From: Alan Mackenzie <acm@muc.de>
To: Dmitry Gutov <dgutov@yandex.ru>
Cc: emacs-devel@gnu.org, Gregory Heytings <gregory@heytings.org>
Subject: Re: Major modes using `widen' is a good, even essential, programming practice.
Date: Mon, 22 Aug 2022 11:26:59 +0000 [thread overview]
Message-ID: <YwNoA1cvCNs03Jlw@ACM> (raw)
In-Reply-To: <bf41df0f-af91-0d22-e0ac-9497221ae22d@yandex.ru>
Hello, Dmitry.
A bit late, but ....
On Sun, Aug 07, 2022 at 20:57:59 +0300, Dmitry Gutov wrote:
> On 06.08.2022 23:13, Alan Mackenzie wrote:
> > Narrowing is primarily a user feature. Users can arbitrarily narrow a
> > buffer to ANY contiguous region of text. So when a major mode needs to
> > examine text even slightly distant from point, it MUST widen, to be sure
> > that the text to be examined is within the visible region.
> Now wouldn't it have been nice if user-level narrowing didn't create an
> *actual* narrowing but only some visual perception of it? IIRC there is
> a third-party package which implements this approach.
I'm not convinced, given how well narrowing currently works. I don't
think it's useful to debate how things _would_ have been, when they are
currently very different.
> From what I've seen of feature requests related to narrowing in my
> packages, it's always along the lines of "please add (save-restriction
> (widen) ...) around the whole implementation".
> Are there actually user-level commands which should not ignore
> narrowing?
Yes, lots and lots of them. goto-char, isearch, occur, and many others.
It might be easier to answer the question which user-level commands are
not restricted by narrowing.
> If not, it would be better if user-level narrowing was implemented as
> something else (e.g. two invisible overlays). Then all other code
> wouldn't have to bother with undoing it.
But "all" other code would instead have to take account of the invisible
overlays instead. I don't think this would be better. It would involve
a _lot_ of work to implement and we'd be left with some other
inconveniences instead of the currently perceived ones.
--
Alan Mackenzie (Nuremberg, Germany).
next prev parent reply other threads:[~2022-08-22 11:26 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
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 [this message]
2022-08-22 23:59 ` Dmitry Gutov
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