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

[Drew Adams]

> Currently you can type a single character and do any of these things:
> * Search for A with or without any accent.
(1)
> * Search for Á only.
(3)
> * Search for À only.
(4)
> * Search for  only.
(5)
> * Search for Ä only.
> and likewise for each accented variant of A that exists in Unicode.
(6)
> 
> With your change, all of those characters would do the same thing:
> search for A with or without any accent.
> 
> So there would be only one thing you can do in regard to searching for
> As, without using some sort of toggling command.

Correct.  We are agreeing about the facts, which is good.  Per proposal:

With char folding ON:

(1) Search for A with or without any accent.
(2) Search for "each accented variant of A that exists in Unicode",
    with or without any accent.

With char folding OFF:

(3), (4), (5), (6) Search for Á, À, Â, Ä only (and likewise for each...)

What the current design misses is possibility (2).  You *cannot*
search using "Müller" and find "Muller" etc.

And yes, with the proposal a user explicitly expresses an intention
to search with or without char folding, by hitting a key to turn it
ON/OFF.  There is no automatic turn-OFF just because there is a char
with a diacritic in the search string.

What's more, a user option can let users choose which behavior they
prefer, instead of hardcoding that choice into the design.  What's
more, a user can (or we could) add a toggle key for flipping that
behavior: both Drew and Richard could quickly switch "designs" on
the fly, if they wanted to.

Why not?