Re: reg expr...

"Gwyn Judd" <gwyn@thislove.dyndns.org>
11 Sep 2002 23:19:16 -0400

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Related articles
reg expr... shoaib@students.cs.mu.OZ.AU (Shoaib Ali BURQ) (2002-09-08)
Re: reg expr... gwyn@thislove.dyndns.org (Gwyn Judd) (2002-09-11)
Re: reg expr... sarah@telergy.com (Sarah Thompson) (2002-09-11)
Re: reg expr... torbenm@diku.dk (Torben Ægidius Mogensen) (2002-09-12)
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From: "Gwyn Judd" <gwyn@thislove.dyndns.org>
Newsgroups: comp.compilers
Date: 11 Sep 2002 23:19:16 -0400
Organization: Xtra
References: 02-09-040
Keywords: lex
Posted-Date: 11 Sep 2002 23:19:16 EDT



"Mein Lufkissenfahrzeug ist voller Aale"
said Shoaib Ali BURQ (shoaib@students.cs.mu.OZ.AU) in
> I'm looking for a regular expression that say:
>
> match the line that does not begin with the string {s}
>
> now the way i see it ... if my s = "abc" then i will have to look for
> (a & b) or (ab & not c) or (abc & not wht_spc) ...
>
> but the longer the s the longer the reg expr ... is there another way to
> do this?


This depends on the regular expression dialect. In Perl you might do:


m/^(?!abc)/


These type of extensions are not supported in every language though. Another
way that does not require a look-ahead is:


!m/^abc/


if you need to combine this with some other action, then you have to use two
operators and combine them with "and":


!m/^abc/ and m/something/


--
Gwyn Judd (print `echo 'tjla@guvfybir.qlaqaf.bet' | rot13`)
diplomacy, n:
Lying in state.

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