Named regex groups

regex.py

import re

class Regex(object):
    """ 
    This is a convenience class for wrapping a regular expression, naming the
    groups in the expression, and retrieving a named tuple as the result of a
    match. For example,

        >>> regex = Regex('filename: (\S*)', 'filename')
        >>> regex.match('filename: my-file.txt')
        RegexResult(filename='my-file.txt')

    While, there is support in the re package for named groups, it can be useful
    to separate the naming of the groups from the expressions themselves. In
    particular, it makes it easier to read the regular expression. It is also
    nice to be able to get the results of the match or search in a named tuple.

    """

    def __init__(self, pattern, names):
        self.result = collections.namedtuple('RegexResult', names)
        self.pattern = re.compile(pattern)
        assert self.pattern.groups == len(self.result._fields)

    def match(self, txt):
        """Return the matching groups

        If this Regex object matches the text string, a named tuple is return
        with the matching groups.

        """
        result = self.pattern.match(txt)
        if result is not None:
            return self.result(*result.groups())

    def search(self, txt):
        """Return the matching groups

        If this Regex object matches the text string, a named tuple is return
        with the matching groups.

        """
        result = self.pattern.search(txt)
        if result is not None:
            return self.result(*result.groups())