From: Eli Zaretskii <eliz@gnu.org>
To: Dmitry Gutov <dgutov@yandex.ru>
Cc: casouri@gmail.com, 60953@debbugs.gnu.org
Subject: bug#60953: The :match predicate with large regexp in tree-sitter font-lock seems inefficient
Date: Wed, 25 Jan 2023 14:49:59 +0200 [thread overview]
Message-ID: <83wn5ag4nc.fsf@gnu.org> (raw)
In-Reply-To: <b1dc100e-1ee9-dc89-00b6-25bb7864e90b@yandex.ru> (message from Dmitry Gutov on Wed, 25 Jan 2023 05:48:13 +0200)
> Cc: 60953@debbugs.gnu.org
> Date: Wed, 25 Jan 2023 05:48:13 +0200
> From: Dmitry Gutov <dgutov@yandex.ru>
>
> > We can probably match the regexp in-place, just limit the match to the range of the node.
>
> That's what I tried to do in the patch attached to the first message:
> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=60953#5
>
> But the effect on performance was surprisingly hard to notice. It also
> broke the actual highlighting, but that's probably because the regexp
> uses anchors \` and \', which don't really work for fast_looking_at
> calls inside a buffer.
The condition for a match in that patch is not correct, AFAIU:
if (val >= 0)
return true;
else
return false;
It should be "if (val > 0)" instead, since fast_looking_at returns the
number of characters that matched (unlike fast_string_match in the
original code, which returns the _index_ of the match).
Also, fast_string_match is capable of succeeding if the match begins
not at the first character, whereas fast_looking_at does an anchored
match. Do we expect the text to match from its beginning in this
case? If not, I think the replacement didn't do what the original
code does, and you should have used search_buffer or maybe
search_buffer_re instead.
next prev parent reply other threads:[~2023-01-25 12:49 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-20 3:53 bug#60953: The :match predicate with large regexp in tree-sitter font-lock seems inefficient Dmitry Gutov
2023-01-24 4:04 ` Dmitry Gutov
2023-01-25 3:13 ` Yuan Fu
2023-01-25 3:48 ` Dmitry Gutov
2023-01-25 12:49 ` Eli Zaretskii [this message]
2023-01-25 23:21 ` Dmitry Gutov
2023-01-26 6:50 ` Eli Zaretskii
2023-01-26 7:17 ` Yuan Fu
2023-01-26 8:10 ` Eli Zaretskii
2023-01-26 17:15 ` Dmitry Gutov
2023-01-26 18:24 ` Eli Zaretskii
2023-01-26 19:35 ` Dmitry Gutov
2023-01-26 20:01 ` Eli Zaretskii
2023-01-26 21:26 ` Dmitry Gutov
2023-01-30 0:49 ` Dmitry Gutov
2023-01-30 14:06 ` Eli Zaretskii
2023-01-30 14:47 ` Dmitry Gutov
2023-01-30 15:08 ` Eli Zaretskii
2023-01-30 17:15 ` Dmitry Gutov
2023-01-30 17:49 ` Eli Zaretskii
2023-01-30 18:20 ` Dmitry Gutov
2023-01-30 18:42 ` Eli Zaretskii
2023-01-30 19:01 ` Dmitry Gutov
2023-01-30 19:05 ` Eli Zaretskii
2023-01-30 19:58 ` Dmitry Gutov
2023-01-30 23:57 ` Yuan Fu
2023-01-31 0:44 ` Dmitry Gutov
2023-01-31 3:23 ` Eli Zaretskii
2023-01-31 18:16 ` Dmitry Gutov
2023-02-01 2:39 ` Dmitry Gutov
2023-02-01 13:39 ` Eli Zaretskii
2023-02-01 15:13 ` Dmitry Gutov
2023-02-01 21:20 ` Dmitry Gutov
2023-02-02 2:16 ` Yuan Fu
2023-02-02 6:34 ` Eli Zaretskii
2023-02-02 12:12 ` Dmitry Gutov
2023-02-02 14:23 ` Eli Zaretskii
2023-02-02 17:03 ` Dmitry Gutov
2023-02-02 17:26 ` Eli Zaretskii
2023-02-02 17:53 ` Dmitry Gutov
2023-02-02 18:03 ` Eli Zaretskii
2023-02-02 19:44 ` Dmitry Gutov
2023-02-01 13:10 ` Eli Zaretskii
2023-02-01 15:15 ` Dmitry Gutov
2023-01-26 17:12 ` Dmitry Gutov
2023-01-26 18:07 ` Dmitry Gutov
2023-01-26 20:46 ` Dmitry Gutov
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