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Wed Aug 8 20:56:58 CEST 2007 · https://mail.python.org/pipermail/python-dev/2007-August/074116.html

On 8-Aug-07, at 2:28 AM, Nick Maclaren wrote:

> I have needed to push my stack to teach REs (don't ask), and am
> taking a look at the RE code.  I may be able to extend it to support
> RFE 694374 and (more importantly) atomic groups and possessive
> quantifiers.  While I regard such things as revolting beyond belief,
> they make a HELL of a difference to the efficiency of recognising
> things like HTML tags in a morass of mixed text.

+1.  I would use such a feature.

> The other approach, which is to stick to true regular expressions,
> and wholly or partially convert to DFAs, has already been rendered
> impossible by even the limited Perl/PCRE extensions that Python
> has adopted.

Impossible?  Surely, a sufficiently-competent re engine could detect  
when a DFA is possible to construct?

-Mike

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[Python-Dev] Regular expressions, Unicode etc.