1 #! /usr/bin/env python

     2 

     3 # 1)  Regular Expressions Test

     4 #

     5 #     Read a file of (extended per egrep) regular expressions (one per line),

     6 #     and apply those to all files whose names are listed on the command line.

     7 #     Basically, an 'egrep -f' simulator.  Test it with 20 "vt100" patterns

     8 #     against a five /etc/termcap files.  Tests using more elaborate patters

     9 #     would also be interesting.  Your code should not break if given hundreds

    10 #     of regular expressions or binary files to scan.

    11 

    12 # This implementation:

    13 # - combines all patterns into a single one using ( ... | ... | ... )

    14 # - reads patterns from stdin, scans files given as command line arguments

    15 # - produces output in the format <file>:<lineno>:<line>

    16 # - is only about 2.5 times as slow as egrep (though I couldn't run

    17 #   Tom's test -- this system, a vanilla SGI, only has /etc/terminfo)

    18 

    19 import string

    20 import sys

    21 import re

    22 

    23 def main():

    24     pats = map(chomp, sys.stdin.readlines())

    25     bigpat = '(' + '|'.join(pats) + ')'

    26     prog = re.compile(bigpat)

    27 

    28     for file in sys.argv[1:]:

    29         try:

    30             fp = open(file, 'r')

    31         except IOError, msg:

    32             print "%s: %s" % (file, msg)

    33             continue

    34         lineno = 0

    35         while 1:

    36             line = fp.readline()

    37             if not line:

    38                 break

    39             lineno = lineno + 1

    40             if prog.search(line):

    41                 print "%s:%s:%s" % (file, lineno, line),

    42 

    43 def chomp(s):

    44     return s.rstrip('\n')

    45 

    46 if __name__ == '__main__':

    47     main()