Re: New buffer-case-table makes search_buffer painfully slow

[Elias Oltmanns]

Richard Stallman <address@hidden> wrote:
>     Emacs 22's EQUIVALENCES table relates i, and thus I as well, to
>     two more characters with character codes 331857 and 331856. On
>     www.unicode.org the character look up engine couldn't find a
>     match for U+51051 or U+51050 saying that most likely those codes
>     weren't assigned to any characters yet.
>
> I think this has to do with the special characters for Turkish,
> lower-case i without dot and upper-case I with dot. In Turkish,
> upcasing and downcasing preserve the dot, or the absence of the dot.
>
> I think these lines in characters.el are the cause of the problem.
>
>   (set-downcase-syntax ?? ?i tbl) (set-upcase-syntax ?I ?? tbl)
>
> They set up only half of what Turkish needs. They make dotless-i
> upcase into I, and they make I-with-dot downcase into i. They can't
> do vice versa because that would break things for other languages.
> So they are not really useful. We could simply delete them.
>
> We could also add a minor mode to set up the case table all the way
> for Turkish.

When I come to think of it, I'm not quite sure I understand what
exactly you have in mind with regard to the minor mode option.
Unfortunately, I don't know anything about Turkish at all, but I'd
imagine that while you're editing pure Turkish texts, you'd like to
have a matching pair of dotless and dotted up- and downcase i
respectively. That way up- and downcasing work properly and case
insensitive searches for an i would not match the dotless
versions---as expected, I suppose.

If you're editing mixed texts as, for instance, Turkish and English,
the current behaviour with i matching all four characters might be
more convenient; the same applies if you switch between Turkish and
other languages rather frequently.

The third option, which from my very biased point of view should be
the default, is that ASCII i should only match its ASCII upcase
counterpart.

How would you realise all these needs?

Regards,

Elias