Re: Emacs should provide more modern item completion out of the box

[Juri Linkov]

>> Using a vertical display while keeping instant feedback of icomplete-mode
>> that doesn't require pressing TABs should be easy to do as well:
> [,,,]
>> (defun minibuffer-quick-update ()
>>   (when (>= (length (minibuffer-contents)) minibuffer-quick-min)
>>     (let ((completion-styles '(flex))
>>           (last-command nil))
>>       (minibuffer-complete))))
>
> Why `minibuffer-complete`?  This will actually perform completion
> (i.e. it may modify the content of the minibuffer).  I think you want to
> use `minibuffer-completion-help` instead

Ah, I completely forgot about the key `?'
(never used it since TAB is more DWIM-ish).

> (and I'm not sure why you bind `completion-styles` since it will only
> take effect during the display but not when the user finally hits RET).

This part I don't understand - it seems its main point is to take effect
during the display.

But anyway completion styles should be customized separately,
e.g. I think 'partial-completion' is more usable than 'flex' :)

> Also, you probably want to run this within a `while-no-input` of some kind.

'while-no-input' feels still too laggy when tried with this:

(defun minibuffer-quick-update ()
  (when (and minibuffer-completion-table
             (>= (length (minibuffer-contents)) minibuffer-quick-min))
    (let ((non-essential t))
      (while-no-input
        (minibuffer-completion-help)))))

Maybe better to use run-with-idle-timer that could be customized with
a number of seconds to delay.