Feat: Actions

[benjamin-kirkbride]

First pass, here is how you would register an action that is only available for Markdown files against Paths:

register_path_action(
    name="foo",
    description="bar",
    callback=lambda: None,
    availability_callbacks=[filetype_availability(["Markdown"])],
)

I was going to have some dedicated arguments for things like filetype availability, whether or not you can use a directory or a file path, etc, but ultimately I think what makes the most sense is having a single callback that takes a list of availability_callbacks, idea being these callbacks will be executed in order, and if any return False, the action is not available. I think that creating helpers for this will be extremely flexible, composable, and dev friendly.

Thoughts on how it is so far?

Fixes #1341

[benjamin-kirkbride]

Instead of having 3 register_*action commands, I could have boolean switches on a single register_action function. What are your thoughts?

[Akuli]

I like the design overall :)

[Akuli]

I think I want the 3 separate functions, at least for now.

[Akuli]

I spent literally 3 hours trying to figure this out

Feel free to ask me if I'm online :D

[Akuli]

Just a few nits.

[benjamin-kirkbride]

I think it's fair to call "actions.py: the action classes, the registry and the related functions" done now

[Akuli]

The last nit...

[Akuli]

The discussion on this PR has become a bit tl;dr to follow. I will hopefully have time to look at this properly during the weekend :)

[benjamin-kirkbride]

@Akuli any update on this? I think it's in a good state.

[rdbende]

Some nits, but otherwise LGTM

[benjamin-kirkbride]

Only thing left at this point is docs IMO. Is it worth doing that before more stuff uses actions?

[Akuli]

Not super happy with this design, but I just want this merged.