re_test_patterns.py

#!/usr/bin/env python

import re


def test_patterns(text, patterns=[]):
    """ Given source text and a list of pattern, look for
    matches for each pattern within the text and print
    them to stdout.
    """
    # Look for each pattern in the text and print the results
    for pattern, desc in patterns:
        print 'Pattern %r (%s)\n' % (pattern, desc)
        print ' %r' % text
        for match in re.finditer(pattern, text):
            s = match.start()
            e = match.end()
            substr = text[s:e]
            n_backslashes = text[:s].count('\\')
            prefix = '.' * (s + n_backslashes)
            print ' %s%r' % (prefix, substr)
        print
    return

if __name__ == '__main__':
    test_patterns('abbaaabbbbaaaaa',
                  [('ab', "'a' followed by 'b'"),
                   ])