GNU bug report logs - #20146
font-lock-extend-jit-lock-region-after-change: results are discarded instead of being returned.

Previous Next

Full log

Message #14 received at 20146 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
To: Alan Mackenzie <acm <at> muc.de>
Cc: 20146 <at> debbugs.gnu.org
Subject: Re: bug#20146: font-lock-extend-jit-lock-region-after-change: results
 are discarded instead of being returned.
Date: Fri, 20 Mar 2015 15:39:10 -0400

> Perhaps we could implement the convention that when a major mode has
> positively set the font-lock region's start and end points, these should
> be accepted by F/J-lock, but when not, F/J-lock should be free to alter
> them (as it typically does now).

No the core of the API is font-lock-fontify-region and it should work
with *any* bounds (i.e. if these need to be extended, it should be done
by font-lock-extend-region-function).

Jit-lock is implemented on top of that API and is hence free to use any
bounds it sees fit.

If you rely on more specific bounds being passed to
font-lock-fontify-region, that means you have a problem on your side.

> The existence of font-lock-extend-after-change-region-function makes
> this distinction possible.

The existence of font-lock-extend-after-change-region-function is an
error on my part (More specifically the result of a weakness on my part:
when you requested this feature, I added
font-lock-extend-region-function (which was the right fix) and
reluctantly accepted to also add
font-lock-extend-after-change-region-function just out of tiredness of
arguing that it was the wrong solution).


        Stefan

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.