Preferred way to add commands to a foreign keymap?

Preferred way to add commands to a foreign keymap?

[Sean McAfee]

I want to add the following command to Dired mode:

(defun mac-open-files (arg)
  (interactive "P")
  (dired-do-shell-command "/usr/bin/open" arg (dired-get-marked-files)))

I can think of two ways to do it:

1.  Twiddle dired-mode's keymap directly:

    (define-key dired-mode-map [(super o)] 'mac-open-files)

2.  Use local-set-key in a hook:

    (add-hook 'dired-mode-hook 
              (lambda () (local-set-key [(super o)] 'mac-open-files)

#1 seems like the (very, very slightly) more efficient appoach, but I
worry that I'm potentially trampling on a dired-mode implementation
detail.

Is there any practical reason to prefer one approach over the other?  Or
is there another way?

Re: Preferred way to add commands to a foreign keymap?

[Xah Lee]

On Sep 16, 5:36 pm, Sean McAfee <eef...@gmail.com> wrote:
> I want to add the following command to Dired mode:
>
> (defun mac-open-files (arg)
>   (interactive "P")
>   (dired-do-shell-command "/usr/bin/open" arg (dired-get-marked-files)))
>
> I can think of two ways to do it:
>
> 1.  Twiddle dired-mode's keymap directly:
>
>     (define-key dired-mode-map [(super o)] 'mac-open-files)
>
> 2.  Use local-set-key in a hook:
>
>     (add-hook 'dired-mode-hook
>               (lambda () (local-set-key [(super o)] 'mac-open-files)
>
> #1 seems like the (very, very slightly) more efficient appoach, but I
> worry that I'm potentially trampling on a dired-mode implementation
> detail.
>
> Is there any practical reason to prefer one approach over the other?  Or
> is there another way?

don't think it matters practically speaking.
The latter is probably better, since it's more general n more higher
level.

The first solution you have to be sure the mode is loaded first, in
the case of dired i think it's always loaded when emacs starts.

 Xah