RE: [External] : Partly deferred font-locking?

[Drew Adams]

> > > Beyond levels, we could imagine being able to
> > > specify a list of particular kinds of fontifying
> > > per mode.  That's not possible with this option
> > > today.  No doubt there's room for improvement.
> >
> > But those levels only let the user turn off some parts
> > of font-locking, but not to defer those parts, right?
> 
> Yes.  I was trying to say that what we offer could
> be improved. ;-)  And that even what we do offer
> (the "levels") doesn't seem to be used (supported
> by modes, so usable by users).

And your example of fontifying symlinks in Dired
is an example of _what_ gets fontified, and not
how, no?

If that symlink font-lock rule is in a higher level
then that already should provide a way to avoid its
cost.  IOW, IIUC, just choosing not to fontify
symlinks should take care of that particular cost.
(But maybe I've misunderstood you.)