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authorDevtools Arcadia <arcadia-devtools@yandex-team.ru>2022-02-07 18:08:42 +0300
committerDevtools Arcadia <arcadia-devtools@mous.vla.yp-c.yandex.net>2022-02-07 18:08:42 +0300
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+PyParsing -- A Python Parsing Module
+====================================
+
+|Build Status| |Coverage|
+
+Introduction
+============
+
+The pyparsing module is an alternative approach to creating and
+executing simple grammars, vs. the traditional lex/yacc approach, or the
+use of regular expressions. The pyparsing module provides a library of
+classes that client code uses to construct the grammar directly in
+Python code.
+
+*[Since first writing this description of pyparsing in late 2003, this
+technique for developing parsers has become more widespread, under the
+name Parsing Expression Grammars - PEGs. See more information on PEGs*
+`here <https://en.wikipedia.org/wiki/Parsing_expression_grammar>`__
+*.]*
+
+Here is a program to parse ``"Hello, World!"`` (or any greeting of the form
+``"salutation, addressee!"``):
+
+.. code:: python
+
+ from pyparsing import Word, alphas
+ greet = Word(alphas) + "," + Word(alphas) + "!"
+ hello = "Hello, World!"
+ print(hello, "->", greet.parseString(hello))
+
+The program outputs the following::
+
+ Hello, World! -> ['Hello', ',', 'World', '!']
+
+The Python representation of the grammar is quite readable, owing to the
+self-explanatory class names, and the use of '+', '|' and '^' operator
+definitions.
+
+The parsed results returned from ``parseString()`` is a collection of type
+``ParseResults``, which can be accessed as a
+nested list, a dictionary, or an object with named attributes.
+
+The pyparsing module handles some of the problems that are typically
+vexing when writing text parsers:
+
+- extra or missing whitespace (the above program will also handle ``"Hello,World!"``, ``"Hello , World !"``, etc.)
+- quoted strings
+- embedded comments
+
+The examples directory includes a simple SQL parser, simple CORBA IDL
+parser, a config file parser, a chemical formula parser, and a four-
+function algebraic notation parser, among many others.
+
+Documentation
+=============
+
+There are many examples in the online docstrings of the classes
+and methods in pyparsing. You can find them compiled into `online docs <https://pyparsing-docs.readthedocs.io/en/latest/>`__. Additional
+documentation resources and project info are listed in the online
+`GitHub wiki <https://github.com/pyparsing/pyparsing/wiki>`__. An
+entire directory of examples can be found `here <https://github.com/pyparsing/pyparsing/tree/master/examples>`__.
+
+License
+=======
+
+MIT License. See header of the `pyparsing.py <https://github.com/pyparsing/pyparsing/blob/master/pyparsing/__init__.py#L1-L23>`__ file.
+
+History
+=======
+
+See `CHANGES <https://github.com/pyparsing/pyparsing/blob/master/CHANGES>`__ file.
+
+.. |Build Status| image:: https://github.com/pyparsing/pyparsing/actions/workflows/ci.yml/badge.svg
+ :target: https://github.com/pyparsing/pyparsing/actions/workflows/ci.yml
+.. |Coverage| image:: https://codecov.io/gh/pyparsing/pyparsing/branch/master/graph/badge.svg
+ :target: https://codecov.io/gh/pyparsing/pyparsing