Re: Mysterious fontification/C++ context issue - Patch for beginning-of-defun-raw.

[Chong Yidong]

> xdisp.c, at ~750k, is an unusually large source file.  A 1.7 GHz machine
> will become unusually old and slow during the lifetime of Emacs 22.

There are plenty of people running Emacs on very old Unix boxes,
especially in academic environments.

>> If the only files misfontified are Emacs source files, I don't think
>> this "fix" is necessary for Emacs 22---especially if the files in
>> question can be tweaked to avoid the bug.
>
> It isn't only Emacs source files.  It happens a lot in normal users'
> files.c.  There's a FAQ about it in the CC Mode manual.  After all,
> having parentheses inside strings and comments in C is perfectly valid
> and acceptable syntax, and it looks like a bug (which indeed it is), if
> Emacs can't fontify such things properly.

If the current problems are already addressed in the FAQ, that should
be enough---especially if adhering to a de facto coding standard
prevents the bug.

With the fix, this FAQ entry would have to be replaced with another
FAQ entry: "Why is CC mode intolerably slow for big C files?"

>> Is it really so bad to revert the changes for now?
>
> Yes.
>
> By "for now", you mean for Emacs 22.  If the changes are reverted "for
> now", they'll stay reverted until the release of Emacs 23, sometime
> around 2011.

If someone can come up with a non-slow way to handle this, it could go
into emacs 22.2.  By the way, one of the reasons the Emacs release
process takes so long is the addition of big problematic changes like
this during pretest.