text: """Text wrapping and filling.
  """
  
  # Copyright (C) 1999-2001 Gregory P. Ward.
  # Copyright (C) 2002, 2003 Python Software Foundation.
  # Written by Greg Ward <gward@python.net>
  
  __revision__ = "$Id: textwrap.py 36379 2007-01-09 16:55:49Z cfbolz $"
  
  import string, re
  
  # Do the right thing with boolean values for all known Python versions
  # (so this module can be copied to projects that don't depend on Python
  # 2.3, e.g. Optik and Docutils).
  try:
      True, False
  except NameError:
      (True, False) = (1, 0)
  
  __all__ = ['TextWrapper', 'wrap', 'fill']
  
  # Hardcode the recognized whitespace characters to the US-ASCII
  # whitespace characters.  The main reason for doing this is that in
  # ISO-8859-1, 0xa0 is non-breaking whitespace, so in certain locales
  # that character winds up in string.whitespace.  Respecting
  # string.whitespace in those cases would 1) make textwrap treat 0xa0 the
  # same as any other whitespace char, which is clearly wrong (it's a
  # *non-breaking* space), 2) possibly cause problems with Unicode,
  # since 0xa0 is not in range(128).
  _whitespace = '\t\n\x0b\x0c\r '
  
  class TextWrapper:
      """
      Object for wrapping/filling text.  The public interface consists of
      the wrap() and fill() methods; the other methods are just there for
      subclasses to override in order to tweak the default behaviour.
      If you want to completely replace the main wrapping algorithm,
      you'll probably have to override _wrap_chunks().
  
      Several instance attributes control various aspects of wrapping:
        width (default: 70)
          the maximum width of wrapped lines (unless break_long_words
          is false)
        initial_indent (default: "")
          string that will be prepended to the first line of wrapped
          output.  Counts towards the line's width.
        subsequent_indent (default: "")
          string that will be prepended to all lines save the first
          of wrapped output; also counts towards each line's width.
        expand_tabs (default: true)
          Expand tabs in input text to spaces before further processing.
          Each tab will become 1 .. 8 spaces, depending on its position in
          its line.  If false, each tab is treated as a single character.
        replace_whitespace (default: true)
          Replace all whitespace characters in the input text by spaces
          after tab expansion.  Note that if expand_tabs is false and
          replace_whitespace is true, every tab will be converted to a
          single space!
        fix_sentence_endings (default: false)
          Ensure that sentence-ending punctuation is always followed
          by two spaces.  Off by default because the algorithm is
          (unavoidably) imperfect.
        break_long_words (default: true)
          Break words longer than 'width'.  If false, those words will not
          be broken, and some lines might be longer than 'width'.
      """
  
      whitespace_trans = string.maketrans(_whitespace, ' ' * len(_whitespace))
  
      unicode_whitespace_trans = {}
      uspace = ord(u' ')
      for x in map(ord, _whitespace):
          unicode_whitespace_trans[x] = uspace
  
      # This funky little regex is just the trick for splitting
      # text up into word-wrappable chunks.  E.g.
      #   "Hello there -- you goof-ball, use the -b option!"
      # splits into
      #   Hello/ /there/ /--/ /you/ /goof-/ball,/ /use/ /the/ /-b/ /option!
      # (after stripping out empty strings).
      wordsep_re = re.compile(
          r'(\s+|'                                  # any whitespace
          r'[^\s\w]*\w+[a-zA-Z]-(?=\w+[a-zA-Z])|'   # hyphenated words
          r'(?<=[\w\!\"\'\&\.\,\?])-{2,}(?=\w))')   # em-dash
  
      # XXX this is not locale- or charset-aware -- string.lowercase
      # is US-ASCII only (and therefore English-only)
      sentence_end_re = re.compile(r'[%s]'              # lowercase letter
                                   r'[\.\!\?]'          # sentence-ending punct.
                                   r'[\"\']?'           # optional end-of-quote
                                   % string.lowercase)
  
  
      def __init__(self,
                   width=70,
                   initial_indent="",
                   subsequent_indent="",
                   expand_tabs=True,
                   replace_whitespace=True,
                   fix_sentence_endings=False,
                   break_long_words=True):
          self.width = width
          self.initial_indent = initial_indent
          self.subsequent_indent = subsequent_indent
          self.expand_tabs = expand_tabs
          self.replace_whitespace = replace_whitespace
          self.fix_sentence_endings = fix_sentence_endings
          self.break_long_words = break_long_words
  
  
      # -- Private methods -----------------------------------------------
      # (possibly useful for subclasses to override)
  
      def _munge_whitespace(self, text):
          """_munge_whitespace(text : string) -> string
  
          Munge whitespace in text: expand tabs and convert all other
          whitespace characters to spaces.  Eg. " foo\tbar\n\nbaz"
          becomes " foo    bar  baz".
          """
          if self.expand_tabs:
              text = text.expandtabs()
          if self.replace_whitespace:
              if isinstance(text, str):
                  text = text.translate(self.whitespace_trans)
              elif isinstance(text, unicode):
                  text = text.translate(self.unicode_whitespace_trans)
          return text
  
  
      def _split(self, text):
          """_split(text : string) -> [string]
  
          Split the text to wrap into indivisible chunks.  Chunks are
          not quite the same as words; see wrap_chunks() for full
          details.  As an example, the text
            Look, goof-ball -- use the -b option!
          breaks into the following chunks:
            'Look,', ' ', 'goof-', 'ball', ' ', '--', ' ',
            'use', ' ', 'the', ' ', '-b', ' ', 'option!'
          """
          chunks = self.wordsep_re.split(text)
          chunks = filter(None, chunks)
          return chunks
  
      def _fix_sentence_endings(self, chunks):
          """_fix_sentence_endings(chunks : [string])
  
          Correct for sentence endings buried in 'chunks'.  Eg. when the
          original text contains "... foo.\nBar ...", munge_whitespace()
          and split() will convert that to [..., "foo.", " ", "Bar", ...]
          which has one too few spaces; this method simply changes the one
          space to two.
          """
          i = 0
          pat = self.sentence_end_re
          while i < len(chunks)-1:
              if chunks[i+1] == " " and pat.search(chunks[i]):
                  chunks[i+1] = "  "
                  i += 2
              else:
                  i += 1
  
      def _handle_long_word(self, reversed_chunks, cur_line, cur_len, width):
          """_handle_long_word(chunks : [string],
                               cur_line : [string],
                               cur_len : int, width : int)
  
          Handle a chunk of text (most likely a word, not whitespace) that
          is too long to fit in any line.
          """
          space_left = max(width - cur_len, 1)
  
          # If we're allowed to break long words, then do so: put as much
          # of the next chunk onto the current line as will fit.
          if self.break_long_words:
              cur_line.append(reversed_chunks[-1][:space_left])
              reversed_chunks[-1] = reversed_chunks[-1][space_left:]
  
          # Otherwise, we have to preserve the long word intact.  Only add
          # it to the current line if there's nothing already there --
          # that minimizes how much we violate the width constraint.
          elif not cur_line:
              cur_line.append(reversed_chunks.pop())
  
          # If we're not allowed to break long words, and there's already
          # text on the current line, do nothing.  Next time through the
          # main loop of _wrap_chunks(), we'll wind up here again, but
          # cur_len will be zero, so the next line will be entirely
          # devoted to the long word that we can't handle right now.
  
      def _wrap_chunks(self, chunks):
          """_wrap_chunks(chunks : [string]) -> [string]
  
          Wrap a sequence of text chunks and return a list of lines of
          length 'self.width' or less.  (If 'break_long_words' is false,
          some lines may be longer than this.)  Chunks correspond roughly
          to words and the whitespace between them: each chunk is
          indivisible (modulo 'break_long_words'), but a line break can
          come between any two chunks.  Chunks should not have internal
          whitespace; ie. a chunk is either all whitespace or a "word".
          Whitespace chunks will be removed from the beginning and end of
          lines, but apart from that whitespace is preserved.
          """
          lines = []
          if self.width <= 0:
              raise ValueError("invalid width %r (must be > 0)" % self.width)
  
          # Arrange in reverse order so items can be efficiently popped
          # from a stack of chucks.
          chunks.reverse()
  
          while chunks:
  
              # Start the list of chunks that will make up the current line.
              # cur_len is just the length of all the chunks in cur_line.
              cur_line = []
              cur_len = 0
  
              # Figure out which static string will prefix this line.
              if lines:
                  indent = self.subsequent_indent
              else:
                  indent = self.initial_indent
  
              # Maximum width for this line.
              width = self.width - len(indent)
  
              # First chunk on line is whitespace -- drop it, unless this
              # is the very beginning of the text (ie. no lines started yet).
              if chunks[-1].strip() == '' and lines:
                  del chunks[-1]
  
              while chunks:
                  l = len(chunks[-1])
  
                  # Can at least squeeze this chunk onto the current line.
                  if cur_len + l <= width:
                      cur_line.append(chunks.pop())
                      cur_len += l
  
                  # Nope, this line is full.
                  else:
                      break
  
              # The current line is full, and the next chunk is too big to
              # fit on *any* line (not just this one).
              if chunks and len(chunks[-1]) > width:
                  self._handle_long_word(chunks, cur_line, cur_len, width)
  
              # If the last chunk on this line is all whitespace, drop it.
              if cur_line and cur_line[-1].strip() == '':
                  del cur_line[-1]
  
              # Convert current line back to a string and store it in list
              # of all lines (return value).
              if cur_line:
                  lines.append(indent + ''.join(cur_line))
  
          return lines
  
  
      # -- Public interface ----------------------------------------------
  
      def wrap(self, text):
          """wrap(text : string) -> [string]
  
          Reformat the single paragraph in 'text' so it fits in lines of
          no more than 'self.width' columns, and return a list of wrapped
          lines.  Tabs in 'text' are expanded with string.expandtabs(),
          and all other whitespace characters (including newline) are
          converted to space.
          """
          text = self._munge_whitespace(text)
          chunks = self._split(text)
          if self.fix_sentence_endings:
              self._fix_sentence_endings(chunks)
          return self._wrap_chunks(chunks)
  
      def fill(self, text):
          """fill(text : string) -> string
  
          Reformat the single paragraph in 'text' to fit in lines of no
          more than 'self.width' columns, and return a new string
          containing the entire wrapped paragraph.
          """
          return "\n".join(self.wrap(text))
  
  
  # -- Convenience interface ---------------------------------------------
  
  def wrap(text, width=70, **kwargs):
      """Wrap a single paragraph of text, returning a list of wrapped lines.
  
      Reformat the single paragraph in 'text' so it fits in lines of no
      more than 'width' columns, and return a list of wrapped lines.  By
      default, tabs in 'text' are expanded with string.expandtabs(), and
      all other whitespace characters (including newline) are converted to
      space.  See TextWrapper class for available keyword args to customize
      wrapping behaviour.
      """
      w = TextWrapper(width=width, **kwargs)
      return w.wrap(text)
  
  def fill(text, width=70, **kwargs):
      """Fill a single paragraph of text, returning a new string.
  
      Reformat the single paragraph in 'text' to fit in lines of no more
      than 'width' columns, and return a new string containing the entire
      wrapped paragraph.  As with wrap(), tabs are expanded and other
      whitespace characters converted to space.  See TextWrapper class for
      available keyword args to customize wrapping behaviour.
      """
      w = TextWrapper(width=width, **kwargs)
      return w.fill(text)
  
  
  # -- Loosely related functionality -------------------------------------
  
  def dedent(text):
      """dedent(text : string) -> string
  
      Remove any whitespace than can be uniformly removed from the left
      of every line in `text`.
  
      This can be used e.g. to make triple-quoted strings line up with
      the left edge of screen/whatever, while still presenting it in the
      source code in indented form.
  
      For example:
  
          def test():
              # end first line with \ to avoid the empty line!
              s = '''\
              hello
                world
              '''
              print repr(s)          # prints '    hello\n      world\n    '
              print repr(dedent(s))  # prints 'hello\n  world\n'
      """
      lines = text.expandtabs().split('\n')
      margin = None
      for line in lines:
          content = line.lstrip()
          if not content:
              continue
          indent = len(line) - len(content)
          if margin is None:
              margin = indent
          else:
              margin = min(margin, indent)
  
      if margin is not None and margin > 0:
          for i in range(len(lines)):
              lines[i] = lines[i][margin:]
  
      return '\n'.join(lines)
  