Re: [External] : Re: Smarter M-x that filters on major-mode

[Stefan Monnier]

>> Perhaps you're using some completion framework
>> that starts displaying candidates without waiting
>> for any input to match?
> Yes. It is equivalent to M-x <TAB> with the default completion system.
> But even if you wait until you type the first character, the filtering
> could cause a perceptible lag.

That is a concern, indeed, but there are many ways to attack the
problem:

- Arrange for the predicates to be "translucid", so you can test them by
  groups that share the same predicate in a way that's a lot more
  efficient (this will strongly depend on details).  I hope we don't
  have to go there.
- Delay the predicate filtering to the last stage and filter lazily, so
  you can stop as soon as you have found enough completions to fill the
  part displayed on screen.
- ...

In any case, this is all very hypothetical for now.
What we need is experience (and there is already some of that
experience, collected from the `smex` experiment).


        Stefan