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

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

As for answering your questions:

>> implementing it for users so it works like `case-fold-search' (you just
>> set something in Customize and all search commands DWYM) seems much
>> harder.

Doing it as part of Emacs is not terribly hard, but it has
disadvantages. Namely, the case-fold-search machinery only relates one
character to another character (1 to 1). At least for latin this would
be enough a lot of the time, e.g. you can use it to relate "á" to "a".
However, there's another way of writing "á" which takes two
characters, and this situation can't be handled (AFAIK) by the
case-fold-search machinery.
The bright side is that I think this two-char way of writing latin
accents is much less common (not 100% sure though, it's hard to tell
the difference). The downside is that I know nothing about other
languages, so maybe using two chars to represent one char is the
default behavior in some other languages?

>> Does anyone have suggestions? Maybe some defadvice magic?

You can use a defadvice around one of the isearch internal functions
(check out the branch I mentioned) to implement something in elisp.
And you can redefine the buffer's case-folding table and use that in
the advice, but that will require that you generate the entire table.