Re: Questions about isearch

[Artur Malabarba <bruce.connor.am@gmail.com>]

2015-11-28 14:41 GMT+00:00 Eli Zaretskii <eliz@gnu.org>:
>> Date: Sat, 28 Nov 2015 10:23:12 +0000
>> From: Artur Malabarba <bruce.connor.am@gmail.com>
>> Cc: Stephen Berman <stephen.berman@gmx.net>, Richard Stallman <rms@gnu.org>,
>>       emacs-devel <emacs-devel@gnu.org>
>>
>> Ok. I'm going to work on the char-folding a little bit more today to
>> implement support for multi-char matches and to combine it with
>> case-folding. Hopefully that will iron out the final inconsistencies.

I'm running bootstrap now to make sure I didn't break anything. Then I'll push.

> Maybe you could also take a look at this document:
>
>   http://www.unicode.org/reports/tr30/tr30-4.html
>
> In particular, section 5.2 there mentions several problematic
> foldings, which we might consider disabling.  For example, the ones
> mentioned in 5.2.1 and 5.2.2.

Thanks for the pointer.
None of those really worry me WRT searching. Char folding is supposed
to be convenient at the cost of being unable to distinguish some
strings.
But I guess they could be a problem for query-replace. Someone
replacing 58 with 59 probably doesn't want to replace 5⑧ with 59.

Since folding is disabled by default on quuery-replace, I think it
would be a bit of shame to disable these "risky" foldings completely.
Perhaps query-replace could use a different char table, with only a
subset. Or it perhaps it would be sufficient to just make this
"danger" very clear in the docstring of `replace-character-fold'.