command remapping problem

[Drew Adams]

1. (substitute-key-definition from to map global-map) is too slow in
   Emacs 22, at least when `from' is `self-insert-command'. It takes
   several seconds on a fast machine. In previous versions of Emacs it
   is instantaneous.

2. More importantly, (define-key map `[remap ,from] to) is an
   inadequate substitute for `substitute-key-definition'.  It
   apparently does not map all bindings of `from' to `to', or perhaps
   it is simply the case that it cannot accomodate the functionality
   of `substitute-key-definition's OLDMAP parameter.

3. Example: emacs -q

(define-key my-map [remap scroll-up] my-scroll-up)

The `scroll-up' binding for `C-v' is remapped to `my-scroll-up', but
the `scroll-up' binding for [next] is not remapped to `my-scroll-up'.

Similarly, (define-key my-map [remap help-command] my-help-command)
does not remap `C-h' to `my-help-command'.

My tests were done with map = `minibuffer-local-completion-map', but
probably the same problem exists for other maps. In
`minibuffer-local-completion-map', I want to substitute (remap,
whatever) all key sequences that are bound in `global-map' to certain
commands, to other commands, for use in minibuffer completion. Using
`global-map' as the OLDMAP parameter of `substitute-key-definition'
works perfectly for this (modulo performance); command remapping does
not.

I'm guessing that the problem is that `define-key' works only with the
bindings that are accessible from its MAP arg, not `global-map'
bindings - for example, [next] is not bound to `scroll-up' in
`minibuffer-local-map', so it is not remapped.

If this is the explanation, and this is not simply a bug, then I guess
that would mean that there is no way to get the behavior of
`substitute-key-definition's OLDMAP argument.  In that case, we have
lost functionality in going to Emacs 22, because
`substitute-key-definition' is unusable (at least with
`self-insert-command'), for performance reasons.

See also emacs-devel thread "Question on remapping keys" from
2006-01-19 to 20.



In GNU Emacs 22.0.50.1 (i386-mingw-nt5.1.2600)
 of 2005-06-26 on NONIQPC
X server distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc
(3.3) --cflags -I../../jpeg-6b-3/include -I../../libpng-1.2.8/include -I../.
./tiff-3.6.1-2/include -I../../xpm-nox-4.2.0/include -I../../zlib-1.2.2/incl
ude'