Show completions for args with declared choices

[rcorre]

Now that cmdutils.argument is being used (c33f0c3), there's some potential for expanding completions for commands.

After inputting --someflag or --someflag= in the command bar, we could show completions if that flag has choices.

1. Is there already someone working on this?
2. Would it be a bad idea to do this before the proposed completion revamp in Completion model/view revamping #74?

I threw together a really rough proof-of-concept in 6b2fb66

[The-Compiler]

Sorry for the delay - I think your proposed code is simple enough to include it before #74, and yay for more discoverability!

I think :bind is the only command which has a flag with an argument though, so it'd be nice if this would also work for positional arguments with choices (e.g. when doing :navigate) if it doesn't yet.

[rcorre]

I think :bind is the only command which has a flag with an argument though, so it'd be nice if this would also work for positional arguments with choices

Yeah, that's part of the plan. I was thinking there'd be more flags with choices, but I guess not. I'd just been working with bind a lot recently so that was on my mind.
Completions for the flags themselves would be nice too. I'll poke around and see how much complexity that will add.

[The-Compiler]

Completions for the flags themselves would be nice too. I'll poke around and see how much complexity that will add.

Yep, I already had that in mind in #32 some while ago 😆

I think that'll be a lot harder, because at that point you need composable completions (since for every command, you can have either the completion for the argument, or flags), which basically is the goal of #74.

FWIW I'd also prefer minimal pull requests, makes things easier to review - so if you have something which seems ready and finished enough, feel free to open a PR and then another one when you improve things!

Also, would you be interested in working on that completion revamping (#74)? I don't really have a master plan in mind for that one, and it's unlikely I'll work on anything completion related in the near future - but at the same time I think it's a very important step towards getting more completions. If you think that'd be something you'd like to work on, would you mind joining the IRC channel to talk about the details?

[rcorre]

Sounds good to me, I'm willing to try revamping completions. I'll jump on IRC, and we can talk about it some time.

[The-Compiler]

I added this to #32 to keep all completion ideas in one place.