key binding only for minor mode

key binding only for minor mode

[Ryo Furue]

Hi emacs users,

I'm quite new to emacs lisp and using it in a learn-as-you-go way.
I'm now trying to disable C-x C-q (normally bound to toggle-read-only)
in the view mode, but I haven't been entirely successful.  So far,
I've
been using local-set-key in the view-mode-hook:

(add-hook 'view-mode-hook
  (lambda ()
   (local-set-key "\C-x\C-q"
	  (lambda () (interactive) (message "C-x C-q disabled.") (ding)))))

which woks---until you toggle off the view-mode by "M-x view-mode".
Once
I exit from the view mode, I want C-x C-q back, but the key binding is
still
disabled.   As I understand, the code above doesn't quite work because
the view mode isn't a major mode.   (local-set-key is local to the
major
mode, if I understand it correctly.)

So, my question is how to solve this problem?  What's the standard
procedure
to disable keys for a minor mode?

Thank you for your attention,
Ryo

Re: key binding only for minor mode

[Ivan Kanis]

Ryo Furue <furue@hawaii.edu> wrote:

> (add-hook 'view-mode-hook
>   (lambda ()
>    (local-set-key "\C-x\C-q"
> 	  (lambda () (interactive) (message "C-x C-q disabled.") (ding)))))

Nested lambda, nice going!

> So, my question is how to solve this problem?  What's the standard
> procedure to disable keys for a minor mode?

Find the keymap for view-mode and set the key to nil.

(add-hook 'view-mode-hook
   (lambda () (define-key view-mode-map (kbd "C-x C-q") nil)))

Kind regards,
-- 
Ivan
Kanis http://kanis.fr

In a room full of top software designers, if any two of them agree,
that is a majority.
    -- Bill Curtis 

Re: key binding only for minor mode

[Teemu Likonen]

On 2009-08-27 19:01 (-0700), Ryo Furue wrote:

> I'm now trying to disable C-x C-q (normally bound to toggle-read-only)
> in the view mode, but I haven't been entirely successful. So far, I've
> been using local-set-key in the view-mode-hook:
>
> (add-hook 'view-mode-hook
>   (lambda ()
>    (local-set-key "\C-x\C-q"
> 	  (lambda () (interactive) (message "C-x C-q disabled.") (ding)))))
>
> which woks---until you toggle off the view-mode by "M-x view-mode".

It's better to change the needed keymap (i.e., view-mode-map) directly:

    (add-hook 'view-mode-hook #'my-view-mode-hook)

    (defun my-view-mode-hook ()
      (define-key view-mode-map (kbd "C-x C-q")
        #'(lambda ()
            (interactive)
            (message "C-x C-q is disabled")
            (ding))))

Re: key binding only for minor mode

[Ryo Furue]

Thank you, Teemu and Ivan.  Your solutions work.  Except . . .

On Aug 27, 7:37 pm, Ivan Kanis <expire-by-2009-09...@kanis.fr> wrote:
> > So, my question is how to solve this problem?  What's the standard
> > procedure to disable keys for a minor mode?
>
> Find the keymap for view-mode and set the key to nil.
>
> (add-hook 'view-mode-hook
>    (lambda () (define-key view-mode-map (kbd "C-x C-q") nil)))

This one doesn't appear to have any effect.  I guess: This one removes
the key C-x C-q from the  local keymap (view-mode-map).  Therefore,
when you pressthe key combination, the global binding is invoked which
is toggle-read-only.  So, I guess we have to bind C-x C-q to something
rather than to undefine it, as in Teemu's example.

By the way, I'm wondering what #' is.  I vaguely know what a single
quote means (quote or don't evaluate it now) but I don't remember
seeing #' .  I tried the official emacs lisp reference manual, but
unless I read it from the top, I wouldn't find it.  (Google isn't of
much use when you want to search for something like '#  . . . ).

Anyway, I'm completely happy with the solution you showed.

Thanks again,
Ryo

Re: key binding only for minor mode

[Bernardo]

Ryo Furue said the following on 29/08/09 10:05:
> 
> By the way, I'm wondering what #' is.  I vaguely know what a single
> quote means (quote or don't evaluate it now) but I don't remember
> seeing #' .  I tried the official emacs lisp reference manual, but
> unless I read it from the top, I wouldn't find it.  (Google isn't of
> much use when you want to search for something like '#  . . . ).
>

look up (info "(elisp)Anonymous Functions")

(or "Quoting" where this is linked from)

Re: key binding only for minor mode

[Ryo Furue]

On Aug 28, 10:04 pm, Bernardo <bernardo.ba...@pobox.com> wrote:
> Ryo Furue said the following on 29/08/09 10:05:
[. . .]
> > By the way, I'm wondering what #' is.  I vaguely know what a single
> > quote means (quote or don't evaluate it now) but I don't remember
> > seeing #' .  I tried the official emacs lisp reference manual, but
> > unless I read it from the top, I wouldn't find it.  (Google isn't of
> > much use when you want to search for something like '#  . . . ).
>
> look up (info "(elisp)Anonymous Functions")

Thank you!  That info page explains it clearly.

Cheers,
Ryo