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

[Dmitry Gutov <dgutov@yandex.ru>]

Hi Alan,

On 25.04.2019 21:36, Alan Mackenzie wrote:

> Some while ago, you were complaining, justifiably, about the
> sluggishness when typing characters into very long C++ raw strings.  To
> demonstrate this, you put xdisp.c into C++ mode, and put a raw string
> round nearly the entire buffer.

It was an argument in a discussion, not exactly a bug report (I don't 
write C++), but it's laudable progress, of course.

> Last week, it was taking over 2 seconds to process a single
> self-insert-command into this string, and my machine is not slow.
> 
> I have now optimized CC Mode, such that each such self-insert-command
> now takes around 0.07s-0.1s.  I used two strategies for this: (i) breaking out
> of (expensive) fontification routines early, when the region being
> fontified is nothing but a string; (ii) Not fontifying the entire raw
> string for a change to only a small part of it.

Pulled the latest changes, rebuilt Emacs and tried this. The result 
still feels fairly sluggish at times (the pauses seem longer than the 
timings you mention, especially when I type or delete the relevant 
double-quote characters), but it should definitely make editing such 
literals possible and even bearable.

Here's a seemingly related discussion you might be interested in: 
https://lists.gnu.org/archive/html/emacs-devel/2019-04/msg00715.html