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Re: Advising in cc-awk.el and namespace
From: |
Alan Mackenzie |
Subject: |
Re: Advising in cc-awk.el and namespace |
Date: |
Thu, 10 Jul 2003 19:31:48 +0000 (GMT) |
[emacs-devel added to the To:]
On Wed, 9 Jul 2003, Stefan Monnier wrote:
>Regarding c-awk-advise-fl-for-awk-region:
A quick summary for others: c-awk-advise-fl-for-awk-region is a macro in
cc-awk.el which advises four font-lock functions (e.g.
font-lock-after-change-function) which get called as
after-change-functions. The advice changes the BEGIN and END arguments
to encompass the complete region which needs refontifying. This is done
by syntactically analysing the AWK mode buffer.
>It would really be helpful if package maintainers could tell us when
>they need an `advice'. It's generally a sign of a shortcoming in the
>basic functionality and so we need to know about it.
I posted "Subject: Font-lock: Major mode should be able to specify
region to fontify." in gnu.emacs.bug on 10 May 2002 21:31:03 +0200. This
post contained tentative patches for font-lock.el, jit-lock.el and
lazy-lock.el. It didn't spark off much discussion.
Personally, I dislike the way font-locking is done at the moment.
jit-lock-mode, though it speeds up the response of Emacs when first
loading a file, is very wasteful of processor cycles. On my 166MHz
machine (OK - but _somebody_'s got to keep pace with Dan J. :-), if I
load a large file (say, ..../emacs/src/keyboard.c) wait for jit-lock to
finish fontifying it in the background, then make a small change near the
beginning of this file, needlessly refontifying ~320kBytes consumes ~55%
of the CPU's power for 3½ minutes.
I have jit-lock-defer-contextually set to t, which is what causes the
above. However, if the major mode were to specify the region to
font-lock, jit-lock deferred "contextual" fontification would never be
needed.
Also, jit-lock sometimes MIS-fontifies code (for example, in Texinfo
mode, if Auto Fill mode breaks up an @code{...} thing, for example, the
new line gets the proper face to begin with, but loses it 3 seconds
later. This happens because jit-lock yanks that line from its syntactic
context before refontifying it. I'm talking about the jit-lock that was
shipped with Emacs 21.1. Sorry if these things have since been fixed.
[ .... ]
> Stefan
--
Alan Mackenzie (Munich, Germany)
- Re: Advising in cc-awk.el and namespace,
Alan Mackenzie <=