Re: Single quotes in Info

[Artur Malabarba]

> If this is implemented in isearch, then IMO doing it for quotes alone
> makes very little sense.

The quotes are just proof of concept. Adding other equivalency classes is easy from here, and I do agree it makes sense to add others.

> It would make a lot of sense if it were
> implemented in info.el, for searching Info manuals

There are ways to do that too if people prefer, but info manuals are not the only ones that contain such characters.
For instance, lots of people use round quotes in org-mode files.

> (in which case it
> should also support the other Unicode characters produced by makeinfo
> that have ASCII equivalents, like ⇒ vs =>. (Note that this is not
> character-for-character equivalence anymore.)

I agree with the idea, but it will be more tricky. Translating a character to any regexp is easy right now. Translating multiple characters into a single is more complicated, but I can do that. But I'm worried about the performance of that.

> If we do this via our private database, that database is going to be
> huge.

Is it? I would expect something on the order of 50 lines. That would be large, but not huge. Each entry relates a key from a simple keyboard to a set of possible characters that are not represented in simple keyboards. But maybe I'm just being naive.

> I suggest to explore an alternative implementation, which uses
> canonical equivalence.

I'd love that.

> We already have infrastructure for that, see
> the description of the 'decomposition' character property in the ELisp
> manual.

Building this on preexisting infrastructure would be great, but does that go the right way? Does it relate a simple character to all its complex equivalents? Or does it relate each complex character to a simple alternative?