Re: Additional cleanup around xterm-mouse

[Stefan Monnier]

> I see a few options:
>
> 1. Change the behavior of the dont-downcase-last parameter to this more
>    extensive meaning.  Update global-set-key (the only other caller who sets
>    dont-downcase-last in Emacs' code) to take this new behavior
>    into account.

I believe `global-set-key` does want to use this new behavior, yes.

> 2. Make the dont-downcase-last parameter have the new behavior only if it is
>    passed some new value (for example: 'all-fallbacks).  Leave the existing
>   behavior for any other value, especially 'nil and 't.
>
> 3. [My preference] Like 2, but with a deprecation message on values other
>    than 'nil, 'all-fallbacks, or 't (or maybe 'downcase-last if we want full
>    explicitness).  This allows maximal ability to define new behaviors in
>   the future.

These sound good as well.  I'd even put a deprecation message on the
`downcase-last` case.

> I like #3 as existing code would run unchanged.  The chance that any
> existing code passed 'all-fallbacks is extremely low.  And anyone supporting
> a package outside of Emacs passing some other value will notice the message
> when they upgrade to Emacs 28.
>
> Thoughts?

By order of preference, I'd say: #1, then #3 and finally #2.
But any one of those 3 is OK for me.


        Stefan