chrome/browser/web_dev_style/regex_check.py

   1 # Copyright 2014 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5
   6 def RegexCheck(re, line_number, line, regex, msg):
   7   """Searches for |regex| in |line| to check for a particular style
   8      violation, returning a message like the one below if the regex matches.
   9      The |regex| must have exactly one capturing group so that the relevant
  10      part of |line| can be highlighted. If more groups are needed, use
  11      "(?:...)" to make a non-capturing group. Sample message:
  12
  13        line 6: Use var instead of const.
  14            const foo = bar();
  15            ^^^^^
  16   """
  17
  18   def _highlight(match):
  19     """Takes a start position and a length, and produces a row of '^'s to
  20        highlight the corresponding part of a string.
  21     """
  22     return match.start(1) * ' ' + (match.end(1) - match.start(1)) * '^'
  23
  24   match = re.search(regex, line)
  25   if match:
  26     assert len(match.groups()) == 1
  27     return '  line %d: %s\n%s\n%s' % (line_number, msg, line, _highlight(match))
  28   return ''