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

[Drew Adams <drew.adams@oracle.com>]

> > > > > We are asking for matches that disregard the diacriticals
> > > > > (and in case of ª also higher-order collation-order variation).
> > > >
> > > > No.  You are asking for that only when you use a search pattern
> > > > that does not use the diacriticals.  When you search with á in
> > > > the pattern you are NOT asking for matches that disregard the
> > > > diacriticals.  And why not?
                       ^^^^^^^^^^^^
> > > Because á does include a diacritical.  By specifying it, the user told
> > > us the diacriticals are important, and shouldn't be disregarded.
> >
> > Again, you are just parroting what the implementation does
> 
> ??? I explained the interpretation of the user input, how's that
> implementation?

You described the current interpretation, by Emacs, of the
user input á.  That's "what the implementation does."

That does not explain why use á in a search string _should_ mean
that diacriticals are important and shouldn't be disregarded.

And that was the question I asked - why should this be the
(only) behavior?  Your answer is, just because it _is_ the
behavior.

Because it is the behavior, users expect it and we can interpret
what they want in terms of it.  Well yes, sure - it's the only
choice they have now.  It _is_ the behavior, so of course they
use it accordingly.  They type á in order to match á.  So what?

> > Again, both options for fold matching should probably be available.
> > There is no reason to hard-code one of them at design time.
> > At least no reason has been put forth so far.
> 
> You've got all the reasons, you just refuse to hear them.
> Time to bail out.

The only reason you gave is that this is what Emacs does now.
And that that means that this is what a user expects.  S?he
types á to match á and a to match a (or variants, with char
folding).  User intention is clear here: s?he gets the behavior
s?he asks Emacs for.  QED.

Sorry, that's not a reason _why_ this should be the (only)
behavior available to a user.  It's just repeating that users
expect this behavior from Emacs and so act accordingly.
That they get what they expect is no proof that that is the
only useful behavior.  It just shows that they know what
Emacs does.