Re: Our regex vs. POSIX on "longest match"

From: hubert depesz lubaczewski <depesz(at)depesz(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Brendan Jurd <direvus(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Our regex vs. POSIX on "longest match"
Date: 2012-03-04 18:37:19
Message-ID: 20120304183719.GA10935@depesz.com
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On Sun, Mar 04, 2012 at 12:34:22PM -0500, Tom Lane wrote:
> Well, that's just an arbitrary example. The cases I remember people
> complaining about in practice were the other way round: greedy
> quantifier followed by non-greedy, and they were unhappy that the
> non-greediness was effectively not respected (because the overall RE was
> taken as greedy). So you can't fix the issue by pointing to POSIX and
> saying "overall greedy is always the right thing".

I was one of the complaining, and my point was that deciding for whole
regexp whether it's greedy or non-greedy is a bug (well, it might be
documented, but it's still *very* unexpected).

I stand on position that mixing greedy and non-greedy operators should
be possible, and that it should work according to POLA - i.e. greedines
of given atom shouldn't be influenced by other atoms.

Best regards,

depesz

--
The best thing about modern society is how easy it is to avoid contact with it.
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