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

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

> > > Currently the user can either search for "any kind of e" or "only é"
> > > or "only è" or "only ê", etc.
> 
> I mean, that the user can do all of these with one character, not
> using any toggle command.

Yes, that is the difference in our views.  Sure, "with one character",
but the flip side is that if you happen to have é in your search string,
however it got there (e.g. by pasting), then with your preferred behavior
you *cannot* use your search string to search for "any kind of e".

This is maybe clearer when you think about copying some text to search
for from outside Emacs, and that text might have curly quotes in it,
in multiple places, and the text that you want to search might use
other kinds of quotes, and you want the matching to match quotes
regardless of type.

In that use case, you are screwed in the current design.  Nothing to
be done, to get char-fold search, until you replace all such non-base
chars in the search string with their corresponding base chars.

(And you talk about difficulty remembering?  Try remembering the base
char of each equivalence class...  Sure, letters and numerals are
easy, but not some others.  And we're just getting started.)

> > That would still be the case.
> > The only difference would be that when s?he wants to search for "any
> > kind of e" s?he can use any of the equivalent e-chars.
> 
> No, another difference would be that NONE of the other options
> is possible with one character -- all would require a toggle command
> that people may not remember.  (I don't.)

NONE of what other options?  All of the same search behaviors are
available.  That is, you can find any search target that you can
find today, using any search string that you use today.

On the difficulty of toggling char folding:

Do you remember how to toggle case sensitivity?  How come you do?
Because you've done it a few times?  And if you forget, you use
`C-s C-h'?  Or you use `C-h f isearch-forward'?  How hard is that?

Anyway, it's not likely I'll convince you to enjoy the feature
yourself.  But maybe you can appreciate giving users the choice?

> > The point is that what you say is true currently would still be the
> > case with what is proposed in this thread.  The user would continue
> > to be able to search for either any kind of e or for only a specific
> > kind of e.
> 
> The user would continue to be able to do this _somehow_, but not as
> now without using a separate toggle command.

Correct.  But at least that use case would still be available.
Currently, the use case that the proposal provides for is not
even possible - not never not noway not nohow.  That's really
the point: provide that possibility.