Re: pcomplete makes assumptions about its interactive entry points

[Vivek Dasmohapatra <vivek@etla.org>]

On Thu, 12 Sep 2013, Stefan Monnier wrote:

>> Hi - pcomplete makes an assumption (I think) about the interactive
>> entry point(s) which can be used to drive it which means that non-
>> native entry points don't get completion cycling.
>
>> Attached is a possible fix plus the alteration required
>> to make erc completion use it.
>
> Could you explain in which circumstance this is needed?

In an erc buffer, I tried to tab-complete a nick: The initial tab completion
showed many possibilities - I typed an extra character, which should have
limited it to a small enough number for tab-completion-cycling to kick in...
but instead TAB just unconditionally completed to the first of the remaining
candidates, and never offered me the chance to pick any of the others.

It turns out that pcomplete assumes that the interactive entry point
(activating command) can only ever be one of a handful of commands,
and specifically checks for those when deciding whether to enter the
code path that starts cycling through the remaining completions.

So modes that use pcomplete but define their own commands for tab 
completion lose the ability to use pcomplete cycling unless they have
a way of adding themselves to the list of entry points that pcomplete
knows about.