How to define minor-mode keybindings conditional on buffer's major-mode?

How to define minor-mode keybindings conditional on buffer's major-mode?

[Thorsten Jolitz]

Hi List, 

assume in a program in minor-mode is activated for a buffer that can
have one of two different major-mode, and different keybindings are
needed for each major-mode to avoid conflicts. 

Here is a kind of "emacs lisp pseudocode" that shows the logic, but
can't work of course:

,----------------------------------------------------------
|   (define-key minor-mode-map
|     (if (eq major-mode 'xyz-mode) "<<key-binding1>>" "<<key-binding1>>" )
|     'minor-mode-command)
`----------------------------------------------------------

How can this be achieved?

-- 
cheers,
Thorsten

Re: How to define minor-mode keybindings conditional on buffer's major-mode?

[Thorsten Jolitz]

Thorsten Jolitz <tjolitz@gmail.com> writes:

ok, sometimes spellchecking would not hurt: this should be more readable
than the first version:

"assume in a program a minor-mode is activated for a buffer that can
have one of two different major-mode, and different keybindings are
needed for each major-mode to avoid conflicts. 

Here is a kind of "emacs lisp pseudocode" that shows the logic, but
can't work of course:

,----------------------------------------------------------
|   (define-key minor-mode-map
|     (if (eq major-mode 'xyz-mode) "<<key-binding1>>" "<<key-binding2>>" )
|     'minor-mode-command)
`----------------------------------------------------------

How can this be achieved?"

-- 
cheers,
Thorsten

Re: How to define minor-mode keybindings conditional on buffer's major-mode?

[Stefan Monnier]

> How can this be achieved?"

You can define two keymaps (probably inheriting from a third one that
contains the shared stuff), and then in the minor-mode function, setup
minor-mode-overriding-map-alist to use the right one.

Or you can do truly evil things like

   (define-key minor-mode-map
     "<<key-binding1>>"
     `(menu-item "" minor-mode-command
       :filter ,(lambda (cmd) (if (eq major-mode 'xyz-mode) cmd))))
   (define-key minor-mode-map
     "<<key-binding2>>"
     `(menu-item "" minor-mode-command
       :filter ,(lambda (cmd) (if (not (eq major-mode 'xyz-mode)) cmd))))


-- Stefan

Re: How to define minor-mode keybindings conditional on buffer's major-mode?

[Thorsten Jolitz]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> How can this be achieved?"
>
> You can define two keymaps (probably inheriting from a third one that
> contains the shared stuff), and then in the minor-mode function, setup
> minor-mode-overriding-map-alist to use the right one.

That is the way I want to go - but I don't get it, unfortunatly

I find examples like this on the web:

,---------------------------------------------------------------------------------------
| (defun ergoemacs-minibuffer-setup-hook ()
|   "Hook for minibuffer to move through history with previous-line and next-line keys."
|
|   (defvar ergoemacs-minibuffer-keymap (copy-keymap ergoemacs-keymap))
|
|   (define-key ergoemacs-minibuffer-keymap ergoemacs-previous-line-key
|   'previous-history-element)
|
|   [...]
|   (add-to-list 'minor-mode-overriding-map-alist (cons 'ergoemacs-mode
|   ergoemacs-minibuffer-keymap)) )
`---------------------------------------------------------------------------------------


so, is it as simple as putting something like this

,----------------------------------------------
| (progn
| (add-to-list 'minor-mode-overriding-map-alist
|  (cons 'major-mode-A A-specific-keymap))
| (add-to-list 'minor-mode-overriding-map-alist
|  (cons 'major-mode-B B-specific-keymap)) )
`----------------------------------------------

at the end of this definition

,-----------------------------------------------------------
| (defun w3m-form-input-textarea-mode (&optional arg)
|   "\\<w3m-form-input-textarea-map>
| Minor mode to edit form textareas of w3m.
|
| \\[w3m-form-input-textarea-set]\
|         Set the value and exit from this textarea.
| \\[w3m-form-input-textarea-exit]\
|         Exit from this textarea without setting the value.
| \\[w3m-form-input-textarea-save]\
|         Save editing data in this textarea.
| "
|   (interactive "P")
|   (when (setq w3m-form-input-textarea-mode
|               (if arg
|                   (> (prefix-numeric-value arg) 0)
|                 (not w3m-form-input-textarea-mode)))
|     (run-hooks 'w3m-form-input-textarea-mode-hook)))
`-----------------------------------------------------------

?

> Or you can do truly evil things like
>
>    (define-key minor-mode-map
>      "<<key-binding1>>"
>      `(menu-item "" minor-mode-command
>        :filter ,(lambda (cmd) (if (eq major-mode 'xyz-mode) cmd))))
>    (define-key minor-mode-map
>      "<<key-binding2>>"
>      `(menu-item "" minor-mode-command
>        :filter ,(lambda (cmd) (if (not (eq major-mode 'xyz-mode)) cmd))))

I rather try not to be evil in this case ...

--
cheers,
Thorsten

Re: How to define minor-mode keybindings conditional on buffer's major-mode?

[Stefan Monnier]

> so, is it as simple as putting something like this

> ,----------------------------------------------
> | (progn
> | (add-to-list 'minor-mode-overriding-map-alist
> |  (cons 'major-mode-A A-specific-keymap))
> | (add-to-list 'minor-mode-overriding-map-alist
> |  (cons 'major-mode-B B-specific-keymap)) )
> `----------------------------------------------

No, you'd put

   (add-to-list 'minor-mode-overriding-map-alist
       (cons 'my-minor-mode (if (eq major-mode 'xyz-mode)
                                xyz-specific-map
                              other-minor-map)))

in your minor mode function.  Or

   (when (eq major-mode 'xyz-mode)
     (add-to-list 'minor-mode-overriding-map-alist
         (cons 'my-minor-mode xyz-specific-map)))


-- Stefan

Re: How to define minor-mode keybindings conditional on buffer's major-mode?

[Thorsten Jolitz]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> so, is it as simple as putting something like this
>
>> ,----------------------------------------------
>> | (progn
>> | (add-to-list 'minor-mode-overriding-map-alist
>> |  (cons 'major-mode-A A-specific-keymap))
>> | (add-to-list 'minor-mode-overriding-map-alist
>> |  (cons 'major-mode-B B-specific-keymap)) )
>> `----------------------------------------------
>
> No, you'd put
>
>    (add-to-list 'minor-mode-overriding-map-alist
>        (cons 'my-minor-mode (if (eq major-mode 'xyz-mode)
>                                 xyz-specific-map
>                               other-minor-map)))
>
> in your minor mode function.  Or
>
>    (when (eq major-mode 'xyz-mode)
>      (add-to-list 'minor-mode-overriding-map-alist
>          (cons 'my-minor-mode xyz-specific-map)))

Thanks, that works - the doc for 'minor-mode-overriding-map-alist' is
actually a bit sparse (or I'm a bit thick ;)

BTW - I just sent a patch (not yet accepted and applied at the time of
this writing) to the emacs-w3m maintainer that adds functionality to the
textarea section of w3m-form.el - which opens a dedicated, minimal size
text-mode edit buffer for the content of a html textarea by default -
for editing textareas containing text in Org-mode syntax in a
(full-size) Org-mode edit buffer.

You can use `w3m-form-textarea-toggle-major-mode' to toggle between
'text-mode and 'org-mode as major modes for the edit buffer. Since the
original keybindings for 'text-mode clash with important Org-mode
keybindings, a specialised keymap is activated for the 'org-mode case. 

This makes emacs-w3m a very good Emacs UI for interactive web apps based
on Org-mode markup syntax - to be announced soon, I hope. 

-- 
cheers,
Thorsten