Re: [HACKERS] regular expressions from hell

> I've noticed there are no less then 10^10 regex implementations.
> Is there a standard? Does ANSI have a regexp standard, or is there
> a regex standard in the ANSI SQL spec? What do we use?
>
> Personally, I'm a perl guy, so everytime I have to bend my brain to
> some other regex syntax, I get a headache. As part of my perl PL
> package, perl regexps will be included as a set of operators.
>
> Is there interest in the release of perl-style regexp operators for
> postgres before the PL is completed? Note that this requires the
> entire perl library to be loaded when the operator is used (possibly
> expensive). But, if you have a shared perl library, this only has to
> happen once.

Well, not to bring this up for discussion again, but there is apparently
a Posix standard, and even better a free implementation:

Article 10705 of comp.os.linux.misc:
Newsgroups: gnu.announce,gnu.utils.bug,comp.os.linux.misc,alt.sources.d
Subject: Rx 1.9
Date: Wed, 10 Jun 1998 10:40:00 -0700 (PDT)
Approved: info-gnu(at)gnu(dot)org

The latest version of Rx, 1.9, is available on the web at:

http://users.lanminds.com/~lord
ftp://emf.net/users/lord/src/rx-1.9.tar.gz
and at ftp://ftp.gnu.org/pub/gnu/rx-1.9.tar.gz and mirrors of that
site (see list below).

Rx is a regexp pattern matching library. The library exports these
functions which are standardized by Posix:

regcomp - compile a regexp
regexec - search for a match
regfree - release storage for a regexp
regerr - translate error codes to strings

The library exports many other functions as well, and does a lot
more than Posix requires.

RECENT CHANGES

1. Rx 1.9
Recent changes: More "dead code" was recently discarded,
and the remaining code simplified.

Benchmark comparisons to GNU regex and older
versions of Rx were added to the distribution.

0. Rx 1.8
Recent changes: Various bug-fixes and small performance improvements.
A great deal of "dead code" was recently discarded,
making the size of the Rx library smaller and the
source easier to maintain (in theory).

[ Most GNU software is compressed using the GNU `gzip' compression program.
Source code is available on most sites distributing GNU software.
Executables for various systems and information about using gzip can be
found at the URL http://www.gzip.org.

For information on how to order GNU software on CD-ROM and
printed GNU manuals, see http://www.gnu.org/order/order.html
or e-mail a request to: gnu(at)gnu(dot)org

By ordering your GNU software from the FSF, you help us continue to
develop more free software. Media revenues are our primary source of
support. Donations to FSF are deductible on US tax returns.

The above software will soon be at these ftp sites as well.
Please try them before ftp.gnu.org as ftp.gnu.org is very busy!
A possibly more up-to-date list is at the URL
http://www.gnu.org/order/ftp.html

thanx -gnu(at)gnu(dot)org

Here are the mirrored ftp sites for the GNU Project, listed by country:

United States:

California - labrea.stanford.edu/pub/gnu, gatekeeper.dec.com/pub/GNU
Hawaii - ftp.hawaii.edu/mirrors/gnu
Illinois - uiarchive.cso.uiuc.edu/pub/gnu (Internet address 128.174.5.14)
Kentucky - ftp.ms.uky.edu/pub/gnu
Maryland - ftp.digex.net/pub/gnu (Internet address 164.109.10.23)
Michigan - gnu.egr.msu.edu/pub/gnu
Missouri - wuarchive.wustl.edu/systems/gnu
New York - ftp.cs.columbia.edu/archives/gnu/prep
Ohio - ftp.cis.ohio-state.edu/mirror/gnu
Utah - jaguar.utah.edu/gnustuff
Virginia - ftp.uu.net/archive/systems/gnu

Africa:

South Africa - ftp.sun.ac.za/pub/gnu

The Americas:

Brazil - ftp.unicamp.br/pub/gnu
Canada - ftp.cs.ubc.ca/mirror2/gnu
Chile - ftp.inf.utfsm.cl/pub/gnu (Internet address 146.83.198.3)
Costa Rica - sunsite.ulatina.ac.cr/GNU
Mexico - ftp.uaem.mx/pub/gnu

Asia and Australia:

Australia - archie.au/gnu (archie.oz or archie.oz.au for ACSnet)
Australia - ftp.progsoc.uts.edu.au/pub/gnu
Japan - tron.um.u-tokyo.ac.jp/pub/GNU/prep
Japan - ftp.cs.titech.ac.jp/pub/gnu
Korea - cair-archive.kaist.ac.kr/pub/gnu (Internet address 143.248.186.3)
Thailand - ftp.nectec.or.th/pub/mirrors/gnu (Internet address - 192.150.251.32)

Europe:

Austria - ftp.univie.ac.at/packages/gnu
Czech Republic - ftp.fi.muni.cz/pub/gnu/
Denmark - ftp.denet.dk/mirror/ftp.gnu.org/pub/gnu
Finland - ftp.funet.fi/pub/gnu (Internet address 128.214.6.100)
France - ftp.univ-lyon1.fr/pub/gnu
France - ftp.irisa.fr/pub/gnu
Germany - ftp.informatik.tu-muenchen.de/pub/comp/os/unix/gnu/
Germany - ftp.informatik.rwth-aachen.de/pub/gnu
Germany - ftp.de.uu.net/pub/gnu
Greece - ftp.ntua.gr/pub/gnu
Greece - ftp.aua.gr/pub/mirrors/GNU (Internet address 143.233.187.61)
Ireland - ftp.ieunet.ie/pub/gnu (Internet address 192.111.39.1)
Netherlands - ftp.eu.net/gnu (Internet address 192.16.202.1)
Netherlands - ftp.nluug.nl/pub/gnu
Netherlands - ftp.win.tue.nl/pub/gnu (Internet address 131.155.70.100)
Norway - ugle.unit.no/pub/gnu (Internet address 129.241.1.97)
Spain - ftp.etsimo.uniovi.es/pub/gnu
Sweden - ftp.isy.liu.se/pub/gnu
Sweden - ftp.stacken.kth.se
Sweden - ftp.luth.se/pub/unix/gnu
Sweden - ftp.sunet.se/pub/gnu (Internet address 130.238.127.3)
Also mirrors the Mailing List Archives.
Switzerland - ftp.eunet.ch/mirrors4/gnu
Switzerland - sunsite.cnlab-switch.ch/mirror/gnu (Internet address 193.5.24.1)
United Kingdom - ftp.mcc.ac.uk/pub/gnu (Internet address 130.88.203.12)
United Kingdom - unix.hensa.ac.uk/mirrors/gnu
United Kingdom - ftp.warwick.ac.uk (Internet address 137.205.192.14)
United Kingdom - SunSITE.doc.ic.ac.uk/gnu (Internet address 193.63.255.4)

]

-dg

David Gould dg(at)illustra(dot)com 510.628.3783 or 510.305.9468
Informix Software (No, really) 300 Lakeside Drive Oakland, CA 94612
"Don't worry about people stealing your ideas. If your ideas are any
good, you'll have to ram them down people's throats." -- Howard Aiken