Re: Updating *Completions* as you type

[Eli Zaretskii]

> From: sbaugh@catern.com
> Date: Thu, 12 Oct 2023 19:53:53 -0400
> 
> 
> It would be nice if there was a built-in customization which caused
> *Completions* to update as you type, as long as that buffer is visible.
> I imagine such a request has been made before, so what is the obstacle
> to adding it?

I think we have alternative completion schemes, like ido.el and
others, which update the list of the completion candidates as you
type, albeit not in the *Completions* buffer.  Why would we need yet
another knob in the default completion scheme?

> (Btw, if we had this behavior, it also seems like it would help with
> another long-time request: asynchronous completion support.  A
> programmed completion table could internally do something asynchronous
> and stateful, and accumulate results over time, and return more and more
> results each time Emacs calls all-completions/try-completion.  If Emacs
> automatically called all-completions with such a programmed completion
> table, the resulting behavior would be an acceptable approximation of
> asynchronous completion, without having to complicate the programmed
> completion API.)

IIUC what you mean by "asynchronous completion", it is a terrible
idea.  How can anyone type text without getting immediate feedback for
what he/she typed?  When I sometimes see this (due to network delays
or system load or whatever), it is a terrible UX.