Utility to locate errors in regular expressions

From	Malte Forkel <malte.forkel@berlin.de>
Subject	Utility to locate errors in regular expressions
Date	2013-05-24 14:58 +0200
Newsgroups	comp.lang.python
Message-ID	<mailman.2062.1369400329.3114.python-list@python.org> (permalink)

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Finding out why a regular expression does not match a given string can
very tedious. I would like to write a utility that identifies the
sub-expression causing the non-match. My idea is to use a parser to
create a tree representing the complete regular expression. Then I could
simplify the expression by dropping sub-expressions one by one from
right to left and from bottom to top until the remaining regex matches.
The last sub-expression dropped should be (part of) the problem.

As a first step, I am looking for a parser for Python regular
expressions, or a Python regex grammar to create a parser from.

But may be my idea is flawed? Or a similar (or better) tools already
exists? Any advice will be highly appreciated!

Malte

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Thread

Utility to locate errors in regular expressions Malte Forkel <malte.forkel@berlin.de> - 2013-05-24 14:58 +0200
  Re: Utility to locate errors in regular expressions Roy Smith <roy@panix.com> - 2013-05-24 09:12 -0400
    Re: Utility to locate errors in regular expressions Neil Cerutti <neilc@norwich.edu> - 2013-05-24 13:58 +0000
  Re: Utility to locate errors in regular expressions rusi <rustompmody@gmail.com> - 2013-05-24 07:09 -0700
  Re: Utility to locate errors in regular expressions Christian Gollwitzer <auriocus@gmx.de> - 2013-05-24 20:21 +0200

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