regexp crossword solution checker

crossword.py

#!/usr/bin/env python

from itertools import izip, chain
import re
import sys


"""

Checks a solution to this regular expression crossword:
http://www.coinheist.com/rubik/a_regular_crossword/index.html

Image version: https://twitter.com/isaach/status/299595370760130561/photo/1

"""


left_clues = (
    r'.*H.*H.*',
    r'(DI|NS|TH|OM)*',
    r'F.*[AO].*[AO].*',
    r'(O|RHH|MM)*',
    r'.*',
    r'C*MC(CCC|MM)*',
    r'[^C]*[^R]*III.*',
    r'(...?)\1*',
    r'([^X]|XCC)*',
    r'(RR|HHH)*.?',
    r'N.*X.X.X.*E',
    r'R*D*M*',
    r'.(C|HH)*',
)


top_clues = (
    r'.*SE.*UE.*',
    r'.*LR.*RL.*',
    r'.*OXR.*',
    r'([^EMC]|EM)*',
    r'(HHX|[^HX])*',
    r'.*PRR.*DDC.*',
    r'.*',
    r'[AM]*CM(RC)*R?',
    r'([^MC]|MM|CC)*',
    r'(E|CR|MN)*',
    r'P+(..)\1.*',
    r'[CHMNOR]*I[CHMNOR]*',
    r'(ND|ET|IN)[^X]*',
)


bottom_clues = (
    r'.*G.*V.*H.*',
    r'[CR]*',
    r'.*XEXM*',
    r'.*DD.*CCM.*',
    r'.*XHCR.*X.*',
    r'.*(.)(.)(.)(.)\4\3\2\1.*',
    r'.*(IN|SE|HI)',
    r'[^C]*MMM[^C]*',
    r'.*(.)C\1X\1.*',
    r'[CEIMU]*OH[AEMOR]*',
    r'(RX|[^R])*',
    r'[^M]*M[^M]*',
    r'(S|MM|HHH)*',
)


def match(pattern, text):
    print "Checking %s against %s" % (text, pattern)
    if re.match(r'^%s$' % pattern, text) is None:
        print "Solution line %s doesn't match pattern %s" % (text, pattern)
        sys.exit(0)


def check_left(solution):
    for clue, text in izip(left_clues, solution):
        match(clue, text)


def tilt_texts(solution):
    square_grid = list()
    for i in xrange(7):
        square_grid.append("%-13s" % solution[i])
    for i in xrange(7, 13):
        square_grid.append("%13s" % solution[i])

    for i in xrange(-1, -14, -1):
        yield ''.join(row[i] for row in square_grid).strip()


def check_top(solution):
    for clue, text in izip(top_clues, tilt_texts(solution)):
        match(clue, text)


def check_bottom(solution):
    bottom_texts = reversed(list(tilt_texts(list(reversed(solution)))))
    for clue, text in izip(bottom_clues, bottom_texts):
        match(clue, text)


def main():
    print "Enter your solution row by row:"
    solution = [x.strip().upper() for x in sys.stdin.readlines() if x.strip()]

    check_left(solution)
    check_top(solution)
    check_bottom(solution)

    print
    print "All correct!"


if __name__ == '__main__':
    main()