(fyn_root, "/", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_foo, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fyn_foo), "foo");
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_scalar_path_array) {
+    struct fy_document *fyd;
+    struct fy_node *fyn_root, *fynt;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL, "--- [ foo, bar, baz ]\n", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn_root = fy_document_root(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_root, NULL);
+
+    /* get the scalars in the array and verify */
+    fynt = fy_node_by_path(fyn_root, "/0", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fynt, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fynt), "foo");
+
+    fynt = fy_node_by_path(fyn_root, "/1", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fynt, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fynt), "bar");
+
+    fynt = fy_node_by_path(fyn_root, "/2", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fynt, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fynt), "baz");
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_nearest_anchor) {
+    struct fy_document *fyd;
+    struct fy_node *fyn, *fyn_root, *fyn_foo, *fyn_notfoo, *fyn_bar, *fyn_baz;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL,
+        "--- &r\n"
+        "  foo: &f\n"
+        "    bar: [ 0, two, baz: what ]\n"
+        "    frob: true\n"
+        "  notfoo: false\n"
+        , FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn_root = fy_document_root(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_root, NULL);
+
+    fyn_foo = fy_node_by_path(fyn_root, "/foo", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_foo, NULL);
+
+    fyn_notfoo = fy_node_by_path(fyn_root, "/notfoo", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_notfoo, NULL);
+
+    fyn_bar = fy_node_by_path(fyn_root, "/foo/bar", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_bar, NULL);
+
+    fyn_baz = fy_node_by_path(fyn_root, "/foo/bar/2/baz", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_baz, NULL);
+
+    /* get nearest anchor of root (is root) */
+    fyn = fy_anchor_node(fy_node_get_nearest_anchor(fyn_root));
+    UNIT_ASSERT_EQUAL(fyn, fyn_root);
+
+    /* get nearest anchor of notfoo (is root) */
+    fyn = fy_anchor_node(fy_node_get_nearest_anchor(fyn_notfoo));
+    UNIT_ASSERT_EQUAL(fyn, fyn_root);
+
+    /* get nearest anchor of baz (is foo) */
+    fyn = fy_anchor_node(fy_node_get_nearest_anchor(fyn_baz));
+    UNIT_ASSERT_EQUAL(fyn, fyn_foo);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_references) {
+    struct fy_document *fyd;
+    struct fy_node *fyn, *fyn_ref, *fyn_root, *fyn_foo, *fyn_notfoo, *fyn_bar, *fyn_baz;
+    char *path;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL,
+        "---\n"
+        "  foo: &f\n"
+        "    bar: [ 0, two, baz: what ]\n"
+        "    frob: true\n"
+        "  notfoo: false\n"
+        , FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn_root = fy_document_root(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_root, NULL);
+
+    fyn_foo = fy_node_by_path(fyn_root, "/foo", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_foo, NULL);
+
+    fyn_notfoo = fy_node_by_path(fyn_root, "/notfoo", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_notfoo, NULL);
+
+    fyn_bar = fy_node_by_path(fyn_root, "/foo/bar", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_bar, NULL);
+
+    fyn_baz = fy_node_by_path(fyn_root, "/foo/bar/2/baz", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_baz, NULL);
+
+    /* get reference to root */
+    path = fy_node_get_reference(fyn_root);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("*/"));
+    free(path);
+
+    /* get reference to /foo */
+    path = fy_node_get_reference(fyn_foo);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("*f"));
+    free(path);
+
+    /* get reference to /notfoo */
+    path = fy_node_get_reference(fyn_notfoo);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("*/notfoo"));
+    free(path);
+
+    /* get reference to /foo/bar/2/baz */
+    path = fy_node_get_reference(fyn_baz);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("*/foo/bar/2/baz"));
+    free(path);
+
+    /* create reference to root and verify it points there */
+    fyn_ref = fy_node_create_reference(fyn_root);
+    UNIT_ASSERT_UNEQUAL(fyn_ref, NULL);
+    fyn = fy_node_resolve_alias(fyn_ref);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_root);
+    fy_node_free(fyn_ref);
+
+    /* get reference to /foo */
+    fyn_ref = fy_node_create_reference(fyn_foo);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    fyn = fy_node_resolve_alias(fyn_ref);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_foo);
+    fy_node_free(fyn_ref);
+
+    /* get reference to /notfoo */
+    fyn_ref = fy_node_create_reference(fyn_notfoo);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    fyn = fy_node_resolve_alias(fyn_ref);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_notfoo);
+    fy_node_free(fyn_ref);
+
+    /* get reference to /bar */
+    fyn_ref = fy_node_create_reference(fyn_bar);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    fyn = fy_node_resolve_alias(fyn_ref);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_bar);
+    fy_node_free(fyn_ref);
+
+    /* get reference to /baz */
+    fyn_ref = fy_node_create_reference(fyn_baz);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    fyn = fy_node_resolve_alias(fyn_ref);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_baz);
+    fy_node_free(fyn_ref);
+
+    /* get relative reference to /foo starting at / */
+    path = fy_node_get_relative_reference(fyn_root, fyn_foo);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("*/foo"));
+    free(path);
+
+    /* get relative reference to /foo/bar/2/baz starting at / */
+    path = fy_node_get_relative_reference(fyn_root, fyn_baz);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("*/foo/bar/2/baz"));
+    free(path);
+
+    /* get relative reference to /foo/bar/2/baz starting at /foo */
+    path = fy_node_get_relative_reference(fyn_foo, fyn_baz);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("*f/bar/2/baz"));
+    free(path);
+
+    /* get relative reference to /notfoo at /foo (will return absolute) */
+    path = fy_node_get_relative_reference(fyn_foo, fyn_notfoo);
+    UNIT_ASSERT_UNEQUAL(path, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(path, TString("*/notfoo"));
+    free(path);
+
+    /* create relative reference to /foo starting at / */
+    fyn_ref = fy_node_create_relative_reference(fyn_root, fyn_foo);
+    UNIT_ASSERT_UNEQUAL(fyn_ref, NULL);
+    fyn = fy_node_resolve_alias(fyn_ref);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_foo);
+    fy_node_free(fyn_ref);
+
+    /* create relative reference to /foo/bar/2/baz starting at / */
+    fyn_ref = fy_node_create_relative_reference(fyn_root, fyn_baz);
+    UNIT_ASSERT_UNEQUAL(fyn_ref, NULL);
+    fyn = fy_node_resolve_alias(fyn_ref);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_baz);
+    fy_node_free(fyn_ref);
+
+    /* create relative reference to /foo/bar/2/baz starting at /foo */
+    fyn_ref = fy_node_create_relative_reference(fyn_foo, fyn_baz);
+    UNIT_ASSERT_UNEQUAL(fyn_ref, NULL);
+    fyn = fy_node_resolve_alias(fyn_ref);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_baz);
+    fy_node_free(fyn_ref);
+
+    /* create relative reference to /notfoo starting at /foo (will use absolute) */
+    fyn_ref = fy_node_create_relative_reference(fyn_foo, fyn_notfoo);
+    UNIT_ASSERT_UNEQUAL(fyn_ref, NULL);
+    fyn = fy_node_resolve_alias(fyn_ref);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_notfoo);
+    fy_node_free(fyn_ref);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_nearest_child_of) {
+    struct fy_document *fyd;
+    struct fy_node *fyn, *fyn_root, *fyn_foo, *fyn_bar, *fyn_baz;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL,
+        "foo:\n"
+        "  bar:\n"
+        "    barz: [ zero, baz: true ]\n"
+        "  frooz: notfoo\n"
+        , FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn_root = fy_document_root(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_root, NULL);
+
+    fyn_foo = fy_node_by_path(fyn_root, "/foo", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_foo, NULL);
+
+    fyn_bar = fy_node_by_path(fyn_root, "/foo/bar", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_bar, NULL);
+
+    fyn_baz = fy_node_by_path(fyn_root, "/foo/bar/barz/1/baz", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_baz, NULL);
+
+    /* nearest child to the root of /foo is /foo */
+    fyn = fy_node_get_nearest_child_of(fyn_root, fyn_foo);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_foo);
+
+    /* nearest child to the root of /foo/bar/barz/1/baz is /foo */
+    fyn = fy_node_get_nearest_child_of(fyn_root, fyn_baz);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_foo);
+
+    /* nearest child to foo of /foo/bar/barz/1/baz is /foo/bar */
+    fyn = fy_node_get_nearest_child_of(fyn_foo, fyn_baz);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+    UNIT_ASSERT_EQUAL(fyn, fyn_bar);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_create_empty_seq1) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    char *buf;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn = fy_node_build_from_string(fyd, "[ ]", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+
+    /* convert to string */
+    buf = fy_emit_node_to_string(fy_document_root(fyd), FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* compare with expected result */
+    UNIT_ASSERT_VALUES_EQUAL(buf, TString("[]"));
+
+    free(buf);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_create_empty_seq2) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    char *buf;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn = fy_node_create_sequence(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+
+    /* convert to string */
+    buf = fy_emit_node_to_string(fy_document_root(fyd), FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* compare with expected result */
+    UNIT_ASSERT_VALUES_EQUAL(buf, TString("[]"));
+
+    free(buf);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_create_empty_map1) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    char *buf;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn = fy_node_build_from_string(fyd, "{ }", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+
+    /* convert to string */
+    buf = fy_emit_node_to_string(fy_document_root(fyd), FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* compare with expected result */
+    UNIT_ASSERT_VALUES_EQUAL(buf, TString("{}"));
+
+    free(buf);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_create_empty_map2) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    char *buf;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn = fy_node_create_mapping(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+
+    /* convert to string */
+    buf = fy_emit_node_to_string(fy_document_root(fyd), FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* compare with expected result */
+    UNIT_ASSERT_VALUES_EQUAL(buf, TString("{}"));
+
+    free(buf);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_create_test_seq1) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    int ret;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn = fy_node_create_sequence(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    ret = fy_node_sequence_append(fyn, fy_node_create_scalar(fyd, "foo", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    ret = fy_node_sequence_append(fyn, fy_node_create_scalar(fyd, "bar", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    ret = fy_node_sequence_append(fyn, fy_node_build_from_string(fyd, "{ baz: frooz }", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    fy_document_set_root(fyd, fyn);
+
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/0", FY_NT, FYNWF_DONT_FOLLOW), "foo", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/1", FY_NT, FYNWF_DONT_FOLLOW), "bar", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/2/baz", FY_NT, FYNWF_DONT_FOLLOW), "frooz", FY_NT) == true);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_create_test_map1) {
+    struct fy_document *fyd;
+    struct fy_node *fyn, *fyn1, *fyn2, *fyn3;
+    int ret;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn = fy_node_create_mapping(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    ret = fy_node_mapping_append(fyn,
+            fy_node_build_from_string(fyd, "seq", FY_NT),
+            fy_node_build_from_string(fyd, "[ zero, one ]", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    ret = fy_node_mapping_append(fyn, NULL,
+            fy_node_build_from_string(fyd, "value-of-null-key", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    ret = fy_node_mapping_append(fyn,
+            fy_node_build_from_string(fyd, "key-of-null-value", FY_NT), NULL);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    fy_document_set_root(fyd, fyn);
+
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/seq/0", FY_NT, FYNWF_DONT_FOLLOW), "zero", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/seq/1", FY_NT, FYNWF_DONT_FOLLOW), "one", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/''", FY_NT, FYNWF_DONT_FOLLOW), "value-of-null-key", FY_NT) == true);
+
+    fyn1 = fy_node_by_path(fy_document_root(fyd), "/key-of-null-value", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_EQUAL(fyn1, NULL);
+
+    /* try to append duplicate key (it should fail) */
+    fyn2 = fy_node_build_from_string(fyd, "seq", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn2, NULL);
+    fyn3 = fy_node_create_scalar(fyd, "dupl", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn3, NULL);
+    ret = fy_node_mapping_append(fyn, fyn2, fyn3);
+    UNIT_ASSERT_UNEQUAL(ret, 0);
+
+    fy_node_free(fyn3);
+    fy_node_free(fyn2);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_insert_remove_seq) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    int ret;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fy_document_set_root(fyd, fy_node_build_from_string(fyd, "[ one, two, four ]", FY_NT));
+
+    /* check that the order is correct */
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/0", FY_NT, FYNWF_DONT_FOLLOW), "one", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/1", FY_NT, FYNWF_DONT_FOLLOW), "two", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/2", FY_NT, FYNWF_DONT_FOLLOW), "four", FY_NT) == true);
+
+    ret = fy_node_sequence_append(fy_document_root(fyd), fy_node_build_from_string(fyd, "five", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    ret = fy_node_sequence_prepend(fy_document_root(fyd), fy_node_build_from_string(fyd, "zero", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    ret = fy_node_sequence_insert_after(fy_document_root(fyd),
+            fy_node_by_path(fy_document_root(fyd), "/2", FY_NT, FYNWF_DONT_FOLLOW),
+            fy_node_build_from_string(fyd, "three", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    ret = fy_node_sequence_insert_before(fy_document_root(fyd),
+            fy_node_by_path(fy_document_root(fyd), "/3", FY_NT, FYNWF_DONT_FOLLOW),
+            fy_node_build_from_string(fyd, "two-and-a-half", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    fyn = fy_node_sequence_remove(fy_document_root(fyd),
+            fy_node_by_path(fy_document_root(fyd), "/3", FY_NT, FYNWF_DONT_FOLLOW));
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_node_free(fyn);
+
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/0", FY_NT, FYNWF_DONT_FOLLOW), "zero", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/1", FY_NT, FYNWF_DONT_FOLLOW), "one", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/2", FY_NT, FYNWF_DONT_FOLLOW), "two", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/3", FY_NT, FYNWF_DONT_FOLLOW), "three", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/4", FY_NT, FYNWF_DONT_FOLLOW), "four", FY_NT) == true);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_insert_remove_map) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    int ret;
+
+    fyd = fy_document_build_from_string(NULL, "{ one: 1, two: 2, four: 4 }", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* check that the order is correct */
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/one", FY_NT, FYNWF_DONT_FOLLOW), "1", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/two", FY_NT, FYNWF_DONT_FOLLOW), "2", FY_NT) == true);
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/four", FY_NT, FYNWF_DONT_FOLLOW), "4", FY_NT) == true);
+
+    ret = fy_node_mapping_append(fy_document_root(fyd),
+            fy_node_build_from_string(fyd, "three", FY_NT),
+            fy_node_build_from_string(fyd, "3", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/three", FY_NT, FYNWF_DONT_FOLLOW), "3", FY_NT) == true);
+
+    ret = fy_node_mapping_prepend(fy_document_root(fyd),
+            fy_node_build_from_string(fyd, "zero", FY_NT),
+            fy_node_build_from_string(fyd, "0", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/zero", FY_NT, FYNWF_DONT_FOLLOW), "0", FY_NT) == true);
+
+    ret = fy_node_mapping_append(fy_document_root(fyd),
+            fy_node_build_from_string(fyd, "two-and-a-half", FY_NT),
+            fy_node_build_from_string(fyd, "2.5", FY_NT));
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    UNIT_ASSERT(fy_node_compare_string(fy_node_by_path(fy_document_root(fyd), "/two-and-a-half", FY_NT, FYNWF_DONT_FOLLOW), "2.5", FY_NT) == true);
+
+    fyn = fy_node_mapping_remove_by_key(fy_document_root(fyd),
+            fy_node_build_from_string(fyd, "two-and-a-half", FY_NT));
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_node_free(fyn);
+
+    /* it must be removed */
+    fyn = fy_node_by_path(fy_document_root(fyd), "/two-and-a-half", FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_EQUAL(fyn, NULL);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_sort) {
+    struct fy_document *fyd;
+    fy_node_pair *fynp;
+    void *iter;
+    int ret, count;
+
+    fyd = fy_document_build_from_string(NULL, "{ a: 5, { z: bar }: 1, z: 7, "
+                      "[ a, b, c] : 3, { a: whee } : 2 , "
+                      "b: 6, [ z ]: 4 }", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    ret = fy_node_sort(fy_document_root(fyd), NULL, NULL);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    /* check for correct count value */
+    count = fy_node_mapping_item_count(fy_document_root(fyd));
+    UNIT_ASSERT_EQUAL(count, 7);
+
+    /* forward iterator first */
+    iter = NULL;
+
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), "1");
+
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), "2");
+
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), "3");
+
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), "4");
+
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), "5");
+
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), "6");
+
+    fynp = fy_node_mapping_iterate(fy_document_root(fyd), &iter);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_pair_value(fynp)), "7");
+
+    fy_document_destroy(fyd);
+}
+
+static char *join_docs(const char *tgt_text, const char *tgt_path,
+               const char *src_text, const char *src_path,
+               const char *emit_path)
+{
+    struct fy_document *fyd_tgt, *fyd_src;
+    struct fy_node *fyn_tgt, *fyn_src, *fyn_emit;
+    char *output;
+    int ret;
+
+    /* insert which overwrites root ( <map> <- <scalar> ) */
+    fyd_tgt = fy_document_build_from_string(NULL, tgt_text, FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd_tgt, NULL);
+
+    fyd_src = fy_document_build_from_string(NULL, src_text, FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd_src, NULL);
+
+    fyn_tgt = fy_node_by_path(fy_document_root(fyd_tgt), tgt_path, FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_tgt, NULL);
+
+    fyn_src = fy_node_by_path(fy_document_root(fyd_src), src_path, FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_src, NULL);
+
+    ret = fy_node_insert(fyn_tgt, fyn_src);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    ret = fy_document_set_parent(fyd_tgt, fyd_src);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    fyn_emit = fy_node_by_path(fy_document_root(fyd_tgt), emit_path, FY_NT, FYNWF_DONT_FOLLOW);
+    UNIT_ASSERT_UNEQUAL(fyn_emit, NULL);
+
+    output = fy_emit_node_to_string(fyn_emit, (fy_emitter_cfg_flags) (FYECF_MODE_FLOW_ONELINE | FYECF_WIDTH_INF));
+    UNIT_ASSERT_UNEQUAL(output, NULL);
+
+    fy_document_destroy(fyd_tgt);
+
+    return output;
+}
+
+Y_UNIT_TEST(doc_join_scalar_to_scalar) {
+    char *output;
+
+    output = join_docs(
+            "foo", "/",    /* target */
+            "bar", "/",    /* source */
+            "/");        /* emit path */
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("bar"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_join_scalar_to_map) {
+    char *output;
+
+    output = join_docs(
+            "{ foo: baz }", "/",    /* target */
+            "bar", "/",        /* source */
+            "/");            /* emit path */
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("bar"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_join_scalar_to_seq) {
+    char *output;
+
+    output = join_docs(
+            "[ foo, baz ]", "/",    /* target */
+            "bar", "/",        /* source */
+            "/");            /* emit path */
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("bar"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_join_map_to_scalar) {
+    char *output;
+
+    output = join_docs(
+            "foo", "/",        /* target */
+            "{bar: baz}", "/",        /* source */
+            "/");            /* emit path */
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("{bar: baz}"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_join_map_to_seq) {
+    char *output;
+
+    output = join_docs(
+            "[foo, frooz]", "/",    /* target */
+            "{bar: baz}", "/",    /* source */
+            "/");            /* emit path */
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("{bar: baz}"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_join_map_to_map) {
+    char *output;
+
+    output = join_docs(
+            "{foo: frooz}", "/",    /* target */
+            "{bar: baz}", "/",    /* source */
+            "/");            /* emit path */
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("{foo: frooz, bar: baz}"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_join_seq_to_scalar) {
+    char *output;
+
+    output = join_docs(
+            "foo", "/",        /* target */
+            "[bar, baz]", "/",        /* source */
+            "/");            /* emit path */
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("[bar, baz]"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_join_seq_to_seq) {
+    char *output;
+
+    output = join_docs(
+            "[foo, frooz]", "/",    /* target */
+            "[bar, baz]", "/",    /* source */
+            "/");            /* emit path */
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("[foo, frooz, bar, baz]"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_join_seq_to_map) {
+    char *output;
+
+    output = join_docs(
+            "{foo: frooz}", "/",    /* target */
+            "[bar, baz]", "/",    /* source */
+            "/");            /* emit path */
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("[bar, baz]"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_join_tags) {
+    char *output;
+
+    output = join_docs(
+        "%TAG !a! tag:a.com,2019:\n"
+        "---\n"
+        "- !a!foo\n"
+        "  foo: bar\n", "/",
+        "%TAG !b! tag:b.com,2019:\n"
+        "---\n"
+        "- !b!bar\n"
+        "  something: other\n", "/",
+        "/");
+
+    UNIT_ASSERT_VALUES_EQUAL(output, TString("[!a!foo {foo: bar}, !b!bar {something: other}]"));
+    free(output);
+}
+
+Y_UNIT_TEST(doc_build_with_tags) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    struct fy_token *fyt;
+    char *buf;
+    int rc;
+
+    /* build document */
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* create a sequence and set it as root */
+    fyn = fy_node_create_sequence(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+    fyn = NULL;
+
+    /* create a node, containing a new tag */
+    fyn = fy_node_build_from_string(fyd, "%TAG !e! tag:example.com,2000:app/\n---\n- foo\n- !e!foo bar\n", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    /* append it to the root of the document */
+    rc = fy_node_sequence_append(fy_document_root(fyd), fyn);
+    UNIT_ASSERT_EQUAL(rc, 0);
+    fyn = NULL;
+
+    /* there must be a new tag */
+    fyt = fy_document_tag_directive_lookup(fyd, "!e!");
+    UNIT_ASSERT_UNEQUAL(fyt, NULL);
+
+    /* try to build another, but with a different !e! prefix, it must fail */
+    fyn = fy_node_build_from_string(fyd, "%TAG !e! tag:example.com,2019:app/\n---\n- foo\n- !e!foo bar\n", FY_NT);
+    UNIT_ASSERT_EQUAL(fyn, NULL);
+
+    /* manually add a tag */
+    rc = fy_document_tag_directive_add(fyd, "!f!", "tag:example.com,2019:f/");
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    /* build a node with a tag that's already in the document */
+    fyn = fy_node_build_from_string(fyd, "!f!whiz frooz\n", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    /* append it to the root of the document */
+    rc = fy_node_sequence_append(fy_document_root(fyd), fyn);
+    UNIT_ASSERT_EQUAL(rc, 0);
+    fyn = NULL;
+
+    /* convert to string */
+    buf = fy_emit_document_to_string(fyd, FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    free(buf);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(doc_attach_check) {
+    struct fy_document *fyd;
+    struct fy_node *fyn, *fyn_seq, *fyn_map;
+    struct fy_node *fyn_foo, *fyn_foo2, *fyn_bar, *fyn_baz;
+    struct fy_node_pair *fynp;
+    int rc;
+
+    /* build document */
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* create a sequence */
+    fyn_seq = fy_node_create_sequence(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_seq, NULL);
+
+    /* create a mapping */
+    fyn_map = fy_node_create_mapping(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_map, NULL);
+
+    /* create a simple scalar node foo */
+    fyn_foo = fy_node_build_from_string(fyd, "foo", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn_foo, NULL);
+
+    /* create another simple scalar node bar */
+    fyn_bar = fy_node_build_from_string(fyd, "bar", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn_bar, NULL);
+
+    /* create another simple scalar node baz */
+    fyn_baz = fy_node_build_from_string(fyd, "baz", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn_baz, NULL);
+
+    /* create a scalar node with the same content as foo */
+    fyn_foo2 = fy_node_build_from_string(fyd, "foo", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn_foo2, NULL);
+
+    /* set the root as the sequence */
+    rc = fy_document_set_root(fyd, fyn_seq);
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    /* should fail since fyn_seq is now attached */
+    rc = fy_document_set_root(fyd, fyn_seq);
+    UNIT_ASSERT_UNEQUAL(rc, 0);
+
+    /* freeing should fail, since it's attached too */
+    rc = fy_node_free(fyn_seq);
+    UNIT_ASSERT_UNEQUAL(rc, 0);
+
+    /* append it to the sequence */
+    rc = fy_node_sequence_append(fyn_seq, fyn_foo);
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    /* freeing should fail, since it's attached to the seq */
+    rc = fy_node_free(fyn_foo);
+    UNIT_ASSERT_UNEQUAL(rc, 0);
+
+    /* trying to append it to the sequence again should fail */
+    rc = fy_node_sequence_append(fyn_seq, fyn_foo);
+    UNIT_ASSERT_UNEQUAL(rc, 0);
+
+    /* append the mapping to the sequence */
+    rc = fy_node_sequence_append(fyn_seq, fyn_map);
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    /* this should fail, since foo is attached to the sequence */
+    rc = fy_node_mapping_append(fyn_map, fyn_foo, fyn_bar);
+    UNIT_ASSERT_UNEQUAL(rc, 0);
+
+    /* this should be OK, since foo2 is not attached */
+    rc = fy_node_mapping_append(fyn_map, fyn_foo2, fyn_bar);
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    /* remove foo from the sequence */
+    fyn = fy_node_sequence_remove(fyn_seq, fyn_foo);
+    UNIT_ASSERT_EQUAL(fyn, fyn_foo);
+
+    /* trying to append the same key should fail */
+    rc = fy_node_mapping_append(fyn_map, fyn_foo, NULL);
+    UNIT_ASSERT_UNEQUAL(rc, 0);
+
+    /* append the baz: NULL mapping */
+    rc = fy_node_mapping_append(fyn_map, fyn_baz, NULL);
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    /* get the baz: null node pair */
+    fynp = fy_node_mapping_lookup_pair(fyn_map, fyn_baz);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_EQUAL(fy_node_pair_key(fynp), fyn_baz);
+    UNIT_ASSERT_EQUAL(fy_node_pair_value(fynp), NULL);
+
+    /* trying to set the same key in the mapping should fail */
+    rc = fy_node_pair_set_key(fynp, fyn_foo);
+    UNIT_ASSERT_UNEQUAL(rc, 0);
+
+    /* get the foo: bar node pair */
+    fynp = fy_node_mapping_lookup_pair(fyn_map, fyn_foo);
+    UNIT_ASSERT_UNEQUAL(fynp, NULL);
+    UNIT_ASSERT_EQUAL(fy_node_pair_key(fynp), fyn_foo2);
+    UNIT_ASSERT_EQUAL(fy_node_pair_value(fynp), fyn_bar);
+
+    /* we're setting the same key to the mapping, but that's OK
+     * since the key is replaced */
+    rc = fy_node_pair_set_key(fynp, fyn_foo);
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    /* fyn_foo has been freed */
+    fyn_foo = NULL;
+
+    /* convert to string */
+    rc = fy_emit_document_to_fp(fyd, FYECF_MODE_FLOW_ONELINE, stderr);
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(manual_scalar_esc) {
+    // FIXME removed \e because it works incorrectly in MS C
+    const std::span MANUAL_SCALAR_ESC = "\\\"\0\a\b\t\v\f\r\xc2\x85\xc2\xa0\xe2\x80\xa8\xe2\x80\xa9";
+    const TStringBuf MANUAL_SCALAR_ESC_TXT = "\"\\\\\\\"\\0\\a\\b\\t\\v\\f\\r\\N\\_\\L\\P\"";
+    const char *what = MANUAL_SCALAR_ESC.data();
+    size_t what_sz = MANUAL_SCALAR_ESC.size() - 1;
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    char *buf;
+    const char *buf2;
+    size_t sz2;
+    int rc;
+
+    /* build document */
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* create a manual scalar with all the escapes */
+    fyn = fy_node_create_scalar(fyd, what, what_sz);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+    fyn = NULL;
+
+    /* emit to a buffer */
+    buf = fy_emit_document_to_string(fyd, FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* destroy the old document */
+    fy_document_destroy(fyd);
+    fyd = NULL;
+
+    /* verify that the resulting document is in the escaped form */
+    UNIT_ASSERT_VALUES_EQUAL(buf, TString(MANUAL_SCALAR_ESC_TXT) + "\n");
+
+    /* now load the result back and verify that it contains exactly the same */
+    fyd = fy_document_build_from_string(NULL, buf, FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* get the scalar content */
+    buf2 = fy_node_get_scalar(fy_document_root(fyd), &sz2);
+    UNIT_ASSERT_UNEQUAL(buf2, NULL);
+
+    /* sizes must match */
+    UNIT_ASSERT_EQUAL(what_sz, sz2);
+
+    /* and the strings too */
+    rc = memcmp(what, buf2, what_sz);
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    /* free the document */
+    fy_document_destroy(fyd);
+    fyd = NULL;
+
+    free(buf);
+}
+
+Y_UNIT_TEST(manual_scalar_quoted) {
+    const TStringBuf MANUAL_SCALAR_QUOTED = "&foo";
+    const TStringBuf MANUAL_SCALAR_QUOTED_TXT = "\"&foo\"";
+    const char *what = MANUAL_SCALAR_QUOTED.data();
+    size_t what_sz = MANUAL_SCALAR_QUOTED.length();
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    char *buf;
+    const char *buf2;
+    size_t sz2;
+    int rc;
+
+    /* build document */
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* create a manual scalar with all the escapes */
+    fyn = fy_node_create_scalar(fyd, what, what_sz);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+    fyn = NULL;
+
+    /* emit to a buffer */
+    buf = fy_emit_document_to_string(fyd, FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* destroy the old document */
+    fy_document_destroy(fyd);
+    fyd = NULL;
+
+    /* verify that the resulting document is in the escaped form */
+    UNIT_ASSERT_VALUES_EQUAL(buf, TString(MANUAL_SCALAR_QUOTED_TXT) + "\n");
+
+    /* now load the result back and verify that it contains exactly the same */
+    fyd = fy_document_build_from_string(NULL, buf, FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* get the scalar content */
+    buf2 = fy_node_get_scalar(fy_document_root(fyd), &sz2);
+    UNIT_ASSERT_UNEQUAL(buf2, NULL);
+
+    /* sizes must match */
+    UNIT_ASSERT_EQUAL(what_sz, sz2);
+
+    /* and the strings too */
+    rc = memcmp(what, buf2, what_sz);
+    UNIT_ASSERT_EQUAL(rc, 0);
+
+    /* free the document */
+    fy_document_destroy(fyd);
+    fyd = NULL;
+
+    free(buf);
+}
+
+Y_UNIT_TEST(manual_scalar_copy) {
+    const TStringBuf MANUAL_SCALAR_COPY = "foo";
+    const char *what = MANUAL_SCALAR_COPY.data();
+    size_t what_sz = MANUAL_SCALAR_COPY.length();
+    char *what_copy;
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    char *buf;
+
+    /* build document */
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    what_copy = (char*)malloc(what_sz);
+    UNIT_ASSERT_UNEQUAL(what_copy, NULL);
+    memcpy(what_copy, what, what_sz);
+
+    /* create a manual scalar with all the escapes */
+    fyn = fy_node_create_scalar_copy(fyd, what_copy, what_sz);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    /* free the data */
+    free(what_copy);
+
+    fy_document_set_root(fyd, fyn);
+    fyn = NULL;
+
+    /* emit to a buffer */
+    buf = fy_emit_document_to_string(fyd, FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* verify that the resulting document is the one we used + '\n' */
+    UNIT_ASSERT_VALUES_EQUAL(buf, TString(MANUAL_SCALAR_COPY) + "\n");
+
+    /* destroy the old document */
+    fy_document_destroy(fyd);
+    fyd = NULL;
+
+    free(buf);
+
+}
+
+Y_UNIT_TEST(manual_scalarf) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    char *buf;
+
+    /* build document */
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* create a manual scalar using the printf interface */
+    fyn = fy_node_create_scalarf(fyd, "foo%d", 13);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+    fyn = NULL;
+
+    /* emit to a buffer */
+    buf = fy_emit_document_to_string(fyd, FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* verify that the resulting document is the one we used + '\n' */
+    UNIT_ASSERT_VALUES_EQUAL(buf, TString("foo13\n"));
+
+    /* destroy the old document */
+    fy_document_destroy(fyd);
+    fyd = NULL;
+
+    free(buf);
+}
+
+Y_UNIT_TEST(manual_valid_anchor) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    int ret;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn = fy_node_create_sequence(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+
+    fyn = fy_node_create_scalar(fyd, "foo", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    ret = fy_node_sequence_append(fy_document_root(fyd), fyn);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    /* create a valid anchor */
+    ret = fy_node_set_anchor(fyn, "foo", FY_NT);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(manual_invalid_anchor) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    int ret;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn = fy_node_create_sequence(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+
+    fyn = fy_node_create_scalar(fyd, "foo", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    ret = fy_node_sequence_append(fy_document_root(fyd), fyn);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    /* create an invalid anchor */
+    ret = fy_node_set_anchor(fyn, "*foo", FY_NT);
+    UNIT_ASSERT_UNEQUAL(ret, 0);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(manual_anchor_removal) {
+    struct fy_document *fyd;
+    struct fy_node *fyn;
+    int ret;
+
+    fyd = fy_document_create(NULL);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn = fy_node_create_sequence(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    fy_document_set_root(fyd, fyn);
+
+    fyn = fy_node_create_scalar(fyd, "foo", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn, NULL);
+
+    ret = fy_node_sequence_append(fy_document_root(fyd), fyn);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    /* create a valid anchor */
+    ret = fy_node_set_anchor(fyn, "foo", FY_NT);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    fprintf(stderr, "---\n# with anchor\n");
+    fy_emit_document_to_fp(fyd, FYECF_MODE_FLOW_ONELINE, stderr);
+
+    /* should fail (an anchor already exists) */
+    ret = fy_node_set_anchor(fyn, "bar", FY_NT);
+    UNIT_ASSERT_UNEQUAL(ret, 0);
+
+    /* should succeed */
+    ret = fy_node_remove_anchor(fyn);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    fprintf(stderr, "---\n# without anchor\n");
+    fy_emit_document_to_fp(fyd, FYECF_MODE_FLOW_ONELINE, stderr);
+
+    fy_document_destroy(fyd);
+}
+
+Y_UNIT_TEST(manual_block_flow_mix) {
+    struct fy_document *fyd;
+    struct fy_node *fyn_mapping, *fyn_key, *fyn_value;
+    char *buf;
+    int ret;
+
+    fyd = fy_document_build_from_string(NULL, "--- &root\n{\n}\n", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn_mapping = fy_document_root(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_mapping, NULL);
+
+    UNIT_ASSERT(fy_node_is_mapping(fyn_mapping) == true);
+
+    fyn_key = fy_node_create_scalar(fyd, "key", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn_key, NULL);
+
+    fyn_value = fy_node_build_from_string(fyd, "|\n  literal\n", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyn_value, NULL);
+
+    ret = fy_node_mapping_append(fyn_mapping, fyn_key, fyn_value);
+    UNIT_ASSERT_EQUAL(ret, 0);
+
+    /* emit document to buffer */
+    buf = fy_emit_document_to_string(fyd, FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+
+    /* destroy the first document */
+    fy_document_destroy(fyd);
+    fyd = NULL;
+
+    /* read the emitted document back */
+    fyd = fy_document_build_from_string(NULL, buf, FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* compare with expected result */
+    UNIT_ASSERT_VALUES_EQUAL(fy_node_get_scalar0(fy_node_by_path(fy_document_root(fyd), "/key", FY_NT, FYNWF_DONT_FOLLOW)), "literal\n");
+
+    /* destroy the second document */
+    fy_document_destroy(fyd);
+    fyd = NULL;
+
+    free(buf);
+
+}
+
+/* FIXME
+ * This test is disabled because we can't make compatible
+ * alloca-based API on windows because original library
+ * uses gcc inline block extensions it will be uncommented
+ * when new API will be introduced
+ */
+#if false
+Y_UNIT_TEST(alloca_check) {
+    struct fy_document *fyd;
+    char *buf;
+    const char *abuf;
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL, "{ "
+        "foo: 10, bar : [ ten, 20 ], baz:{ frob: boo, deep: { deeper: yet } }, "
+        "}", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    /* fy_emit_document_to_string*() */
+    buf = fy_emit_document_to_string(fyd, FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+    abuf = fy_emit_document_to_string_alloca(fyd, FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(abuf, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(buf, abuf);
+    free(buf);
+
+    /* fy_emit_node_to_string*() */
+    buf = fy_emit_node_to_string(fy_node_by_path(fy_document_root(fyd), "/foo", FY_NT, FYNWF_DONT_FOLLOW), FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+    abuf = fy_emit_node_to_string_alloca(fy_node_by_path(fy_document_root(fyd), "/foo", FY_NT, FYNWF_DONT_FOLLOW), FYECF_MODE_FLOW_ONELINE);
+    UNIT_ASSERT_UNEQUAL(abuf, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(buf, abuf);
+    free(buf);
+
+    /* path check eq */
+    buf = fy_node_get_path(fy_node_by_path(fy_document_root(fyd), "/foo", FY_NT, FYNWF_DONT_FOLLOW));
+    UNIT_ASSERT_UNEQUAL(buf, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(buf, "/foo");
+    abuf = fy_node_get_path_alloca(fy_node_by_path(fy_document_root(fyd), "/foo", FY_NT, FYNWF_DONT_FOLLOW));
+    UNIT_ASSERT_UNEQUAL(abuf, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(abuf, "/foo");
+    UNIT_ASSERT_VALUES_EQUAL(buf, abuf);
+    free(buf);
+
+    /* check that a bad path is "" */
+    abuf = fy_node_get_path_alloca(NULL);
+    UNIT_ASSERT_UNEQUAL(abuf, NULL);
+    UNIT_ASSERT_VALUES_EQUAL(abuf, "");
+
+    fy_document_destroy(fyd);
+
+}
+#endif
+
+Y_UNIT_TEST(scanf_check) {
+    struct fy_document *fyd;
+    struct fy_node *fyn_root;
+    int ret, ival;
+    char sval[256];
+
+    /* build document */
+    fyd = fy_document_build_from_string(NULL, "{ "
+        "foo: 10, bar : 20, baz:{ frob: boo }, "
+        "frooz: [ 1, { key: value }, three ]"
+        "}", FY_NT);
+    UNIT_ASSERT_UNEQUAL(fyd, NULL);
+
+    fyn_root = fy_document_root(fyd);
+    UNIT_ASSERT_UNEQUAL(fyn_root, NULL);
+
+    /* check scanf accesses to scalars */
+    ret = fy_node_scanf(fyn_root, "/foo %d", &ival);
+    UNIT_ASSERT_EQUAL(ret, 1);
+    UNIT_ASSERT_EQUAL(ival, 10);
+
+    ret = fy_node_scanf(fyn_root, "/bar %d", &ival);
+    UNIT_ASSERT_EQUAL(ret, 1);
+    UNIT_ASSERT_EQUAL(ival, 20);
+
+    ret = fy_node_scanf(fyn_root, "/baz/frob %s", sval);
+    UNIT_ASSERT_EQUAL(ret, 1);
+    UNIT_ASSERT_VALUES_EQUAL(sval, "boo");
+
+    ret = fy_node_scanf(fyn_root, "/frooz/0 %d", &ival);
+    UNIT_ASSERT_EQUAL(ret, 1);
+    UNIT_ASSERT_EQUAL(ival, 1);
+
+    ret = fy_node_scanf(fyn_root, "/frooz/1/key %s", sval);
+    UNIT_ASSERT_EQUAL(ret, 1);
+    UNIT_ASSERT_VALUES_EQUAL(sval, "value");
+
+    ret = fy_node_scanf(fyn_root, "/frooz/2 %s", sval);
+    UNIT_ASSERT_EQUAL(ret, 1);
+    UNIT_ASSERT_VALUES_EQUAL(sval, "three");
+
+    fy_document_destroy(fyd);
+}
+
+}
diff --git a/ydb/core/cms/console/CMakeLists.darwin.txt b/ydb/core/cms/console/CMakeLists.darwin.txt
index 8bb5a23073..d54a54e73a 100644
--- a/ydb/core/cms/console/CMakeLists.darwin.txt
+++ b/ydb/core/cms/console/CMakeLists.darwin.txt
@@ -8,6 +8,7 @@
 
 add_subdirectory(ut)
 add_subdirectory(validators)
+add_subdirectory(yaml_config)
 
 add_library(core-cms-console)
 target_link_libraries(core-cms-console PUBLIC
diff --git a/ydb/core/cms/console/CMakeLists.linux-aarch64.txt b/ydb/core/cms/console/CMakeLists.linux-aarch64.txt
index c84d3d57b7..485fe439c9 100644
--- a/ydb/core/cms/console/CMakeLists.linux-aarch64.txt
+++ b/ydb/core/cms/console/CMakeLists.linux-aarch64.txt
@@ -8,6 +8,7 @@
 
 add_subdirectory(ut)
 add_subdirectory(validators)
+add_subdirectory(yaml_config)
 
 add_library(core-cms-console)
 target_link_libraries(core-cms-console PUBLIC
diff --git a/ydb/core/cms/console/CMakeLists.linux.txt b/ydb/core/cms/console/CMakeLists.linux.txt
index c84d3d57b7..485fe439c9 100644
--- a/ydb/core/cms/console/CMakeLists.linux.txt
+++ b/ydb/core/cms/console/CMakeLists.linux.txt
@@ -8,6 +8,7 @@
 
 add_subdirectory(ut)
 add_subdirectory(validators)
+add_subdirectory(yaml_config)
 
 add_library(core-cms-console)
 target_link_libraries(core-cms-console PUBLIC
diff --git a/ydb/core/cms/console/yaml_config/CMakeLists.darwin.txt b/ydb/core/cms/console/yaml_config/CMakeLists.darwin.txt
new file mode 100644
index 0000000000..7f2bea933d
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/CMakeLists.darwin.txt
@@ -0,0 +1,21 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+find_package(OpenSSL REQUIRED)
+add_subdirectory(ut)
+
+add_library(cms-console-yaml_config)
+target_link_libraries(cms-console-yaml_config PUBLIC
+  contrib-libs-cxxsupp
+  yutil
+  cpp-yaml-fyamlcpp
+  OpenSSL::OpenSSL
+)
+target_sources(cms-console-yaml_config PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/core/cms/console/yaml_config/yaml_config.cpp
+)
diff --git a/ydb/core/cms/console/yaml_config/CMakeLists.linux-aarch64.txt b/ydb/core/cms/console/yaml_config/CMakeLists.linux-aarch64.txt
new file mode 100644
index 0000000000..4064d3d798
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/CMakeLists.linux-aarch64.txt
@@ -0,0 +1,22 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+find_package(OpenSSL REQUIRED)
+add_subdirectory(ut)
+
+add_library(cms-console-yaml_config)
+target_link_libraries(cms-console-yaml_config PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  cpp-yaml-fyamlcpp
+  OpenSSL::OpenSSL
+)
+target_sources(cms-console-yaml_config PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/core/cms/console/yaml_config/yaml_config.cpp
+)
diff --git a/ydb/core/cms/console/yaml_config/CMakeLists.linux.txt b/ydb/core/cms/console/yaml_config/CMakeLists.linux.txt
new file mode 100644
index 0000000000..4064d3d798
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/CMakeLists.linux.txt
@@ -0,0 +1,22 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+find_package(OpenSSL REQUIRED)
+add_subdirectory(ut)
+
+add_library(cms-console-yaml_config)
+target_link_libraries(cms-console-yaml_config PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  cpp-yaml-fyamlcpp
+  OpenSSL::OpenSSL
+)
+target_sources(cms-console-yaml_config PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/core/cms/console/yaml_config/yaml_config.cpp
+)
diff --git a/ydb/core/cms/console/yaml_config/CMakeLists.txt b/ydb/core/cms/console/yaml_config/CMakeLists.txt
new file mode 100644
index 0000000000..5bb4faffb4
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/CMakeLists.txt
@@ -0,0 +1,15 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+if (CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux-aarch64.txt)
+elseif (APPLE AND CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
+  include(CMakeLists.darwin.txt)
+elseif (CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux.txt)
+endif()
diff --git a/ydb/core/cms/console/yaml_config/ut/CMakeLists.darwin.txt b/ydb/core/cms/console/yaml_config/ut/CMakeLists.darwin.txt
new file mode 100644
index 0000000000..cb4ff48218
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/ut/CMakeLists.darwin.txt
@@ -0,0 +1,63 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_executable(ydb-core-cms-console-yaml_config-ut)
+target_include_directories(ydb-core-cms-console-yaml_config-ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/core/cms/console/yaml_config
+)
+target_link_libraries(ydb-core-cms-console-yaml_config-ut PUBLIC
+  contrib-libs-cxxsupp
+  yutil
+  library-cpp-cpuid_check
+  cpp-testing-unittest_main
+  cms-console-yaml_config
+)
+target_link_options(ydb-core-cms-console-yaml_config-ut PRIVATE
+  -Wl,-no_deduplicate
+  -Wl,-sdk_version,10.15
+  -fPIC
+  -fPIC
+)
+target_sources(ydb-core-cms-console-yaml_config-ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/core/cms/console/yaml_config/yaml_config_ut.cpp
+)
+set_property(
+  TARGET
+  ydb-core-cms-console-yaml_config-ut
+  PROPERTY
+  SPLIT_FACTOR
+  1
+)
+add_yunittest(
+  NAME
+  ydb-core-cms-console-yaml_config-ut
+  TEST_TARGET
+  ydb-core-cms-console-yaml_config-ut
+  TEST_ARG
+  --print-before-suite
+  --print-before-test
+  --fork-tests
+  --print-times
+  --show-fails
+)
+set_yunittest_property(
+  TEST
+  ydb-core-cms-console-yaml_config-ut
+  PROPERTY
+  LABELS
+  SMALL
+)
+set_yunittest_property(
+  TEST
+  ydb-core-cms-console-yaml_config-ut
+  PROPERTY
+  PROCESSORS
+  1
+)
+vcs_info(ydb-core-cms-console-yaml_config-ut)
diff --git a/ydb/core/cms/console/yaml_config/ut/CMakeLists.linux-aarch64.txt b/ydb/core/cms/console/yaml_config/ut/CMakeLists.linux-aarch64.txt
new file mode 100644
index 0000000000..c4c6551459
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/ut/CMakeLists.linux-aarch64.txt
@@ -0,0 +1,68 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_executable(ydb-core-cms-console-yaml_config-ut)
+target_include_directories(ydb-core-cms-console-yaml_config-ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/core/cms/console/yaml_config
+)
+target_link_libraries(ydb-core-cms-console-yaml_config-ut PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  library-cpp-lfalloc
+  cpp-testing-unittest_main
+  cms-console-yaml_config
+)
+target_link_options(ydb-core-cms-console-yaml_config-ut PRIVATE
+  -ldl
+  -lrt
+  -Wl,--no-as-needed
+  -fPIC
+  -fPIC
+  -lpthread
+  -lrt
+  -ldl
+)
+target_sources(ydb-core-cms-console-yaml_config-ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/core/cms/console/yaml_config/yaml_config_ut.cpp
+)
+set_property(
+  TARGET
+  ydb-core-cms-console-yaml_config-ut
+  PROPERTY
+  SPLIT_FACTOR
+  1
+)
+add_yunittest(
+  NAME
+  ydb-core-cms-console-yaml_config-ut
+  TEST_TARGET
+  ydb-core-cms-console-yaml_config-ut
+  TEST_ARG
+  --print-before-suite
+  --print-before-test
+  --fork-tests
+  --print-times
+  --show-fails
+)
+set_yunittest_property(
+  TEST
+  ydb-core-cms-console-yaml_config-ut
+  PROPERTY
+  LABELS
+  SMALL
+)
+set_yunittest_property(
+  TEST
+  ydb-core-cms-console-yaml_config-ut
+  PROPERTY
+  PROCESSORS
+  1
+)
+vcs_info(ydb-core-cms-console-yaml_config-ut)
diff --git a/ydb/core/cms/console/yaml_config/ut/CMakeLists.linux.txt b/ydb/core/cms/console/yaml_config/ut/CMakeLists.linux.txt
new file mode 100644
index 0000000000..6e9bb14df4
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/ut/CMakeLists.linux.txt
@@ -0,0 +1,70 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_executable(ydb-core-cms-console-yaml_config-ut)
+target_include_directories(ydb-core-cms-console-yaml_config-ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/core/cms/console/yaml_config
+)
+target_link_libraries(ydb-core-cms-console-yaml_config-ut PUBLIC
+  contrib-libs-linux-headers
+  contrib-libs-cxxsupp
+  yutil
+  cpp-malloc-tcmalloc
+  libs-tcmalloc-no_percpu_cache
+  library-cpp-cpuid_check
+  cpp-testing-unittest_main
+  cms-console-yaml_config
+)
+target_link_options(ydb-core-cms-console-yaml_config-ut PRIVATE
+  -ldl
+  -lrt
+  -Wl,--no-as-needed
+  -fPIC
+  -fPIC
+  -lpthread
+  -lrt
+  -ldl
+)
+target_sources(ydb-core-cms-console-yaml_config-ut PRIVATE
+  ${CMAKE_SOURCE_DIR}/ydb/core/cms/console/yaml_config/yaml_config_ut.cpp
+)
+set_property(
+  TARGET
+  ydb-core-cms-console-yaml_config-ut
+  PROPERTY
+  SPLIT_FACTOR
+  1
+)
+add_yunittest(
+  NAME
+  ydb-core-cms-console-yaml_config-ut
+  TEST_TARGET
+  ydb-core-cms-console-yaml_config-ut
+  TEST_ARG
+  --print-before-suite
+  --print-before-test
+  --fork-tests
+  --print-times
+  --show-fails
+)
+set_yunittest_property(
+  TEST
+  ydb-core-cms-console-yaml_config-ut
+  PROPERTY
+  LABELS
+  SMALL
+)
+set_yunittest_property(
+  TEST
+  ydb-core-cms-console-yaml_config-ut
+  PROPERTY
+  PROCESSORS
+  1
+)
+vcs_info(ydb-core-cms-console-yaml_config-ut)
diff --git a/ydb/core/cms/console/yaml_config/ut/CMakeLists.txt b/ydb/core/cms/console/yaml_config/ut/CMakeLists.txt
new file mode 100644
index 0000000000..5bb4faffb4
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/ut/CMakeLists.txt
@@ -0,0 +1,15 @@
+
+# This file was generated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+if (CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux-aarch64.txt)
+elseif (APPLE AND CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
+  include(CMakeLists.darwin.txt)
+elseif (CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64" AND UNIX AND NOT APPLE AND NOT ANDROID)
+  include(CMakeLists.linux.txt)
+endif()
diff --git a/ydb/core/cms/console/yaml_config/yaml_config.cpp b/ydb/core/cms/console/yaml_config/yaml_config.cpp
new file mode 100644
index 0000000000..3c43828476
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/yaml_config.cpp
@@ -0,0 +1,500 @@
+#include "yaml_config.h"
+#include "yaml_config_impl.h"
+
+namespace NYamlConfig {
+
+inline const TMap<TString, EYamlConfigLabelTypeClass> ClassMapping{
+    std::pair{TString("enum"), EYamlConfigLabelTypeClass::Closed},
+    std::pair{TString("string"), EYamlConfigLabelTypeClass::Open},
+};
+
+inline const TStringBuf inheritMapTag{"!inherit"};
+inline const TStringBuf inheritSeqTag{"!inherit:"};
+inline const TStringBuf inheritMapInSeqTag{"!inherit"};
+inline const TStringBuf removeTag{"!remove"};
+
+TString GetKey(const NFyaml::TNodeRef& node, TString key) {
+    auto map = node.Map();
+    auto k = map.at(key).Scalar();
+    return k;
+}
+
+TString CalcHash(const NFyaml::TDocument& resolved) {
+    TStringStream ss;
+    ss << resolved;
+    TString s = ss.Str();
+    SHA256_CTX sha;
+    SHA256_Init(&sha);
+    SHA256_Update(&sha, s.data(), s.size());
+    unsigned char hash[SHA256_DIGEST_LENGTH];
+    SHA256_Final(hash, &sha);
+    return TString(reinterpret_cast<char*>(hash), sizeof(hash));
+}
+
+bool Fit(const TSelector& selector, const TSet<TNamedLabel>& labels) {
+    bool result = true;
+    size_t matched = 0;
+    for (auto& label : labels) {
+        if (auto it = selector.NotIn.find(label.Name); it != selector.NotIn.end()
+            && it->second.Values.contains(label.Value)) {
+
+            return false;
+        }
+
+        if (auto it = selector.In.find(label.Name); it != selector.In.end()) {
+            if (!it->second.Values.contains(label.Value)) {
+                result = false;
+            } else {
+                ++matched;
+            }
+        }
+    }
+    return (matched == selector.In.size()) && result;
+}
+
+TSelector ParseSelector(const NFyaml::TNodeRef& selectors) {
+    TSelector result;
+    if (selectors) {
+        auto selectorsMap = selectors.Map();
+
+        for (auto it = selectorsMap.begin(); it != selectorsMap.end(); ++it) {
+            switch (it->Value().Type()) {
+                case NFyaml::ENodeType::Scalar:
+                {
+                    auto [label, _] = result.In.try_emplace(
+                        it->Key().Scalar(),
+                        TLabelValueSet{});
+                    label->second.Values.insert(it->Value().Scalar());
+                }
+                break;
+                case NFyaml::ENodeType::Mapping:
+                {
+                    auto in = it->Value().Map()["in"];
+                    auto notIn = it->Value().Map()["not_in"];
+                    if (in && notIn) {
+                        ythrow TYamlConfigEx() << "Using both in and not_in for same label: "
+                            << it->Value().Path();
+                    }
+
+                    if (in) {
+                        auto inSeq = in.Sequence();
+                        auto [label, _] = result.In.try_emplace(
+                            it->Key().Scalar(),
+                            TLabelValueSet{});
+                        for(auto it3 = inSeq.begin(); it3 != inSeq.end(); ++it3) {
+                            label->second.Values.insert(it3->Scalar());
+                        }
+                    }
+
+                    if (notIn) {
+                        auto notInSeq = notIn.Sequence();
+                        auto [label, _] = result.NotIn.try_emplace(
+                            it->Key().Scalar(),
+                            TLabelValueSet{});
+                        for(auto it3 = notInSeq.begin(); it3 != notInSeq.end(); ++it3) {
+                            label->second.Values.insert(it3->Scalar());
+                        }
+                    }
+                }
+                break;
+                default:
+                {
+                    ythrow TYamlConfigEx() << "Selector should be scalar, \"in\" or \"not_in\": "
+                        << it->Value().Path();
+                }
+                break;
+            }
+        }
+    } else {
+        ythrow TYamlConfigEx() << "Selector shouldn't be empty";
+    }
+    return result;
+}
+
+TYamlConfigModel ParseConfig(NFyaml::TDocument& doc) {
+    TYamlConfigModel res{.Doc = doc};
+    auto root = doc.Root().Map();
+    res.Config = root.at("config");
+
+    auto allowedLabels = root.at("allowed_labels").Map();
+
+    for (auto it = allowedLabels.begin(); it != allowedLabels.end(); ++it) {
+        auto type = it->Value().Map().at("type");
+        if (!type || type.Type() != NFyaml::ENodeType::Scalar) {
+            ythrow TYamlConfigEx() << "Label type should be Scalar";
+        }
+
+        EYamlConfigLabelTypeClass classType;
+
+        if (auto classIt = ClassMapping.find(type.Scalar()); classIt != ClassMapping.end()) {
+            classType = classIt->second;
+        } else {
+            ythrow TYamlConfigEx() << "Unsupported label type: " << type.Scalar();
+        }
+
+        auto label = res.AllowedLabels.try_emplace(
+            it->Key().Scalar(),
+            TLabelType{classType, TSet<TString>{""}});
+
+        if (auto labelDesc = it->Value().Map()["values"]; labelDesc) {
+            auto values = labelDesc.Map();
+            for(auto it2 = values.begin(); it2 != values.end(); ++it2) {
+                label.first->second.Values.insert(it2->Key().Scalar());
+            }
+        }
+    }
+
+    auto selectorConfig = root.at("selector_config").Sequence();
+
+    for (auto it = selectorConfig.begin(); it != selectorConfig.end(); ++it) {
+        TYamlConfigModel::TSelectorModel selector;
+
+        auto selectorRoot = it->Map();
+        selector.Description = selectorRoot.at("description").Scalar();
+        selector.Config = selectorRoot.at("config");
+        selector.Selector = ParseSelector(selectorRoot.at("selector"));
+
+        res.Selectors.push_back(selector);
+    }
+
+    return res;
+}
+
+TMap<TString, TLabelType> CollectLabels(NFyaml::TDocument& doc) {
+
+    auto config = ParseConfig(doc);
+
+    TMap<TString, TLabelType> result = config.AllowedLabels;
+
+    for (auto& selector : config.Selectors) {
+        for (auto& [name, valueSet] : selector.Selector.In) {
+            result[name].Values.insert(valueSet.Values.begin(), valueSet.Values.end());
+        }
+
+        for (auto& [name, valueSet] : selector.Selector.NotIn) {
+            result[name].Values.insert(valueSet.Values.begin(), valueSet.Values.end());
+        }
+    }
+
+    return result;
+}
+
+bool IsMapInherit(const NFyaml::TNodeRef& node) {
+    if (auto tag = node.Tag(); tag) {
+        switch (node.Type()) {
+            case NFyaml::ENodeType::Mapping:
+                return *tag == inheritMapTag;
+            case NFyaml::ENodeType::Sequence:
+                return tag->StartsWith(inheritSeqTag);
+            case NFyaml::ENodeType::Scalar:
+                return false;
+        }
+    }
+    return false;
+}
+
+bool IsSeqInherit(const NFyaml::TNodeRef& node) {
+    if (auto tag = node.Tag(); tag) {
+        switch (node.Type()) {
+            case NFyaml::ENodeType::Mapping:
+                return *tag == inheritMapInSeqTag;
+            case NFyaml::ENodeType::Sequence:
+                return false;
+            case NFyaml::ENodeType::Scalar:
+                return false;
+        }
+    }
+    return false;
+}
+
+bool IsRemove(const NFyaml::TNodeRef& node) {
+    if (auto tag = node.Tag(); tag) {
+        return *tag == removeTag;
+    }
+    return false;
+}
+
+void Inherit(NFyaml::TMapping& toMap, const NFyaml::TMapping& fromMap) {
+    for (auto it = fromMap.begin(); it != fromMap.end(); ++it) {
+        if (auto toEntry = toMap.pair_at_opt(it->Key().Scalar()); toEntry) {
+            auto fromNode = it->Value();
+            auto toNode = toEntry.Value();
+
+            if (IsMapInherit(fromNode)) {
+                Apply(toNode, fromNode);
+            } else {
+                toMap.Remove(toEntry.Key());
+                toMap.Append(it->Key().Copy().Ref(), it->Value().Copy().Ref());
+            }
+        } else {
+            toMap.Append(it->Key().Copy().Ref(), it->Value().Copy().Ref());
+        }
+    }
+}
+
+void Inherit(NFyaml::TSequence& toSeq, const NFyaml::TSequence& fromSeq, const TString& key) {
+    TMap<TString, NFyaml::TNodeRef> nodes;
+
+    for (auto it = toSeq.begin(); it != toSeq.end(); ++it) {
+        nodes[GetKey(*it, key)] = *it;
+    }
+
+    for (auto it = fromSeq.begin(); it != fromSeq.end(); ++it) {
+        auto fromKey = GetKey(*it, key);
+
+        if (nodes.contains(fromKey)) {
+            if (IsSeqInherit(*it)) {
+                Apply(nodes[fromKey], *it);
+            } else if (IsRemove(*it)) {
+                toSeq.Remove(nodes[fromKey]);
+                nodes.erase(fromKey);
+            } else {
+                auto newNode = it->Copy();
+                toSeq.InsertAfter(nodes[fromKey], newNode.Ref());
+                toSeq.Remove(nodes[fromKey]);
+                nodes[fromKey] = newNode.Ref();
+            }
+        } else {
+            auto newNode = it->Copy();
+            toSeq.Append(newNode.Ref());
+            nodes[fromKey] = newNode.Ref();
+        }
+    }
+}
+
+void Apply(NFyaml::TNodeRef& to, const NFyaml::TNodeRef& from) {
+    Y_ENSURE_EX(to, TYamlConfigEx() << "Overriding empty value: "
+                << to.Path() << " <- " << from.Path());
+    Y_ENSURE_EX(to.Type() == from.Type(), TYamlConfigEx() << "Overriding value with different types: "
+                << to.Path() << " <- " << from.Path());
+
+    switch (from.Type()) {
+        case NFyaml::ENodeType::Mapping:
+        {
+            auto toMap = to.Map();
+            auto fromMap = from.Map();
+            Inherit(toMap, fromMap);
+        }
+        break;
+        case NFyaml::ENodeType::Sequence:
+        {
+            auto tag = from.Tag();
+            auto key = tag->substr(inheritSeqTag.length());
+            auto toSeq = to.Sequence();
+            auto fromSeq = from.Sequence();
+            Inherit(toSeq, fromSeq, key);
+        }
+        break;
+        case NFyaml::ENodeType::Scalar:
+        {
+            ythrow TYamlConfigEx() << "Override with scalar: "
+                << to.Path() << " <- " << from.Path();
+        }
+        break;
+    }
+}
+
+void RemoveTags(NFyaml::TDocument& doc) {
+    for (auto it = doc.begin(); it != doc.end(); ++it) {
+        it->RemoveTag();
+    }
+}
+
+TDocumentConfig Resolve(
+    const NFyaml::TDocument& doc,
+    const TSet<TNamedLabel>& labels)
+{
+    TDocumentConfig res{doc.Clone(), NFyaml::TNodeRef{}};
+    res.first.Resolve();
+
+    auto rootMap = res.first.Root().Map();
+    auto config = rootMap.at("config");
+    auto selectorConfig = rootMap.at("selector_config").Sequence();
+
+    for (auto it = selectorConfig.begin(); it != selectorConfig.end(); ++it) {
+        auto selectorMap = it->Map();
+        auto desc = selectorMap.at("description").Scalar();
+        auto selectorNode = selectorMap.at("selector");
+        auto selector = ParseSelector(selectorNode);
+        if (Fit(selector, labels)) {
+            Apply(config, selectorMap.at("config"));
+        }
+    }
+
+    RemoveTags(res.first);
+
+    res.second = config;
+
+    return res;
+}
+
+void Combine(
+    TVector<TVector<TLabel>>& labelCombinations,
+    TVector<TLabel>& combination,
+    const TVector<std::pair<TString, TSet<TLabel>>>& labels,
+    size_t offset)
+{
+    if (offset == labels.size()) {
+        labelCombinations.push_back(combination);
+        return;
+    }
+
+    for (auto& label : labels[offset].second) {
+        combination[offset] = label;
+        Combine(labelCombinations, combination, labels, offset + 1);
+    }
+}
+
+bool Fit(
+    const TSelector& selector,
+    const TVector<TLabel>& labels,
+    const TVector<std::pair<TString, TSet<TLabel>>>& names)
+{
+    for (size_t i = 0; i < labels.size(); ++ i) {
+        auto& label = labels[i];
+        auto& name = names[i].first;
+        switch(label.Type) {
+            case TLabel::EType::Negative:
+                if (selector.In.contains(name)) {
+                    return false;
+                }
+                break;
+            case TLabel::EType::Empty: [[fallthrough]];
+            case TLabel::EType::Common:
+                if (auto it = selector.In.find(name); it != selector.In.end()
+                    && !it->second.Values.contains(label.Value)) {
+
+                    return false;
+                }
+                if (auto it = selector.NotIn.find(name); it != selector.NotIn.end()
+                    && it->second.Values.contains(label.Value)) {
+
+                    return false;
+                }
+                break;
+        }
+    }
+
+    return true;
+}
+
+TResolvedConfig ResolveAll(NFyaml::TDocument& doc)
+{
+    TVector<TString> labelNames;
+    TVector<std::pair<TString, TSet<TLabel>>> labels;
+
+    auto config = ParseConfig(doc);
+    auto namedLabels = CollectLabels(doc);
+
+    for (auto& [name, values]: namedLabels) {
+        TSet<TLabel> set;
+        if (values.Class == EYamlConfigLabelTypeClass::Open) {
+            set.insert(TLabel{TLabel::EType::Negative, {}});
+        }
+        for (auto& value: values.Values) {
+            if (value != "") {
+                set.insert(TLabel{TLabel::EType::Common, value});
+            } else {
+                set.insert(TLabel{TLabel::EType::Empty, {}});
+            }
+        }
+        labels.push_back({name, set});
+        labelNames.push_back(name);
+    }
+
+    TVector<TVector<TLabel>> labelCombinations;
+
+    TVector<TLabel> combination;
+    combination.resize(labels.size());
+
+    Combine(labelCombinations, combination, labels, 0);
+
+    auto cmp = [](const TVector<int>& lhs, const TVector<int>& rhs) {
+        auto lhsIt = lhs.begin();
+        auto rhsIt = rhs.begin();
+
+        while (lhsIt != lhs.end() && rhsIt != rhs.end() && (*lhsIt == *rhsIt)) {
+            lhsIt++;
+            rhsIt++;
+        }
+
+        if (lhsIt == lhs.end()) {
+            return false;
+        } else if (rhsIt == rhs.end()) {
+            return true;
+        }
+
+        return *lhsIt < *rhsIt;
+    };
+
+    using TTriePath = TVector<int>;
+
+    struct TTrieNode {
+        TSimpleSharedPtr<TDocumentConfig> ResolvedConfig;
+        TVector<TVector<TLabel>> LabelCombinations;
+    };
+
+    std::map<TTriePath, TSimpleSharedPtr<TDocumentConfig>, decltype(cmp)> selectorsTrie(cmp);
+    std::map<TTriePath, TTrieNode, decltype(cmp)> appliedSelectors(cmp);
+
+    auto rootConfig = TTrieNode {
+        MakeSimpleShared<TDocumentConfig>(std::move(doc), config.Config),
+        {},
+    };
+
+    selectorsTrie[{0}] = rootConfig.ResolvedConfig;
+
+    for (size_t j = 0; j < labelCombinations.size(); ++j) {
+        TSimpleSharedPtr<TDocumentConfig> cur = rootConfig.ResolvedConfig;
+        TTriePath triePath({0});
+
+        for (size_t i = 0; i < config.Selectors.size(); ++i) {
+            if (Fit(config.Selectors[i].Selector, labelCombinations[j], labels)) {
+                triePath.push_back(i + 1);
+                if (auto it = selectorsTrie.find(triePath); it != selectorsTrie.end()) {
+                    cur = it->second;
+                } else {
+                    auto clone = cur->first.Clone();
+                    auto cloneConfig = ParseConfig(clone);
+
+                    Apply(cloneConfig.Config, cloneConfig.Selectors[i].Config);
+
+                    cur = MakeSimpleShared<std::pair<NFyaml::TDocument, NFyaml::TNodeRef>>(
+                        std::move(clone),
+                        cloneConfig.Config),
+                    selectorsTrie[triePath] = cur;
+                }
+            }
+        }
+
+        if (auto it = appliedSelectors.find(triePath); it != appliedSelectors.end()) {
+            it->second.LabelCombinations.push_back(labelCombinations[j]);
+        } else {
+            appliedSelectors.try_emplace(triePath, TTrieNode{
+                    cur,
+                    {labelCombinations[j]}
+                });
+        }
+    }
+
+    selectorsTrie.clear();
+
+    TMap<TSet<TVector<TLabel>>, TDocumentConfig> configs;
+
+    for (auto& [_, value]: appliedSelectors) {
+        configs.try_emplace(
+            TSet<TVector<TLabel>>(
+                value.LabelCombinations.begin(),
+                value.LabelCombinations.end()),
+            std::make_pair(std::move(value.ResolvedConfig->first), value.ResolvedConfig->second));
+    }
+
+    return {labelNames, std::move(configs)};
+}
+
+} // namespace NYamlConfig
+
+template <>
+void Out<NYamlConfig::TLabel>(IOutputStream& out, const NYamlConfig::TLabel& value) {
+    out << (int)value.Type << ":" << value.Value;
+}
diff --git a/ydb/core/cms/console/yaml_config/yaml_config.h b/ydb/core/cms/console/yaml_config/yaml_config.h
new file mode 100644
index 0000000000..7c4c5e7d40
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/yaml_config.h
@@ -0,0 +1,145 @@
+#pragma once
+
+#include <library/cpp/yaml/fyamlcpp/fyamlcpp.h>
+
+#include <openssl/sha.h>
+
+#include <util/generic/string.h>
+#include <util/generic/vector.h>
+#include <util/generic/set.h>
+#include <util/generic/map.h>
+#include <util/stream/str.h>
+
+#include <unordered_map>
+#include <map>
+#include <string>
+
+namespace NYamlConfig {
+
+struct TYamlConfigEx : public yexception {};
+
+using TDocumentConfig = std::pair<NFyaml::TDocument, NFyaml::TNodeRef>;
+
+/**
+ * Open - labels like tenant, where we don't know final set of values
+ * Closed - labels with predefined set of values, e.g. size
+ */
+enum class EYamlConfigLabelTypeClass {
+    Open,
+    Closed,
+};
+
+/**
+ * TNamedLabel - representation of label used for selector
+ */
+class TNamedLabel {
+public:
+    TString Name;
+    TString Value;
+    bool Inv = false;
+
+    bool operator<(const TNamedLabel& other) const { return Name < other.Name; }
+};
+
+/**
+ * TLabelType - represents known set of values for a label with its type
+ */
+class TLabelType {
+public:
+    EYamlConfigLabelTypeClass Class;
+    TSet<TString> Values;
+
+    bool operator==(const TLabelType& other) const { return Values == other.Values; }
+};
+
+class TLabelValueSet {
+public:
+    TSet<TString> Values;
+
+    bool operator==(const TLabelValueSet& other) const { return Values == other.Values; }
+};
+
+class TSelector {
+public:
+    TMap<TString, TLabelValueSet> In;
+    TMap<TString, TLabelValueSet> NotIn;
+};
+
+struct TYamlConfigModel {
+    struct TSelectorModel {
+        TString Description;
+        TSelector Selector;
+        NFyaml::TNodeRef Config;
+    };
+
+    const NFyaml::TDocument& Doc;
+    NFyaml::TNodeRef Config;
+    TMap<TString, TLabelType> AllowedLabels;
+    TVector<TSelectorModel> Selectors;
+};
+
+/**
+ * Collects all labels present in document
+ * For Open labels gathers all labels from all selectors
+ * For Closed labels additionally validates that there is no additional labels
+ */
+TMap<TString, TLabelType> CollectLabels(NFyaml::TDocument& doc);
+
+/**
+ * Parses config and fills corresponding struct
+ */
+TYamlConfigModel ParseConfig(NFyaml::TDocument& doc);
+
+/**
+ * Generates config for specific set of labels applying all matching selectors
+ */
+TDocumentConfig Resolve(
+    const NFyaml::TDocument& doc,
+    const TSet<TNamedLabel>& labels);
+
+/**
+ * TLabel is a representation of label for config resolution
+ *
+ * It can be in three states:
+ * - Empty with Type == EType::Empty and Value == ""
+ *   it equals empty or undefined label
+ * - Common with Type == EType::Common and Value == arbitrary string
+ *   it equals defined label with corresponding value
+ * - Negative with Type == EType::Negative and Value == ""
+ *   it is used for Open labels and equals any label not present in labels
+ *   discovered by CollectLabels (and also not equals Empty label)
+ */
+struct TLabel {
+    enum class EType {
+        Negative = 0,
+        Empty,
+        Common,
+    };
+
+    EType Type;
+    TString Value;
+
+    bool operator<(const TLabel& other) const {
+        int lhs = static_cast<int>(Type);
+        int rhs = static_cast<int>(other.Type);
+        return std::tie(lhs, Value) < std::tie(rhs, other.Value);
+    }
+
+    bool operator==(const TLabel& other) const {
+        int lhs = static_cast<int>(Type);
+        int rhs = static_cast<int>(other.Type);
+        return std::tie(lhs, Value) == std::tie(rhs, other.Value);
+    }
+};
+
+struct TResolvedConfig {
+    TVector<TString> Labels;
+    TMap<TSet<TVector<TLabel>>, TDocumentConfig> Configs;
+};
+
+/**
+ * Generates configs for all label combinations
+ */
+TResolvedConfig ResolveAll(NFyaml::TDocument& doc);
+
+}// namespace NYamlConfig
diff --git a/ydb/core/cms/console/yaml_config/yaml_config_impl.h b/ydb/core/cms/console/yaml_config/yaml_config_impl.h
new file mode 100644
index 0000000000..2f9a6f7646
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/yaml_config_impl.h
@@ -0,0 +1,47 @@
+#pragma once
+
+#include "yaml_config.h"
+
+namespace NYamlConfig {
+
+class TLabelSet {
+public:
+    TString Name;
+    TSet<TString> Values;
+    bool Inv = false;
+
+    bool operator<(const TLabelSet& other) const { return Name < other.Name; }
+};
+
+TString GetKey(const NFyaml::TNodeRef& node, TString key);
+
+bool Fit(const TSelector& selector, const TSet<TNamedLabel>& labels);
+
+bool Fit(
+    const TSelector& selector,
+    const TVector<TLabel>& labels,
+    const TVector<std::pair<TString, TSet<TLabel>>>& names);
+
+bool IsMapInherit(const NFyaml::TNodeRef& node);
+
+bool IsSeqInherit(const NFyaml::TNodeRef& node);
+
+bool IsRemove(const NFyaml::TNodeRef& node);
+
+void RemoveTags(NFyaml::TDocument& doc);
+
+void Inherit(NFyaml::TMapping& toMap, const NFyaml::TMapping& fromMap);
+
+void Inherit(NFyaml::TSequence& toSeq, const NFyaml::TSequence& fromSeq, const TString& key);
+
+void Apply(NFyaml::TNodeRef& to, const NFyaml::TNodeRef& from);
+
+void Combine(
+    TVector<TVector<TLabel>>& labelCombinations,
+    TVector<TLabel>& combination,
+    const TVector<std::pair<TString, TSet<TLabel>>>& labels,
+    size_t offset);
+
+TSelector ParseSelector(const NFyaml::TNodeRef& selectors);
+
+} // namespace NYamlConfig
diff --git a/ydb/core/cms/console/yaml_config/yaml_config_ut.cpp b/ydb/core/cms/console/yaml_config/yaml_config_ut.cpp
new file mode 100644
index 0000000000..5099bb3e0f
--- /dev/null
+++ b/ydb/core/cms/console/yaml_config/yaml_config_ut.cpp
@@ -0,0 +1,1328 @@
+#include "yaml_config.h"
+
+#include <library/cpp/testing/unittest/registar.h>
+
+const char *WholeConfig = R"(---
+cluster: test
+version: 12.1
+config: &default_config
+  log_config: &default_log_config
+    entry:
+    - component: ZERO
+      level: -1
+    - component: TEST
+      level: -1
+  actor_system_config:
+    executor:
+    - type: BASIC
+      threads: 9
+      spin_threshold: 1
+      name: System
+    - type: BASIC
+      threads: 16
+      spin_threshold: 1
+      name: User
+    - type: BASIC
+      threads: 7
+      spin_threshold: 1
+      name: Batch
+    - type: IO
+      threads: 1
+      name: IO
+    - type: BASIC
+      threads: 3
+      spin_threshold: 10
+      name: IC
+      time_per_mailbox_micro_secs: 100
+    scheduler:
+      resolution: 64
+      spin_threshold: 0
+      progress_threshold: 10000
+    sys_executor: 0
+    user_executor: 1
+    io_executor: 3
+    batch_executor: 2
+    service_executor:
+    - service_name: Interconnect
+      executor_id: 4
+
+allowed_labels:
+  tenant:
+    type: string
+  flavour:
+    type: enum
+    values:
+      ? small
+      ? medium
+      ? big
+
+selector_config:
+- description: set BLOB_DEPOT level to 1
+  selector:
+    tenant: /ru/tenant2
+  config: !inherit
+    new_item: 1
+- description: set initial log config
+  selector:
+    tenant: /ru/tenant1
+  config: !inherit
+    log_config:
+      entry: !inherit:component
+      - component: ZERO
+        level: 7
+      - component: BLOB_DEPOT
+        level: 0
+      - component: TEST
+        level: 11
+- description: set BLOB_DEPOT level to 1
+  selector:
+    tenant: /ru/tenant1
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - component: BLOB_DEPOT
+        level: 1
+- description: set BLOB_DEPOT level to 2
+  selector:
+    tenant: /ru/tenant2
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - component: BLOB_DEPOT
+        level: 2
+- description: set TEST level to 111
+  selector:
+    tenant: /ru/tenant1
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - component: TEST
+        level: 111
+- description: set TEST level to 112
+  selector:
+    tenant:
+      in:
+      - /ru/tenant1
+      - /ru/tenant3
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - component: TEST
+        level: 112
+      default: 10
+- description: set TEST level to 113
+  selector:
+    tenant:
+      not_in:
+        - /ru/tenant1
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - component: TEST
+        level: 113
+- description: set ACTOR level to 16
+  selector:
+    tenant: /ru/tenant1
+    flavour: small
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - component: ACTOR
+        level: 16
+- description: set ACTOR level to 17
+  selector:
+    flavour: big
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - component: ACTOR
+        level: 17
+- description: add add to ACTOR
+  selector:
+    flavour: small
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - !inherit
+        component: ZERO
+        add: test
+- description: rewrite ZERO to empty
+  selector:
+    flavour: medium
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - component: ZERO
+- description: rewrite ZERO to empty
+  selector:
+    tenant: /ru/tenant1
+    flavour: medium
+  config: !inherit
+    log_config: !inherit
+      entry: !inherit:component
+      - !remove
+        component: ZERO
+      - component: BLOB_DEPOT
+        level: 2
+      - component: BLOB_DEPOT
+        level: 3
+)";
+
+
+const char *BigTenant1Config = R"(---
+log_config:
+  entry:
+  - component: ZERO
+    level: 7
+  - component: BLOB_DEPOT
+    level: 1
+  - component: TEST
+    level: 112
+  - component: ACTOR
+    level: 17
+  default: 10
+actor_system_config:
+  executor:
+  - type: BASIC
+    threads: 9
+    spin_threshold: 1
+    name: System
+  - type: BASIC
+    threads: 16
+    spin_threshold: 1
+    name: User
+  - type: BASIC
+    threads: 7
+    spin_threshold: 1
+    name: Batch
+  - type: IO
+    threads: 1
+    name: IO
+  - type: BASIC
+    threads: 3
+    spin_threshold: 10
+    name: IC
+    time_per_mailbox_micro_secs: 100
+  scheduler:
+    resolution: 64
+    spin_threshold: 0
+    progress_threshold: 10000
+  sys_executor: 0
+  user_executor: 1
+  io_executor: 3
+  batch_executor: 2
+  service_executor:
+  - service_name: Interconnect
+    executor_id: 4
+)";
+
+const char *Tenant2Config = R"(---
+log_config: &default_log_config
+  entry:
+  - component: ZERO
+    level: -1
+  - component: TEST
+    level: 113
+  - component: BLOB_DEPOT
+    level: 2
+actor_system_config:
+  executor:
+  - type: BASIC
+    threads: 9
+    spin_threshold: 1
+    name: System
+  - type: BASIC
+    threads: 16
+    spin_threshold: 1
+    name: User
+  - type: BASIC
+    threads: 7
+    spin_threshold: 1
+    name: Batch
+  - type: IO
+    threads: 1
+    name: IO
+  - type: BASIC
+    threads: 3
+    spin_threshold: 10
+    name: IC
+    time_per_mailbox_micro_secs: 100
+  scheduler:
+    resolution: 64
+    spin_threshold: 0
+    progress_threshold: 10000
+  sys_executor: 0
+  user_executor: 1
+  io_executor: 3
+  batch_executor: 2
+  service_executor:
+  - service_name: Interconnect
+    executor_id: 4
+new_item: 1
+)";
+
+const char *SmallConfig = R"(---
+log_config: &default_log_config
+  entry:
+  - component: ZERO
+    level: -1
+    add: test
+  - component: TEST
+    level: 113
+actor_system_config:
+  executor:
+  - type: BASIC
+    threads: 9
+    spin_threshold: 1
+    name: System
+  - type: BASIC
+    threads: 16
+    spin_threshold: 1
+    name: User
+  - type: BASIC
+    threads: 7
+    spin_threshold: 1
+    name: Batch
+  - type: IO
+    threads: 1
+    name: IO
+  - type: BASIC
+    threads: 3
+    spin_threshold: 10
+    name: IC
+    time_per_mailbox_micro_secs: 100
+  scheduler:
+    resolution: 64
+    spin_threshold: 0
+    progress_threshold: 10000
+  sys_executor: 0
+  user_executor: 1
+  io_executor: 3
+  batch_executor: 2
+  service_executor:
+  - service_name: Interconnect
+    executor_id: 4
+)";
+
+const char *MediumConfig = R"(---
+log_config: &default_log_config
+  entry:
+  - component: ZERO
+  - component: TEST
+    level: 113
+actor_system_config:
+  executor:
+  - type: BASIC
+    threads: 9
+    spin_threshold: 1
+    name: System
+  - type: BASIC
+    threads: 16
+    spin_threshold: 1
+    name: User
+  - type: BASIC
+    threads: 7
+    spin_threshold: 1
+    name: Batch
+  - type: IO
+    threads: 1
+    name: IO
+  - type: BASIC
+    threads: 3
+    spin_threshold: 10
+    name: IC
+    time_per_mailbox_micro_secs: 100
+  scheduler:
+    resolution: 64
+    spin_threshold: 0
+    progress_threshold: 10000
+  sys_executor: 0
+  user_executor: 1
+  io_executor: 3
+  batch_executor: 2
+  service_executor:
+  - service_name: Interconnect
+    executor_id: 4
+)";
+
+const char *MediumTenant1Config = R"(---
+log_config: &default_log_config
+  entry:
+  - component: BLOB_DEPOT
+    level: 3
+  - component: TEST
+    level: 112
+  default: 10
+actor_system_config:
+  executor:
+  - type: BASIC
+    threads: 9
+    spin_threshold: 1
+    name: System
+  - type: BASIC
+    threads: 16
+    spin_threshold: 1
+    name: User
+  - type: BASIC
+    threads: 7
+    spin_threshold: 1
+    name: Batch
+  - type: IO
+    threads: 1
+    name: IO
+  - type: BASIC
+    threads: 3
+    spin_threshold: 10
+    name: IC
+    time_per_mailbox_micro_secs: 100
+  scheduler:
+    resolution: 64
+    spin_threshold: 0
+    progress_threshold: 10000
+  sys_executor: 0
+  user_executor: 1
+  io_executor: 3
+  batch_executor: 2
+  service_executor:
+  - service_name: Interconnect
+    executor_id: 4
+)";
+
+const char *UnresolvedSimpleConfig1 = R"(---
+cluster: test
+version: 12.1
+config:
+  num:
+    ? 0
+allowed_labels:
+  tenant:
+    type: string
+
+selector_config:
+- description: 1
+  selector:
+    tenant: abc
+  config: !inherit
+    num: !inherit
+      ? 1
+)";
+
+const char *ResolvedSimpleConfig1Negative = R"(---
+config:
+  num:
+    ? 0
+)";
+
+const char *ResolvedSimpleConfig1Empty = R"(---
+config:
+  num:
+    ? 0
+)";
+
+const char *ResolvedSimpleConfig1Abc = R"(---
+config:
+  num:
+    ? 0
+    ? 1
+)";
+
+const char *UnresolvedSimpleConfig2 = R"(---
+cluster: test
+version: 12.1
+config:
+  num:
+    ? 0
+allowed_labels:
+  tenant:
+    type: string
+
+selector_config:
+- description: 1
+  selector:
+    tenant: abc
+  config: !inherit
+    num: !inherit
+      ? 1
+- description: 2
+  selector:
+    tenant: ""
+  config: !inherit
+    num: !inherit
+      ? 2
+)";
+
+const char *ResolvedSimpleConfig2Negative = R"(---
+config:
+  num:
+    ? 0
+)";
+
+const char *ResolvedSimpleConfig2Empty = R"(---
+config:
+  num:
+    ? 0
+    ? 2
+)";
+
+const char *ResolvedSimpleConfig2Abc = R"(---
+config:
+  num:
+    ? 0
+    ? 1
+)";
+
+const char *UnresolvedSimpleConfig3 = R"(---
+cluster: test
+version: 12.1
+config:
+  num:
+    ? 0
+allowed_labels:
+  tenant:
+    type: string
+
+selector_config:
+- description: 1
+  selector:
+    tenant:
+      not_in:
+        - abc
+  config: !inherit
+    num: !inherit
+      ? 1
+)";
+
+const char *ResolvedSimpleConfig3Negative = R"(---
+config:
+  num:
+    ? 0
+    ? 1
+)";
+
+const char *ResolvedSimpleConfig3Empty = R"(---
+config:
+  num:
+    ? 0
+    ? 1
+)";
+
+const char *ResolvedSimpleConfig3Abc = R"(---
+config:
+  num:
+    ? 0
+)";
+
+const char *UnresolvedAllConfig = R"(---
+cluster: test
+version: 12.1
+config:
+  num:
+    ? 0
+allowed_labels:
+  tenant:
+    type: string
+  flavour:
+    type: enum
+    values:
+      ? def
+      ? jkl
+  kind:
+    type: enum
+    values:
+      ? mno
+      ? pqr
+  type:
+    type: enum
+    values:
+      ? foo
+
+selector_config:
+- description: 1
+  selector:
+    tenant: abc
+  config: !inherit
+    num: !inherit
+      ? 1
+- description: 2
+  selector:
+    flavour: def
+  config: !inherit
+    num: !inherit
+      ? 2
+- description: 3
+  selector:
+    tenant: abc
+    flavour: def
+  config:
+    num:
+      ? 3
+- description: 4
+  selector:
+    tenant: abc
+  config: !inherit
+    num: !inherit
+      ? 4
+- description: 5
+  selector:
+    tenant: ghi
+  config: !inherit
+    num: !inherit
+      ? 5
+- description: 6
+  selector:
+    flavour: jkl
+  config: !inherit
+    num: !inherit
+      ? 6
+- description: 7
+  selector:
+    kind: mno
+  config: !inherit
+    num: !inherit
+      ? 7
+- description: 8
+  selector:
+    kind: pqr
+  config: !inherit
+    num: !inherit
+      ? 8
+- description: 9
+  selector:
+    kind:
+      not_in:
+      - pqr
+  config: !inherit
+    num: !inherit
+      ? 9
+- description: 10
+  selector:
+    flavour:
+      in:
+      - def
+      - jkl
+  config: !inherit
+    num: !inherit
+      ? 10
+- description: 11
+  selector:
+    flavour:
+      not_in:
+      - def
+    kind: mno
+    tenant: abc
+  config: !inherit
+    num: !inherit
+      ? 11
+- description: 12
+  selector:
+    type: foo
+  config: !inherit
+    num: !inherit
+      ? 12
+- description: 13
+  selector:
+    tenant:
+      not_in:
+      - abc
+    type:
+      not_in:
+      - foo
+    flavour: def
+    kind: mno
+  config: !inherit
+    num: !inherit
+      ? 13)";
+
+const char *UnresolvedAllConfig14 = R"(---
+- description: 14
+  selector:
+    tenant:
+      in:
+      - aaa0
+      - bbb0
+      - ccc0
+      - ddd0
+      - eee0
+      - fff0
+      - ggg0
+      - kkk0
+      - lll0
+      - mmm0
+      - aaa1
+      - bbb1
+      - ccc1
+      - ddd1
+      - eee1
+      - fff1
+      - ggg1
+      - kkk1
+      - lll1
+      - mmm1
+      - aaa2
+      - bbb2
+      - ccc2
+      - ddd2
+      - eee2
+      - fff2
+      - ggg2
+      - kkk2
+      - lll2
+      - mmm2
+      - aaa3
+      - bbb3
+      - ccc3
+      - ddd3
+      - eee3
+      - fff3
+      - ggg3
+      - kkk3
+      - lll3
+      - mmm3
+      - aaa4
+      - bbb4
+      - ccc4
+      - ddd4
+      - eee4
+      - fff4
+      - ggg4
+      - kkk4
+      - lll4
+      - mmm4
+      - aaa5
+      - bbb5
+      - ccc5
+      - ddd5
+      - eee5
+      - fff5
+      - ggg5
+      - kkk5
+      - lll5
+      - mmm5
+  config: !inherit
+    num: !inherit
+      ? 14
+)";
+
+using EType = NYamlConfig::TLabel::EType;
+
+TMap<TSet<TVector<NYamlConfig::TLabel>>, TVector<int>> ExpectedResolved =
+{
+    std::pair{
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (pqr  )  (ghi  )  (foo  ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("pqr")}, {EType::Common, TString("ghi")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   5,   6,   8,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (pqr  )  (abc  ) _(     ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("pqr")}, {EType::Common, TString("abc")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   1,   4,   6,   8,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (mno  )  (abc  )  (foo  ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("mno")}, {EType::Common, TString("abc")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   1,   4,   6,   7,   9,   10,   11,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (mno  ) !(     ) _(     ) ],
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("mno")}, {EType::Negative, TString()}, {EType::Empty, TString()}},
+            // [ (jkl  )  (mno  ) _(     ) _(     ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("mno")}, {EType::Empty, TString()}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   6,   7,   9,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (mno  ) !(     )  (foo  ) ],
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("mno")}, {EType::Negative, TString()}, {EType::Common, TString("foo")}},
+            // [ (jkl  )  (mno  ) _(     )  (foo  ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("mno")}, {EType::Empty, TString()}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   6,   7,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  ) _(     )  (ghi  )  (foo  ) ]
+            {{EType::Common, TString("jkl")}, {EType::Empty, TString()}, {EType::Common, TString("ghi")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   5,   6,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  ) _(     )  (ghi  ) _(     ) ]
+            {{EType::Common, TString("jkl")}, {EType::Empty, TString()}, {EType::Common, TString("ghi")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   5,   6,   9,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  ) _(     )  (abc  )  (foo  ) ]
+            {{EType::Common, TString("jkl")}, {EType::Empty, TString()}, {EType::Common, TString("abc")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   1,   4,   6,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  ) _(     )  (abc  ) _(     ) ]
+            {{EType::Common, TString("jkl")}, {EType::Empty, TString()}, {EType::Common, TString("abc")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   1,   4,   6,   9,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  ) _(     ) !(     )  (foo  ) ],
+            {{EType::Common, TString("jkl")}, {EType::Empty, TString()}, {EType::Negative, TString()}, {EType::Common, TString("foo")}},
+            // [ (jkl  ) _(     ) _(     )  (foo  ) ]
+            {{EType::Common, TString("jkl")}, {EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   6,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  ) _(     ) !(     ) _(     ) ],
+            {{EType::Common, TString("jkl")}, {EType::Empty, TString()}, {EType::Negative, TString()}, {EType::Empty, TString()}},
+            // [ (jkl  ) _(     ) _(     ) _(     ) ]
+            {{EType::Common, TString("jkl")}, {EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   6,   9,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (mno  )  (abc  )  (foo  ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("mno")}, {EType::Common, TString("abc")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{3,   4,   7,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (pqr  ) !(     ) _(     ) ],
+            {{EType::Common, TString("def")}, {EType::Common, TString("pqr")}, {EType::Negative, TString()}, {EType::Empty, TString()}},
+            // [ (def  )  (pqr  ) _(     ) _(     ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("pqr")}, {EType::Empty, TString()}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   2,   8,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (mno  )  (abc  ) _(     ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("mno")}, {EType::Common, TString("abc")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{3,   4,   7,   9,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (mno  )  (ghi  )  (foo  ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("mno")}, {EType::Common, TString("ghi")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   2,   5,   7,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (mno  )  (ghi  ) _(     ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("mno")}, {EType::Common, TString("ghi")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   5,   6,   7,   9,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (pqr  )  (ghi  ) _(     ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("pqr")}, {EType::Common, TString("ghi")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   2,   5,   8,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (mno  ) !(     ) _(     ) ],
+            {{EType::Common, TString("def")}, {EType::Common, TString("mno")}, {EType::Negative, TString()}, {EType::Empty, TString()}},
+            // [ (def  )  (mno  ) _(     ) _(     ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("mno")}, {EType::Empty, TString()}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   2,   7,   9,   10,   13},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  ) _(     )  (ghi  )  (foo  ) ]
+            {{EType::Common, TString("def")}, {EType::Empty, TString()}, {EType::Common, TString("ghi")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   2,   5,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (pqr  )  (abc  )  (foo  ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("pqr")}, {EType::Common, TString("abc")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   1,   4,   8,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (mno  )  (ghi  ) _(     ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("mno")}, {EType::Common, TString("ghi")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   2,   5,   7,   9,   10,   13},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  ) _(     )  (abc  )  (foo  ) ]
+            {{EType::Common, TString("def")}, {EType::Empty, TString()}, {EType::Common, TString("abc")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{3,   4,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     ) _(     ) !(     ) _(     ) ],
+            {{EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Negative, TString()}, {EType::Empty, TString()}},
+            // [_(     ) _(     ) _(     ) _(     ) ]
+            {{EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   9},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  ) _(     )  (ghi  ) _(     ) ]
+            {{EType::Common, TString("def")}, {EType::Empty, TString()}, {EType::Common, TString("ghi")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   2,   5,   9,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  ) _(     ) !(     )  (foo  ) ],
+            {{EType::Common, TString("def")}, {EType::Empty, TString()}, {EType::Negative, TString()}, {EType::Common, TString("foo")}},
+            // [ (def  ) _(     ) _(     )  (foo  ) ]
+            {{EType::Common, TString("def")}, {EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   2,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (mno  )  (ghi  ) _(     ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("mno")}, {EType::Common, TString("ghi")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   5,   7,   9},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (pqr  )  (ghi  )  (foo  ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("pqr")}, {EType::Common, TString("ghi")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   5,   8,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  ) _(     )  (abc  ) _(     ) ]
+            {{EType::Common, TString("def")}, {EType::Empty, TString()}, {EType::Common, TString("abc")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{3,   4,   9,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (pqr  ) !(     )  (foo  ) ],
+            {{EType::Empty, TString()}, {EType::Common, TString("pqr")}, {EType::Negative, TString()}, {EType::Common, TString("foo")}},
+            // [_(     )  (pqr  ) _(     )  (foo  ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("pqr")}, {EType::Empty, TString()}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   8,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (pqr  )  (abc  ) _(     ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("pqr")}, {EType::Common, TString("abc")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{3,   4,   8,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (pqr  )  (ghi  ) _(     ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("pqr")}, {EType::Common, TString("ghi")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   5,   6,   8,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (pqr  )  (ghi  ) _(     ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("pqr")}, {EType::Common, TString("ghi")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   5,   8},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (pqr  ) !(     )  (foo  ) ],
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("pqr")}, {EType::Negative, TString()}, {EType::Common, TString("foo")}},
+            // [ (jkl  )  (pqr  ) _(     )  (foo  ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("pqr")}, {EType::Empty, TString()}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   6,   8,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (pqr  ) !(     )  (foo  ) ],
+            {{EType::Common, TString("def")}, {EType::Common, TString("pqr")}, {EType::Negative, TString()}, {EType::Common, TString("foo")}},
+            // [ (def  )  (pqr  ) _(     )  (foo  ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("pqr")}, {EType::Empty, TString()}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   2,   8,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (mno  ) !(     )  (foo  ) ],
+            {{EType::Common, TString("def")}, {EType::Common, TString("mno")}, {EType::Negative, TString()}, {EType::Common, TString("foo")}},
+            // [ (def  )  (mno  ) _(     )  (foo  ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("mno")}, {EType::Empty, TString()}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   2,   7,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (pqr  ) !(     ) _(     ) ],
+            {{EType::Empty, TString()}, {EType::Common, TString("pqr")}, {EType::Negative, TString()}, {EType::Empty, TString()}},
+            // [_(     )  (pqr  ) _(     ) _(     ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("pqr")}, {EType::Empty, TString()}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   8},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (pqr  ) !(     ) _(     ) ],
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("pqr")}, {EType::Negative, TString()}, {EType::Empty, TString()}},
+            // [ (jkl  )  (pqr  ) _(     ) _(     ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("pqr")}, {EType::Empty, TString()}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   6,   8,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (mno  )  (ghi  )  (foo  ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("mno")}, {EType::Common, TString("ghi")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   5,   7,   9,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (pqr  )  (abc  ) _(     ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("pqr")}, {EType::Common, TString("abc")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   1,   4,   8},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (pqr  )  (abc  )  (foo  ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("pqr")}, {EType::Common, TString("abc")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   1,   4,   6,   8,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (mno  )  (abc  ) _(     ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("mno")}, {EType::Common, TString("abc")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   1,   4,   6,   7,   9,   10,   11},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     ) _(     )  (abc  ) _(     ) ]
+            {{EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Common, TString("abc")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   1,   4,   9},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     ) _(     )  (abc  )  (foo  ) ]
+            {{EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Common, TString("abc")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   1,   4,   9,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (mno  ) !(     )  (foo  ) ],
+            {{EType::Empty, TString()}, {EType::Common, TString("mno")}, {EType::Negative, TString()}, {EType::Common, TString("foo")}},
+            // [_(     )  (mno  ) _(     )  (foo  ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("mno")}, {EType::Empty, TString()}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   7,   9,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  ) _(     ) !(     ) _(     ) ],
+            {{EType::Common, TString("def")}, {EType::Empty, TString()}, {EType::Negative, TString()}, {EType::Empty, TString()}},
+            // [ (def  ) _(     ) _(     ) _(     ) ]
+            {{EType::Common, TString("def")}, {EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   2,   9,   10},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (jkl  )  (mno  )  (ghi  )  (foo  ) ]
+            {{EType::Common, TString("jkl")}, {EType::Common, TString("mno")}, {EType::Common, TString("ghi")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   5,   6,   7,   9,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (mno  )  (abc  )  (foo  ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("mno")}, {EType::Common, TString("abc")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   1,   4,   7,   9,   11,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     ) _(     )  (ghi  ) _(     ) ]
+            {{EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Common, TString("ghi")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   5,   9},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (mno  )  (abc  ) _(     ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("mno")}, {EType::Common, TString("abc")}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   1,   4,   7,   9,   11},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     )  (mno  ) !(     ) _(     ) ],
+            {{EType::Empty, TString()}, {EType::Common, TString("mno")}, {EType::Negative, TString()}, {EType::Empty, TString()}},
+            // [_(     )  (mno  ) _(     ) _(     ) ]
+            {{EType::Empty, TString()}, {EType::Common, TString("mno")}, {EType::Empty, TString()}, {EType::Empty, TString()}},
+        },
+        TVector<int>{0,   7,   9},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (pqr  )  (abc  )  (foo  ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("pqr")}, {EType::Common, TString("abc")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{3,   4,   8,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     ) _(     ) !(     )  (foo  ) ],
+            {{EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Common, TString("foo")}},
+            // [_(     ) _(     ) _(     )  (foo  ) ]
+            {{EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Negative, TString()}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   9,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [ (def  )  (pqr  )  (ghi  )  (foo  ) ]
+            {{EType::Common, TString("def")}, {EType::Common, TString("pqr")}, {EType::Common, TString("ghi")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   2,   5,   8,   10,   12},
+    },
+    {
+        TSet<TVector<NYamlConfig::TLabel>>{
+            // [_(     ) _(     )  (ghi  )  (foo  ) ]
+            {{EType::Empty, TString()}, {EType::Empty, TString()}, {EType::Common, TString("ghi")}, {EType::Common, TString("foo")}},
+        },
+        TVector<int>{0,   5,   9,   12},
+    },
+};
+
+Y_UNIT_TEST_SUITE(YamlConfig) {
+    Y_UNIT_TEST(CollectLabels) {
+        auto doc = NFyaml::TDocument::Parse(WholeConfig);
+
+        auto labels = NYamlConfig::CollectLabels(doc);
+
+        // TODO: forbid enum extension
+        TMap<TString, NYamlConfig::TLabelType> expectedLabels = {
+            {"flavour", NYamlConfig::TLabelType{NYamlConfig::EYamlConfigLabelTypeClass::Closed, TSet<TString>{"", "big", "medium", "small"}}},
+            {"tenant", NYamlConfig::TLabelType{NYamlConfig::EYamlConfigLabelTypeClass::Open, TSet<TString>{/*"-*", */"", "/ru/tenant1", "/ru/tenant2", "/ru/tenant3"}}},
+        };
+
+        UNIT_ASSERT_EQUAL(labels, expectedLabels);
+    }
+
+    Y_UNIT_TEST(MaterializeSpecificConfig) {
+        auto doc = NFyaml::TDocument::Parse(WholeConfig);
+
+        {
+            auto expected = NFyaml::TDocument::Parse(BigTenant1Config);
+
+            auto [resolved, node] = NYamlConfig::Resolve(
+                doc,
+                {
+                    NYamlConfig::TNamedLabel{"flavour", "big"},
+                    NYamlConfig::TNamedLabel{"tenant", "/ru/tenant1"},
+                }
+            );
+
+            UNIT_ASSERT(node.DeepEqual(expected.Root()));
+        }
+
+        {
+            auto expected = NFyaml::TDocument::Parse(Tenant2Config);
+
+            auto [resolved, node] = NYamlConfig::Resolve(
+                doc,
+                {
+                    NYamlConfig::TNamedLabel{"tenant", "/ru/tenant2"},
+                }
+            );
+
+            UNIT_ASSERT(node.DeepEqual(expected.Root()));
+        }
+
+        {
+            auto expected = NFyaml::TDocument::Parse(SmallConfig);
+
+            auto [resolved, node] = NYamlConfig::Resolve(
+                doc,
+                {
+                    NYamlConfig::TNamedLabel{"flavour", "small"},
+                }
+            );
+
+            UNIT_ASSERT(node.DeepEqual(expected.Root()));
+        }
+
+        {
+            auto expected = NFyaml::TDocument::Parse(MediumConfig);
+
+            auto [resolved, node] = NYamlConfig::Resolve(
+                doc,
+                {
+                    NYamlConfig::TNamedLabel{"flavour", "medium"},
+                }
+            );
+
+            UNIT_ASSERT(node.DeepEqual(expected.Root()));
+        }
+
+        {
+            auto expected = NFyaml::TDocument::Parse(MediumTenant1Config);
+
+            auto [resolved, node] = NYamlConfig::Resolve(
+                doc,
+                {
+                    NYamlConfig::TNamedLabel{"flavour", "medium"},
+                    NYamlConfig::TNamedLabel{"tenant", "/ru/tenant1"},
+                }
+            );
+
+            UNIT_ASSERT(node.DeepEqual(expected.Root()));
+        }
+    }
+
+    Y_UNIT_TEST(MaterializeAllConfigSimple) {
+        TVector<TString> expectedLabels{"tenant"};
+
+        {
+            auto doc = NFyaml::TDocument::Parse(UnresolvedSimpleConfig1);
+            auto resolved = NYamlConfig::ResolveAll(doc);
+            UNIT_ASSERT_VALUES_EQUAL(resolved.Labels, expectedLabels);
+
+            auto empty = NFyaml::TDocument::Parse(ResolvedSimpleConfig1Empty);
+            auto negative = NFyaml::TDocument::Parse(ResolvedSimpleConfig1Negative);
+            auto abc = NFyaml::TDocument::Parse(ResolvedSimpleConfig1Abc);
+
+            TSet<TVector<NYamlConfig::TLabel>> first = {
+                {NYamlConfig::TLabel{EType::Empty, ""}},
+                {NYamlConfig::TLabel{EType::Negative, ""}},
+            };
+
+            auto firstIt = resolved.Configs.find(first);
+            UNIT_ASSERT_UNEQUAL(firstIt, resolved.Configs.end());
+            UNIT_ASSERT(firstIt->second.second.DeepEqual(empty.Root().Map()["config"]));
+            UNIT_ASSERT(firstIt->second.second.DeepEqual(negative.Root().Map()["config"]));
+
+            TSet<TVector<NYamlConfig::TLabel>> second = {
+                {NYamlConfig::TLabel{EType::Common, "abc"}},
+            };
+
+            auto secondIt = resolved.Configs.find(second);
+            UNIT_ASSERT_UNEQUAL(secondIt, resolved.Configs.end());
+            UNIT_ASSERT(secondIt->second.second.DeepEqual(abc.Root().Map()["config"]));
+        }
+
+        {
+            auto doc = NFyaml::TDocument::Parse(UnresolvedSimpleConfig2);
+            auto resolved = NYamlConfig::ResolveAll(doc);
+            UNIT_ASSERT_VALUES_EQUAL(resolved.Labels, expectedLabels);
+
+            auto empty = NFyaml::TDocument::Parse(ResolvedSimpleConfig2Empty);
+            auto negative = NFyaml::TDocument::Parse(ResolvedSimpleConfig2Negative);
+            auto abc = NFyaml::TDocument::Parse(ResolvedSimpleConfig2Abc);
+
+            TSet<TVector<NYamlConfig::TLabel>> first = {
+                {NYamlConfig::TLabel{EType::Empty, ""}},
+            };
+
+            auto firstIt = resolved.Configs.find(first);
+            UNIT_ASSERT_UNEQUAL(firstIt, resolved.Configs.end());
+            UNIT_ASSERT(firstIt->second.second.DeepEqual(empty.Root().Map()["config"]));
+
+            TSet<TVector<NYamlConfig::TLabel>> second = {
+                {NYamlConfig::TLabel{EType::Common, "abc"}},
+            };
+
+            auto secondIt = resolved.Configs.find(second);
+            UNIT_ASSERT_UNEQUAL(secondIt, resolved.Configs.end());
+            UNIT_ASSERT(secondIt->second.second.DeepEqual(abc.Root().Map()["config"]));
+        }
+
+        {
+            auto doc = NFyaml::TDocument::Parse(UnresolvedSimpleConfig3);
+            auto resolved = NYamlConfig::ResolveAll(doc);
+            UNIT_ASSERT_VALUES_EQUAL(resolved.Labels, expectedLabels);
+
+            auto empty = NFyaml::TDocument::Parse(ResolvedSimpleConfig3Empty);
+            auto negative = NFyaml::TDocument::Parse(ResolvedSimpleConfig3Negative);
+            auto abc = NFyaml::TDocument::Parse(ResolvedSimpleConfig3Abc);
+
+            TSet<TVector<NYamlConfig::TLabel>> first = {
+                {NYamlConfig::TLabel{EType::Empty, ""}},
+                {NYamlConfig::TLabel{EType::Negative, ""}},
+            };
+
+            auto firstIt = resolved.Configs.find(first);
+            UNIT_ASSERT_UNEQUAL(firstIt, resolved.Configs.end());
+            UNIT_ASSERT(firstIt->second.second.DeepEqual(empty.Root().Map()["config"]));
+            UNIT_ASSERT(firstIt->second.second.DeepEqual(negative.Root().Map()["config"]));
+
+            TSet<TVector<NYamlConfig::TLabel>> second = {
+                {NYamlConfig::TLabel{EType::Common, "abc"}},
+            };
+
+            auto secondIt = resolved.Configs.find(second);
+            UNIT_ASSERT_UNEQUAL(secondIt, resolved.Configs.end());
+            UNIT_ASSERT(secondIt->second.second.DeepEqual(abc.Root().Map()["config"]));
+        }
+    }
+
+    Y_UNIT_TEST(MaterializeAllConfigs) {
+        TVector<TString> expectedLabels{"flavour", "kind", "tenant", "type"};
+
+        {
+            auto doc = NFyaml::TDocument::Parse(UnresolvedAllConfig);
+            auto resolved = NYamlConfig::ResolveAll(doc);
+            TMap<TSet<TVector<NYamlConfig::TLabel>>, TVector<int>> compacted;
+            for(auto& [k, v] : resolved.Configs) {
+                TVector<int> nums;
+                for (auto& kv: v.second.Map()["num"].Map()) {
+                    nums.push_back(std::stoi(kv.Key().Scalar()));
+                }
+                compacted[k] = nums;
+            }
+
+            UNIT_ASSERT_VALUES_EQUAL(resolved.Labels, expectedLabels);
+            UNIT_ASSERT_VALUES_EQUAL(compacted.size(), ExpectedResolved.size());
+            UNIT_ASSERT_VALUES_EQUAL(compacted, ExpectedResolved);
+        }
+
+        {
+            auto config = TString(UnresolvedAllConfig) + UnresolvedAllConfig14;
+            auto doc = NFyaml::TDocument::Parse(config.c_str());
+            auto resolved = NYamlConfig::ResolveAll(doc);
+
+            UNIT_ASSERT_VALUES_EQUAL(resolved.Labels, expectedLabels);
+            UNIT_ASSERT_VALUES_EQUAL(resolved.Configs.size(), 72);
+            // TODO extend ExpectedResolved manually and compare
+        }
+    }
+}