RE: char equivalence classes in search - why not symmetric?

[Drew Adams]

> Since it is possible to search for only 'á', it would be nice to have
> some convenient way to search only for 'a' with no accents.
> 
> The only convenient interface I can think of is that you type, in a
> postfix input method, a ' DEL.  Currently that is equivalent to typing
> just  a.  But we could conceivably make it different.
> 
> Can someone think of some other interface for this?

Yes, I mentioned this.  And see the proposal from Juri in this thread:

During Isearch, `M-s '' (he wrote `M-'' but I think he meant `M-s '')
would toggle character folding, just as `M-c' toggles case folding.

If char folding is on then `a' matches all of the variants (á etc.).
But if it it is off then `a' matches only `a'.

Users could customize the default (on or off), just as they can today
customize `case-fold-search'.

So someone could leave char folding on most of the time, and toggle it
off anytime using `M-s '', or vice versa, leave it off most of the time
and toggle it on.

If it is on and you want to search for only `a', not also á etc.:

C-s M-s ' a