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From: Tassilo Horn <tassilo@member.fsf.org>
To: help-gnu-emacs@gnu.org
Subject: Re: does emacs regular expression support (?!expression)
Date: Thu, 02 Feb 2012 22:45:04 +0100	[thread overview]
Message-ID: <87ipjo52qn.fsf@thinkpad.tsdh.de> (raw)
In-Reply-To: m31uqdlyyn.fsf@passepartout.tim-landscheidt.de

Tim Landscheidt <tim@tim-landscheidt.de> writes:

Hi Tim,

>> It would be more helpful if you'd tell us what (?!expression) would
>> match, preferably with some examples.  Syntactically, emacs regexp's shy
>> groups look similar.  The regular expression
>
>>   "\\(:?foo\\|bar\\)\\([0-9]+\\)"

BTW, that should have been (?:...).

>> matches "foo19" or "bar23", but doesn't capture foo or bar, so that
>> (match-string 1) is the number.
>
> In Perl, "(?!pattern)" is a zero-width negative look-ahead
> assertion.  Emacs does not support these AFAIK.

I see.  So when you do /foo(?!bar)/ in Perl, you'd need to do
"foo\\(?:[^b][^a][^r]\\)" in elisp.

Bye,
Tassilo




  reply	other threads:[~2012-02-02 21:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-02 14:02 does emacs regular expression support (?!expression) 土星五号
2012-02-02 18:56 ` Tassilo Horn
2012-02-02 21:14   ` Tim Landscheidt
2012-02-02 21:45     ` Tassilo Horn [this message]
2012-02-02 22:11       ` Tim Landscheidt
2012-02-02 22:17         ` Tim Landscheidt
2012-02-03  0:37       ` Kevin Rodgers
2012-02-03  2:12         ` 土星五号
2012-02-03  8:30           ` Thien-Thi Nguyen
2012-02-03 11:17             ` Tim Landscheidt
2012-02-03 11:48               ` Thien-Thi Nguyen
2012-02-04 10:12                 ` Tim Landscheidt
2012-02-04 12:16                   ` 土星五号
2012-02-04 15:26                   ` Thien-Thi Nguyen
2012-02-05 11:57                     ` Tim Landscheidt
2012-02-02 22:09     ` Glenn Morris

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