Re: A simple implementation of context-sensitive keys

[Stefan Monnier <monnier@iro.umontreal.ca>]

> So I've come up with this macro, which creates such a dispatching
> command automagically.  If none of the context predicates match, the
> default command bound to the key will be executed.

Another way to get a similar result is:

(define-key <map> <key> '(menu-item "dummy" <binding>
                          :filter (lambda (binding)
                                    (when <condition> binding))))

It's tempting to use the :enable property instead of :filter, but sadly,
the :enable property is only obeyed by the menu-construction code, not
by the key-lookup code.

In any case, the main problem with such things (whichever way they're
implemented) is that the rest of Emacs doesn't know and/or expect such
condition bindings, so C-h k gives only partial information, and
similarly where-is doesn't know how to tell the whole story.


        Stefan