Re: Split off some backends from Company?

[Dmitry Gutov]

On 08/13/2014 04:38 PM, Stefan Monnier wrote:

> > Probably not: using yasnippet as a completion source is a questionable
> > decision, which each user should make themselves. It replaces the advertised
> > way to interact with yasnippet (type the snippet key, press TAB), and the
> > recommended way to use this backend is to group it with others, not by
> > itself (think `completion-table-merge' instead of
> > `completion-table-in-turn'), so putting it in
> > `completion-at-point-functions' would probably be misguided.
>
> I see what you mean, but why does this need another package?
> It seems the code could/should be in yasnippet, controlled by
> something like a minor-mode.

It could be in yasnippet, but then it would implicitly depend on Company 
anyway. A minor mode would, again, be something like an on/off switch, 
and company-yasnippet requires manual configuration to be useful, and 
users probably have to pick a good combination for each major mode they 
intend to use it in.

And some users just bind a key sequence to this command (which all 
Company backend double as), to invoke instead of pressing TAB for 
yasnippet expansion. I guess this specific usage could be facilitated 
via a minor mode, but I don't know how popular it is.

> > Hmm, yes. I guess we could do that if the user explicitly
> > installed a backend package.
>
> I think it's "should" rather than "could", because it's important for
> the installation to be as straightforward as possible.

On the one hand, the simplest setup is desirable. On the other hand, 
`company-backends' is designed to be customized, and to allow users to 
mix backends, to there's no single way to use a specific backend (see 
https://github.com/iquiw/company-ghc#4note as an example of alternative 
setup). So the simplicity has to be balanced against the odds of users 
being forced to undo the automatic setup.

Further, there is a convention in the third-party developer community of 
not doing too much in autoloads ("installing the package shouldn't turn 
it on", or something along these lines). I don't entirely agree with it 
(here's one discussion on the subject: 
https://github.com/skeeto/skewer-mode/issues/22#issuecomment-18454897), 
but I prefer to do less, rather than more, when the choice is not obvious.