Re: Reliable after-change-functions (via: Using incremental parsing in Emacs)

[Alan Mackenzie]

Hello, Eli.

On Wed, Apr 01, 2020 at 07:14:09 +0300, Eli Zaretskii wrote:
> On April 1, 2020 6:49:45 AM GMT+03:00, Dmitry Gutov <address@hidden> wrote:
> > On 01.04.2020 05:28, Eli Zaretskii wrote:
> > >> Cc: address@hidden, address@hidden, address@hidden,
> > >>   address@hidden
> > >> From: Dmitry Gutov <address@hidden>
> > >> Date: Tue, 31 Mar 2020 22:50:43 +0300

> In general, there's no "preliminary processing" by the major mode's
> fontification facilities except what happens as part of jit-lock, i.e.
> at redisplay time or as side effect of functions that simulate display
> for redisplay purposes.  I'd be very surprised to see a major mode
> which somehow preprocesses the buffer on its own in preparation for
> fontification.  CC Mode certainly doesn't seem to do that.

CC Mode does do this.  It marks syntax-table text properties throughout
the buffer at find-file time, and keeps them valid thereafter in
before/after-change-functions.

This doesn't seem to affect starting up performance that badly.  On my
machine (a 3 yo AMD Ryzen) visiting xdisp.c (including the fontification
of the first screenful of comments) is taking 0.18s.

-- 
Alan Mackenzie (Nuremberg, Germany).