Re: [PATCH] Re: Other details about completion.

[Ergus <spacibba@aol.com>]

On Thu, Apr 07, 2022 at 08:57:17PM +0300, Juri Linkov wrote:
>>> So why do you think that switching to the Completions window
>>> is required to select a completion candidate?
>>
>> Basically because we don't need that exact behavior in all the details
>> as our use case is a bit different different (and simpler). we use
>> single commands most if the time. I mean, most of the completion we need
>> are for single commands/candidates/files because we can't do things
>> like: "M-x find-file /my/file/path" in a single line. (there are some
>> exceptions line shell-commands or so... but those are the exception, not
>> the rule)
>>
>> But also because emulating that from completions is straight forward
>> considering that Completions is read-only and any edit attempt (insert a
>> letter) will emit an error we can handle moving to the minibuffer and
>> executing there whatever we need.
>>
>> zsh adds an extra space before the letter so even if it does not leave
>> the command line completely there is a switch to a state where arrows
>> navigate, a letter inserts a space and C-g restores to the initial... So
>> there is a mode and context change.
>
>So inserting a letter from the Completions buffer is the only thing
>that you miss from zsh? 

Actually yes, that and remove the mode-line to completions...

>But you also said above that this feature is
>not important because such cases are rare: "M-x find-file /my/file/path".
>
I can live with that. Lets say in our case adding a space does not make
much sense, but just inserting the letter in place without completion
may be a better behavior... But again... I can live with this.

>In all other regards, currently it works exactly like in zsh:
>'TAB TAB' selects the Completions window, and C-g cancels it.
>
Yes...

>>> But in zsh <up> and <down> wrap to the top/bottom of the same column.
>>
>> Yes, I already implemented that and you didn't liked because it was a
>> bit long ;p... Now this is getting longer and longer....
>
>Indeed, its logic looks complicated.  But maybe we could implement
>simple rules like in zsh?  Then <up> ans <down> in the Completions
>buffer could be bound to new commands.
>
Let's cleanup master and move to our own branch then??

>>> Also in zsh TAB moves vertically when columns are sorted vertically.
>>> Shouldn't TAB in Emacs move vertically too when 'completions-format'
>>> is 'vertical'?
>>
>> Actually yes... But implementation will be long and ugly... I don't
>> think it worth it...
>>
>> The ideal case may be to have some modes completions-vertical,
>> completions-horizontal and completions-one-column that will handle all
>> the pack together (bindings, order, formats)... but may break some of
>> the external packages. Otherwise we will end with a code full of if-else
>> and hard to maintain or extend...
>
>Looks like the right thing to do.