Stanford Scientists Put Free Text-Analysis Tool on the Web(engineering.stanford.edu)

    """ SPLIT INPUT INTO SENTENCES"""
    verbose_regex = r'''(?<!\d)  # I can't actually tell
      (?<![A-Z]\.)(?<!\.[a-z]\.) # what you're doing here...
      (?<!\.\.\.)(?<!etc\.)      # Is this one big group, or is
      (?<![Mm]r\.)(?<![Pp]rof\.) # it several groups, with
      (?<![Dd]r\.)(?<![Mm]rs\.)  # different prefixes?
      (?<![Mm]s\.)(?<![Mm]z\.)(?<![Mm]me\.) # Clearly, it's got something to do
      (?:(?<=[.!?])|(?<=[.!?]['"]))[\s]+?(?=[\S])''' # with
                 # not matching the dot at the end of Dr.
                 # or as part of an ellipsis as the end of a
                 # sentence? But my point was that if such a
                 # regex is built-up and tested with comments
                 # it can be quite readable

      god_awful_regex = re.compile(verbose_regex,
                                     re.VERBOSE)
      # continue here...