Re: `character-fold-search' should be a user option, like `case-fold-search'

[Juri Linkov <juri@linkov.net>]

> Subject line says it all.  Users should be able to customize
> this variable, to decide for themselves, without fiddling with
> `setq', whether search starts by default with or without
> character folding.  They should be able to find this easily,
> as an option in custom group `matching', right alongside
> `case-fold-search'.
>
> No?
>
> I customized `case-fold-search' to nil long ago, and I will
> likely do the same for `char-fold-search': set it to nil.
> By default I want search to distinguish different characters.
>
> Different users have different uses and different preferences.
>
> Fortunately, the behavior can be toggled.  But the default
> behavior should also be customizable.  Users should not need
> to use `setq' for `char-fold-search' but be able to customize
> `case-fold-search'.  This is a (minor) step backward, IMO.

Like with ‘case-fold-search’ and ‘isearch-case-fold-search’ we could
make ‘char-fold-search’ customizable and ‘isearch-char-fold-search’
togglable, i.e. when ‘char-fold-search’ is t:

‘C-s a’     matches [aä]
‘C-s a M-'’ matches [a]
‘C-s ä’     matches [ä]
‘C-s ä M-'’ matches [aä]

when ‘char-fold-search’ is nil:

‘C-s a’     matches [a]
‘C-s ä’     matches [ä]