Re: POSIX regex performance bug in 7.3 Vs. 7.2

On Tue, 2003-02-04 at 17:15, Neil Conway wrote:
> On Tue, 2003-02-04 at 11:59, Tom Lane wrote:
> > I'm about to go off and look at whether we can absorb the Tcl regex
> > package, which is Spencer's new baby. That will not be a solution for
> > 7.3.anything, but it could be an answer for 7.4.
>
> Sounds like we had about the same idea at about the same time -- I
> emailed Henry Spencer inquiring about the new RE engine last night. I
> came across a post this post that indicates he was planning to package
> the new RE engine separately:
>
> http://infosoc.uni-koeln.de/pipermail/php/1999-February/000019.html
>
> but I wasn't able to find a release of it anywhere -- I'll let the list
> know if/when he gets back to me.
>
> Another option is to consider a different regular expression engine. At
> least according to the benchmarks here,
>
> http://ourworld.compuserve.com/homepages/john_maddock/proposals/exregex.htm

I did not see anything about MULTIBYTE there, so it might be worth
experimenting on some MB charsets as well.

> Spencer's implementation is outperformed by some other RE engines,
> notably PCRE (www.pcre.org) But switching to another engine might
> impose backward-compatibility problems, in terms of the details of the
> RE syntax.

Yeah, it seems that POSIX (seemingly Spencers code) there is unable to
do some tests (the NA's in benchmark tables).

We could try a soft switch by having both implementations for a release
or two with different operators. At least good for comparing/testing.

--
Hannu Krosing <hannu(at)tm(dot)ee>