On Mon, Jul 12, 2010 at 8:18 AM, Michael Foord <fuzzy...@voidspace.org.uk> wrote: > On 12/07/2010 15:07, Nick Coghlan wrote: >> >> On Mon, Jul 12, 2010 at 9:42 AM, Steven D'Aprano<st...@pearwood.info> >> wrote: >> >>> >>> On Sun, 11 Jul 2010 09:37:22 pm Eric Smith wrote: >>> >>>>> >>>>> re2 comparison is interesting from the point of if it should be >>>>> included in stdlib. >>>>> >>>> >>>> Is "it" re2 or regex? I don't see having 2 regular expression engines >>>> in the stdlib. >>>> >>> >>> There's precedence though... the old regex engine and the new re engine >>> were side-by-side for many years before regex was deprecated and >>> finally removed in 2.5. Hypothetically, re2 could similarly be added to >>> the standard library while re is deprecated. >>> >> >> re2 deliberately omits some features for efficiency reasons, hence is >> not even on the table as a possible replacement for the standard >> library version. If someone is in a position where re2 can solve their >> problems with the re module, they should also be in a position where >> they can track it down for themselves. >> >> > > If it has *partial* compatibility, and big enough performance improvements > for common cases, it could perhaps be used where the regex doesn't use > unsupported features. This would have some extra cost in the compile phase, > but would mean Python could ship with two regex engines but only one > interface exposed to the programmer...
FWIW, this has all been discussed before: http://aspn.activestate.com/ASPN/Mail/Message/python-dev/3829265. In particular, I still believe that, "it's not obvious that enough Python regexes would benefit from re2's performance/restrictions tradeoff to make such a hybrid system worthwhile in the long term. (There is no representative corpus of real-world Python regexes weighted for dynamic execution frequency to use in assessing such tradeoffs empirically like there is for JavaScript.)" Collin >> MRAB's module offers a superset of re's features rather than a subset >> though, so once it has had more of a chance to bake on PyPI it may be >> worth another look. >> >> Cheers, >> Nick. >> >> > > > -- > http://www.ironpythoninaction.com/ > http://www.voidspace.org.uk/blog > > READ CAREFULLY. By accepting and reading this email you agree, on behalf of > your employer, to release me from all obligations and waivers arising from > any and all NON-NEGOTIATED agreements, licenses, terms-of-service, > shrinkwrap, clickwrap, browsewrap, confidentiality, non-disclosure, > non-compete and acceptable use policies (”BOGUS AGREEMENTS”) that I have > entered into with your employer, its partners, licensors, agents and > assigns, in perpetuity, without prejudice to my ongoing rights and > privileges. You further represent that you have the authority to release me > from any BOGUS AGREEMENTS on behalf of your employer. > > > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/collinwinter%40google.com > _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
