Re: PROPOSAL: Repurpose one key and reserve it for third-party packages

[Jean Louis <bugs@gnu.support>]

* Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org> [2021-02-13 15:45]:
> > For example none of Super key bindings is used by Emacs.
> > That makes alone possibly 7000-10000 possible combinations.
> 
> Unheard of.

How about trying it?

If s-a is prefix key, 26 letters + 26 upper case letters + 10 numbers
plus 32 symbols on my keyboard is 94 combinations multiplied by 94
possible other following keys, not counting possible middle suffix
keys, yields ations is 8836 possible bindings with Super key on this
keyboard.

Make s-a prefix key:

s-a a
s-a b
s-a 1
s-a 2
s-a !
etc.

Make s-A prefix key:

s-A a
s-A b
s-A 1
s-A 2
s-A !
etc.

Then continue for each key as prefix key and multiply by other
combinations. I think 8836 minimum is here. International keyboards
could have more than that.

Example binding that works:

(global-set-key (kbd "s-U u") (lambda () (interactive) (message "Hello")))

Then if we add combinations with Control on my keyboard that becomes
94 x 94 x 94 with Control, so there are 830584 possible key bindings
by using Super key and Super combined with Control key.

Example binding:

(global-set-key (kbd "C-s-b i") (lambda () (interactive) (message "Hello")))

Super can be combined with Meta or Alternative key. So that adds
another multiplication by 94 and we end up with 78,074,896 possible
key bindings that use Super key.

Example bindings:

(global-set-key (kbd "M-s-b b") (lambda () (interactive) (message "Hello")))

(global-set-key (kbd "M-s-b C-s-c") (lambda () (interactive) (message "Hello")))

(global-set-key (kbd "M-s-b M-s-7") (lambda () (interactive) (message "Hello")))

If we then make the second key also prefix the number of possible
bindings grows and grows.

If my calculation is wrong, then please make your own calculation and
make cross checks to verify it and post it here.

As currently we have situation that some people will say that Super
often collides with Window Manager, but is that often more than 94
combinations by 94 combinations?

If s-p collides then maybe s-; does not. If s-; is prefix key that
alone opens 94 possible combinations on this keyboard. If I wish I
could use a middle prefix key in that combination and get 8836
combinations.

Example where s-; a is prefix key:

(global-set-key (kbd "s-; a 1") (lambda () (interactive) (message "Hello")))
(global-set-key (kbd "s-; a 2") (lambda () (interactive) (message "Hello")))
(global-set-key (kbd "s-; a 3") (lambda () (interactive) (message "Hello")))
(global-set-key (kbd "s-; b 1") (lambda () (interactive) (message "Hello")))
(global-set-key (kbd "s-; B 1") (lambda () (interactive) (message "Hello there")))

The demonstration is there to show that combinations are more or less
endless. I have no problem using s-; B 1 or remembering it. It is
nothing less usable than C-x 5 0 or similar known commands.

C-x 8 ' U gives me in Emacs = Ú -- so if I need that I will
remember. I often use C-x 8 L to specify pounds as money symbol like
£200 and I remember it. Personally I use C-x 7 as prefix for years
already. C-x 9 is also free.

Problem is in console, but maybe that problem can be solved. What you
think how to solve Super key in console? Maybe kernel developers need
to be contacted?

We justdid not find how. That it can be solved is already clear as
Super does work in X, so detection will work in console but it could
be that it was tradiitonally just forgotten. Virtually all users have
today Super key. If they change it in kernel then Super key becomes
really super.

Jean