Re: Processing speed in large C++ raw strings.

[Alan Mackenzie <acm@muc.de>]

Hello again, Tadeus.

On Sat, Apr 27, 2019 at 17:35:16 +0200, Tadeus Prastowo wrote:
> Hi Alan,

> On Sat, Apr 27, 2019 at 1:37 PM Alan Mackenzie <acm@muc.de> wrote:

> > Thanks for drawing my attention to this problem with lots of templates.

> My pleasure.  And, thank you very much for looking into this.

> > The bug is that, in a certain low-level place, CC Mode was failing to
> > mark the < and > "as parentheses" (with syntax-table text properties),
> > hence a lot of unneeded buffer scanning was being done.

> > The following patch should speed up the scrolling operation markedly.
> > It does not become instantaneous, but takes a fraction of a second,
> > compared with the several seconds it has taken up to now.  Would you
> > please try it out.

> I apply the following patch to master at commit
> 8dc00b2f1e6523c634df3e24379afbe712a32b27, and I confirm that the
> following patch works to solve not only the buffer scrolling
> sluggishness but also the template parameter editing sluggishness,
> including the one that I sent to Stefan earlier today.  Thank you very
> much, Alan, I really appreciate it.  Three lines of a diff to solve my
> two-year old sluggishness problem.

Thanks indeed!  Thanks also for such a rapid reply.

I've just committed the patch to all the usual places (including the
Emacs master branch).  So I think the bug is now fixed.

> > diff -r 1940f96b9799 cc-engine.el
> > --- a/cc-engine.el      Fri Apr 26 01:01:07 2019 +0000
> > +++ b/cc-engine.el      Sat Apr 27 11:30:06 2019 +0000
> > @@ -5539,7 +5539,9 @@
> >                       (prog1 (looking-at "\\s(")
> >                         (forward-char))))
> >           (backward-char)
> > -         (if (c-forward-<>-arglist nil) ; Should always work.
> > +         (if (let ((c-parse-and-markup-<>-arglists t)
> > +                   (c-restricted-<>-arglists t))
> > +               (c-forward-<>-arglist nil)) ; Should always work.
> >               (when (> (point) to)
> >                 (setq bound-<> (point)))
> >             (forward-char)))

> -- 
> Best regards,
> Tadeus

-- 
Alan Mackenzie (Nuremberg, Germany).