From: Alan Mackenzie <acm@muc.de>
Cc: Richard Stallman <rms@gnu.org>, emacs-devel@gnu.org
Subject: Re: Last steps for pretesting (font-lock-extend-region-function)
Date: Wed, 26 Apr 2006 08:30:25 +0000 (GMT) [thread overview]
Message-ID: <Pine.LNX.3.96.1060426074539.345D-100000@acm.acm> (raw)
In-Reply-To: <87u08harmc.fsf-monnier+emacs@gnu.org>
Hi, Stefan!
On Wed, 26 Apr 2006, Stefan Monnier wrote:
>>> I'm not saying the hook is a kludge: I'm saying the code that uses it is
>>> a kludge, compared to the code that uses font-lock-multiline.
>> OK. I feel that existing code in AWK Mode is natural. (OK, I wrote it,
>> so I'm not in a position to judge it dispassionately, but ...). It notes
>> the logical EOL before a change. It notes the logical EOL after a
>> change. The later one is the end position for fontification.
>Why doesn't the BOL before change matter?
Maybe it does/would do in some major modes. It happens not to have any effect
in AWK.
>Why does the EOL before change matter?
Because a buffer change can alter this EOL's syntactic context.
>> By contrast, the f-l-multiline method (ab)uses the structure for setting
>> face properties to set region boundaries for possible future changes.
>Abuses the structure of what?
font-lock-keywords. The purpose of this structure is to fontify strings
matching specific regular expressions. Using it to expand the region to
be font-locked at a future fontification seems utterly disconnected with
this purpose.
>There two issues about multiline elements:
>- properly notice them when they appear
>- properly *re*fontify them when they change
I cannot bring myself to consider the extension of a font lock region as
"the manipulation of a multiline element". It just feels too contorted.
I have always understood the term "multiline element" to mean an element
within the font-lock region which crosses a line boundary. [Such things
occur a lot in Texinfo Mode, for example, and turning on the
f-l-multiline variable does indeed make these elements fontify properly.]
>The first is taken care of by font-lock-fontify-region-function.
The AWK Mode regular expressions, even those that can straddle line
breaks, match just fine without having to turn on the f-l-multiline
variable.
>The second talks about *re*fontification, so it's natural that it would
>involves saving some info during fontification for the next time around.
I think I would agree, except that font-lock brutally erases these
properties at every fontification, only to have to recalculate them.
This wastes processor time, probably quite a lot of it. What is the
point of doing this, unless there has been a buffer change? The same
applies to the syntax-table property.
>Doing it in a-c-f is fundamentally not the right place since it doesn't
>know whether and how the changed text was fontified: it works, of
>course, but it's not particularly more natural.
To know how text is to be refontified, you need to know how it has been
changed. before/after-change-functions is a perfectly natural place to
find this out.
> Stefan
--
Alan.
next prev parent reply other threads:[~2006-04-26 8:30 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-17 0:56 Last steps for pretesting Richard Stallman
2006-04-17 8:01 ` Ramprasad B
2006-04-17 8:37 ` Eli Zaretskii
2006-04-18 1:42 ` Richard Stallman
2006-04-19 3:54 ` Ramprasad B
2006-04-19 15:40 ` Richard Stallman
2006-04-20 5:23 ` Ramprasad B
2006-04-18 17:31 ` Bill Wohler
2006-04-19 17:02 ` Alan Mackenzie
2006-04-19 21:23 ` Stefan Monnier
2006-04-19 21:30 ` David Kastrup
2006-04-20 21:35 ` Stefan Monnier
2006-04-20 21:37 ` David Kastrup
2006-04-20 21:44 ` Stefan Monnier
2006-04-20 21:46 ` David Kastrup
2006-04-20 22:50 ` Alan Mackenzie
2006-04-19 22:43 ` Last steps for pretesting (font-lock-extend-region-function) Alan Mackenzie
2006-04-20 9:13 ` Alan Mackenzie
2006-04-20 17:46 ` Stefan Monnier
2006-04-20 18:12 ` Alan Mackenzie
2006-04-20 20:58 ` Stefan Monnier
2006-04-20 22:40 ` Alan Mackenzie
2006-04-20 23:34 ` Stefan Monnier
2006-04-21 7:58 ` Alan Mackenzie
2006-04-21 12:18 ` Stefan Monnier
2006-04-21 19:51 ` Alan Mackenzie
2006-04-21 22:28 ` Stefan Monnier
2006-04-24 19:28 ` Alan Mackenzie
2006-04-24 21:06 ` Stefan Monnier
2006-04-25 6:21 ` Ralf Angeli
2006-04-25 10:53 ` Alan Mackenzie
2006-04-25 18:37 ` Ralf Angeli
2006-04-25 22:00 ` Alan Mackenzie
2006-04-26 6:14 ` Ralf Angeli
2006-04-25 19:26 ` Stefan Monnier
2006-04-25 20:10 ` font-lock-multiline for cc-awk Stefan Monnier
2006-04-26 7:37 ` Alan Mackenzie
2006-04-26 13:55 ` Stefan Monnier
2006-04-25 19:23 ` Last steps for pretesting (font-lock-extend-region-function) Stefan Monnier
2006-04-25 20:18 ` Stefan Monnier
2006-04-25 11:33 ` Alan Mackenzie
2006-04-25 11:59 ` David Kastrup
2006-04-25 12:33 ` Stefan Monnier
2006-04-25 14:07 ` Alan Mackenzie
2006-04-25 16:05 ` Stefan Monnier
2006-04-25 16:09 ` Stefan Monnier
2006-04-25 21:52 ` Alan Mackenzie
2006-04-25 21:49 ` Alan Mackenzie
2006-04-26 4:50 ` Stefan Monnier
2006-04-24 21:20 ` Stefan Monnier
2006-04-25 7:45 ` Alan Mackenzie
2006-04-25 12:12 ` Stefan Monnier
2006-04-25 21:15 ` Alan Mackenzie
2006-04-26 4:33 ` Stefan Monnier
2006-04-26 8:30 ` Alan Mackenzie [this message]
2006-04-26 13:36 ` Stefan Monnier
2006-04-24 21:33 ` Stefan Monnier
2006-04-25 7:27 ` Alan Mackenzie
2006-04-25 12:03 ` Stefan Monnier
2006-04-25 13:14 ` Alan Mackenzie
2006-04-26 0:22 ` Miles Bader
2006-04-25 4:39 ` Tomas Zerolo
2006-04-25 19:02 ` Ralf Angeli
2006-04-25 19:30 ` Stefan Monnier
2006-04-25 20:12 ` Ralf Angeli
2006-04-25 20:26 ` Stefan Monnier
2006-04-25 20:58 ` Ralf Angeli
2006-04-25 21:11 ` Stefan Monnier
2006-04-25 22:30 ` Alan Mackenzie
2006-04-26 4:25 ` Stefan Monnier
2006-04-26 7:44 ` Alan Mackenzie
2006-04-25 22:16 ` Alan Mackenzie
2006-04-26 4:36 ` Stefan Monnier
2006-04-21 23:14 ` Drew Adams
2006-04-19 22:53 ` Last steps for pretesting (true file names in load-history?) Alan Mackenzie
2006-04-20 1:14 ` Last steps for pretesting Richard Stallman
2006-04-24 17:52 ` Richard Stallman
2006-04-20 10:54 ` Reiner Steib
2006-04-21 0:10 ` Richard Stallman
2006-04-21 5:46 ` David Kastrup
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