Help mode keybindings

Help mode keybindings

[Emanuel Berg]

How do I bind C-j to "jump-to-register" in help mode?

I'd like that globally, so I bound it so in .emacs. But, in some modes
it was bound locally. For example, in "Lisp Interaction" mode, I had to
locally unset C-j to clear the path to the global binding, and this
worked with no problems:

(add-hook 'lisp-interaction-mode-hook
          (lambda () (local-unset-key (kbd "C-j"))) )

But, that didn't work for Help mode: the local binding wasn't
dropped. Not even setting it explicitly work, as in the below
code. Strangely, the "j" (not C-j) version worked!

(add-hook 'help-mode-hook
 (lambda ()
  ; ...
  (define-key help-mode-map (kbd "j")   'jump-to-register)    ; works
  (define-key help-mode-map (kbd "C-j") 'jump-to-register) )) ; not so

Are the Help mode keybindings set in stone?
-- 
Emanuel Berg - programmer (hire me! CV below)
computer projects: http://user.it.uu.se/~embe8573
internet activity: http://home.student.uu.se/embe8573

Re: Help mode keybindings

[Emanuel Berg]

(I got this by mail, and can't find it on the list. Anyway, I suppose
it was intended for the list as well.)

> Works for me in Emacs 24.  Not in Emacs 23, however.  The cause seems
> to be that in Emacs 23, *Help* is in `view-mode', which has a binding
> for C-j.

> Note that minor mode bindings take precedence over local (major-mode)
> bindings.

Aha, I see. Perhaps I should upgrade to Emacs 24. 

> Probably there is no trivial way to achieve what you want.  You could
> use a minor mode yourself - or find a key that is not already used at
> multiple places.

Hm, to write a minor mode to shadow the view-mode sounds like
overkill. Wouldn't it be simpler to change the view minor mode? Or is
there something making that more difficult than I thought, as well?

> I myself try to avoid re-binding such pre-defined keys.  Often you
> later find a mode where, to keep the example, the original binding of
> C-j is something you really want, and you have to find another key
> for that one or give up that your own binding is available everywhere
> etc.

In general, I agree, but, no rule without an exception... That key
works for all the zillion modes I use, it is in my muscle memory, and
it is a "close" shortcut (my index finger already at 'J'). I use
registers to navigate my entire file system, and any project I
currently work on, so I'm not giving it up.

> Or make a binding in `key-translation-map'.

How would I do that?

-- 
Emanuel Berg - programmer (hire me! CV below)
computer projects: http://user.it.uu.se/~embe8573
internet activity: http://home.student.uu.se/embe8573

Re: Help mode keybindings

[Emanuel Berg]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> Works for me in Emacs 24.  Not in Emacs 23, however.  The cause seems
> to be that in Emacs 23, *Help* is in `view-mode', which has a binding
> for C-j.

I think I just solved it (thanks to your identification of the
problem), simply by disabling the blocking minor mode. I don't know if
there are any side effects to it; time will tell.

(add-hook 'help-mode-hook
   (lambda ()
      (set-help-mode-line)
      (view-mode -1) ))

-- 
Emanuel Berg - programmer (hire me! CV below)
computer projects: http://user.it.uu.se/~embe8573
internet activity: http://home.student.uu.se/embe8573

Re: Help mode keybindings

[Michael Heerdegen]

Emanuel Berg <embe8573@student.uu.se> writes:

> (add-hook 'help-mode-hook
>    (lambda ()
>       (set-help-mode-line)
>       (view-mode -1) ))

This won't solve the problem in other situations where view-mode is
enabled.  I think

(define-key view-mode-map [?\C-j] nil)

would be a bit better.


Regards,

Michael.

Re: Help mode keybindings

[Emanuel Berg]

Michael Heerdegen <michael_heerdegen@web.de> writes:

>> (add-hook 'help-mode-hook
>>    (lambda ()
>>       (view-mode -1) ))
>
> This won't solve the problem in other situations where view-mode is
> enabled.

No, but those other situations have hooks as well. But I see your
point.

>I think
>
> (define-key view-mode-map [?\C-j] nil)
>
> would be a bit better.

Should I put it as it is in .emacs? Because, if I do, I get

    Symbol's value as variable is void: view-mode-map

Or do I have to initiate something before it works?

-- 
Emanuel Berg - programmer (hire me! CV below)
computer projects: http://user.it.uu.se/~embe8573
internet activity: http://home.student.uu.se/embe8573

Re: Help mode keybindings

[Michael Heerdegen]

Emanuel Berg <embe8573@student.uu.se> writes:

> > (define-key view-mode-map [?\C-j] nil)

> Should I put it as it is in .emacs? Because, if I do, I get
>
>     Symbol's value as variable is void: view-mode-map

Sorry, right - view.el is not loaded by default.  You can do it that way
in your .emacs:

  (eval-after-load 'view '(define-key view-mode-map [?\C-j] nil))

Also loading view.el explicitly before undefining the key would work.


Michael.

Re: Help mode keybindings

[Emanuel Berg]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> (eval-after-load 'view '(define-key view-mode-map [?\C-j] nil))

OK, thanks, it works. Wow, never seen `eval-after-load'. But loading
seems more robust.

-- 
Emanuel Berg - programmer (hire me! CV below)
computer projects: http://user.it.uu.se/~embe8573
internet activity: http://home.student.uu.se/embe8573

Re: Help mode keybindings

[Michael Heerdegen]

Emanuel Berg <embe8573@student.uu.se> writes:

> (I got this by mail, and can't find it on the list. Anyway, I suppose
> it was intended for the list as well.)

Thanks for the hint - my mistake.

> > Probably there is no trivial way to achieve what you want.  You could
> > use a minor mode yourself - or find a key that is not already used at
> > multiple places.
>
> Hm, to write a minor mode to shadow the view-mode sounds like
> overkill.

It would have the advantage that you would not have to treat any mode
that binds C-j individually.

But it would have the disadvantage that you would have to ensure that
your new minor mode has a higher priority than any other minor mode it
should "shadow".

> Wouldn't it be simpler to change the view minor mode? Or is
> there something making that more difficult than I thought, as well?

No, it's easy - just do

(define-key view-mode-map [?\C-j] nil)

> > Or make a binding in `key-translation-map'.
>
> How would I do that?

Better don't - it's possible, but only the last solution one should
think about.  Let's try to do without.


Michael.