Re: Partly deferred font-locking?

[Michael Heerdegen <michael_heerdegen@web.de>]

Eli Zaretskii <eliz@gnu.org> writes:

> My point is that your example is the exception rather than the rule.
> Fontifications almost never access files or do any other fancy stuff
> like that.  At least AFAIK.

Yes yes, all good.

But I missed a feature like this for several times.  One application is
syntax-based highlighting of el-search matches, for example.  Or a
hi-lock like thing but not restricted to simple regexps.

I implemented the el-search hi-lock library more or less without
font-lock, but were reinventing parts of it.

Maybe there would be more use cases if Emacs would support this kind of
highlighting, I don't know.


If you wanted to add some more expensive on-the-fly highlighting, how
would you do it?

Currently, one can't use font-lock directly: when the additional deferred
highlighting doesn't happen for a buffer chunk but normal font-locking
was performed, the deferred highlighting would not be triggered again
when that buffer area gets visible again.
So I think I would have to remember which parts of the buffer where
treated by the deferred highlighting by myself, I would have to keep
that information in an additional variable.  That feels a bit odd
since this is one of the things that font-lock naturally does.
I need to reinvent parts of font-lock.


Michael.