RE: "whether the global keymap C-x 4 will be replaced by a command,"

[Drew Adams]

> > `C-h r C-h' already lists all of the `C-x 4' keys
> > and their commands.  And choosing any of those
> > then shows you its complete help.
> 
> If you mean "C-x 4 C-h", yes 

Yep.  Finger-flunked; sorry.

> but, "C-h k C-x 4" is left waiting for further input
> and "C-h k C-x 4 C-h" just says there is no binding for it.

> There is no universal way to get further information at that point.

I guess the info you want at that point is the
info you'd get from `C-x 4 C-h'.  Is that right?

> If "C-h k" had a solution it would apply uniformly and not require mucking
> about which changing any (other) key bindings.

OK.

> Should there be a general rule than any partial key sequence have "C-h"
> show the possible options?

Maybe.

Have you really found this to be a problem?

I haven't.  But I know that some users don't
know about using `C-h' after a prefix key.

And I do get your point, about not wanting to
abandon `C-h k C-x 4' and use `C-x 4 C-h' at
that point.  That doesn't bother me, but OK.

> And if so wouldn't it be more straight
> forward to not have to manually define for each possible key sequence,
> but still have any exi[s]ting such binding still work?

Definitely.  But only if implementing that
doesn't remove/break something else (unlike
what's being proposed in this thread).

No one has to explicitly define a binding for
`C-h' after a prefix key, for example.  (And
as you point out, there is in fact _no_ such
key binding.)  Yes, the same should apply for
what you suggest.

But I don't think the overall discussion is
really about `C-h k' and its getting to the
help for a prefix key (e.g. help like what
`C-h 4 C-h' shows).

But if it were, then my reply would be (besides
perhaps doing something such as you suggest -
which AFAIK doesn't require changes such as
those proposed), to instead provide something
like the help that key completion (library
Key See or Icicles) or `which-key' provides.

https://www.emacswiki.org/emacs/KeySee

https://www.emacswiki.org/emacs/Icicles

https://github.com/justbur/emacs-which-key

Those all, like an appended `C-h', let you see
the keys that complete a prefix key, as well
as their commands.  And unlike `C-h', they
don't interrupt use of the prefix key.

(In addition, Icicles lets you get the full
doc string for any such completing key.)