Re: [christopher.ian.moore@gmail.com: Emacs very slow opening file]

[Juri Linkov <juri@jurta.org>]

>> One idea is to restrict what strings can be used as the "prefix"
>> in a local variables list, so that local variables lists in diff output
>> are not obeyed.
>
> I'm afraid it won't be that easy.  Typical prefix chars in diffs are
> "-", "+" and "!" most (all?) of them are used for comments in some
> languages (eg. Ada, Postscript).  Even worse: context lines aren't
> prefixed at all.

One quite reliable solution is to store the original values of
prefix/suffix strings in the Local Variables section by adding new
variables `local-variables-prefix' and `local-variables-suffix', e.g.:

-/* Local Variables: */
-/* local-variables-prefix:"/* " */
-/* local-variables-suffix:" */" */
-/* mode:c */
-/* eval:(load-library "time-stamp") */
-/* eval:(make-local-variable 'write-file-hooks) */
-/* eval:(add-hook 'write-file-hooks 'time-stamp) */
-/* End: */

That way `hack-local-variables' could treat these variables specially:
by extracting their values from the Local Variables section, and testing
if they match the real prefix and suffix around the `Local Variables:'.

So the Local Variables section in the example above wouldn't be
interpreted, because the value of `local-variables-prefix' ("/* ")
is not the same as the prefix "-/* " in the diff file.

Of course, this wouldn't work with existing Local-Variables sections,
but for new sections adding these special variables would be easy
with a new command (from etc/TODO) that will make a local variables
section and write the values of `local-variables-prefix' and
`local-variables-suffix' automatically.

-- 
Juri Linkov
http://www.jurta.org/emacs/