Re: Limit what M-x TAB lists?

["Óscar Fuentes" <ofv@wanadoo.es>]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> If these predicates become very complex, then `M-x fooTAB' would become
> exceedingly slow, though...

Instead of a predicate for every function, the usual Emacs idiom of "if
it is a symbol, filter by mode, if it is a function, it must be a
predicate returning non-nil if the command is applicable blah blah...".
I'll bet that 99% of the commands fall in the "symbol" case, which is
fast.

>> Of course, this will require many changes in many packages before it
>> becomes really useful.
>
> Yes, but modes could be converted gradually, and things would get better
> and better as time passes...

I'm definitely interested on this idea. It is annoying (as in "Emacs
looks stupid and counterproductive") to always see useless candidates on
M-x. If you put the underlying machinery in place, I volunteer for the
command hunt.

It would be nice if the annotations were backwards compatible, so they
could be added to external packages without making them incompatible
with past Emacs releases.