Fix bug with IPythonInputSplitter in block input mode.

IPython/core/inputsplitter.py

@@ -1,839 +1,858 b''
 """Analysis of text input into executable blocks.
 
 The main class in this module, :class:`InputSplitter`, is designed to break
 input from either interactive, line-by-line environments or block-based ones,
 into standalone blocks that can be executed by Python as 'single' statements
 (thus triggering sys.displayhook).
 
 A companion, :class:`IPythonInputSplitter`, provides the same functionality but
 with full support for the extended IPython syntax (magics, system calls, etc).
 
 For more details, see the class docstring below.
 
 Syntax Transformations
 ----------------------
 
 One of the main jobs of the code in this file is to apply all syntax
 transformations that make up 'the IPython language', i.e. magics, shell
 escapes, etc.  All transformations should be implemented as *fully stateless*
 entities, that simply take one line as their input and return a line.
 Internally for implementation purposes they may be a normal function or a
 callable object, but the only input they receive will be a single line and they
 should only return a line, without holding any data-dependent state between
 calls.
 
 As an example, the EscapedTransformer is a class so we can more clearly group
 together the functionality of dispatching to individual functions based on the
 starting escape character, but the only method for public use is its call
 method.
 
 
 ToDo
 ----
 
 - Should we make push() actually raise an exception once push_accepts_more()
   returns False?
 
 - Naming cleanups.  The tr_* names aren't the most elegant, though now they are
   at least just attributes of a class so not really very exposed.
 
 - Think about the best way to support dynamic things: automagic, autocall,
   macros, etc.
 
 - Think of a better heuristic for the application of the transforms in
   IPythonInputSplitter.push() than looking at the buffer ending in ':'.  Idea:
   track indentation change events (indent, dedent, nothing) and apply them only
   if the indentation went up, but not otherwise.
 
 - Think of the cleanest way for supporting user-specified transformations (the
   user prefilters we had before).
 
 Authors
 -------
 
 * Fernando Perez
 * Brian Granger
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 # stdlib
 import codeop
 import re
 import sys
 
 # IPython modules
 from IPython.utils.text import make_quoted_expr
-
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # The escape sequences that define the syntax transformations IPython will
 # apply to user input.  These can NOT be just changed here: many regular
 # expressions and other parts of the code may use their hardcoded values, and
 # for all intents and purposes they constitute the 'IPython syntax', so they
 # should be considered fixed.
 
 ESC_SHELL  = '!'
 ESC_SH_CAP = '!!'
 ESC_HELP   = '?'
 ESC_HELP2  = '??'
 ESC_MAGIC  = '%'
 ESC_QUOTE  = ','
 ESC_QUOTE2 = ';'
 ESC_PAREN  = '/'
 
 #-----------------------------------------------------------------------------
 # 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(r'^\s+raise|^\s+return|^\s+pass')
 ini_spaces_re = re.compile(r'^([ \t\r\f\v]+)')
 
 
 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 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):
     """An object that can split Python source input in executable blocks.
 
     This object is designed to be used in one of two basic modes:
 
     1. By feeding it python source line-by-line, using :meth:`push`.  In this
        mode, 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.
 
     2. By calling :meth:`split_blocks` with a single, multiline Python string,
        that is then split into blocks each of which can be executed
        interactively as a single statement.
 
     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
     # Input mode
     input_mode = 'append'
     
     # 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
     
     def __init__(self, input_mode=None):
         """Create a new InputSplitter instance.
 
         Parameters
         ----------
         input_mode : str
 
-          One of 'append', 'replace', default is 'append'.  This controls how
+          One of ['append', 'replace']; default is 'append'.  This controls how
           new inputs are used: in 'append' mode, they are appended to the
           existing buffer and the whole buffer is compiled; in 'replace' mode,
           each new input completely replaces all prior inputs.  Replace mode is
           thus equivalent to prepending a full reset() to every push() call.
 
           In practice, line-oriented clients likely want to use 'append' mode
           while block-oriented ones will want to use 'replace'.
         """
         self._buffer = []
         self._compile = codeop.CommandCompiler()
         self.encoding = get_input_encoding()
         self.input_mode = InputSplitter.input_mode if input_mode is None \
                           else input_mode
 
     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._full_dedent = False
 
     def source_reset(self):
         """Return the input source and perform a full reset.
         """
         out = self.source
         self.reset()
         return out
 
     def push(self, lines):
         """Push one ore 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.
         """
         if self.input_mode == 'replace':
             self.reset()
         
         # If the source code has leading blanks, add 'if 1:\n' to it
         # this allows execution of indented pasted code. It is tempting
         # to add '\n' at the end of source to run commands like ' a=1'
         # directly, but this fails for more complicated scenarios
         if not self._buffer and lines[:1] in [' ', '\t']:
             lines = 'if 1:\n%s' % lines
         
         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._update_indent(lines)
         try:
             self.code = self._compile(source)
         # 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):
             self._is_complete = 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 only when either a
         SyntaxError is raised, or *all* of the following are true:
 
         1. The input compiles to a complete statement.
         
         2. The indentation level is flush-left (because if we are indented,
            like inside a function definition or for loop, we need to keep
            reading new input).
           
         3. There is one extra line consisting only of whitespace.
 
         Because of condition #3, this method should be used only by
         *line-oriented* frontends, since it means that intermediate blank lines
         are not allowed in function definitions (or any other indented block).
 
         Block-oriented frontends that have a separate keyboard event to
         indicate execution should use the :meth:`split_blocks` method instead.
 
         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.
         """
             
         if not self._is_complete:
             return True
 
         if self.indent_spaces==0:
             return False
         
         last_line = self.source.splitlines()[-1]
         return bool(last_line and not last_line.isspace())
         
     def split_blocks(self, lines):
         """Split a multiline string into multiple input blocks.
 
         Note: this method starts by performing a full reset().
         
         Parameters
         ----------
         lines : str
           A possibly multiline string.
 
         Returns
         -------
         blocks : list
           A list of strings, each possibly multiline.  Each string corresponds
           to a single block that can be compiled in 'single' mode (unless it
           has a syntax error)."""
 
         # This code is fairly delicate.  If you make any changes here, make
         # absolutely sure that you do run the full test suite and ALL tests
         # pass.
 
         self.reset()
         blocks = []
         
         # Reversed copy so we can use pop() efficiently and consume the input
         # as a stack
         lines = lines.splitlines()[::-1]
         # Outer loop over all input
         while lines:
             # Inner loop to build each block
             while True:
                 # Safety exit from inner loop
                 if not lines:
                     break
                 # Grab next line but don't push it yet
                 next_line = lines.pop()
                 # Blank/empty lines are pushed as-is
                 if not next_line or next_line.isspace():
                     self.push(next_line)
                     continue
 
                 # Check indentation changes caused by the *next* line
                 indent_spaces, _full_dedent = self._find_indent(next_line)
 
                 # If the next line causes a dedent, it can be for two differnt
                 # reasons: either an explicit de-dent by the user or a
                 # return/raise/pass statement.  These MUST be handled
                 # separately:
                 #
                 # 1. the first case is only detected when the actual explicit
                 # dedent happens, and that would be the *first* line of a *new*
                 # block.  Thus, we must put the line back into the input buffer
                 # so that it starts a new block on the next pass.
                 #
                 # 2. the second case is detected in the line before the actual
                 # dedent happens, so , we consume the line and we can break out
                 # to start a new block.
 
                 # Case 1, explicit dedent causes a break
                 if _full_dedent and not next_line.startswith(' '):
                     lines.append(next_line)
                     break
                 
                 # Otherwise any line is pushed
                 self.push(next_line)
 
                 # Case 2, full dedent with full block ready:
                 if _full_dedent or \
                        self.indent_spaces==0 and not self.push_accepts_more():
                     break
             # Form the new block with the current source input
             blocks.append(self.source_reset())
             
         return blocks
 
     #------------------------------------------------------------------------
     # 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[-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):
         """Store one or more lines of input.
 
         If input lines are not newline-terminated, a newline is automatically
         appended."""
 
         if lines.endswith('\n'):
             self._buffer.append(lines)
         else:
             self._buffer.append(lines+'\n')
         self._set_source()
 
     def _set_source(self):
         self.source = ''.join(self._buffer).encode(self.encoding)
 
 
 #-----------------------------------------------------------------------------
 # Functions and classes for IPython-specific syntactic support
 #-----------------------------------------------------------------------------
 
 # RegExp for splitting line contents into pre-char//first word-method//rest.
 # For clarity, each group in on one line.
 
 line_split = re.compile("""
              ^(\s*)              # any leading space
              ([,;/%]|!!?|\?\??)  # escape character or characters
              \s*([\w\.]*)        # function/method part (mix of \w and '.')
              (\s+.*$|$)          # rest of line
              """, re.VERBOSE)
 
 
 def split_user_input(line):
     """Split user input into early whitespace, esc-char, function part and rest.
 
     This is currently handles lines with '=' in them in a very inconsistent
     manner.
 
     Examples
     ========
     >>> split_user_input('x=1')
     ('', '', 'x=1', '')
     >>> split_user_input('?')
     ('', '?', '', '')
     >>> split_user_input('??')
     ('', '??', '', '')
     >>> split_user_input(' ?')
     (' ', '?', '', '')
     >>> split_user_input(' ??')
     (' ', '??', '', '')
     >>> split_user_input('??x')
     ('', '??', 'x', '')
     >>> split_user_input('?x=1')
     ('', '', '?x=1', '')
     >>> split_user_input('!ls')
     ('', '!', 'ls', '')
     >>> split_user_input('  !ls')
     ('  ', '!', 'ls', '')
     >>> split_user_input('!!ls')
     ('', '!!', 'ls', '')
     >>> split_user_input('  !!ls')
     ('  ', '!!', 'ls', '')
     >>> split_user_input(',ls')
     ('', ',', 'ls', '')
     >>> split_user_input(';ls')
     ('', ';', 'ls', '')
     >>> split_user_input('  ;ls')
     ('  ', ';', 'ls', '')
     >>> split_user_input('f.g(x)')
     ('', '', 'f.g(x)', '')
     >>> split_user_input('f.g (x)')
     ('', '', 'f.g', '(x)')
     """
     match = line_split.match(line)
     if match:
         lspace, esc, fpart, rest = match.groups()
     else:
         # print "match failed for line '%s'" % line
         try:
             fpart, rest = line.split(None, 1)
         except ValueError:
             # print "split failed for line '%s'" % line
             fpart, rest = line,''
         lspace = re.match('^(\s*)(.*)', line).groups()[0]
         esc = ''
 
     # fpart has to be a valid python identifier, so it better be only pure
     # ascii, no unicode:
     try:
         fpart = fpart.encode('ascii')
     except UnicodeEncodeError:
         lspace = unicode(lspace)
         rest = fpart + u' ' + rest
         fpart = u''
 
     #print 'line:<%s>' % line # dbg
     #print 'esc <%s> fpart <%s> rest <%s>' % (esc,fpart.strip(),rest) # dbg
     return lspace, esc, fpart.strip(), rest.lstrip()
 
 
 # The escaped translators ALL receive a line where their own escape has been
 # stripped.  Only '?' is valid at the end of the line, all others can only be
 # placed at the start.
 
 class LineInfo(object):
     """A single line of input and associated info.
 
     This is a utility class that mostly wraps the output of
     :func:`split_user_input` into a convenient object to be passed around
     during input transformations.
 
     Includes the following as properties: 
 
     line
       The original, raw line
 
     lspace
       Any early whitespace before actual text starts.
 
     esc
       The initial esc character (or characters, for double-char escapes like
       '??' or '!!').
     
     fpart
       The 'function part', which is basically the maximal initial sequence
       of valid python identifiers and the '.' character.  This is what is
       checked for alias and magic transformations, used for auto-calling,
       etc.
     
     rest
       Everything else on the line.
     """
     def __init__(self, line):
         self.line = line
         self.lspace, self.esc, self.fpart, self.rest = \
                              split_user_input(line)
 
     def __str__(self):                                                         
         return "LineInfo [%s|%s|%s|%s]" % (self.lspace, self.esc,
                                            self.fpart, self.rest)
 
 
 # Transformations of the special syntaxes that don't rely on an explicit escape
 # character but instead on patterns on the input line
 
 # The core transformations are implemented as standalone functions that can be
 # tested and validated in isolation.  Each of these uses a regexp, we
 # pre-compile these and keep them close to each function definition for clarity
 
 _assign_system_re = re.compile(r'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
                                r'\s*=\s*!\s*(?P<cmd>.*)')
 
 def transform_assign_system(line):
     """Handle the `files = !ls` syntax."""
     # FIXME: This transforms the line to use %sc, but we've listed that magic
     # as deprecated.  We should then implement this functionality in a
     # standalone api that we can transform to, without going through a
     # deprecated magic.
     m = _assign_system_re.match(line)
     if m is not None:
         cmd = m.group('cmd')
         lhs = m.group('lhs')
         expr = make_quoted_expr("sc -l = %s" % cmd)
         new_line = '%s = get_ipython().magic(%s)' % (lhs, expr)
         return new_line
     return line
 
 
 _assign_magic_re = re.compile(r'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
                                r'\s*=\s*%\s*(?P<cmd>.*)')
 
 def transform_assign_magic(line):
     """Handle the `a = %who` syntax."""
     m = _assign_magic_re.match(line)
     if m is not None:
         cmd = m.group('cmd')
         lhs = m.group('lhs')
         expr = make_quoted_expr(cmd)
         new_line = '%s = get_ipython().magic(%s)' % (lhs, expr)
         return new_line
     return line
 
 
 _classic_prompt_re = re.compile(r'^([ \t]*>>> |^[ \t]*\.\.\. )')
 
 def transform_classic_prompt(line):
     """Handle inputs that start with '>>> ' syntax."""
 
     if not line or line.isspace():
         return line
     m = _classic_prompt_re.match(line)
     if m:
         return line[len(m.group(0)):]
     else:
         return line
 
 
 _ipy_prompt_re = re.compile(r'^([ \t]*In \[\d+\]: |^[ \t]*\ \ \ \.\.\.+: )')
 
 def transform_ipy_prompt(line):
     """Handle inputs that start classic IPython prompt syntax."""
 
     if not line or line.isspace():
         return line
+    #print 'LINE:  %r' % line # dbg
     m = _ipy_prompt_re.match(line)
     if m:
+        #print 'MATCH! %r -> %r' % (line, line[len(m.group(0)):]) # dbg
         return line[len(m.group(0)):]
     else:
         return line
 
 
 class EscapedTransformer(object):
     """Class to transform lines that are explicitly escaped out."""
 
     def __init__(self):
         tr = { ESC_SHELL  : self._tr_system,
                ESC_SH_CAP : self._tr_system2,
                ESC_HELP   : self._tr_help,
                ESC_HELP2  : self._tr_help,
                ESC_MAGIC  : self._tr_magic,
                ESC_QUOTE  : self._tr_quote,
                ESC_QUOTE2 : self._tr_quote2,
                ESC_PAREN  : self._tr_paren }
         self.tr = tr
         
     # Support for syntax transformations that use explicit escapes typed by the
     # user at the beginning of a line
     @staticmethod
     def _tr_system(line_info):
         "Translate lines escaped with: !"
         cmd = line_info.line.lstrip().lstrip(ESC_SHELL)
         return '%sget_ipython().system(%s)' % (line_info.lspace,
                                                make_quoted_expr(cmd))
 
     @staticmethod
     def _tr_system2(line_info):
         "Translate lines escaped with: !!"
         cmd = line_info.line.lstrip()[2:]
         return '%sget_ipython().getoutput(%s)' % (line_info.lspace,
                                                   make_quoted_expr(cmd))
 
     @staticmethod
     def _tr_help(line_info):
         "Translate lines escaped with: ?/??"
         # A naked help line should just fire the intro help screen
         if not line_info.line[1:]:
             return 'get_ipython().show_usage()'
 
         # There may be one or two '?' at the end, move them to the front so that
         # the rest of the logic can assume escapes are at the start
         line = line_info.line
         if line.endswith('?'):
             line = line[-1] + line[:-1]
         if line.endswith('?'):
             line = line[-1] + line[:-1]
         line_info = LineInfo(line)
 
         # From here on, simply choose which level of detail to get.
         if line_info.esc == '?':
             pinfo = 'pinfo'
         elif line_info.esc == '??':
             pinfo = 'pinfo2'
 
         tpl = '%sget_ipython().magic("%s %s")'
         return tpl % (line_info.lspace, pinfo,
                       ' '.join([line_info.fpart, line_info.rest]).strip())
 
     @staticmethod
     def _tr_magic(line_info):
         "Translate lines escaped with: %"
         tpl = '%sget_ipython().magic(%s)'
         cmd = make_quoted_expr(' '.join([line_info.fpart,
                                          line_info.rest]).strip())
         return tpl % (line_info.lspace, cmd)
 
     @staticmethod
     def _tr_quote(line_info):
         "Translate lines escaped with: ,"
         return '%s%s("%s")' % (line_info.lspace, line_info.fpart,
                              '", "'.join(line_info.rest.split()) )
 
     @staticmethod
     def _tr_quote2(line_info):
         "Translate lines escaped with: ;"
         return '%s%s("%s")' % (line_info.lspace, line_info.fpart,
                                line_info.rest)
 
     @staticmethod
     def _tr_paren(line_info):
         "Translate lines escaped with: /"
         return '%s%s(%s)' % (line_info.lspace, line_info.fpart,
                              ", ".join(line_info.rest.split()))
 
     def __call__(self, line):
         """Class to transform lines that are explicitly escaped out.
 
         This calls the above _tr_* static methods for the actual line
         translations."""
 
         # Empty lines just get returned unmodified
         if not line or line.isspace():
             return line
 
         # Get line endpoints, where the escapes can be
         line_info = LineInfo(line)
 
         # If the escape is not at the start, only '?' needs to be special-cased.
         # All other escapes are only valid at the start
         if not line_info.esc in self.tr:
             if line.endswith(ESC_HELP):
                 return self._tr_help(line_info)
             else:
                 # If we don't recognize the escape, don't modify the line
                 return line
 
         return self.tr[line_info.esc](line_info)
 
 
 # A function-looking object to be used by the rest of the code.  The purpose of
 # the class in this case is to organize related functionality, more than to
 # manage state.
 transform_escaped = EscapedTransformer()
 
 
 class IPythonInputSplitter(InputSplitter):
     """An input splitter that recognizes all of IPython's special syntax."""
 
     def push(self, lines):
         """Push one or more lines of IPython input.
         """
         if not lines:
             return super(IPythonInputSplitter, self).push(lines)
 
         lines_list = lines.splitlines()
 
         transforms = [transform_escaped, transform_assign_system,
                       transform_assign_magic, transform_ipy_prompt,
                       transform_classic_prompt]
 
         # Transform logic
         #
         # We only apply the line transformers to the input if we have either no
         # input yet, or complete input, or if the last line of the buffer ends
         # with ':' (opening an indented block).  This prevents the accidental
         # transformation of escapes inside multiline expressions like
         # triple-quoted strings or parenthesized expressions.
         #
         # The last heuristic, while ugly, ensures that the first line of an
         # indented block is correctly transformed.
         #
         # FIXME: try to find a cleaner approach for this last bit.
 
-        for line in lines_list:
-            if self._is_complete or not self._buffer or \
-               (self._buffer and self._buffer[-1].rstrip().endswith(':')):
-                for f in transforms:
-                    line = f(line)
-                
-            out = super(IPythonInputSplitter, self).push(line)
+        # If we were in 'replace' mode, since we're going to pump the parent
+        # class by hand line by line, we need to temporarily switch out to
+        # 'append' mode, do a single manual reset and then feed the lines one
+        # by one.  Note that this only matters if the input has more than one
+        # line.
+        changed_input_mode = False
+        
+        if len(lines_list)>1 and self.input_mode == 'replace':
+            self.reset()
+            changed_input_mode = True
+            saved_input_mode = 'replace'
+            self.input_mode = 'append'
 
+        try:
+            push = super(IPythonInputSplitter, self).push
+            for line in lines_list:
+                if self._is_complete or not self._buffer or \
+                   (self._buffer and self._buffer[-1].rstrip().endswith(':')):
+                    for f in transforms:
+                        line = f(line)
+
+                out = push(line)
+        finally:
+            if changed_input_mode:
+                self.input_mode = saved_input_mode
+        
         return out

IPython/core/tests/test_inputsplitter.py

@@ -1,622 +1,648 b''
 # -*- coding: utf-8 -*-
 """Tests for the inputsplitter module.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2010  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 # stdlib
 import unittest
 import sys
 
 # Third party
 import nose.tools as nt
 
 # Our own
 from IPython.core import inputsplitter as isp
 
 #-----------------------------------------------------------------------------
 # Semi-complete examples (also used as tests)
 #-----------------------------------------------------------------------------
 
 # Note: at the bottom, there's a slightly more complete version of this that
 # can be useful during development of code here.
 
 def mini_interactive_loop(raw_input):
     """Minimal example of the logic of an interactive interpreter loop.
 
     This serves as an example, and it is used by the test system with a fake
     raw_input that simulates interactive input."""
 
     from IPython.core.inputsplitter import InputSplitter
     
     isp = InputSplitter()
     # In practice, this input loop would be wrapped in an outside loop to read
     # input indefinitely, until some exit/quit command was issued.  Here we
     # only illustrate the basic inner loop.
     while isp.push_accepts_more():
         indent = ' '*isp.indent_spaces
         prompt = '>>> ' + indent
         line = indent + raw_input(prompt)
         isp.push(line)
 
     # Here we just return input so we can use it in a test suite, but a real
     # interpreter would instead send it for execution somewhere.
     src = isp.source_reset()
     #print 'Input source was:\n', src  # dbg
     return src
 
 #-----------------------------------------------------------------------------
 # Test utilities, just for local use
 #-----------------------------------------------------------------------------
 
 def assemble(block):
     """Assemble a block into multi-line sub-blocks."""
     return ['\n'.join(sub_block)+'\n' for sub_block in block]
 
 
 def pseudo_input(lines):
     """Return a function that acts like raw_input but feeds the input list."""
     ilines = iter(lines)
     def raw_in(prompt):
         try:
             return next(ilines)
         except StopIteration:
             return ''
     return raw_in
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 def test_spaces():
     tests = [('', 0),
              (' ', 1),
              ('\n', 0),
              (' \n', 1),
              ('x', 0),
              (' x', 1),
              ('  x',2),
              ('    x',4),
              # Note: tabs are counted as a single whitespace!
              ('\tx', 1),
              ('\t x', 2),
              ]
     
     for s, nsp in tests:
         nt.assert_equal(isp.num_ini_spaces(s), nsp)
 
 
 def test_remove_comments():
     tests = [('text', 'text'),
              ('text # comment', 'text '),
              ('text # comment\n', 'text \n'),
              ('text # comment \n', 'text \n'),
              ('line # c \nline\n','line \nline\n'),
              ('line # c \nline#c2  \nline\nline #c\n\n',
               'line \nline\nline\nline \n\n'),
              ]
 
     for inp, out in tests:
         nt.assert_equal(isp.remove_comments(inp), out)
 
 
 def test_get_input_encoding():
     encoding = isp.get_input_encoding()
     nt.assert_true(isinstance(encoding, basestring))
     # simple-minded check that at least encoding a simple string works with the
     # encoding we got.
     nt.assert_equal('test'.encode(encoding), 'test')
 
 
 class NoInputEncodingTestCase(unittest.TestCase):
     def setUp(self):
         self.old_stdin = sys.stdin
         class X: pass
         fake_stdin = X()
         sys.stdin = fake_stdin
         
     def test(self):
         # Verify that if sys.stdin has no 'encoding' attribute we do the right
         # thing
         enc = isp.get_input_encoding()
         self.assertEqual(enc, 'ascii')
         
     def tearDown(self):
         sys.stdin = self.old_stdin
 
 
 class InputSplitterTestCase(unittest.TestCase):
     def setUp(self):
         self.isp = isp.InputSplitter()
 
     def test_reset(self):
         isp = self.isp
         isp.push('x=1')
         isp.reset()
         self.assertEqual(isp._buffer, [])
         self.assertEqual(isp.indent_spaces, 0)
         self.assertEqual(isp.source, '')
         self.assertEqual(isp.code, None)
         self.assertEqual(isp._is_complete, False)
 
     def test_source(self):
         self.isp._store('1')
         self.isp._store('2')
         self.assertEqual(self.isp.source, '1\n2\n')
         self.assertTrue(len(self.isp._buffer)>0)
         self.assertEqual(self.isp.source_reset(), '1\n2\n')
         self.assertEqual(self.isp._buffer, [])
         self.assertEqual(self.isp.source, '')
         
     def test_indent(self):
         isp = self.isp # shorthand
         isp.push('x=1')
         self.assertEqual(isp.indent_spaces, 0)
         isp.push('if 1:\n    x=1')
         self.assertEqual(isp.indent_spaces, 4)
         isp.push('y=2\n')
         self.assertEqual(isp.indent_spaces, 0)
         isp.push('if 1:')
         self.assertEqual(isp.indent_spaces, 4)
         isp.push('    x=1')
         self.assertEqual(isp.indent_spaces, 4)
         # Blank lines shouldn't change the indent level
         isp.push(' '*2)
         self.assertEqual(isp.indent_spaces, 4)
 
     def test_indent2(self):
         isp = self.isp
         # When a multiline statement contains parens or multiline strings, we
         # shouldn't get confused.
         isp.push("if 1:")
         isp.push("    x = (1+\n    2)")
         self.assertEqual(isp.indent_spaces, 4)
 
     def test_dedent(self):
         isp = self.isp # shorthand
         isp.push('if 1:')
         self.assertEqual(isp.indent_spaces, 4)
         isp.push('    pass')
         self.assertEqual(isp.indent_spaces, 0)
         
     def test_push(self):
         isp = self.isp
         self.assertTrue(isp.push('x=1'))
 
     def test_push2(self):
         isp = self.isp
         self.assertFalse(isp.push('if 1:'))
         for line in ['  x=1', '# a comment', '  y=2']:
             self.assertTrue(isp.push(line))
             
     def test_push3(self):
         """Test input with leading whitespace"""
         isp = self.isp
         isp.push('  x=1')
         isp.push('  y=2')
         self.assertEqual(isp.source, 'if 1:\n  x=1\n  y=2\n')
 
     def test_replace_mode(self):
         isp = self.isp
         isp.input_mode = 'replace'
         isp.push('x=1')
         self.assertEqual(isp.source, 'x=1\n')
         isp.push('x=2')
         self.assertEqual(isp.source, 'x=2\n')
 
     def test_push_accepts_more(self):
         isp = self.isp
         isp.push('x=1')
         self.assertFalse(isp.push_accepts_more())
 
     def test_push_accepts_more2(self):
         isp = self.isp
         isp.push('if 1:')
         self.assertTrue(isp.push_accepts_more())
         isp.push('  x=1')
         self.assertTrue(isp.push_accepts_more())
         isp.push('')
         self.assertFalse(isp.push_accepts_more())
         
     def test_push_accepts_more3(self):
         isp = self.isp
         isp.push("x = (2+\n3)")
         self.assertFalse(isp.push_accepts_more())
 
     def test_push_accepts_more4(self):
         isp = self.isp
         # When a multiline statement contains parens or multiline strings, we
         # shouldn't get confused.
         # FIXME: we should be able to better handle de-dents in statements like
         # multiline strings and multiline expressions (continued with \ or
         # parens).  Right now we aren't handling the indentation tracking quite
         # correctly with this, though in practice it may not be too much of a
         # problem.  We'll need to see.
         isp.push("if 1:")
         isp.push("    x = (2+")
         isp.push("    3)")
         self.assertTrue(isp.push_accepts_more())
         isp.push("    y = 3")
         self.assertTrue(isp.push_accepts_more())
         isp.push('')
         self.assertFalse(isp.push_accepts_more())
 
     def test_syntax_error(self):
         isp = self.isp
         # 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.
         isp.push('run foo')
         self.assertFalse(isp.push_accepts_more())
 
     def check_split(self, block_lines, compile=True):
         blocks = assemble(block_lines)
         lines = ''.join(blocks)
         oblock = self.isp.split_blocks(lines)
         self.assertEqual(oblock, blocks)
         if compile:
             for block in blocks:
                 self.isp._compile(block)
 
     def test_split(self):
         # All blocks of input we want to test in a list.  The format for each
         # block is a list of lists, with each inner lists consisting of all the
         # lines (as single-lines) that should make up a sub-block.
 
         # Note: do NOT put here sub-blocks that don't compile, as the
         # check_split() routine makes a final verification pass to check that
         # each sub_block, as returned by split_blocks(), does compile
         # correctly.
         all_blocks = [ [['x=1']],
 
                        [['x=1'],
                         ['y=2']],
 
                        [['x=1'],
                         ['# a comment'],
                         ['y=11']],
 
                        [['if 1:',
                          '  x=1'],
                         ['y=3']],
 
                        [['def f(x):',
                          '  return x'],
                         ['x=1']],
 
                        [['def f(x):',
                          '  x+=1',
                          '  ',
                          '  return x'],
                         ['x=1']],
 
                        [['def f(x):',
                          '  if x>0:',
                          '    y=1',
                          '  # a comment',
                          '  else:',
                          '    y=4',
                          ' ',
                          '  return y'],
                         ['x=1'],
                         ['if 1:',
                          '  y=11'] ],
                        
                        [['for i in range(10):'
                          '  x=i**2']],
 
                        [['for i in range(10):'
                          '  x=i**2'],
                         ['z = 1']],
                        ]
         for block_lines in all_blocks:
             self.check_split(block_lines)
         
     def test_split_syntax_errors(self):
         # Block splitting with invalid syntax
         all_blocks = [ [['a syntax error']],
             
                        [['x=1'],
                         ['a syntax error']],
 
                        [['for i in range(10):'
                          '  an error']],
                        
                        ]
         for block_lines in all_blocks:
             self.check_split(block_lines, compile=False)
 
 
 class InteractiveLoopTestCase(unittest.TestCase):
     """Tests for an interactive loop like a python shell.
     """
     def check_ns(self, lines, ns):
         """Validate that the given input lines produce the resulting namespace.
 
         Note: the input lines are given exactly as they would be typed in an
         auto-indenting environment, as mini_interactive_loop above already does
         auto-indenting and prepends spaces to the input.
         """
         src = mini_interactive_loop(pseudo_input(lines))
         test_ns = {}
         exec src in test_ns
         # We can't check that the provided ns is identical to the test_ns,
         # because Python fills test_ns with extra keys (copyright, etc).  But
         # we can check that the given dict is *contained* in test_ns
         for k,v in ns.items():
             self.assertEqual(test_ns[k], v)
         
     def test_simple(self):
         self.check_ns(['x=1'], dict(x=1))
 
     def test_simple2(self):
         self.check_ns(['if 1:', 'x=2'], dict(x=2))
 
     def test_xy(self):
         self.check_ns(['x=1; y=2'], dict(x=1, y=2))
 
     def test_abc(self):
         self.check_ns(['if 1:','a=1','b=2','c=3'], dict(a=1, b=2, c=3))
     
     def test_multi(self):
         self.check_ns(['x =(1+','1+','2)'], dict(x=4))
     
 
 def test_LineInfo():
     """Simple test for LineInfo construction and str()"""
     linfo = isp.LineInfo('  %cd /home')
     nt.assert_equals(str(linfo), 'LineInfo [  |%|cd|/home]')
 
 
 def test_split_user_input():
     """Unicode test - split_user_input already has good doctests"""
     line = u"Pérez Fernando"
     parts = isp.split_user_input(line)
     parts_expected = (u'', u'', u'', line)
     nt.assert_equal(parts, parts_expected)
 
 
 # Transformer tests
 def transform_checker(tests, func):
     """Utility to loop over test inputs"""
     for inp, tr in tests:
         nt.assert_equals(func(inp), tr)
 
 # Data for all the syntax tests in the form of lists of pairs of
 # raw/transformed input.  We store it here as a global dict so that we can use
 # it both within single-function tests and also to validate the behavior of the
 # larger objects
 
 syntax = \
   dict(assign_system =
        [('a =! ls', 'a = get_ipython().magic("sc -l = ls")'),
         ('b = !ls', 'b = get_ipython().magic("sc -l = ls")'),
         ('x=1', 'x=1'), # normal input is unmodified
         ('    ','    '),  # blank lines are kept intact
         ],
 
        assign_magic =
        [('a =% who', 'a = get_ipython().magic("who")'),
         ('b = %who', 'b = get_ipython().magic("who")'),
         ('x=1', 'x=1'), # normal input is unmodified
         ('    ','    '),  # blank lines are kept intact
         ],
 
        classic_prompt =
        [('>>> x=1', 'x=1'),
         ('x=1', 'x=1'), # normal input is unmodified
-        ('    ','    '),  # blank lines are kept intact
+        ('    ', '    '),  # blank lines are kept intact
+        ('... ', ''), # continuation prompts
         ],
 
        ipy_prompt =
        [('In [1]: x=1', 'x=1'),
         ('x=1', 'x=1'), # normal input is unmodified
         ('    ','    '),  # blank lines are kept intact
+        ('   ....: ', ''), # continuation prompts
         ],
 
        # Tests for the escape transformer to leave normal code alone
        escaped_noesc =
        [ ('    ', '    '),
          ('x=1', 'x=1'),
          ],
 
        # System calls
        escaped_shell =
        [ ('!ls', 'get_ipython().system("ls")'),
          # Double-escape shell, this means to capture the output of the
          # subprocess and return it
          ('!!ls', 'get_ipython().getoutput("ls")'),
          ],
 
        # Help/object info
        escaped_help =
        [ ('?', 'get_ipython().show_usage()'),
          ('?x1', 'get_ipython().magic("pinfo x1")'),
          ('??x2', 'get_ipython().magic("pinfo2 x2")'),
          ('x3?', 'get_ipython().magic("pinfo x3")'),
          ('x4??', 'get_ipython().magic("pinfo2 x4")'),
          ],
 
        # Explicit magic calls
        escaped_magic =
        [ ('%cd', 'get_ipython().magic("cd")'),
          ('%cd /home', 'get_ipython().magic("cd /home")'),
          ('    %magic', '    get_ipython().magic("magic")'),
          ],
        
        # Quoting with separate arguments
        escaped_quote =
        [ (',f', 'f("")'),
          (',f x', 'f("x")'),
          ('  ,f y', '  f("y")'),
          (',f a b', 'f("a", "b")'),
          ],
        
        # Quoting with single argument
        escaped_quote2 = 
        [ (';f', 'f("")'),
          (';f x', 'f("x")'),
          ('  ;f y', '  f("y")'),
          (';f a b', 'f("a b")'),
          ],
        
        # Simply apply parens
        escaped_paren = 
        [ ('/f', 'f()'),
          ('/f x', 'f(x)'),
          ('  /f y', '  f(y)'),
          ('/f a b', 'f(a, b)'),
          ],
 
-       # More complex multiline tests
-       ## escaped_multiline =
-       ## [()],
        )
 
 # multiline syntax examples.  Each of these should be a list of lists, with
 # each entry itself having pairs of raw/transformed input.  The union (with
 # '\n'.join() of the transformed inputs is what the splitter should produce
 # when fed the raw lines one at a time via push.
 syntax_ml = \
   dict(classic_prompt =
        [ [('>>> for i in range(10):','for i in range(10):'),
           ('...     print i','    print i'),
           ('... ', ''),
           ],
         ],
 
        ipy_prompt =
        [ [('In [24]: for i in range(10):','for i in range(10):'),
           ('   ....:     print i','    print i'),
           ('   ....: ', ''),
           ],
          ],
        )
 
 
 def test_assign_system():
     transform_checker(syntax['assign_system'], isp.transform_assign_system)
 
     
 def test_assign_magic():
     transform_checker(syntax['assign_magic'], isp.transform_assign_magic)
 
 
 def test_classic_prompt():
     transform_checker(syntax['classic_prompt'], isp.transform_classic_prompt)
     for example in syntax_ml['classic_prompt']:
         transform_checker(example, isp.transform_classic_prompt)
     
 
 def test_ipy_prompt():
     transform_checker(syntax['ipy_prompt'], isp.transform_ipy_prompt)
     for example in syntax_ml['ipy_prompt']:
         transform_checker(example, isp.transform_ipy_prompt)
     
 
 def test_escaped_noesc():
     transform_checker(syntax['escaped_noesc'], isp.transform_escaped)
 
 
 def test_escaped_shell():
     transform_checker(syntax['escaped_shell'], isp.transform_escaped)
 
 
 def test_escaped_help():
     transform_checker(syntax['escaped_help'], isp.transform_escaped)
 
 
 def test_escaped_magic():
     transform_checker(syntax['escaped_magic'], isp.transform_escaped)
 
 
 def test_escaped_quote():
     transform_checker(syntax['escaped_quote'], isp.transform_escaped)
 
 
 def test_escaped_quote2():
     transform_checker(syntax['escaped_quote2'], isp.transform_escaped)
 
 
 def test_escaped_paren():
     transform_checker(syntax['escaped_paren'], isp.transform_escaped)
 
 
 class IPythonInputTestCase(InputSplitterTestCase):
     """By just creating a new class whose .isp is a different instance, we
     re-run the same test battery on the new input splitter.
 
     In addition, this runs the tests over the syntax and syntax_ml dicts that
     were tested by individual functions, as part of the OO interface.
     """
+
     def setUp(self):
-        self.isp = isp.IPythonInputSplitter()
+        self.isp = isp.IPythonInputSplitter(input_mode='append')
 
     def test_syntax(self):
         """Call all single-line syntax tests from the main object"""
         isp = self.isp
         for example in syntax.itervalues():
             for raw, out_t in example:
                 if raw.startswith(' '):
                     continue
                 
                 isp.push(raw)
                 out = isp.source_reset().rstrip()
                 self.assertEqual(out, out_t)
-        
+
     def test_syntax_multiline(self):
         isp = self.isp
         for example in syntax_ml.itervalues():
             out_t_parts = []
             for line_pairs in example:
                 for raw, out_t_part in line_pairs:
                     isp.push(raw)
                     out_t_parts.append(out_t_part)
 
                 out = isp.source_reset().rstrip()
                 out_t = '\n'.join(out_t_parts).rstrip()
                 self.assertEqual(out, out_t)
                 
-        
+
+class BlockIPythonInputTestCase(IPythonInputTestCase):
+
+    # Deactivate tests that don't make sense for the block mode
+    test_push3 = test_split = lambda s: None
+    
+    def setUp(self):
+        self.isp = isp.IPythonInputSplitter(input_mode='replace')
+
+    def test_syntax_multiline(self):
+        isp = self.isp
+        for example in syntax_ml.itervalues():
+            raw_parts = []
+            out_t_parts = []
+            for line_pairs in example:
+                for raw, out_t_part in line_pairs:
+                    raw_parts.append(raw)
+                    out_t_parts.append(out_t_part)
+
+                raw = '\n'.join(raw_parts)
+                out_t = '\n'.join(out_t_parts)
+
+                isp.push(raw)
+                out = isp.source_reset()
+                # Match ignoring trailing whitespace
+                self.assertEqual(out.rstrip(), out_t.rstrip())
+    
+
 #-----------------------------------------------------------------------------
-# Main - use as a script
+# Main - use as a script, mostly for developer experiments
 #-----------------------------------------------------------------------------
 
 if __name__ == '__main__':
     # A simple demo for interactive experimentation.  This code will not get
-    # picked up by any test suite.  Useful mostly for illustration and during
-    # development.
+    # picked up by any test suite.
     from IPython.core.inputsplitter import InputSplitter, IPythonInputSplitter
 
     # configure here the syntax to use, prompt and whether to autoindent
     #isp, start_prompt = InputSplitter(), '>>> '
     isp, start_prompt = IPythonInputSplitter(), 'In> '
 
     autoindent = True
     #autoindent = False
     
     try:
         while True:
             prompt = start_prompt
             while isp.push_accepts_more():
                 indent = ' '*isp.indent_spaces
                 if autoindent:
                     line = indent + raw_input(prompt+indent)
                 else:
                     line = raw_input(prompt)
                 isp.push(line)
                 prompt = '... '
 
             # Here we just return input so we can use it in a test suite, but a
             # real interpreter would instead send it for execution somewhere.
             #src = isp.source; raise EOFError # dbg
             src = isp.source_reset()
             print 'Input source was:\n', src
     except EOFError:
         print 'Bye'

IPython/frontend/qt/console/ipython_widget.py

@@ -1,343 +1,343 b''
 """ A FrontendWidget that emulates the interface of the console IPython and
     supports the additional functionality provided by the IPython kernel.
 
     TODO: Add support for retrieving the system default editor. Requires code
           paths for Windows (use the registry), Mac OS (use LaunchServices), and
           Linux (use the xdg system).
 """
 
 # Standard library imports
 from subprocess import Popen
 
 # System library imports
 from PyQt4 import QtCore, QtGui
 
 # Local imports
 from IPython.core.inputsplitter import IPythonInputSplitter
 from IPython.core.usage import default_banner
 from frontend_widget import FrontendWidget
 
 
 class IPythonPromptBlock(object):
     """ An internal storage object for IPythonWidget.
     """
     def __init__(self, block, length, number):
         self.block = block
         self.length = length
         self.number = number
 
 
 class IPythonWidget(FrontendWidget):
     """ A FrontendWidget for an IPython kernel.
     """
 
     # Signal emitted when an editor is needed for a file and the editor has been
     # specified as 'custom'. See 'set_editor' for more information.
     custom_edit_requested = QtCore.pyqtSignal(object, object)
 
     # The default stylesheet: black text on a white background.
     default_stylesheet = """
         .error { color: red; }
         .in-prompt { color: navy; }
         .in-prompt-number { font-weight: bold; }
         .out-prompt { color: darkred; }
         .out-prompt-number { font-weight: bold; }
     """
 
     # A dark stylesheet: white text on a black background.
     dark_stylesheet = """
         QPlainTextEdit, QTextEdit { background-color: black; color: white }
         QFrame { border: 1px solid grey; }
         .error { color: red; }
         .in-prompt { color: lime; }
         .in-prompt-number { color: lime; font-weight: bold; }
         .out-prompt { color: red; }
         .out-prompt-number { color: red; font-weight: bold; }
     """
 
     # Default prompts.
     in_prompt = 'In [<span class="in-prompt-number">%i</span>]: '
     out_prompt = 'Out[<span class="out-prompt-number">%i</span>]: '
 
     # FrontendWidget protected class variables.
-    #_input_splitter_class = IPythonInputSplitter
+    _input_splitter_class = IPythonInputSplitter
 
     # IPythonWidget protected class variables.
     _payload_source_edit = 'IPython.zmq.zmqshell.ZMQInteractiveShell.edit_magic'
     _payload_source_page = 'IPython.zmq.page.page'
 
     #---------------------------------------------------------------------------
     # 'object' interface
     #---------------------------------------------------------------------------
     
     def __init__(self, *args, **kw):
         super(IPythonWidget, self).__init__(*args, **kw)
 
         # IPythonWidget protected variables.
         self._previous_prompt_obj = None
 
         # Set a default editor and stylesheet.
         self.set_editor('default')
         self.reset_styling()
 
     #---------------------------------------------------------------------------
     # 'BaseFrontendMixin' abstract interface
     #---------------------------------------------------------------------------
 
     def _handle_history_reply(self, msg):
         """ Implemented to handle history replies, which are only supported by
             the IPython kernel.
         """
         history_dict = msg['content']['history']
         items = [ history_dict[key] for key in sorted(history_dict.keys()) ]
         self._set_history(items)
 
     def _handle_prompt_reply(self, msg):
         """ Implemented to handle prompt number replies, which are only
             supported by the IPython kernel.
         """
         content = msg['content']
         self._show_interpreter_prompt(content['prompt_number'], 
                                       content['input_sep'])
 
     def _handle_pyout(self, msg):
         """ Reimplemented for IPython-style "display hook".
         """
         if not self._hidden and self._is_from_this_session(msg):
             content = msg['content']
             prompt_number = content['prompt_number']
             self._append_plain_text(content['output_sep'])
             self._append_html(self._make_out_prompt(prompt_number))
             self._append_plain_text(content['data'] + '\n' + 
                                     content['output_sep2'])
 
     def _started_channels(self):
         """ Reimplemented to make a history request.
         """
         super(IPythonWidget, self)._started_channels()
         # FIXME: Disabled until history requests are properly implemented.
         #self.kernel_manager.xreq_channel.history(raw=True, output=False)
 
     #---------------------------------------------------------------------------
     # 'FrontendWidget' interface
     #---------------------------------------------------------------------------
 
     def execute_file(self, path, hidden=False):
         """ Reimplemented to use the 'run' magic.
         """
         self.execute('%%run %s' % path, hidden=hidden)
 
     #---------------------------------------------------------------------------
     # 'FrontendWidget' protected interface
     #---------------------------------------------------------------------------
 
     def _get_banner(self):
         """ Reimplemented to return IPython's default banner.
         """
         return default_banner + '\n'
 
     def _process_execute_error(self, msg):
         """ Reimplemented for IPython-style traceback formatting.
         """
         content = msg['content']
         traceback = '\n'.join(content['traceback']) + '\n'
         if False:
             # FIXME: For now, tracebacks come as plain text, so we can't use
             # the html renderer yet.  Once we refactor ultratb to produce
             # properly styled tracebacks, this branch should be the default
             traceback = traceback.replace(' ', '&nbsp;')
             traceback = traceback.replace('\n', '<br/>')
 
             ename = content['ename']
             ename_styled = '<span class="error">%s</span>' % ename
             traceback = traceback.replace(ename, ename_styled)
 
             self._append_html(traceback)
         else:
             # This is the fallback for now, using plain text with ansi escapes
             self._append_plain_text(traceback)
 
     def _process_execute_payload(self, item):
         """ Reimplemented to handle %edit and paging payloads.
         """
         if item['source'] == self._payload_source_edit:
             self._edit(item['filename'], item['line_number'])
             return True
         elif item['source'] == self._payload_source_page:
             self._page(item['data'])
             return True
         else:
             return False
 
     def _show_interpreter_prompt(self, number=None, input_sep='\n'):
         """ Reimplemented for IPython-style prompts.
         """
         # If a number was not specified, make a prompt number request.
         if number is None:
             self.kernel_manager.xreq_channel.prompt()
             return
 
         # Show a new prompt and save information about it so that it can be
         # updated later if the prompt number turns out to be wrong.
         self._append_plain_text(input_sep)
         self._show_prompt(self._make_in_prompt(number), html=True)
         block = self._control.document().lastBlock()
         length = len(self._prompt)
         self._previous_prompt_obj = IPythonPromptBlock(block, length, number)
 
         # Update continuation prompt to reflect (possibly) new prompt length.
         self._set_continuation_prompt(
             self._make_continuation_prompt(self._prompt), html=True)
 
     def _show_interpreter_prompt_for_reply(self, msg):
         """ Reimplemented for IPython-style prompts.
         """
         # Update the old prompt number if necessary.
         content = msg['content']
         previous_prompt_number = content['prompt_number']
         if self._previous_prompt_obj and \
                 self._previous_prompt_obj.number != previous_prompt_number:
             block = self._previous_prompt_obj.block
 
             # Make sure the prompt block has not been erased.
             if block.isValid() and not block.text().isEmpty():
 
                 # Remove the old prompt and insert a new prompt.
                 cursor = QtGui.QTextCursor(block)
                 cursor.movePosition(QtGui.QTextCursor.Right,
                                     QtGui.QTextCursor.KeepAnchor, 
                                     self._previous_prompt_obj.length)
                 prompt = self._make_in_prompt(previous_prompt_number)
                 self._prompt = self._insert_html_fetching_plain_text(
                     cursor, prompt)
 
                 # When the HTML is inserted, Qt blows away the syntax
                 # highlighting for the line, so we need to rehighlight it.
                 self._highlighter.rehighlightBlock(cursor.block())
 
             self._previous_prompt_obj = None
 
         # Show a new prompt with the kernel's estimated prompt number.
         next_prompt = content['next_prompt']
         self._show_interpreter_prompt(next_prompt['prompt_number'], 
                                       next_prompt['input_sep'])
 
     #---------------------------------------------------------------------------
     # 'IPythonWidget' interface
     #---------------------------------------------------------------------------
 
     def reset_styling(self):
         """ Restores the default IPythonWidget styling.
         """
         self.set_styling(self.default_stylesheet, syntax_style='default')
         #self.set_styling(self.dark_stylesheet, syntax_style='monokai')
 
     def set_editor(self, editor, line_editor=None):
         """ Sets the editor to use with the %edit magic.
 
         Parameters:
         -----------
         editor : str
             A command for invoking a system text editor. If the string contains
             a {filename} format specifier, it will be used. Otherwise, the 
             filename will be appended to the end the command.
 
             This parameter also takes a special value:
                 'custom'  : Emit a 'custom_edit_requested(str, int)' signal 
                             instead of opening an editor.
 
         line_editor : str, optional
             The editor command to use when a specific line number is
             requested. The string should contain two format specifiers: {line}
             and {filename}. If this parameter is not specified, the line number
             option to the %edit magic will be ignored.
         """
         self._editor = editor
         self._editor_line = line_editor
 
     def set_styling(self, stylesheet, syntax_style=None):
         """ Sets the IPythonWidget styling.
 
         Parameters:
         -----------
         stylesheet : str
             A CSS stylesheet. The stylesheet can contain classes for:
                 1. Qt: QPlainTextEdit, QFrame, QWidget, etc
                 2. Pygments: .c, .k, .o, etc (see PygmentsHighlighter)
                 3. IPython: .error, .in-prompt, .out-prompt, etc.
 
         syntax_style : str or None [default None]
             If specified, use the Pygments style with given name. Otherwise, 
             the stylesheet is queried for Pygments style information.
         """
         self.setStyleSheet(stylesheet)
         self._control.document().setDefaultStyleSheet(stylesheet)
         if self._page_control:
             self._page_control.document().setDefaultStyleSheet(stylesheet)
 
         if syntax_style is None:
             self._highlighter.set_style_sheet(stylesheet)
         else:
             self._highlighter.set_style(syntax_style)
 
     #---------------------------------------------------------------------------
     # 'IPythonWidget' protected interface
     #---------------------------------------------------------------------------
 
     def _edit(self, filename, line=None):
         """ Opens a Python script for editing.
 
         Parameters:
         -----------
         filename : str
             A path to a local system file.
 
         line : int, optional
             A line of interest in the file.
         """
         if self._editor == 'custom':
             self.custom_edit_requested.emit(filename, line)
         elif self._editor == 'default':
             self._append_plain_text('No default editor available.\n')
         else:
             try:
                 filename = '"%s"' % filename
                 if line and self._editor_line:
                     command = self._editor_line.format(filename=filename,
                                                        line=line)
                 else:
                     try:
                         command = self._editor.format()
                     except KeyError:
                         command = self._editor.format(filename=filename)
                     else:
                         command += ' ' + filename
             except KeyError:
                 self._append_plain_text('Invalid editor command.\n')
             else:
                 try:
                     Popen(command, shell=True)
                 except OSError:
                     msg = 'Opening editor with command "%s" failed.\n'
                     self._append_plain_text(msg % command)
 
     def _make_in_prompt(self, number):
         """ Given a prompt number, returns an HTML In prompt.
         """
         body = self.in_prompt % number
         return '<span class="in-prompt">%s</span>' % body
 
     def _make_continuation_prompt(self, prompt):
         """ Given a plain text version of an In prompt, returns an HTML
             continuation prompt.
         """
         end_chars = '...: '
         space_count = len(prompt.lstrip('\n')) - len(end_chars)
         body = '&nbsp;' * space_count + end_chars
         return '<span class="in-prompt">%s</span>' % body
         
     def _make_out_prompt(self, number):
         """ Given a prompt number, returns an HTML Out prompt.
         """
         body = self.out_prompt % number
         return '<span class="out-prompt">%s</span>' % body