GNU bug report logs - #18013
looking-back is inefficient

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Message #24 received at 18013 <at> debbugs.gnu.org (full text, mbox):

From: Andreas Schwab <schwab <at> suse.de>
To: Kevin Rodgers <kevin.d.rodgers <at> gmail.com>
Cc: 18013 <at> debbugs.gnu.org
Subject: Re: bug#18013: 24.3.92;
 looking-back "[^\n]" taking a lot of time in large buffers
Date: Tue, 15 Jul 2014 09:21:12 +0200

Kevin Rodgers <kevin.d.rodgers <at> gmail.com> writes:

> On 7/14/14 5:12 AM, Nicolas Richard wrote:
>> As you see it takes more than 8 seconds on my system, most of that time
>> is spent looking-back (inserting the file is quick).
>>
>> (looking-back "[^\n]") is bad code, so I totally deserve this. Still, is
>> it possible to make the search smarter when the match is supposed to be
>> "anchored" at point ? Otherwise let's just close this bug.
>
> Use "\\=" to match the empty string at point.

That's what looking-back does.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab <at> suse.de
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