Demo/comparisons/regextest.py

   1 #! /usr/local/bin/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 regex
  22 from regex_syntax import *
  23
  24 regex.set_syntax(RE_SYNTAX_EGREP)
  25
  26 def main():
  27         pats = map(chomp, sys.stdin.readlines())
  28         bigpat = '(' + string.joinfields(pats, '|') + ')'
  29         prog = regex.compile(bigpat)
  30
  31         for file in sys.argv[1:]:
  32                 try:
  33                         fp = open(file, 'r')
  34                 except IOError, msg:
  35                         print "%s: %s" % (file, msg)
  36                         continue
  37                 lineno = 0
  38                 while 1:
  39                         line = fp.readline()
  40                         if not line:
  41                                 break
  42                         lineno = lineno + 1
  43                         if prog.search(line) >= 0:
  44                                 print "%s:%s:%s" % (file, lineno, line),
  45
  46 def chomp(s):
  47         if s[-1:] == '\n': return s[:-1]
  48         else: return s
  49
  50 main()