Re: BIKESHED: completion faces

[Dmitry Gutov]

On 05.11.2019 17:44, Stefan Monnier wrote:
> > I've tried to implement my idea, but somehow the added highlighting gets
> > eaten before the buffer is displayed. But the attached patch should
> > illustrate it anyway.
>
> Regardless of how we implement this, the question remains: do we want to
> highlight the common-part of the prefix/basic completion differently
> from the other cases?

We might. But I'd rather do that per-completion rather per completion 
style, hence the proposed patch.

>          Stefan
>
>
> PS: I think the approach used in your patch will lead to undesirable
> behavior when some matches (but not all) have all chars before
> first-diff highlighted with common-part.  E.g.
>
>      src/emacs -Q --eval '(setq completion-styles (quote (partial-completion)))'
>      M-x re-b ?
>
> where `re-builder` would be highlighted with a "trivial common part"
                     ^ won't be                   ^nontrivial

> whereas `rename-buffer` would be highlighted differently.

Indeed. That's the whole idea. "re" and "-b" in "rename-buffer" would 
indeed be highlighted since the match is nontrivial.

> You might consider it as a feature, of course.

Yes. That's the idea.

As for how it would work in practice, we'll have to see once the patch 
is functioning.