From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Josh Jore <josh(at)greentechnologist(dot)org>, pgsql-general(at)postgresql(dot)org |
Subject: | Re: Psql regex is NFA or DFA? |
Date: | 2002-09-10 17:21:11 |
Message-ID: | 200209101721.g8AHLBg29786@candle.pha.pa.us |
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Lists: | pgsql-general |
Tom Lane wrote:
> Josh Jore <josh(at)greentechnologist(dot)org> writes:
> > So I've finished reading Jeffery Friedl's _Mastering Regular Expressions_
> > and while I don't need regex in PostgreSQL I know I'll do it for something
> > - eventually. The book makes a distinction between DFA, POSIX NFA and
> > Traditional NFA and then ascribes some properties and behaviours to each.
> > So what sort does PostgreSQL have?
>
> Well, you could read the code (src/backend/regex), or you could apply
> the tests that Friedl suggests to distinguish the type of an unknown
> engine ...
>
> My guess is that it's an NFA, but I dunno if Spencer did the POSIX
> semantics or not.
I am continuing to talk to Henry about getting a newer version of his
regex library. He is working on it but is not yet finished.
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073
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