[Python-Dev] Some questions about maintenance of the regular expression code.

[Gary Herron]

On Wednesday 26 February 2003 01:08 am, M.-A. Lemburg wrote:
> Gary Herron wrote:
> > The first glance at the regular expression bug list and the _sre.c
> > code results in the observation that several of the bugs are related
> > to running over the recursion limit.  The problem comes from using a
> > pattern containing ".*?" in a situation where it is expected to match
> > many thousands of characters.  Each character matched by ".*?" causes
> > one level or recursion, quickly overflowing the recursion limit.
>
> Wouldn't it be possible for the RE compiler to issue a warning in
> case these kind of patterns are used ? This would be much more helpful
> than trying to work-around the user problem.

I think not.  It's not the pattern that's the problem.  A pattern
containing ".*?" is perfectly legitimate and useful.  The problem
arises when the pattern is used on a string which has thousands of
characters which match.  By that point the RE compiler is right out of
the picture.

Gary Herron