Restoring authorship annotation for Mikhail Borisov <borisov.mikhail@gmail.com>. Commit 2 of 2.

1 files changed, 681 insertions, 681 deletions

diff --git a/contrib/python/ipython/py2/IPython/core/inputsplitter.py b/contrib/python/ipython/py2/IPython/core/inputsplitter.py
index 2c7125f88d..ac14747d69 100644
--- a/contrib/python/ipython/py2/IPython/core/inputsplitter.py
+++ b/contrib/python/ipython/py2/IPython/core/inputsplitter.py
@@ -1,681 +1,681 @@
-"""Input handling and transformation machinery. 
- 
-The first class in this module, :class:`InputSplitter`, is designed to tell when 
-input from a line-oriented frontend is complete and should be executed, and when 
-the user should be prompted for another line of code instead. The name 'input 
-splitter' is largely for historical reasons. 
- 
-A companion, :class:`IPythonInputSplitter`, provides the same functionality but 
-with full support for the extended IPython syntax (magics, system calls, etc). 
-The code to actually do these transformations is in :mod:`IPython.core.inputtransformer`. 
-:class:`IPythonInputSplitter` feeds the raw code to the transformers in order 
-and stores the results. 
- 
-For more details, see the class docstrings below. 
-""" 
- 
-# Copyright (c) IPython Development Team. 
-# Distributed under the terms of the Modified BSD License. 
-import ast 
-import codeop 
-import re 
-import sys 
-import warnings 
- 
-from IPython.utils.py3compat import cast_unicode 
-from IPython.core.inputtransformer import (leading_indent, 
-                                           classic_prompt, 
-                                           ipy_prompt, 
-                                           strip_encoding_cookie, 
-                                           cellmagic, 
-                                           assemble_logical_lines, 
-                                           help_end, 
-                                           escaped_commands, 
-                                           assign_from_magic, 
-                                           assign_from_system, 
-                                           assemble_python_lines, 
-                                           ) 
- 
-# These are available in this module for backwards compatibility. 
-from IPython.core.inputtransformer import (ESC_SHELL, ESC_SH_CAP, ESC_HELP, 
-                                        ESC_HELP2, ESC_MAGIC, ESC_MAGIC2, 
-                                        ESC_QUOTE, ESC_QUOTE2, ESC_PAREN, ESC_SEQUENCES) 
- 
-#----------------------------------------------------------------------------- 
-# Utilities 
-#----------------------------------------------------------------------------- 
- 
-# FIXME: These are general-purpose utilities that later can be moved to the 
-# general ward.  Kept here for now because we're being very strict about test 
-# coverage with this code, and this lets us ensure that we keep 100% coverage 
-# while developing. 
- 
-# compiled regexps for autoindent management 
-dedent_re = re.compile('|'.join([ 
-    r'^\s+raise(\s.*)?$', # raise statement (+ space + other stuff, maybe) 
-    r'^\s+raise\([^\)]*\).*$', # wacky raise with immediate open paren 
-    r'^\s+return(\s.*)?$', # normal return (+ space + other stuff, maybe) 
-    r'^\s+return\([^\)]*\).*$', # wacky return with immediate open paren 
-    r'^\s+pass\s*$', # pass (optionally followed by trailing spaces) 
-    r'^\s+break\s*$', # break (optionally followed by trailing spaces) 
-    r'^\s+continue\s*$', # continue (optionally followed by trailing spaces) 
-])) 
-ini_spaces_re = re.compile(r'^([ \t\r\f\v]+)') 
- 
-# regexp to match pure comment lines so we don't accidentally insert 'if 1:' 
-# before pure comments 
-comment_line_re = re.compile('^\s*\#') 
- 
- 
-def num_ini_spaces(s): 
-    """Return the number of initial spaces in a string. 
- 
-    Note that tabs are counted as a single space.  For now, we do *not* support 
-    mixing of tabs and spaces in the user's input. 
- 
-    Parameters 
-    ---------- 
-    s : string 
- 
-    Returns 
-    ------- 
-    n : int 
-    """ 
- 
-    ini_spaces = ini_spaces_re.match(s) 
-    if ini_spaces: 
-        return ini_spaces.end() 
-    else: 
-        return 0 
- 
-def last_blank(src): 
-    """Determine if the input source ends in a blank. 
- 
-    A blank is either a newline or a line consisting of whitespace. 
- 
-    Parameters 
-    ---------- 
-    src : string 
-      A single or multiline string. 
-    """ 
-    if not src: return False 
-    ll  = src.splitlines()[-1] 
-    return (ll == '') or ll.isspace() 
- 
- 
-last_two_blanks_re = re.compile(r'\n\s*\n\s*$', re.MULTILINE) 
-last_two_blanks_re2 = re.compile(r'.+\n\s*\n\s+$', re.MULTILINE) 
- 
-def last_two_blanks(src): 
-    """Determine if the input source ends in two blanks. 
- 
-    A blank is either a newline or a line consisting of whitespace. 
- 
-    Parameters 
-    ---------- 
-    src : string 
-      A single or multiline string. 
-    """ 
-    if not src: return False 
-    # The logic here is tricky: I couldn't get a regexp to work and pass all 
-    # the tests, so I took a different approach: split the source by lines, 
-    # grab the last two and prepend '###\n' as a stand-in for whatever was in 
-    # the body before the last two lines.  Then, with that structure, it's 
-    # possible to analyze with two regexps.  Not the most elegant solution, but 
-    # it works.  If anyone tries to change this logic, make sure to validate 
-    # the whole test suite first! 
-    new_src = '\n'.join(['###\n'] + src.splitlines()[-2:]) 
-    return (bool(last_two_blanks_re.match(new_src)) or 
-            bool(last_two_blanks_re2.match(new_src)) ) 
- 
- 
-def remove_comments(src): 
-    """Remove all comments from input source. 
- 
-    Note: comments are NOT recognized inside of strings! 
- 
-    Parameters 
-    ---------- 
-    src : string 
-      A single or multiline input string. 
- 
-    Returns 
-    ------- 
-    String with all Python comments removed. 
-    """ 
- 
-    return re.sub('#.*', '', src) 
- 
- 
-def get_input_encoding(): 
-    """Return the default standard input encoding. 
- 
-    If sys.stdin has no encoding, 'ascii' is returned.""" 
-    # There are strange environments for which sys.stdin.encoding is None. We 
-    # ensure that a valid encoding is returned. 
-    encoding = getattr(sys.stdin, 'encoding', None) 
-    if encoding is None: 
-        encoding = 'ascii' 
-    return encoding 
- 
-#----------------------------------------------------------------------------- 
-# Classes and functions for normal Python syntax handling 
-#----------------------------------------------------------------------------- 
- 
-class InputSplitter(object): 
-    r"""An object that can accumulate lines of Python source before execution. 
- 
-    This object is designed to be fed python source line-by-line, using 
-    :meth:`push`. It will return on each push whether the currently pushed 
-    code could be executed already. In addition, it provides a method called 
-    :meth:`push_accepts_more` that can be used to query whether more input 
-    can be pushed into a single interactive block. 
- 
-    This is a simple example of how an interactive terminal-based client can use 
-    this tool:: 
- 
-        isp = InputSplitter() 
-        while isp.push_accepts_more(): 
-            indent = ' '*isp.indent_spaces 
-            prompt = '>>> ' + indent 
-            line = indent + raw_input(prompt) 
-            isp.push(line) 
-        print 'Input source was:\n', isp.source_reset(), 
-    """ 
-    # Number of spaces of indentation computed from input that has been pushed 
-    # so far.  This is the attributes callers should query to get the current 
-    # indentation level, in order to provide auto-indent facilities. 
-    indent_spaces = 0 
-    # String, indicating the default input encoding.  It is computed by default 
-    # at initialization time via get_input_encoding(), but it can be reset by a 
-    # client with specific knowledge of the encoding. 
-    encoding = '' 
-    # String where the current full source input is stored, properly encoded. 
-    # Reading this attribute is the normal way of querying the currently pushed 
-    # source code, that has been properly encoded. 
-    source = '' 
-    # Code object corresponding to the current source.  It is automatically 
-    # synced to the source, so it can be queried at any time to obtain the code 
-    # object; it will be None if the source doesn't compile to valid Python. 
-    code = None 
- 
-    # Private attributes 
- 
-    # List with lines of input accumulated so far 
-    _buffer = None 
-    # Command compiler 
-    _compile = None 
-    # Mark when input has changed indentation all the way back to flush-left 
-    _full_dedent = False 
-    # Boolean indicating whether the current block is complete 
-    _is_complete = None 
-    # Boolean indicating whether the current block has an unrecoverable syntax error 
-    _is_invalid = False 
- 
-    def __init__(self): 
-        """Create a new InputSplitter instance. 
-        """ 
-        self._buffer = [] 
-        self._compile = codeop.CommandCompiler() 
-        self.encoding = get_input_encoding() 
- 
-    def reset(self): 
-        """Reset the input buffer and associated state.""" 
-        self.indent_spaces = 0 
-        self._buffer[:] = [] 
-        self.source = '' 
-        self.code = None 
-        self._is_complete = False 
-        self._is_invalid = False 
-        self._full_dedent = False 
- 
-    def source_reset(self): 
-        """Return the input source and perform a full reset. 
-        """ 
-        out = self.source 
-        self.reset() 
-        return out 
- 
-    def check_complete(self, source): 
-        """Return whether a block of code is ready to execute, or should be continued 
-         
-        This is a non-stateful API, and will reset the state of this InputSplitter. 
-         
-        Parameters 
-        ---------- 
-        source : string 
-          Python input code, which can be multiline. 
-         
-        Returns 
-        ------- 
-        status : str 
-          One of 'complete', 'incomplete', or 'invalid' if source is not a 
-          prefix of valid code. 
-        indent_spaces : int or None 
-          The number of spaces by which to indent the next line of code. If 
-          status is not 'incomplete', this is None. 
-        """ 
-        self.reset() 
-        try: 
-            self.push(source) 
-        except SyntaxError: 
-            # Transformers in IPythonInputSplitter can raise SyntaxError, 
-            # which push() will not catch. 
-            return 'invalid', None 
-        else: 
-            if self._is_invalid: 
-                return 'invalid', None 
-            elif self.push_accepts_more(): 
-                return 'incomplete', self.indent_spaces 
-            else: 
-                return 'complete', None 
-        finally: 
-            self.reset() 
- 
-    def push(self, lines): 
-        """Push one or more lines of input. 
- 
-        This stores the given lines and returns a status code indicating 
-        whether the code forms a complete Python block or not. 
- 
-        Any exceptions generated in compilation are swallowed, but if an 
-        exception was produced, the method returns True. 
- 
-        Parameters 
-        ---------- 
-        lines : string 
-          One or more lines of Python input. 
- 
-        Returns 
-        ------- 
-        is_complete : boolean 
-          True if the current input source (the result of the current input 
-          plus prior inputs) forms a complete Python execution block.  Note that 
-          this value is also stored as a private attribute (``_is_complete``), so it 
-          can be queried at any time. 
-        """ 
-        self._store(lines) 
-        source = self.source 
- 
-        # Before calling _compile(), reset the code object to None so that if an 
-        # exception is raised in compilation, we don't mislead by having 
-        # inconsistent code/source attributes. 
-        self.code, self._is_complete = None, None 
-        self._is_invalid = False 
- 
-        # Honor termination lines properly 
-        if source.endswith('\\\n'): 
-            return False 
- 
-        self._update_indent(lines) 
-        try: 
-            with warnings.catch_warnings(): 
-                warnings.simplefilter('error', SyntaxWarning) 
-                self.code = self._compile(source, symbol="exec") 
-        # Invalid syntax can produce any of a number of different errors from 
-        # inside the compiler, so we have to catch them all.  Syntax errors 
-        # immediately produce a 'ready' block, so the invalid Python can be 
-        # sent to the kernel for evaluation with possible ipython 
-        # special-syntax conversion. 
-        except (SyntaxError, OverflowError, ValueError, TypeError, 
-                MemoryError, SyntaxWarning): 
-            self._is_complete = True 
-            self._is_invalid = True 
-        else: 
-            # Compilation didn't produce any exceptions (though it may not have 
-            # given a complete code object) 
-            self._is_complete = self.code is not None 
- 
-        return self._is_complete 
- 
-    def push_accepts_more(self): 
-        """Return whether a block of interactive input can accept more input. 
- 
-        This method is meant to be used by line-oriented frontends, who need to 
-        guess whether a block is complete or not based solely on prior and 
-        current input lines.  The InputSplitter considers it has a complete 
-        interactive block and will not accept more input when either: 
-         
-        * A SyntaxError is raised 
- 
-        * The code is complete and consists of a single line or a single 
-          non-compound statement 
- 
-        * The code is complete and has a blank line at the end 
- 
-        If the current input produces a syntax error, this method immediately 
-        returns False but does *not* raise the syntax error exception, as 
-        typically clients will want to send invalid syntax to an execution 
-        backend which might convert the invalid syntax into valid Python via 
-        one of the dynamic IPython mechanisms. 
-        """ 
- 
-        # With incomplete input, unconditionally accept more 
-        # A syntax error also sets _is_complete to True - see push() 
-        if not self._is_complete: 
-            #print("Not complete")  # debug 
-            return True 
-         
-        # The user can make any (complete) input execute by leaving a blank line 
-        last_line = self.source.splitlines()[-1] 
-        if (not last_line) or last_line.isspace(): 
-            #print("Blank line")  # debug 
-            return False 
-         
-        # If there's just a single line or AST node, and we're flush left, as is 
-        # the case after a simple statement such as 'a=1', we want to execute it 
-        # straight away. 
-        if self.indent_spaces==0: 
-            if len(self.source.splitlines()) <= 1: 
-                return False 
-             
-            try: 
-                code_ast = ast.parse(u''.join(self._buffer)) 
-            except Exception: 
-                #print("Can't parse AST")  # debug 
-                return False 
-            else: 
-                if len(code_ast.body) == 1 and \ 
-                                    not hasattr(code_ast.body[0], 'body'): 
-                    #print("Simple statement")  # debug 
-                    return False 
- 
-        # General fallback - accept more code 
-        return True 
- 
-    #------------------------------------------------------------------------ 
-    # Private interface 
-    #------------------------------------------------------------------------ 
- 
-    def _find_indent(self, line): 
-        """Compute the new indentation level for a single line. 
- 
-        Parameters 
-        ---------- 
-        line : str 
-          A single new line of non-whitespace, non-comment Python input. 
- 
-        Returns 
-        ------- 
-        indent_spaces : int 
-          New value for the indent level (it may be equal to self.indent_spaces 
-        if indentation doesn't change. 
- 
-        full_dedent : boolean 
-          Whether the new line causes a full flush-left dedent. 
-        """ 
-        indent_spaces = self.indent_spaces 
-        full_dedent = self._full_dedent 
- 
-        inisp = num_ini_spaces(line) 
-        if inisp < indent_spaces: 
-            indent_spaces = inisp 
-            if indent_spaces <= 0: 
-                #print 'Full dedent in text',self.source # dbg 
-                full_dedent = True 
- 
-        if line.rstrip()[-1] == ':': 
-            indent_spaces += 4 
-        elif dedent_re.match(line): 
-            indent_spaces -= 4 
-            if indent_spaces <= 0: 
-                full_dedent = True 
- 
-        # Safety 
-        if indent_spaces < 0: 
-            indent_spaces = 0 
-            #print 'safety' # dbg 
- 
-        return indent_spaces, full_dedent 
- 
-    def _update_indent(self, lines): 
-        for line in remove_comments(lines).splitlines(): 
-            if line and not line.isspace(): 
-                self.indent_spaces, self._full_dedent = self._find_indent(line) 
- 
-    def _store(self, lines, buffer=None, store='source'): 
-        """Store one or more lines of input. 
- 
-        If input lines are not newline-terminated, a newline is automatically 
-        appended.""" 
- 
-        if buffer is None: 
-            buffer = self._buffer 
- 
-        if lines.endswith('\n'): 
-            buffer.append(lines) 
-        else: 
-            buffer.append(lines+'\n') 
-        setattr(self, store, self._set_source(buffer)) 
- 
-    def _set_source(self, buffer): 
-        return u''.join(buffer) 
- 
- 
-class IPythonInputSplitter(InputSplitter): 
-    """An input splitter that recognizes all of IPython's special syntax.""" 
- 
-    # String with raw, untransformed input. 
-    source_raw = '' 
-     
-    # Flag to track when a transformer has stored input that it hasn't given 
-    # back yet. 
-    transformer_accumulating = False 
-     
-    # Flag to track when assemble_python_lines has stored input that it hasn't 
-    # given back yet. 
-    within_python_line = False 
- 
-    # Private attributes 
- 
-    # List with lines of raw input accumulated so far. 
-    _buffer_raw = None 
- 
-    def __init__(self, line_input_checker=True, physical_line_transforms=None, 
-                    logical_line_transforms=None, python_line_transforms=None): 
-        super(IPythonInputSplitter, self).__init__() 
-        self._buffer_raw = [] 
-        self._validate = True 
-         
-        if physical_line_transforms is not None: 
-            self.physical_line_transforms = physical_line_transforms 
-        else: 
-            self.physical_line_transforms = [ 
-                                             leading_indent(), 
-                                             classic_prompt(), 
-                                             ipy_prompt(), 
-                                             cellmagic(end_on_blank_line=line_input_checker), 
-                                             strip_encoding_cookie(), 
-                                            ] 
-         
-        self.assemble_logical_lines = assemble_logical_lines() 
-        if logical_line_transforms is not None: 
-            self.logical_line_transforms = logical_line_transforms 
-        else: 
-            self.logical_line_transforms = [ 
-                                            help_end(), 
-                                            escaped_commands(), 
-                                            assign_from_magic(), 
-                                            assign_from_system(), 
-                                           ] 
-         
-        self.assemble_python_lines = assemble_python_lines() 
-        if python_line_transforms is not None: 
-            self.python_line_transforms = python_line_transforms 
-        else: 
-            # We don't use any of these at present 
-            self.python_line_transforms = [] 
-     
-    @property 
-    def transforms(self): 
-        "Quick access to all transformers." 
-        return self.physical_line_transforms + \ 
-            [self.assemble_logical_lines] + self.logical_line_transforms + \ 
-            [self.assemble_python_lines]  + self.python_line_transforms 
-     
-    @property 
-    def transforms_in_use(self): 
-        """Transformers, excluding logical line transformers if we're in a 
-        Python line.""" 
-        t = self.physical_line_transforms[:] 
-        if not self.within_python_line: 
-            t += [self.assemble_logical_lines] + self.logical_line_transforms 
-        return t + [self.assemble_python_lines] + self.python_line_transforms 
- 
-    def reset(self): 
-        """Reset the input buffer and associated state.""" 
-        super(IPythonInputSplitter, self).reset() 
-        self._buffer_raw[:] = [] 
-        self.source_raw = '' 
-        self.transformer_accumulating = False 
-        self.within_python_line = False 
- 
-        for t in self.transforms: 
-            try: 
-                t.reset() 
-            except SyntaxError: 
-                # Nothing that calls reset() expects to handle transformer 
-                # errors 
-                pass 
-     
-    def flush_transformers(self): 
-        def _flush(transform, outs): 
-            """yield transformed lines 
-             
-            always strings, never None 
-             
-            transform: the current transform 
-            outs: an iterable of previously transformed inputs. 
-                 Each may be multiline, which will be passed 
-                 one line at a time to transform. 
-            """ 
-            for out in outs: 
-                for line in out.splitlines(): 
-                    # push one line at a time 
-                    tmp = transform.push(line) 
-                    if tmp is not None: 
-                        yield tmp 
-             
-            # reset the transform 
-            tmp = transform.reset() 
-            if tmp is not None: 
-                yield tmp 
-         
-        out = [] 
-        for t in self.transforms_in_use: 
-            out = _flush(t, out) 
-         
-        out = list(out) 
-        if out: 
-            self._store('\n'.join(out)) 
- 
-    def raw_reset(self): 
-        """Return raw input only and perform a full reset. 
-        """ 
-        out = self.source_raw 
-        self.reset() 
-        return out 
-     
-    def source_reset(self): 
-        try: 
-            self.flush_transformers() 
-            return self.source 
-        finally: 
-            self.reset() 
- 
-    def push_accepts_more(self): 
-        if self.transformer_accumulating: 
-            return True 
-        else: 
-            return super(IPythonInputSplitter, self).push_accepts_more() 
- 
-    def transform_cell(self, cell): 
-        """Process and translate a cell of input. 
-        """ 
-        self.reset() 
-        try: 
-            self.push(cell) 
-            self.flush_transformers() 
-            return self.source 
-        finally: 
-            self.reset() 
- 
-    def push(self, lines): 
-        """Push one or more lines of IPython input. 
- 
-        This stores the given lines and returns a status code indicating 
-        whether the code forms a complete Python block or not, after processing 
-        all input lines for special IPython syntax. 
- 
-        Any exceptions generated in compilation are swallowed, but if an 
-        exception was produced, the method returns True. 
- 
-        Parameters 
-        ---------- 
-        lines : string 
-          One or more lines of Python input. 
- 
-        Returns 
-        ------- 
-        is_complete : boolean 
-          True if the current input source (the result of the current input 
-          plus prior inputs) forms a complete Python execution block.  Note that 
-          this value is also stored as a private attribute (_is_complete), so it 
-          can be queried at any time. 
-        """ 
- 
-        # We must ensure all input is pure unicode 
-        lines = cast_unicode(lines, self.encoding) 
-        # ''.splitlines() --> [], but we need to push the empty line to transformers 
-        lines_list = lines.splitlines() 
-        if not lines_list: 
-            lines_list = [''] 
- 
-        # Store raw source before applying any transformations to it.  Note 
-        # that this must be done *after* the reset() call that would otherwise 
-        # flush the buffer. 
-        self._store(lines, self._buffer_raw, 'source_raw') 
- 
-        for line in lines_list: 
-            out = self.push_line(line) 
- 
-        return out 
-     
-    def push_line(self, line): 
-        buf = self._buffer 
-         
-        def _accumulating(dbg): 
-            #print(dbg) 
-            self.transformer_accumulating = True 
-            return False 
-         
-        for transformer in self.physical_line_transforms: 
-            line = transformer.push(line) 
-            if line is None: 
-                return _accumulating(transformer) 
-         
-        if not self.within_python_line: 
-            line = self.assemble_logical_lines.push(line) 
-            if line is None: 
-                return _accumulating('acc logical line')         
-         
-            for transformer in self.logical_line_transforms: 
-                line = transformer.push(line) 
-                if line is None: 
-                    return _accumulating(transformer) 
-         
-        line = self.assemble_python_lines.push(line) 
-        if line is None: 
-            self.within_python_line = True 
-            return _accumulating('acc python line') 
-        else: 
-            self.within_python_line = False 
-         
-        for transformer in self.python_line_transforms: 
-            line = transformer.push(line) 
-            if line is None: 
-                return _accumulating(transformer) 
- 
-        #print("transformers clear") #debug 
-        self.transformer_accumulating = False 
-        return super(IPythonInputSplitter, self).push(line) 
+"""Input handling and transformation machinery.
+
+The first class in this module, :class:`InputSplitter`, is designed to tell when
+input from a line-oriented frontend is complete and should be executed, and when
+the user should be prompted for another line of code instead. The name 'input
+splitter' is largely for historical reasons.
+
+A companion, :class:`IPythonInputSplitter`, provides the same functionality but
+with full support for the extended IPython syntax (magics, system calls, etc).
+The code to actually do these transformations is in :mod:`IPython.core.inputtransformer`.
+:class:`IPythonInputSplitter` feeds the raw code to the transformers in order
+and stores the results.
+
+For more details, see the class docstrings below.
+"""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+import ast
+import codeop
+import re
+import sys
+import warnings
+
+from IPython.utils.py3compat import cast_unicode
+from IPython.core.inputtransformer import (leading_indent,
+                                           classic_prompt,
+                                           ipy_prompt,
+                                           strip_encoding_cookie,
+                                           cellmagic,
+                                           assemble_logical_lines,
+                                           help_end,
+                                           escaped_commands,
+                                           assign_from_magic,
+                                           assign_from_system,
+                                           assemble_python_lines,
+                                           )
+
+# These are available in this module for backwards compatibility.
+from IPython.core.inputtransformer import (ESC_SHELL, ESC_SH_CAP, ESC_HELP,
+                                        ESC_HELP2, ESC_MAGIC, ESC_MAGIC2,
+                                        ESC_QUOTE, ESC_QUOTE2, ESC_PAREN, ESC_SEQUENCES)
+
+#-----------------------------------------------------------------------------
+# Utilities
+#-----------------------------------------------------------------------------
+
+# FIXME: These are general-purpose utilities that later can be moved to the
+# general ward.  Kept here for now because we're being very strict about test
+# coverage with this code, and this lets us ensure that we keep 100% coverage
+# while developing.
+
+# compiled regexps for autoindent management
+dedent_re = re.compile('|'.join([
+    r'^\s+raise(\s.*)?$', # raise statement (+ space + other stuff, maybe)
+    r'^\s+raise\([^\)]*\).*$', # wacky raise with immediate open paren
+    r'^\s+return(\s.*)?$', # normal return (+ space + other stuff, maybe)
+    r'^\s+return\([^\)]*\).*$', # wacky return with immediate open paren
+    r'^\s+pass\s*$', # pass (optionally followed by trailing spaces)
+    r'^\s+break\s*$', # break (optionally followed by trailing spaces)
+    r'^\s+continue\s*$', # continue (optionally followed by trailing spaces)
+]))
+ini_spaces_re = re.compile(r'^([ \t\r\f\v]+)')
+
+# regexp to match pure comment lines so we don't accidentally insert 'if 1:'
+# before pure comments
+comment_line_re = re.compile('^\s*\#')
+
+
+def num_ini_spaces(s):
+    """Return the number of initial spaces in a string.
+
+    Note that tabs are counted as a single space.  For now, we do *not* support
+    mixing of tabs and spaces in the user's input.
+
+    Parameters
+    ----------
+    s : string
+
+    Returns
+    -------
+    n : int
+    """
+
+    ini_spaces = ini_spaces_re.match(s)
+    if ini_spaces:
+        return ini_spaces.end()
+    else:
+        return 0
+
+def last_blank(src):
+    """Determine if the input source ends in a blank.
+
+    A blank is either a newline or a line consisting of whitespace.
+
+    Parameters
+    ----------
+    src : string
+      A single or multiline string.
+    """
+    if not src: return False
+    ll  = src.splitlines()[-1]
+    return (ll == '') or ll.isspace()
+
+
+last_two_blanks_re = re.compile(r'\n\s*\n\s*$', re.MULTILINE)
+last_two_blanks_re2 = re.compile(r'.+\n\s*\n\s+$', re.MULTILINE)
+
+def last_two_blanks(src):
+    """Determine if the input source ends in two blanks.
+
+    A blank is either a newline or a line consisting of whitespace.
+
+    Parameters
+    ----------
+    src : string
+      A single or multiline string.
+    """
+    if not src: return False
+    # The logic here is tricky: I couldn't get a regexp to work and pass all
+    # the tests, so I took a different approach: split the source by lines,
+    # grab the last two and prepend '###\n' as a stand-in for whatever was in
+    # the body before the last two lines.  Then, with that structure, it's
+    # possible to analyze with two regexps.  Not the most elegant solution, but
+    # it works.  If anyone tries to change this logic, make sure to validate
+    # the whole test suite first!
+    new_src = '\n'.join(['###\n'] + src.splitlines()[-2:])
+    return (bool(last_two_blanks_re.match(new_src)) or
+            bool(last_two_blanks_re2.match(new_src)) )
+
+
+def remove_comments(src):
+    """Remove all comments from input source.
+
+    Note: comments are NOT recognized inside of strings!
+
+    Parameters
+    ----------
+    src : string
+      A single or multiline input string.
+
+    Returns
+    -------
+    String with all Python comments removed.
+    """
+
+    return re.sub('#.*', '', src)
+
+
+def get_input_encoding():
+    """Return the default standard input encoding.
+
+    If sys.stdin has no encoding, 'ascii' is returned."""
+    # There are strange environments for which sys.stdin.encoding is None. We
+    # ensure that a valid encoding is returned.
+    encoding = getattr(sys.stdin, 'encoding', None)
+    if encoding is None:
+        encoding = 'ascii'
+    return encoding
+
+#-----------------------------------------------------------------------------
+# Classes and functions for normal Python syntax handling
+#-----------------------------------------------------------------------------
+
+class InputSplitter(object):
+    r"""An object that can accumulate lines of Python source before execution.
+
+    This object is designed to be fed python source line-by-line, using
+    :meth:`push`. It will return on each push whether the currently pushed
+    code could be executed already. In addition, it provides a method called
+    :meth:`push_accepts_more` that can be used to query whether more input
+    can be pushed into a single interactive block.
+
+    This is a simple example of how an interactive terminal-based client can use
+    this tool::
+
+        isp = InputSplitter()
+        while isp.push_accepts_more():
+            indent = ' '*isp.indent_spaces
+            prompt = '>>> ' + indent
+            line = indent + raw_input(prompt)
+            isp.push(line)
+        print 'Input source was:\n', isp.source_reset(),
+    """
+    # Number of spaces of indentation computed from input that has been pushed
+    # so far.  This is the attributes callers should query to get the current
+    # indentation level, in order to provide auto-indent facilities.
+    indent_spaces = 0
+    # String, indicating the default input encoding.  It is computed by default
+    # at initialization time via get_input_encoding(), but it can be reset by a
+    # client with specific knowledge of the encoding.
+    encoding = ''
+    # String where the current full source input is stored, properly encoded.
+    # Reading this attribute is the normal way of querying the currently pushed
+    # source code, that has been properly encoded.
+    source = ''
+    # Code object corresponding to the current source.  It is automatically
+    # synced to the source, so it can be queried at any time to obtain the code
+    # object; it will be None if the source doesn't compile to valid Python.
+    code = None
+
+    # Private attributes
+
+    # List with lines of input accumulated so far
+    _buffer = None
+    # Command compiler
+    _compile = None
+    # Mark when input has changed indentation all the way back to flush-left
+    _full_dedent = False
+    # Boolean indicating whether the current block is complete
+    _is_complete = None
+    # Boolean indicating whether the current block has an unrecoverable syntax error
+    _is_invalid = False
+
+    def __init__(self):
+        """Create a new InputSplitter instance.
+        """
+        self._buffer = []
+        self._compile = codeop.CommandCompiler()
+        self.encoding = get_input_encoding()
+
+    def reset(self):
+        """Reset the input buffer and associated state."""
+        self.indent_spaces = 0
+        self._buffer[:] = []
+        self.source = ''
+        self.code = None
+        self._is_complete = False
+        self._is_invalid = False
+        self._full_dedent = False
+
+    def source_reset(self):
+        """Return the input source and perform a full reset.
+        """
+        out = self.source
+        self.reset()
+        return out
+
+    def check_complete(self, source):
+        """Return whether a block of code is ready to execute, or should be continued
+        
+        This is a non-stateful API, and will reset the state of this InputSplitter.
+        
+        Parameters
+        ----------
+        source : string
+          Python input code, which can be multiline.
+        
+        Returns
+        -------
+        status : str
+          One of 'complete', 'incomplete', or 'invalid' if source is not a
+          prefix of valid code.
+        indent_spaces : int or None
+          The number of spaces by which to indent the next line of code. If
+          status is not 'incomplete', this is None.
+        """
+        self.reset()
+        try:
+            self.push(source)
+        except SyntaxError:
+            # Transformers in IPythonInputSplitter can raise SyntaxError,
+            # which push() will not catch.
+            return 'invalid', None
+        else:
+            if self._is_invalid:
+                return 'invalid', None
+            elif self.push_accepts_more():
+                return 'incomplete', self.indent_spaces
+            else:
+                return 'complete', None
+        finally:
+            self.reset()
+
+    def push(self, lines):
+        """Push one or more lines of input.
+
+        This stores the given lines and returns a status code indicating
+        whether the code forms a complete Python block or not.
+
+        Any exceptions generated in compilation are swallowed, but if an
+        exception was produced, the method returns True.
+
+        Parameters
+        ----------
+        lines : string
+          One or more lines of Python input.
+
+        Returns
+        -------
+        is_complete : boolean
+          True if the current input source (the result of the current input
+          plus prior inputs) forms a complete Python execution block.  Note that
+          this value is also stored as a private attribute (``_is_complete``), so it
+          can be queried at any time.
+        """
+        self._store(lines)
+        source = self.source
+
+        # Before calling _compile(), reset the code object to None so that if an
+        # exception is raised in compilation, we don't mislead by having
+        # inconsistent code/source attributes.
+        self.code, self._is_complete = None, None
+        self._is_invalid = False
+
+        # Honor termination lines properly
+        if source.endswith('\\\n'):
+            return False
+
+        self._update_indent(lines)
+        try:
+            with warnings.catch_warnings():
+                warnings.simplefilter('error', SyntaxWarning)
+                self.code = self._compile(source, symbol="exec")
+        # Invalid syntax can produce any of a number of different errors from
+        # inside the compiler, so we have to catch them all.  Syntax errors
+        # immediately produce a 'ready' block, so the invalid Python can be
+        # sent to the kernel for evaluation with possible ipython
+        # special-syntax conversion.
+        except (SyntaxError, OverflowError, ValueError, TypeError,
+                MemoryError, SyntaxWarning):
+            self._is_complete = True
+            self._is_invalid = True
+        else:
+            # Compilation didn't produce any exceptions (though it may not have
+            # given a complete code object)
+            self._is_complete = self.code is not None
+
+        return self._is_complete
+
+    def push_accepts_more(self):
+        """Return whether a block of interactive input can accept more input.
+
+        This method is meant to be used by line-oriented frontends, who need to
+        guess whether a block is complete or not based solely on prior and
+        current input lines.  The InputSplitter considers it has a complete
+        interactive block and will not accept more input when either:
+        
+        * A SyntaxError is raised
+
+        * The code is complete and consists of a single line or a single
+          non-compound statement
+
+        * The code is complete and has a blank line at the end
+
+        If the current input produces a syntax error, this method immediately
+        returns False but does *not* raise the syntax error exception, as
+        typically clients will want to send invalid syntax to an execution
+        backend which might convert the invalid syntax into valid Python via
+        one of the dynamic IPython mechanisms.
+        """
+
+        # With incomplete input, unconditionally accept more
+        # A syntax error also sets _is_complete to True - see push()
+        if not self._is_complete:
+            #print("Not complete")  # debug
+            return True
+        
+        # The user can make any (complete) input execute by leaving a blank line
+        last_line = self.source.splitlines()[-1]
+        if (not last_line) or last_line.isspace():
+            #print("Blank line")  # debug
+            return False
+        
+        # If there's just a single line or AST node, and we're flush left, as is
+        # the case after a simple statement such as 'a=1', we want to execute it
+        # straight away.
+        if self.indent_spaces==0:
+            if len(self.source.splitlines()) <= 1:
+                return False
+            
+            try:
+                code_ast = ast.parse(u''.join(self._buffer))
+            except Exception:
+                #print("Can't parse AST")  # debug
+                return False
+            else:
+                if len(code_ast.body) == 1 and \
+                                    not hasattr(code_ast.body[0], 'body'):
+                    #print("Simple statement")  # debug
+                    return False
+
+        # General fallback - accept more code
+        return True
+
+    #------------------------------------------------------------------------
+    # Private interface
+    #------------------------------------------------------------------------
+
+    def _find_indent(self, line):
+        """Compute the new indentation level for a single line.
+
+        Parameters
+        ----------
+        line : str
+          A single new line of non-whitespace, non-comment Python input.
+
+        Returns
+        -------
+        indent_spaces : int
+          New value for the indent level (it may be equal to self.indent_spaces
+        if indentation doesn't change.
+
+        full_dedent : boolean
+          Whether the new line causes a full flush-left dedent.
+        """
+        indent_spaces = self.indent_spaces
+        full_dedent = self._full_dedent
+
+        inisp = num_ini_spaces(line)
+        if inisp < indent_spaces:
+            indent_spaces = inisp
+            if indent_spaces <= 0:
+                #print 'Full dedent in text',self.source # dbg
+                full_dedent = True
+
+        if line.rstrip()[-1] == ':':
+            indent_spaces += 4
+        elif dedent_re.match(line):
+            indent_spaces -= 4
+            if indent_spaces <= 0:
+                full_dedent = True
+
+        # Safety
+        if indent_spaces < 0:
+            indent_spaces = 0
+            #print 'safety' # dbg
+
+        return indent_spaces, full_dedent
+
+    def _update_indent(self, lines):
+        for line in remove_comments(lines).splitlines():
+            if line and not line.isspace():
+                self.indent_spaces, self._full_dedent = self._find_indent(line)
+
+    def _store(self, lines, buffer=None, store='source'):
+        """Store one or more lines of input.
+
+        If input lines are not newline-terminated, a newline is automatically
+        appended."""
+
+        if buffer is None:
+            buffer = self._buffer
+
+        if lines.endswith('\n'):
+            buffer.append(lines)
+        else:
+            buffer.append(lines+'\n')
+        setattr(self, store, self._set_source(buffer))
+
+    def _set_source(self, buffer):
+        return u''.join(buffer)
+
+
+class IPythonInputSplitter(InputSplitter):
+    """An input splitter that recognizes all of IPython's special syntax."""
+
+    # String with raw, untransformed input.
+    source_raw = ''
+    
+    # Flag to track when a transformer has stored input that it hasn't given
+    # back yet.
+    transformer_accumulating = False
+    
+    # Flag to track when assemble_python_lines has stored input that it hasn't
+    # given back yet.
+    within_python_line = False
+
+    # Private attributes
+
+    # List with lines of raw input accumulated so far.
+    _buffer_raw = None
+
+    def __init__(self, line_input_checker=True, physical_line_transforms=None,
+                    logical_line_transforms=None, python_line_transforms=None):
+        super(IPythonInputSplitter, self).__init__()
+        self._buffer_raw = []
+        self._validate = True
+        
+        if physical_line_transforms is not None:
+            self.physical_line_transforms = physical_line_transforms
+        else:
+            self.physical_line_transforms = [
+                                             leading_indent(),
+                                             classic_prompt(),
+                                             ipy_prompt(),
+                                             cellmagic(end_on_blank_line=line_input_checker),
+                                             strip_encoding_cookie(),
+                                            ]
+        
+        self.assemble_logical_lines = assemble_logical_lines()
+        if logical_line_transforms is not None:
+            self.logical_line_transforms = logical_line_transforms
+        else:
+            self.logical_line_transforms = [
+                                            help_end(),
+                                            escaped_commands(),
+                                            assign_from_magic(),
+                                            assign_from_system(),
+                                           ]
+        
+        self.assemble_python_lines = assemble_python_lines()
+        if python_line_transforms is not None:
+            self.python_line_transforms = python_line_transforms
+        else:
+            # We don't use any of these at present
+            self.python_line_transforms = []
+    
+    @property
+    def transforms(self):
+        "Quick access to all transformers."
+        return self.physical_line_transforms + \
+            [self.assemble_logical_lines] + self.logical_line_transforms + \
+            [self.assemble_python_lines]  + self.python_line_transforms
+    
+    @property
+    def transforms_in_use(self):
+        """Transformers, excluding logical line transformers if we're in a
+        Python line."""
+        t = self.physical_line_transforms[:]
+        if not self.within_python_line:
+            t += [self.assemble_logical_lines] + self.logical_line_transforms
+        return t + [self.assemble_python_lines] + self.python_line_transforms
+
+    def reset(self):
+        """Reset the input buffer and associated state."""
+        super(IPythonInputSplitter, self).reset()
+        self._buffer_raw[:] = []
+        self.source_raw = ''
+        self.transformer_accumulating = False
+        self.within_python_line = False
+
+        for t in self.transforms:
+            try:
+                t.reset()
+            except SyntaxError:
+                # Nothing that calls reset() expects to handle transformer
+                # errors
+                pass
+    
+    def flush_transformers(self):
+        def _flush(transform, outs):
+            """yield transformed lines
+            
+            always strings, never None
+            
+            transform: the current transform
+            outs: an iterable of previously transformed inputs.
+                 Each may be multiline, which will be passed
+                 one line at a time to transform.
+            """
+            for out in outs:
+                for line in out.splitlines():
+                    # push one line at a time
+                    tmp = transform.push(line)
+                    if tmp is not None:
+                        yield tmp
+            
+            # reset the transform
+            tmp = transform.reset()
+            if tmp is not None:
+                yield tmp
+        
+        out = []
+        for t in self.transforms_in_use:
+            out = _flush(t, out)
+        
+        out = list(out)
+        if out:
+            self._store('\n'.join(out))
+
+    def raw_reset(self):
+        """Return raw input only and perform a full reset.
+        """
+        out = self.source_raw
+        self.reset()
+        return out
+    
+    def source_reset(self):
+        try:
+            self.flush_transformers()
+            return self.source
+        finally:
+            self.reset()
+
+    def push_accepts_more(self):
+        if self.transformer_accumulating:
+            return True
+        else:
+            return super(IPythonInputSplitter, self).push_accepts_more()
+
+    def transform_cell(self, cell):
+        """Process and translate a cell of input.
+        """
+        self.reset()
+        try:
+            self.push(cell)
+            self.flush_transformers()
+            return self.source
+        finally:
+            self.reset()
+
+    def push(self, lines):
+        """Push one or more lines of IPython input.
+
+        This stores the given lines and returns a status code indicating
+        whether the code forms a complete Python block or not, after processing
+        all input lines for special IPython syntax.
+
+        Any exceptions generated in compilation are swallowed, but if an
+        exception was produced, the method returns True.
+
+        Parameters
+        ----------
+        lines : string
+          One or more lines of Python input.
+
+        Returns
+        -------
+        is_complete : boolean
+          True if the current input source (the result of the current input
+          plus prior inputs) forms a complete Python execution block.  Note that
+          this value is also stored as a private attribute (_is_complete), so it
+          can be queried at any time.
+        """
+
+        # We must ensure all input is pure unicode
+        lines = cast_unicode(lines, self.encoding)
+        # ''.splitlines() --> [], but we need to push the empty line to transformers
+        lines_list = lines.splitlines()
+        if not lines_list:
+            lines_list = ['']
+
+        # Store raw source before applying any transformations to it.  Note
+        # that this must be done *after* the reset() call that would otherwise
+        # flush the buffer.
+        self._store(lines, self._buffer_raw, 'source_raw')
+
+        for line in lines_list:
+            out = self.push_line(line)
+
+        return out
+    
+    def push_line(self, line):
+        buf = self._buffer
+        
+        def _accumulating(dbg):
+            #print(dbg)
+            self.transformer_accumulating = True
+            return False
+        
+        for transformer in self.physical_line_transforms:
+            line = transformer.push(line)
+            if line is None:
+                return _accumulating(transformer)
+        
+        if not self.within_python_line:
+            line = self.assemble_logical_lines.push(line)
+            if line is None:
+                return _accumulating('acc logical line')        
+        
+            for transformer in self.logical_line_transforms:
+                line = transformer.push(line)
+                if line is None:
+                    return _accumulating(transformer)
+        
+        line = self.assemble_python_lines.push(line)
+        if line is None:
+            self.within_python_line = True
+            return _accumulating('acc python line')
+        else:
+            self.within_python_line = False
+        
+        for transformer in self.python_line_transforms:
+            line = transformer.push(line)
+            if line is None:
+                return _accumulating(transformer)
+
+        #print("transformers clear") #debug
+        self.transformer_accumulating = False
+        return super(IPythonInputSplitter, self).push(line)