Re: emacs coding modes need 'Suspend Disbelief' button

[Stefan Monnier <monnier@iro.umontreal.ca>]

> then, when I  enter '"' or "'", the rest of the text
> would not be colored - this is really annoying and greatly
> slows down editing of large files -

Normally when you insert " only the current line gets "colored"
immediately, and the rest of the buffer is only re-"colored" by
jit-lock's contextual highlighting, i.e. after jit-lock-context-time of
idle time.  So if keep Emacs busy enough until you hit the closing " the
rest of the buffer should not be re-"colored" incorrectly even temporarily.

This said, even if it is re-"colored", that shouldn't slow anything down
(IOW if there's a noticeable slowdown, please report it so we can try
and fix it).

> The insistence of modern emacs on always unconditionally
> syntax checking everything greatly slows down typing and
> is a major inhibition to quick editing of large source files.

IIUC you're bumping into some performance problems.
If so, please report them (with M-x report-emacs-bug and enough details
that we can try and reproduce them) so we can try to fix them.

> And in some modes, such as shell script mode, and also
> cc-mode, it is still possible to core-dump Emacs (latest 25.2 version)

Core dumps are serious bugs, so please M-x report-emacs-bug.
We try pretty hard to fix those promptly.
If they're difficult to reproduce, the best is for you to run Emacs
within GDB and then send us the output of "bt" when it crashes.

> I have core-dumped emacs several times recently by doing this -
> one example that works pretty reliably is to start defining a
> function within a function in shell-script - there is a timing
> related bug , if you don't enter the opening '{' fast enough,
> emacs will core-dump .

My best guess here is that maybe your system has a stack-space limit
that's lower than what Emacs expects for some reason, so that the code
we have to try and check that we don't overflow the stack (e.g. in the
regexp matcher) doesn't do its job.


        Stefan