Pathological regular expression
franck
pommereau at univ-paris12.fr
Fri Apr 17 16:48:06 EDT 2009
> To my mind, this is a bug in the RE engine. Is there any reason to not
> treat it as a bug?
It's not a bug, it's a feature! ;-)
Indeed, in order to handle constructs like (?P=name), RE engines have
to use inefficient algorithms. In my opinion, this is not the problem
of using a pathological regular expression, but rather a problem of
the RE engine that is not optimized to use the faster approach when
possible.
This is well known problem very well explained on:
http://swtch.com/~rsc/regexp/regexp1.html
Cheers,
Franck
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