Re: ASCII-folded search [was: Re: Upcoming loss of usability ...]

[Artur Malabarba]

> Yes.  But I'd still want to know what would it take to make this
> applicable to other types of search.

Essentially, this patch does two things.
1. It provides a function that takes a string S and returns a regexp
that matches anything that folds into S. This is why it only works on
non-regexp searching, because it takes a regular string and turns it
into a regexp. But other than that, it's generic (it's not specific to
isearch).
2. It also uses this function to implement character-fold matching in
`isearch' and in `query-replace'. In order to use this
character-folding with other searches, these need to call the
conversion function too.

For instance, to get this character folding behavior with
`search-forward', instead of writing
    (search-forward STRING)
I would instead write (conditional on a variable being non-nil)
    (search-forward-regexp (isearch--character-folded-regexp STRING))

But I can't do that directly inside search-forward, because that's a c
function. So it needs to be done in the functions that call
search-forward. I was aware of isearch and query-replace, but there's
no reason it won't work on others.