#!/bin/env python

"""Sentence matching regular expression

This module shows a moderately complicated sentence matching regular
expression.
"""

import re

sent = re.compile('''
(?P<sentence>      # Match a sentence and label it
   (?:             # Tokens are grouped together into a sentence
      (?:\w+|,)+   # Sentence tokens are words and/or commas
      \s*          # Tokens are delimited by whitespace
   )+              # A sentence may have more than one token
   [.?!]           # Sentences end with . ! or ?
)
\s*             # Allow trailing spaces after the sentence
''', re.VERBOSE)


if __name__ == '__main__':
    import sys

    print "\n".join([s.group('sentence') \
                     for s in sent.finditer(' '.join(sys.argv[1:]))])