Re: view-mode keymap

[Daimrod]

Daimrod <daimrod@gmail.com> writes:

> Jambunathan K <kjambunathan@gmail.com> writes:
>
>> Daimrod <daimrod@gmail.com> writes:
>>
>>> Jambunathan K <kjambunathan@gmail.com> writes:
>>>
>>>> I think, `make-composed-keymap' can help here.
>>>>
>>>>
>>>>> I like `view-mode' but it conflicts with others minor mode map (paredit
>>>>> in my case).
>>>>>
>>>>> I would like to know if there is a better way to make a keymap that
>>>>> takes precedence over the others than manipulating
>>>>> `minor-mode-map-alist'.
>>>>>
>>>>> Here is my current implementation:
>>>>>
>>>>> (add-hook 'view-mode-hook
>>>>>           (lambda ()
>>>>>             ;; Makes sure `view-mode-map' is the first minor mode map
>>>>>             ;; available in `minor-mode-map-alist', because in case of
>>>>>             ;; conflicting bindings, the first one is used.
>>>>>             (unless (eq 'view-mode (caar minor-mode-map-alist))
>>>>>               (setf minor-mode-map-alist
>>>>>                     (cons (cons 'view-mode view-mode-map)
>>>>>                           (cl-remove 'view-mode minor-mode-map-alist
>>>>>                                      :key #'car))))))
>>>
>>> I've looked at it but I don't see how it can help. I don't want to
>>> create a new keymap, I want `view-mode-map' to take priority over other
>>> keymaps.
>>
>> I was hoping that something like this
>>
>>     (use-local-map
>>      (make-composed-keymap view-mode-map
>>                            (current-local-map)))    
>>         
>> will put `view-mode-map' on top of the keymap stack and thus overwrite
>> paredit's bindings.
>>
>> I see that DEL (backspace) key is shared between view-mode and paredit.
>> My little experimentation that the above snippet failst to produce the
>> effect expected by me.
>>
>> Do you think I am reading the doc of the APIs (used above) incorrectly?
>
> No, the problem is not the way you're building the keymap, but how
> keymaps are searched.
>
> From (info "(elisp) Searching Keymaps")
>> (or (cond
>>      (overriding-terminal-local-map
>>       (FIND-IN overriding-terminal-local-map))
>>      (overriding-local-map
>>       (FIND-IN overriding-local-map))
>>      ((or (FIND-IN (get-char-property (point) 'keymap))
>>           (FIND-IN TEMP-MAP)
>>           (FIND-IN-ANY emulation-mode-map-alists)
>>           (FIND-IN-ANY minor-mode-overriding-map-alist)
>>           (FIND-IN-ANY minor-mode-map-alist)
>>           (if (get-text-property (point) 'local-map)
>>               (FIND-IN (get-char-property (point) 'local-map))
>>             (FIND-IN (current-local-map))))))
>>     (FIND-IN (current-global-map)))
>
> It searches through `minor-mode-map-alist' _before_ looking at
> `current-local-map'.
>
> I could use `overriding-local-map' instead of `current-local-map' if it
> was a buffer local variable. But it's not, and I'm afraid that making it
> buffer local might break things in a weird way.

However I've just noticed that I can use `minor-mode-overriding-map-alist'
instead of `minor-mode-map-alist'.

So now my code is:

(add-hook 'view-mode-hook
          (lambda ()
            ;; In `view-mode', `view-mode-map' overrides other minor
            ;; mode maps.
            (pushnew (cons 'view-mode view-mode-map)
                     minor-mode-overriding-map-alist
                     :key #'car)))

A bit more cleaner :)

>>> I've looked at the documentation and it seems that changing the order in
>>> `minor-mode-map-alist' is the only way to manage priorities between
>>> keymap, because they shouldn't conflict in there first place.

-- 
Daimrod/Greg