From: Alan Mackenzie <acm@muc.de>
To: Eli Zaretskii <eliz@gnu.org>
Cc: gregory@heytings.org, emacs-devel@gnu.org
Subject: Re: Major modes using `widen' is a good, even essential, programming practice.
Date: Sun, 7 Aug 2022 17:01:09 +0000 [thread overview]
Message-ID: <Yu/v1bmvRhXq186v@ACM> (raw)
In-Reply-To: <83y1w0w0gk.fsf@gnu.org>
Hello, Eli.
On Sun, Aug 07, 2022 at 18:13:47 +0300, Eli Zaretskii wrote:
> > Date: Sun, 7 Aug 2022 14:59:06 +0000
> > Cc: gregory@heytings.org, emacs-devel@gnu.org
> > From: Alan Mackenzie <acm@muc.de>
> > > jit-lock calls the functions with two arguments, BEG and END, and
> > > expects them to work only on that chunk of text.
> > I don't think you really mean that.
> No, I really do.
> > Consider the second jit-lock chunk
> > at the beginning of xdisp.c. Fontifying that chunk involves looking
> > back 1500 characters before BEG to see that it needs
> > font-lock-comment-face. You might argue that that information will be
> > in a cache anyway, but that's not dependable.
> Either in the cache or in the buffer: the previous chunk was
> fontified, so its end has the font-lock-comment-face. So you know.
No, you don't. The buffer might be being opened by desktop in a large
comment in the middle of the file.
What jit-lock/font-lock actually do at the moment is to widen, then use
syntax-ppss, i.e. in effect scan from BOB.
> > Also, the (BEG END) region will typically get rounded up to whole lines,
> > again "violating" that chunk.
> That's a far cry from going to BOB. And if you ask nicely, we could
> arrange that jit-lock calls you only on line boundaries (unless lines
> are longer than some reasonable value).
The search for line boundaries is done by font-lock.el.
> > In principle, font-lock needs to look outside of (BEG END).
> No, it doesn't. A string cannot begin before a beginning of a
> function, for example. And if you need to go too far, just give up
> and blame the user who writes such code. It is much better than
> letting every use of CC Mode wait because once in a blue moon someone
> could have a very long string.
That "needing to go too far" is an instantaneous jump, not a scanning.
The string start will be in a parse-partial-sexp result somewhere.
Sometimes people write long strings. They certainly write long comments.
--
Alan Mackenzie (Nuremberg, Germany).
next prev parent reply other threads:[~2022-08-07 17:01 UTC|newest]
Thread overview: 136+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-06 20:13 Major modes using `widen' is a good, even essential, programming practice Alan Mackenzie
2022-08-06 21:05 ` Stefan Monnier
2022-08-07 6:03 ` Eli Zaretskii
2022-08-07 13:31 ` Gregory Heytings
2022-08-07 14:13 ` Alan Mackenzie
2022-08-07 14:20 ` Eli Zaretskii
2022-08-07 14:59 ` Alan Mackenzie
2022-08-07 15:13 ` Eli Zaretskii
2022-08-07 17:01 ` Alan Mackenzie [this message]
2022-08-07 17:23 ` Eli Zaretskii
2022-08-07 17:53 ` Dmitry Gutov
2022-08-07 18:00 ` Eli Zaretskii
2022-08-07 18:05 ` Dmitry Gutov
2022-08-07 18:37 ` Eli Zaretskii
2022-08-07 23:02 ` Stefan Monnier
2022-08-07 18:49 ` Óscar Fuentes
2022-08-07 18:59 ` Eli Zaretskii
2022-08-07 18:56 ` Lars Ingebrigtsen
2022-08-07 19:20 ` Alan Mackenzie
2022-08-07 19:26 ` Dmitry Gutov
2022-08-08 2:36 ` Eli Zaretskii
2022-08-08 9:58 ` Alan Mackenzie
2022-08-08 11:39 ` Eli Zaretskii
2022-08-08 15:05 ` CC Mode with font-lock-maximum-decoration 2 [Was Major modes using `widen' is a good, even essential, programming practice.] Alan Mackenzie
2022-08-08 15:51 ` Gregory Heytings
2022-08-08 16:05 ` CC Mode with font-lock-maximum-decoration 2 Alan Mackenzie
2022-08-08 16:50 ` Gregory Heytings
2022-08-09 19:49 ` Gregory Heytings
2022-08-08 17:15 ` CC Mode with font-lock-maximum-decoration 2 [Was Major modes using `widen' is a good, even essential, programming practice.] Eli Zaretskii
2022-08-08 17:41 ` Eli Zaretskii
2022-08-08 18:41 ` CC Mode with font-lock-maximum-decoration 2 Alan Mackenzie
2022-08-08 18:51 ` Eli Zaretskii
2022-08-08 19:09 ` Alan Mackenzie
2022-08-09 2:24 ` Eli Zaretskii
2022-08-09 8:00 ` Alan Mackenzie
2022-08-09 11:07 ` Eli Zaretskii
2022-08-09 11:24 ` Alan Mackenzie
2022-08-09 11:57 ` Eli Zaretskii
2022-08-09 16:36 ` Alan Mackenzie
2022-08-09 16:59 ` Eli Zaretskii
2022-08-09 17:43 ` Alan Mackenzie
2022-08-09 17:55 ` Eli Zaretskii
2022-08-10 0:22 ` Why tree-sitter instead of Semantic? (was Re: CC Mode with font-lock-maximum-decoration 2) Lynn Winebarger
2022-08-10 2:14 ` Po Lu
2022-08-10 2:42 ` Eli Zaretskii
2022-08-10 10:05 ` Lynn Winebarger
2022-08-10 10:49 ` Po Lu
2022-08-10 11:31 ` Eli Zaretskii
2022-08-12 12:37 ` Lynn Winebarger
2022-08-12 12:50 ` Eli Zaretskii
2022-08-12 21:50 ` Ideal performance of ELisp (was: Why tree-sitter instead of Semantic? (was Re: CC Mode with font-lock-maximum-decoration 2)) Stefan Monnier
2022-08-12 23:26 ` Lynn Winebarger
2022-08-13 2:11 ` Ideal performance of ELisp Stefan Monnier
2022-08-13 10:51 ` Lynn Winebarger
2022-08-13 11:13 ` Lynn Winebarger
2022-08-13 14:07 ` Stefan Monnier
2022-08-13 14:56 ` Lynn Winebarger
2022-08-16 16:46 ` Lynn Winebarger
2022-08-16 17:22 ` Stefan Monnier
2022-08-17 12:41 ` Lynn Winebarger
2022-08-17 14:04 ` Stefan Monnier
2022-08-17 14:19 ` Mattias Engdegård
2022-08-17 22:18 ` Stefan Monnier
2022-08-17 14:25 ` Lynn Winebarger
2022-08-13 4:39 ` Ideal performance of ELisp (was: Why tree-sitter instead of Semantic? (was Re: CC Mode with font-lock-maximum-decoration 2)) Ihor Radchenko
2022-08-13 7:45 ` Ideal performance of ELisp Philip Kaludercic
2022-08-13 11:58 ` Ihor Radchenko
2022-08-13 14:15 ` Stefan Monnier
2022-08-14 9:25 ` Andrea Corallo
2022-08-14 9:34 ` Ihor Radchenko
2022-08-14 13:01 ` Eli Zaretskii
2022-08-16 19:23 ` Andrea Corallo
2022-08-14 13:01 ` Stefan Monnier
2022-08-16 8:59 ` Andrea Corallo
2022-08-16 9:50 ` Ihor Radchenko
2022-08-16 18:21 ` Andrea Corallo
2022-08-17 9:48 ` Ihor Radchenko
2022-08-17 12:02 ` Eli Zaretskii
2022-08-16 15:06 ` Lynn Winebarger
2022-08-16 18:24 ` Andrea Corallo
2022-08-17 13:04 ` Lynn Winebarger
2022-08-17 14:18 ` Andrea Corallo
2022-08-18 12:17 ` Lynn Winebarger
2022-08-12 16:00 ` Why tree-sitter instead of Semantic? (was Re: CC Mode with font-lock-maximum-decoration 2) Akib Azmain Turja
2022-08-12 19:06 ` tomas
2022-08-13 4:41 ` Akib Azmain Turja
2022-08-13 5:14 ` tomas
2022-08-13 11:57 ` Lynn Winebarger
2022-08-13 14:28 ` Akib Azmain Turja
2022-08-14 19:24 ` Eric Ludlam
2022-08-16 10:42 ` Lynn Winebarger
2022-08-17 1:56 ` Eric Ludlam
2022-08-10 17:03 ` Tassilo Horn
2022-08-13 14:40 ` Jostein Kjønigsen
2022-08-14 1:23 ` Po Lu
2022-08-16 9:06 ` Lynn Winebarger
2022-08-16 11:05 ` Po Lu
2022-08-16 11:41 ` Eli Zaretskii
2022-08-16 16:33 ` Lynn Winebarger
2022-08-16 17:19 ` Stefan Monnier
2022-08-16 17:40 ` Lynn Winebarger
2022-08-17 1:41 ` Eric Ludlam
2022-08-18 12:34 ` Lynn Winebarger
2022-08-20 13:15 ` Eric Ludlam
2022-08-08 18:20 ` CC Mode with font-lock-maximum-decoration 2 Alan Mackenzie
2022-08-07 20:17 ` Major modes using `widen' is a good, even essential, programming practice Gregory Heytings
2022-08-07 20:46 ` Alan Mackenzie
2022-08-07 20:53 ` Gregory Heytings
2022-08-08 2:37 ` Eli Zaretskii
2022-08-08 10:33 ` Alan Mackenzie
2022-08-08 11:41 ` Eli Zaretskii
2022-08-07 23:21 ` Stefan Monnier
2022-08-08 2:29 ` Eli Zaretskii
2022-08-08 9:25 ` Stefan Monnier
2022-08-08 11:16 ` Lynn Winebarger
2022-08-08 11:47 ` Eli Zaretskii
2022-08-08 14:24 ` Lynn Winebarger
2022-08-08 11:30 ` Eli Zaretskii
2022-08-08 12:05 ` Stefan Monnier
2022-08-08 12:40 ` Eli Zaretskii
2022-08-08 17:22 ` Stefan Monnier
2022-08-08 17:34 ` Eli Zaretskii
2022-08-08 21:16 ` Dmitry Gutov
2022-08-09 11:30 ` Eli Zaretskii
2022-08-09 14:38 ` Dmitry Gutov
2022-08-09 16:12 ` Eli Zaretskii
2022-08-09 16:52 ` Dmitry Gutov
2022-08-09 17:05 ` Eli Zaretskii
2022-08-09 18:52 ` Dmitry Gutov
2022-08-09 19:46 ` Gregory Heytings
2022-08-08 10:38 ` Alan Mackenzie
2022-08-08 11:49 ` Eli Zaretskii
2022-08-08 10:41 ` Gregory Heytings
2022-08-07 17:57 ` Dmitry Gutov
2022-08-22 11:26 ` Alan Mackenzie
2022-08-22 23:59 ` Dmitry Gutov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Yu/v1bmvRhXq186v@ACM \
--to=acm@muc.de \
--cc=eliz@gnu.org \
--cc=emacs-devel@gnu.org \
--cc=gregory@heytings.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).