expand pattern and return sequence

ex.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-

'''
ex.py

expand pattern and return sequence.

Kosei Moriyama <cou929@gmail.com>

>>> expand('report_[01-05].pdf')
['report_01.pdf', 'report_02.pdf', 'report_03.pdf', 'report_04.pdf', 'report_05.pdf']
'''

import re
from optparse import OptionParser

re_brackets = re.compile('(.*?)\[([0-9\-!,]+?)\]([^\(\{]*?)$')
re_braces = re.compile('(.*?)\{(.*?)\}([^\(\{]*?)$')
re_range = re.compile('(!)?([0-9]+)(-([0-9]+))?')

def expand(line):
    '''    
    >>> expand('[1-3].jpg')
    ['1.jpg', '2.jpg', '3.jpg']

    >>> expand('[01-03].jpg')
    ['01.jpg', '02.jpg', '03.jpg']

    >>> expand('www.example.{com,co.jp}')
    ['www.example.com', 'www.example.co.jp']

    >>> expand('foo_[001-005,!002-003].txt')
    ['foo_001.txt', 'foo_004.txt', 'foo_005.txt']

    >>> expand('www.foo[01-03].batch.{com,co.jp}')
    ['www.foo01.batch.com', 'www.foo02.batch.com', 'www.foo03.batch.com', 'www.foo01.batch.co.jp', 'www.foo02.batch.co.jp', 'www.foo03.batch.co.jp']

    >>> expand('foobarbaz')
    ['foobarbaz']
    '''

    q = [line]
    ret = []

    while len(q) > 0:
        cur = q.pop(0)

        # expand []
        res_brackets = re_brackets.match(cur)
        if res_brackets:
            pre, pattern, post = res_brackets.groups()
            for token in pattern.split(','):
                neg, low, null, high= re_range.match(token).groups()
                if not high:
                    high = low
                if len(low) == len(high) and int(low) <= int(high):
                    format = '{0:0' + str(len(low)) + 'd}'
                    for i in range(int(low), int(high) + 1):
                        l = pre + format.format(i) + post
                        if neg:
                            q = filter(lambda x: x != l, q)
                            ret = filter(lambda x: x != l, ret)
                        else:
                            q.append(l)
            continue

        # expand {}
        res_braces = re_braces.search(cur)
        if res_braces:
            pre, pattern, post = res_braces.groups()
            map(lambda x: q.append(pre + x + post), pattern.split(','))
            continue

        # expanded
        ret.append(cur)
            
    return ret

if __name__ == "__main__":
    parser = OptionParser(usage='%prog PATTERN')
    parser.add_option("-t", "--test", action="store_true",
                      dest="run_doctest", default=False, help="run_doctest")
    options, args = parser.parse_args()

    if options.run_doctest:
        import doctest
        doctest.testmod()
    elif len(args) <= 0:
        parser.print_help()
        exit()
    else:
        for arg in args:
            print "\n".join(expand(arg))