Re: Single quotes in Info

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

2015-01-24 15:00 GMT-02:00 Marcin Borkowski <mbork@wmi.amu.edu.pl>:
>
> On 2015-01-24, at 16:11, Drew Adams <drew.adams@oracle.com> wrote:
>
>> This is conceptually related to, but it need not necessarily be
>> extended to, discussion about being able to Isearch abstracting from
>> diacritical marks etc.  (E.g. bug #13041:
>> http://debbugs.gnu.org/cgi/bugreport.cgi?bug=13041.)
>>
>> IOW, being able to easily specify equivalence classes of chars for
>> search (and other) purposes, and preferably being able to quickly
>> choose whether to make use of them (this one or that one) - e.g.,
>> as we can do now for case-sensitivity (`a' ~ `A').
>
> This is a great idea.  Maybe even not only for isearch.
>

I also really like this idea, so much so that I've gone ahead and
implemented it. It is implemented on the branch
`scratch/isearch-character-group-folding'. I called it group-folding,
but we can call it class folding or whatever sounds more intuitive to
most people.

The implementation is very much up for debate. Currently, what it does
is use regexps (behind the scenes) so that a plain double quote
matches all those unicode double quotes, and the same for a hard
single quote. The way it is written, it is trivial to add more groups
by adding entries to `isearch-groups-alist'.
Of course, other characters are appropriately regexp-quoted behind the
scenes, so that everything else works as expected. The surface is
exactly like regular isearch, except for these two characters.

The set of groups is defined by `isearch-groups-alist', and the
folding only happens if `isearch-fold-groups' is non-nil.
Other groups that maybe should be added are latin accented letters.

Cheers to all,