bug#66948: [PATCH] Add Completion Preview mode

[Eshel Yaron via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Philip Kaludercic <philipk@posteo.net> writes:

> Eshel Yaron <me@eshelyaron.com> writes:
>
>> Tags: patch
>>
>> Following the recent discussion on emacs-devel[0], I'm attaching a patch
>> that adds a new Completion Preview minor mode.
>
> I didn't follow the discussion in detail, but is this related to the
> capf-autosuggest package?

`capf-autosuggest` didn't really come up so far.  It is related to
Completion Preview, but `capf-autosuggest` only deals with `comint`-like
buffers, while Completion Preview works in all buffers.  I don't know if
and how `capf-autosuggest` could be extended to work in arbitrary buffers.

> FWIW From a brief test, my main annoyances have been that DEL drops any
> completion

Thanks for testing.  To have DEL not dismiss the completion preview, add
`delete-backward-char` to `completion-preview-commands`.  Actually,
would it make sense to have that behavior by default?

> and that there is no option to cycle between inexact completions.

That's interesting, can you elaborate about the use case that you have
in mind?  I thought about adding a command to do that, but I wasn't sure
there'd be a good use case for it since you can always dismiss the
preview (e.g. with `C-g`) and say `C-M-i` to pick another candidate.

>> [0] https://lists.gnu.org/archive/html/emacs-devel/2023-10/msg00693.html
>>
>> +  (pcase (bounds-of-thing-at-point 'symbol)
>
> [...]
>
> You can use `pcase-let' here.
>

Good idea, I'll try it out.


Best,

Eshel