Which regular expression engine do you use?

davidjam

For PHP regular expressions, which one do you use? And why?

dalecosp

POSIX, 'cuz Bunkermaster told me that PHP means "People Hate Perl."

Actually, I haven't yet bothered to learn any PERL compatible stuff, although I can occasionally remember how to call a script or even install a module from CPAN via the PERL shell.....

Oh, BTW, I hope you remembered to time limit your poll?😉

bubblenut

PCRE for me for me PCRE for me 😃

It's generally quicker and has a few extra features such as lookaheads (and behinds, but it's not polite to look at behinds :p)

davidjam

Originally posted by dalecosp
Oh, BTW, I hope you remembered to time limit your poll?😉

Nope I didn't. But I'll remember for next time. Thanks. (if a Mod wants to edit my poll and put a time limit on it, that'd be great)

Sxooter

posix regex for very simple stuff, perl for more complex things. especially the ability to limit greed in matching is nice. back references come in handy too.

Elizabeth

Ask and ye shall receive- the poll has been limited to 30 days.

csn

PCRE. I don't know of any advantage ereg has over preg. PHP's docs are full of warnings, tips, links, and notices saying you should use preg (more features, often faster, etc.).

davidjam

Originally posted by csn
PCRE. I don't know of any advantage ereg has over preg...

MySQL uses the POSIX standard and I figure why learn two different regex styles when one will do. (that's my current opinion. However, when I come across a need that only PCRE can fulfill, I may venture forth...)

csn

I don't use regular expression much at all in queries (since they can really hurt perfomance). And neither mysql nor postgresql have pcre, so...? I use PCRE in PHP, Perl, shell scripts, et al. and it's much more powerful. Sticking to POSIX regexps just because that's what databases support is silly to me - I do a lot of other stuff besides database work.

davidjam

Really? I was under the impression that if there was something that could be done on the database server, then it was generally faster than processing the equivelant through PHP... :bemused:

Sxooter

PostgreSQL supports Posix and the wonky SQL Standard regular expression syntax. It's goofy (think "from the people who brought you like" to get an idea) but it works.

If you want Perl regex in postgresql, just use plperl or plperlu.

If you mark the function immutable, you can even index on the danged thing!

When are Oracle, MySQL, Firebird, or Ingres gonna implement that?

(Do ANY other databases support the wide variety of procedural langages that postgresql does???)

csn

Don't use a hammer for everything...

csn

Originally posted by Sxooter
PostgreSQL supports Posix and the wonky SQL Standard regular expression syntax. It's goofy (think "from the people who brought you like" to get an idea) but it works.

If you want Perl regex in postgresql, just use plperl or plperlu.

If you mark the function immutable, you can even index on the danged thing!

When are Oracle, MySQL, Firebird, or Ingres gonna implement that?

(Do ANY other databases support the wide variety of procedural langages that postgresql does???)

Don't forget plpythonu! 😉 I just started using it (figured I'd try to get past my python newbieness since it seems to be the language du jour these days). Python doesn't get me excited, really, but being able to use so many procedure languages in Postgres rocks, and Postgres makes it so easy. I'd use plphp, but I couldn't get that to compile - apparently they've recently posted new instructions on their mailing list though.

Sxooter

I think the latest version only compiles against 7.4/8.0, or maybe even just 8.0.

It's very cool to write a trigger or function in PHP, then write an app in php that calls postgres, which calls php, which...

well anyway, you get the picture.

And then there's pltcl, plR, plruby, plpgsql, plsh, plJ, and a few others I can't remember right now.

It's funny that postgresql has more languages capable of being used inside it than .net probably does. hehe

csn

Originally posted by Sxooter
I think the latest version only compiles against 7.4/8.0, or maybe even just 8.0.

It's very cool to write a trigger or function in PHP, then write an app in php that calls postgres, which calls php, which...

well anyway, you get the picture.

And then there's pltcl, plR, plruby, plpgsql, plsh, plJ, and a few others I can't remember right now.

It's funny that postgresql has more languages capable of being used inside it than .net probably does. hehe

Heh, yeah. 🙂 I hadn't heard about plruby or plsh - I'll have to check into those. It appears with plphp they're just supporting 8.x from now on - I got a message from them saying the latest version is 1.1 (as opposed to 7.x/8.x versions) and it only supports 8.0.

Weedpacket

Of course, the hard part about translating a POSIX regexp into PCRE syntax is attaching the // expression delimiters; there's therefore not a lot of point using both.

Going the other way is a sight more complicated.

The fact that there are more PCRE-based functions than POSIXregexp-based ones is more cosmetic than anything. But then so are the differences in syntax.

Sxooter

Having played with 8.0 I have to say I'm pretty damned impressed. Faster, more features, and the docs just keep getting better.

dalecosp

Originally posted by Weedpacket
Of course, the hard part about translating a POSIX regexp into PCRE syntax is attaching the // expression delimiters; there's therefore not a lot of point using both.

Going the other way is a sight more complicated.

If one can read it at all 😃

The fact that there are more PCRE-based functions than POSIXregexp-based ones is more cosmetic than anything. But then so are the differences in syntax.

I guess so; sooner or later it's all an "off" or an "on" anyway, right?

csn

Originally posted by Sxooter
Having played with 8.0 I have to say I'm pretty damned impressed. Faster, more features, and the docs just keep getting better.

No problems at all? I'm always leary to upgrade to Major.0.x releases right away. PG seems to have transitioned to 8 rather smoothly though. I'll probably upgrade real soon.

Sxooter

I haven't had any problems, but our usage is pretty straight forward.

While I've seen a few issues go by in the lists, now that 8.0.2 is out things seem to be settling down. I'll probably start testing 8.0.3 or 4 for promotion to production in the next few months...

Just the $ quoting mechanism is worth the upgrade.

And since we run Slon, It's possible to use that to test the new version as well as bring the slaves up to speed on data and then convert over late at night.