Re: extending case-fold-search to remove nonspacing marks (diacritics etc.)

[Ted Zlatanov <tzz@lifelogs.com>]

On Fri, 06 Feb 2015 09:29:33 +0200 Eli Zaretskii <eliz@gnu.org> wrote: 

>> From: Ted Zlatanov <tzz@lifelogs.com>
>> Date: Thu, 05 Feb 2015 17:16:04 -0500
>> 
>> https://emacs.stackexchange.com/questions/7992/how-to-search-an-arabic-word-in-text-without-its-diacritics-accents
>> suggested it would be useful if diacritics were ignored when searching
>> for text in various situations. This is similar to `case-fold-search'
>> but more generic. Here's what I suggested as the answer at the ELisp
>> level:
...

EZ> That doesn't do what we want, it's only a partial solution to that
EZ> problem.  E.g., it doesn't equate the initial, medial, and final
EZ> variants of the letters used by Arabic and other Semitic scripts.
EZ> Moreover, you cannot even search for "a" and find "á", AFAICS.

Thanks for explaining. I am certainly not an expert in this area and
don't even speak or write Arabic, but my solution did work for the given
parameters so I thought it might be useful.

EZ> The way to solve this correctly and generally was discussed here some
EZ> time ago, so if there are people here for whom this is an itch to
EZ> scratch, please let's do this as discussed there.  We already have all
EZ> the necessary information for that in Emacs databases.

I am not one of those people. There's little I can contribute other than
this suggestion and testing for Romance languages with accents.

The general need seems to be for extending `case-fold-search', perhaps
with a new variable like `fold-search' that's a set of symbols. But I'm
sure you've already thought of that.

The performance concerns are justified but IMHO a correct solution is
easy to optimize later, so I wouldn't worry too much about it.

Ted