regular expressions ... slow

[Terry Reedy]

Jerry Hill wrote:
> On Mon, Nov 17, 2008 at 4:37 PM, Uwe Schmitt
> <rocksportrocker at googlemail.com> wrote:
>> Hi,
>>
>> Is anobody aware of this post:  http://swtch.com/~rsc/regexp/regexp1.html ?
> 
> Yes, it's been brought up here, on python-dev and python-ideas several
> times in the past year and a half.
> 
>> Are there any plans  to speed up Pythons regular expression module ?
>> Or
>> is the example in this artricle too far from reality ???
> 
> I don't think anyone has taken any concrete steps towards re-writing
> the regular expression module.  My understanding from previous threads
> on the topic is that the core developers would be willing to accept a
> re-written regular expression engine, but none of them are interested
> in doing it themselves.  The general consensus seemed to be that the
> pathological cases hilited in that article are not very common in the
> real world, and that simply switching to the alternative approach
> advocated there would require giving up things like backreferences
> that are actually used in the real world, which is probably
> unacceptable.
> 
> Some references:
> http://mail.python.org/pipermail/python-dev/2007-March/072241.html
> http://mail.python.org/pipermail/python-list/2007-February/427604.html
> http://mail.python.org/pipermail/python-ideas/2007-April/000405.html
> 
> Personally, I know very little about the nitty gritty of regular
> expression engines, but there's some reference material for you to
> chew on.

Searching the tracker for open items with 'regular expression' in the 
text brings up about 20 items to also consider.