find a string in a file's include set

tufind.py

#!/usr/bin/env python2.7

import itertools
import sys

def contains(filename, string):
  '''Determine whether a file contains a string.'''
  with open(filename) as f:
    for num, line in zip(itertools.count(1), f.readlines()):
      if string in line:
        return filename, num, line
  return False

def includes(filename):
  '''Generate the relative includes of a file.'''
  with open(filename) as f:
    for line in f:
      if line.startswith('#include "'):
        yield line[line.index('"')+1:line.rindex('"')]

def explore(filename, string):
  '''Find the first ocurrence of a string in a file's includes.'''
  try:
    result = contains(filename, string)
    if result:
      return result
    for include in includes(filename):
      found = explore(include, string)
      if found:
        return found
  except:
    pass
  return False

if __name__ == '__main__':
  try:
    filename, string = sys.argv[1], sys.argv[2]
  except:
    print 'Usage: finddecl.py filename string'
    sys.exit(1)
  found = explore(filename, string)
  if found:
    print '%s:%d %s' % found
  sys.exit(0 if found else 1)