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## Re: Mysterious fontification/C++ context issue - Patch for beginning-of-

 From: David Kastrup Subject: Re: Mysterious fontification/C++ context issue - Patch for beginning-of-defun-raw. Date: Fri, 15 Dec 2006 23:20:25 +0100 User-agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.91 (gnu/linux)

> Yet we're Emacs experts.  I think we're placing too little
> importance on the shock and emotional distress that such a bug
> [totally hosed fontification over an entire screen] will cause an
> ordinary Emacs user.  Even highlighting these parens might well
> puzzle, rather than help, this user.

Fontification is known not to be perfect, and there is an easy way
around if you feel shocked: change the input.  Such a change is
required for a number of other source code management tools like ctags
anyway.

This is a one-time effect.  In contrast, editing slowdowns are
permanent and incurable.

There are other modes, like LaTeX-mode, where the fontification engine
has no chance of figuring out everything correctly.  So one uses
simple hacks like

\def\xxx#1{\if$#1%$

where a comment is added that does nothing but close a \$ math
environment that would otherwise be highlighted permanently.

People are _used_ to putting such stuff in if it annoys them too much.
It _is_ important, however, that there are easy workarounds.  For that
reason, AUCTeX matches dollar signs in line comments (one developer
made them ignored out of "correctness" concerns, and I vetoes this,
since it is impossible to get TeX fontification correct automatically,
anyway, and making the workarounds harder is a nuisance).

In the case of C-mode, there is a perfect workaround that requires no
undue amount of tap-dancing.

I don't see any reason to introduce little-tested, slow code that
already has lead to infinite loops and quite a bit of trouble at this
point of time in pretest.

--
David Kastrup, Kriemhildstr. 15, 44793 Bochum