Re: Questions about isearch

[Marcin Borkowski]

On 2015-11-25, at 21:14, Artur Malabarba <address@hidden> wrote:

> On 25 Nov 2015 6:41 pm, "Eli Zaretskii" <address@hidden> wrote:
>> 1. Character folding doesn't catch ligatures, such as æ (should it match
>> the two characters "ae")?
>
> I've no idea. It would be easy to add.
> Those who use ligatures need to tell us whether that makes sense.

I'm not sure whether this is relevant, but a place where ligatures come
up naturally is TeX's pdf files, which can be isearched with pdf-tools.
Currently, searching for "fi" when the document contains the
corresponding ligature Just Works™.  I'm not sure what would happen in
case of e.g. a result of a pdf->text conversion.

>> 4. What is the equivalent of case-replace and the letter-case related
>> behavior of replace commands to character folding?  E.g., if the
>> replace command specifies to replace "foo" with "bar", and we found
>> "föo", should we replace it with "bär" or something, by analogy with
>> letter-case behavior?
>
> I don't think we should do that. Case replacement makes sense because the
> way you capitalize a word is frequently (though not always) independent of
> the word itself. That's not the case with char folding. At least in
> Portuguese, accents only go in very specific places, and I would _never_
> want emacs to add an accent to the replacement text just because the word
> being replaced happened to have an accent.

+1.  In Polish, e.g. "a" and "ą" (or "n" and "ń", etc.) are different
letters, representing different sounds, and possibly changing the
meaning of a word (for instance, "kat" is an executioner and "kąt" is an
angle).

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University