Assigning keymaps / menu shorts / changing menu items

Assigning keymaps / menu shorts / changing menu items

[David Reitter]

I would like to do a couple of global-set-keys for a few basic 
functions that appear in the menu bar. However, the new shortcuts don't 
appear in the menu items, since they are still assigned (and should 
be).

I understand the menu item shortcuts show what's defined first. Is 
there a command like global-set-key that would insert the new keymap at 
the beginning of the list associated with the function? Here's what I 
do:

(global-set-key [(alt v)] 'yank)

'yank has a menu entry in the Edit menu that currently says "Paste 
(C-y)".

Also, I would like to change the way the keyboard shortcuts appear in 
the menu. Can I redefine a function to do that? What would that be?

Lastly: how do I change a menu item?
I know how to add submenus to a menu with easychange.el, but I couldn't 
figure out how to actually change the text of an arbitrary item. Is 
that possible?

I've been looking for something like that in various places - maybe 
someone here could give me a hint regarding any of these things, I'd be 
very grateful.

Re: Assigning keymaps / menu shorts / changing menu items

[Stefan Monnier]

> I understand the menu item shortcuts show what's defined first. Is there
> a command like global-set-key that would insert the new keymap at the
> beginning of the list associated with the function? Here's what I do:

> (global-set-key [(alt v)] 'yank)

> 'yank has a menu entry in the Edit menu that currently says "Paste (C-y)".

The shortcuts displayed in the menus try not only to only mention *key*
bindings, but also favor key sequences that can be generated on any
terminal, i.e. ascii chars (maybe combined with the meta modifier).  C-y is
an ascii char so it is preferred over A-v.

So if you really want to see A-v in the menu, you need to either somehow
hide the C-y binding, or put the info up there explicitly (using
the :key-sequence parameter in the menu-item).

The first option can be done with something like

    (defalias 'hidden-yank 'yank)
    (global-set-key [(control y)] 'hidden-yank)

But the second option is preferable since it allows things like C-h f to
still list *all* the bindings.

> Also, I would like to change the way the keyboard shortcuts appear in the
> menu. Can I redefine a function to do that?

IIRC it's key-description and it's written in C.  Also it's called directly
from C, so if you redefine it in elisp, Emacs will not everywhere use your
redefined version.

> Lastly: how do I change a menu item?
> I know how to add submenus to a menu with easychange.el, but I couldn't
> figure out how to actually change the text of an arbitrary item. Is
> that possible?

Find the key-sequence corresponding to it with C-h k, then
(define-key [theseysequence] '(menu-item ...)).
See the elisp manual's description of menus and `menu-item' for more info.

        Stefan

Re: Assigning keymaps / menu shorts / changing menu items

[David Reitter]

Many thanks for your hints.

> > Lastly: how do I change a menu item?
> > I know how to add submenus to a menu with easychange.el, but I 
> couldn't
> > figure out how to actually change the text of an arbitrary item. Is
> > that possible?
>
> Find the key-sequence corresponding to it with C-h k, then
> (define-key [theseysequence] '(menu-item ...)).
> See the elisp manual's description of menus and `menu-item' for more 
> info.

OK, but I wouldn't want to contruct a completely new menu-item, I would 
just want to exchange the text. Now, when I do something like

(lookup-key global-map [menu-bar file open-file])

all I get is the pure command, 'find-file-existing, in this case - but 
not the arguments :enable and :help that were defined in menu-bar.el:

(define-key menu-bar-file-menu [open-file]
   '(menu-item "Open File..." find-file-existing
	      :enable (not (window-minibuffer-p
			    (frame-selected-window menu-updating-frame)))
	      :help "Read an existing file into an Emacs buffer"))

So in order to _change_ single elements of a menu-item, I need to read 
out everything that define-key was called with in menu-bar.el.

Of course, I could tinker with menu-bar.el directly or copy stuff out 
of it, but that would be no fun to keep up to date...

Thanks in advance
-- Dave

Re: Assigning keymaps / menu shorts / changing menu items

[Stefan Monnier]

>> Find the key-sequence corresponding to it with C-h k, then
>> (define-key [theseysequence] '(menu-item ...)).
>> See the elisp manual's description of menus and `menu-item' for more info.

> OK, but I wouldn't want to contruct a completely new menu-item, I would just
> want to exchange the text. Now, when I do something like

> (lookup-key global-map [menu-bar file open-file])

> all I get is the pure command, 'find-file-existing, in this case - but not
> the arguments :enable and :help that were defined in menu-bar.el:

Yes, that's a problem I'm familar with.  It should be pretty easy to fix,
all we need is a way to tell lookup-key to return the "raw" binding.
Please send a feature request to gnu.emacs.bug about it.

As a workaround you can try

   (cdr (assq 'open-file (lookup-key global-map [menu-bar file])))

which will probably work in most cases.  Note that doing a `setcar' or
`setcdr' operation on the menu-item you found, tho appealing, should be
avoided since it may fail (this data is often located in pure-storage
which is readonly).  Instead you'll have to reconstruct a new menu-item with
most of the content unchanged, using non-destructive operators like
`append', `cons', ...


        Stefan