Re: GNU Emacs 22.0.50 fails to find ä in different ISO Latin encodings

[David Kastrup <dak@gnu.org>]

Kenichi Handa <handa@m17n.org> writes:

> Peter Dyballa <Peter_Dyballa@Web.DE> writes:
>
>> Launched with -Q
>
>> 	unify-8859-on-decoding-mode is nil
>> 	unify-8859-on-encoding-mode is t
>
>> I start i-search in an Unicode encoded buffer (*Help*). In an ISO  
>> 8859-1 encoded buffer ä and Ä are found, also in ISO 8859-10, ISO  
>> 8859-13 (except for Ä), ISO 8859-14, and ISO 8859-16 encoded buffers,  
>> but fails in ISO 8859-2, ISO 8859-3, ISO 8859-4, ISO 8859-9, and ISO  
>> 8859-15. It is similiar to ö and ü, accept that these are not found  
>> in the ISO 8859-14 encoded buffer. Changing unify-8859-on-decoding- 
>> mode's value makes no difference.
>
> This is the story I remember.
>
> A while ago, I proposed to change isearch so that it
> translates characters by translation-table-for-input to
> solve such a problem, but there raised an objection that
> read-char should do that translation.  RMS asked to check if
> such a change to read-char is surely safe or not, but as
> such a check is very difficult and time-consuiming, no one
> took on the job.
>
> So, this problem is still unfixed.
>
> I again propose to change isearch.  When we know that
> changing read-char is safe in the future, we can cancel that
> change in isearch.

"in the future", namely after the release, we are going to switch to
the unicode2 branch and presumably the problem will go away.  So it
does not sound like we should attempt any complicated fix for Emacs 22
that is not going to stay around, anyway.  If the one problem where
people are complaining is search-and-replace, we should fix that case
for Emacs 22 and that's it for Emacs 22, in my opinion.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum