From: Michael Heerdegen <michael_heerdegen@web.de>
To: help-gnu-emacs@gnu.org
Subject: Re: `looking-back' strange warning
Date: Fri, 02 Oct 2015 03:19:03 +0200 [thread overview]
Message-ID: <87612q6pa0.fsf@web.de> (raw)
In-Reply-To: jwvk2r6f7qs.fsf-monnier+gmane.emacs.help@gnu.org
Stefan Monnier <monnier@iro.umontreal.ca> writes:
> You can pass (point-min) for the limit if that's what you want.
> Making it optional Encourages people to think that looking-at is just
> like looking-back, with the same performance characteristic, whereas
> making it mandatory encourages people to put a reasonable limit and
> hence avoid pathological behavior at the end of large buffers.
My two cents: Even if you specify an optimal limit, `looking-back' can
still be unnecessarily slow. For example,
(looking-back "xy" 2)
is much slower than
(and (> (point) 2)
(save-excursion
(goto-char (- (point) 2))
(looking-at "xy")))
where "xy" stands for any plain string.
Michael.
next prev parent reply other threads:[~2015-10-02 1:19 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-30 8:25 `looking-back' strange warning Andreas Röhler
2015-10-01 6:20 ` Michael Heerdegen
2015-10-01 6:25 ` Tassilo Horn
2015-10-01 6:50 ` Dmitry Gutov
2015-10-01 7:49 ` Andreas Röhler
2015-10-01 8:20 ` Tassilo Horn
2015-10-01 8:46 ` Andreas Röhler
2015-10-01 9:29 ` Tassilo Horn
2015-10-02 0:10 ` Stefan Monnier
2015-10-02 15:21 ` Tassilo Horn
2015-10-01 16:00 ` Drew Adams
2015-10-01 17:56 ` Dmitry Gutov
2015-10-01 18:24 ` Andreas Röhler
2015-10-01 18:59 ` Dmitry Gutov
2015-10-01 19:55 ` Andreas Röhler
2015-10-01 20:26 ` Dmitry Gutov
2015-10-02 0:15 ` Stefan Monnier
2015-10-02 1:18 ` Michael Heerdegen
2015-10-02 5:13 ` Drew Adams
2015-10-02 20:28 ` Drew Adams
2015-10-02 20:59 ` Tassilo Horn
2015-10-02 21:35 ` Drew Adams
2015-10-03 6:26 ` Tassilo Horn
2015-10-03 6:45 ` Andreas Röhler
2015-10-03 15:20 ` Drew Adams
2015-10-03 15:17 ` Drew Adams
2015-10-02 1:19 ` Michael Heerdegen [this message]
2015-10-02 5:12 ` Drew Adams
2015-10-02 6:16 ` Andreas Röhler
2015-10-02 6:36 ` Michael Heerdegen
2015-10-02 12:46 ` Stefan Monnier
2015-10-02 15:02 ` Drew Adams
2015-10-02 19:08 ` Tom Tromey
2015-10-02 19:33 ` Stefan Monnier
2015-10-03 18:11 ` Stefan Monnier
[not found] ` <mailman.176.1443721449.16064.help-gnu-emacs@gnu.org>
2015-10-01 18:50 ` Barry Margolin
[not found] ` <<barmar-D40496.14502501102015@88-209-239-213.giganet.hu>
2015-10-01 23:42 ` Drew Adams
2015-10-02 0:12 ` Stefan Monnier
2015-10-02 5:10 ` Drew Adams
2015-10-02 12:48 ` Stefan Monnier
2015-10-02 15:03 ` Drew Adams
2015-10-02 15:21 ` Stefan Monnier
2015-10-02 15:24 ` Drew Adams
2015-10-02 19:28 ` Stefan Monnier
2015-10-01 12:35 ` Artur Malabarba
[not found] <<560B9C7F.2060301@easy-emacs.de>
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