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

[Alan Mackenzie <acm@muc.de>]

Hi, Chong!

On Thu, Dec 14, 2006 at 12:29:18PM -0500, Chong Yidong wrote:
> > 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.

OK.  We need options here.

> >> 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.

It's not enough.  The misfontification is perceived by users as a bug.
And sorry, I made a mistake there - it's not in the FAQ.

> 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?"

Well, more like "CC mode is intolerably slow for big files, what can I
do about it?".

> >> 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.

This change was made to fix a bug.  It has uncovered vagueness,
misunderstanding and missing functionality.  It is better that such
things are resolved before the release.

-- 
Alan.