Re: vertical fido-mode (new branch)

[Ergus]

On Tue, Aug 25, 2020 at 07:42:23PM -0400, Stefan Monnier wrote:
> When introducing hooks, often it's a good idea to try and think of
> *replacing* rather than *adding*.  E.g. Maybe instead of running
> `minibuffer-hide-completions-hook` after hiding the buffer, you want to
> have a `minibuffer-hide-completions-function` which defaults to `bury-buffer`.
>
> I'm not sure if it'd be better in this specific instance, but...
Hi Stefan:

Yes I also thought that, but as there is the `completion-setup-hook`
called when the completions are shown I just thought in a `symmetric`
hook to call when closing.

In my opinion the hook here was just simpler. Also because the
bury-buffer runs inside a with-selected-window and the action I need are
in the minibuffer.

> ... I think here it might be a good idea: introduce
> a `minibuffer-tab-through-completions-function` which by default would
> do the scrolling, i.e.:
>
>    (let ((window minibuffer-scroll-window))
>      (with-current-buffer (window-buffer window)
>        (if (pos-visible-in-window-p (point-max) window)
>            ;; If end is in view, scroll up to the beginning.
>            (set-window-start window (point-min) nil)
>          ;; Else scroll down one screen.
>          (with-selected-window window
>             (scroll-up)))
>        nil)))
>
> and which you could override to your liking.
This is exactly what I did ;p thanks for the name cause mine was worst.

> This makes me think maybe you were thinking exactly the same and we're
> just in violent agreement.
>
>
>        Stefan
I have 2 questions:

1) Why the function needs to return nil if the return value of
completion--in-region-1 is not used anywhere so far?

2) What's the "canonical method" to add a keymap to the minibuffer (and
*Completions*) when enabling the mode but restoring it cleanly at the
end?

Is it possible to do something like push/pop a keymap to another?

I see we have inheritance for keymaps but maybe there is a simpler
method?

How can I restrict the mode-keymap to the minibuffer for example?

Thanks in advance,
Ergus