Re: [Emacs-diffs] master b0e318d 2/2: Score flex-style completions according to match tightness

[Dmitry Gutov]

On 17.03.2019 23:46, João Távora wrote:

> > Another thing I'd like to note: with flex completion, RET doesn't select
> > the current candidate anymore (working as intended, of course). But it's
> > a bit disorienting.
>
> In what situation exactly? Emacs -Q + (setq completion-styles '(flex)) + what?

+ input is not a prefix match. E.g. M-x describe-variable, then input 
'compst'. RET won't select the completion.

> You're right, more or less, at least judging from some benchmarks:
>
> (benchmark-run-compiled 100
>    (let ((completion-styles '(flex)))
>      (completion-all-completions "kill" obarray nil 0))) ; => 4.76s
>
> (benchmark-run-compiled 100
>    (let ((completion-styles '(basic)))
>      (completion-all-completions "kill" obarray nil 0))) ; => 3.7s
>
> ... and the first returns a much larger list.

Try a smaller input, like just 'k'. The difference is more stark in that 
case, and the lists of completions are longer.

For the same reason (lots of matches), I'm afraid simply moving matching 
to C won't bring a noticeable improvement.

> I was expecting to see much larger differences, though, since my
> icomplete and company-based experience is really sluggish. But
> I wasn't using these much for the default completion style anyway.
> Or maybe the sluggishness is coming from somewhere else.
>
> Anyway, as I predicted, most of the work is the matching in
> completion-pcm--all-completions.  I'll try to hack something
> there when the pattern has some simple flex-like form.

All right. Please let us know of the results.