RE: [External] : Re: Concern about new binding.

[Drew Adams]

>   > I can understand why we should avoid changing C-x o o behaviour,
>   > but what's the rationale for the capital letter after C-x rule?
> 
> I think the reason is the simplicity of C-x -- that users should not
> have to remember one meaning for C-x a and one for C-x A, one for C-x
> b and one for C-x B, and so on.

I can understand that.  That reason is a bit similar
to why `case-fold-search' is t by default, I guess.

And it could be considered similar to what we do wrt
"shift translation" - (elisp) `Key Sequence Input'.

On the other hand, the argument about needing to
_remember_ is not too strong IMO.  (That's perhaps
especially the case nowadays, with better, including
incremental, help with key bindings.)

If there are separate bindings for `C-x a' and
`C-x A', I think it's pretty much always the case
(and I expect likely always will be the case) that
the `C-x a' binding was introduced first to Emacs,
and it will likely be bound to the more commonly
used of the two commands.  And a user who uses
either and expects the other will soon enough
discover the existence of both, I think.

There are a limited number of easy-to-use keys.
I favor allowing both upper- and lowercase keys in
this context, even keys that Emacs binds by default.
(Just one opinion.)

> That's not a super-important reason.  It would not be a terrible loss
> to eliminate that rule.  And if there were only one capital letter
> with a special meaning after C-x, that would not be a great cost.
> But I don't think it would remain just one for very long.

I too don't think there would remain just one for
long.  But I also don't think having multiple such
is an important problem/inconvenience.