bug#50679: 28.0.50; outline-minor-mode-cycle should be able to only cycle at the begining of a line

[Philip Kaludercic]

Augusto Stoffel <arstoffel@gmail.com> writes:

> On Mon, 20 Sep 2021 at 15:35, Philip Kaludercic <philipk@posteo.net> wrote:
>
>> Juri Linkov <juri@linkov.net> writes:
>>
>>>>> I didn't necessarily propose anything, it might only be able to solve
>>>>> this using a option like
>>>>>
>>>>>      (defcustom outline-minor-mode-cycle-predicate ...)
>>>>>
>>>>> as to allow for users to configure cycling as they see fit. Of course if
>>>>> some consistent behaviour could be found that respects other options and
>>>>> modes, then something automatic could also be used.
>>>>
>>>> Probably offloading the decision to the users with a customizable option
>>>> is all what we can do here, indeed.
>>>
>>> Maybe something like:
>>>
>>>  (defvar outline-mode-cycle-map
>>>    (let ((map (make-sparse-keymap)))
>>>      (let ((tab-binding `(menu-item
>>>                           "" outline-cycle
>>>                           ;; Only takes effect if point is on a heading.
>>>                           :filter ,(lambda (cmd)
>>> -                                    (when (outline-on-heading-p) cmd)))))
>>> +                                    (when (and (outline-on-heading-p)
>>> +                                               (or (not (functionp 
>>> outline-mode-cycle-filter))
>>> +                                                   (funcall 
>>> outline-mode-cycle-filter)))
>>> +                                      cmd)))))
>>>        (define-key map (kbd "TAB") tab-binding)
>>>        (define-key map (kbd "<backtab>") #'outline-cycle-buffer))
>>>      map)
>>>
>>> Then you can customize it to 'bolp'.
>>
>> I just tried it out, and it looks good. The only thing I wonder is if
>> this should apply to both outline-minor-mode and outline-mode?
>
> FWIW, I think it would be nice to provide a simple way to define other
> “speed keys” in `outline-minor-mode [1], or even provide some
> pre-configured ones [2].
>
> Looking at the code, it seems that adding bindings to
> `outline-mode-cycle-map` would achieve precisely that, but the name
> of the keymap doesn't reflect that.

I would appreciate something like this too, but you are right that it
sounds like a separate functionality. Compared to
outline-mode-cycle-map, this would most certainly have to operate on the
beginning of a line, otherwise apparently random keys would suddenly
throw the user around without them expecting it.

> [1]: Cf. https://orgmode.org/manual/Speed-Keys.html
>
> [2]: I personally use these speed keys in outline-minor-mode, which are
> probably very similar to those from Org mode:
>
>         "<tab>" 'outline-cycle
>         "<backtab>" 'outline-cycle-buffer
>         "f" 'outline-forward-same-level
>         "b" 'outline-backward-same-level
>         "n" 'outline-next-visible-heading
>         "p" 'outline-previous-visible-heading
>         "u" 'outline-up-heading
>         "F" 'outline-move-subtree-down
>         "B" 'outline-move-subtree-up
>         "@" 'outline-mark-subtree

-- 
        Philip Kaludercic