Plugin callbacks for commands (cd)

[mkhl]

Hi there,

I'm looking to build a plugin for direnv integration but if I understand correctly plugin functions can only be defined for actions, not for commands, and the thing I'm interested in (cd) is a command.

Is there any other callback that I could use instead, maybe checking if cwd has changed every time a BufPane is focused?

Would a mechanism for this (plugin callbacks for actions) be of interest to folks?

[dmaluka]

Is there any other callback that I could use instead, maybe checking if cwd has changed every time a BufPane is focused?

AFAICS there is the onSetActive callback exactly for that. (It is even documented, wow)

BTW I was once thinking about a radical approach to such use cases: introduce onAnyEvent callback, which would be called, literally, after any event, so that a plugin could compare a state before and after any event, and thus potentially would be able to catch any changes of any states.

Would a mechanism for this (plugin callbacks for actions) be of interest to folks?

You mean, plugin callbacks for commands. Maybe...

In the meantime, you can always add your own custom command instead of cd.

[mkhl]

Is there any other callback that I could use instead, maybe checking if cwd has changed every time a BufPane is focused?

AFAICS there is the onSetActive callback exactly for that. (It is even documented, wow)

I missed that one, thanks!
Sadly I can only get that to fire by clicking with my mouse; switching tabs or buffers or executing commands doesn't seem to do it.

BTW I was once thinking about a radical approach to such use cases: introduce onAnyEvent callback, which would be called, literally, after any event, so that a plugin could compare a state before and after any event, and thus potentially would be able to catch any changes of any states.

That would be perfect!

Would a mechanism for this (plugin callbacks for actions) be of interest to folks?

You mean, plugin callbacks for commands. Maybe...

In the meantime, you can always add your own custom command instead of cd.

I was really hoping to make it seamless, but it seems like I'll have to try this way instead.
Thank you!

[dmaluka]

Sadly I can only get that to fire by clicking with my mouse; switching tabs or buffers or executing commands doesn't seem to do it.

Indeed, as I can see, onSetActive fires only when switching to another pane in the same tab, but doesn't fire when switching to another tab. Seems like a bug worth fixing.

Moreover, onSetActive needlessly fires when clicking mouse on a pane which is already active. This also seems like a bug worth fixing.

But when it comes to firing it even when switching between a normal pane and the command bar, e.g. after executing any command (which seems to be what you are most interested in), I suppose that might not be the behavior desired by the creators of onSetActive. @taconi right?

(It is sad that #2885 doesn't contain even the slightest description of a use case for onSetActive.)

[taconi]

[...] I suppose that might not be the behavior desired [...]

The behavior of onSetActive would allow plugins to know when the panel has changed.

[...] description of a use case for onSetActive

LSP plugins can present a use case for this functionality.
To avoid starting multiple lsp clients or starting only the client from the file that is opened when starting micro, clients can be run as soon as necessary.
So the lsp client for python is only started when a python file is opened, and if I switch to a lua file the lsp client for it will be started.

Another use case would be to use the same keybinding but with a different function depending on the file type.

[dmaluka]

The behavior of onSetActive would allow plugins to know when the panel has changed.

There is no such thing as a "panel". There is such thing as a "pane".

The point is that the command line at the bottom is a pane too, just a special one. So, the question is, should onSetActive be called also when the active buffer pane doesn't change but the command-line pane becomes focused, i.e. when the user starts typing a command?

LSP plugins can present a use case for this functionality. To avoid starting multiple lsp clients or starting only the client from the file that is opened when starting micro, clients can be run as soon as necessary. So the lsp client for python is only started when a python file is opened, and if I switch to a lua file the lsp client for it will be started.

Hmm, so you want the callback to run when you switch to a file first time? Isn't it the same as when you open this file first time? IOW, why is onBufferOpen or onBufPaneOpen not enough?

Another use case would be to use the same keybinding but with a different function depending on the file type.

Hmm, wouldn't it be more straightforward to bind this keybinding to the same function all the time and just check the filetype inside this function?

[taconi]

As you said onBufferOpen and onBufPaneOpen already do this, this callback wouldn't enter the opening but in the exchange between buffers already open: when I have two buffers open next to each other, whenever I change from one to another buffer onSetActive will be called.
The idea would be to make it possible for plugins to know when the type of the file the user is currently editing has changed, so that the plugin can take action (looking at the current documentation now only makes things more confusing, apart from the panel typo of pane).

Now, about the callback being called when entering the command bar, I prefer to abstain because I no longer maintain any plugins and I believe that this decision should come from the maintainers of plugins that make use of this callback.

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But I think what is being asked is how to create callbacks that will be executed before or after a command.

Maybe something like preCdCmd, onCdCmd.

The place to add this might be in the HandleCommand
Something like this:

config.RunPluginFn("pre" + inputCmd + "Cmd", luar.New(ulua.L, h), luar.New(ulua.L, args[1:]))

config.RunPluginFn("on" + inputCmd + "Cmd", luar.New(ulua.L, h), luar.New(ulua.L, args[1:]))

But I didn't look too deeply to see if it needed to be somewhere else.

[dmaluka]

I've uploaded PR #3244 which implements the onAnyEvent callback I mentioned earlier.

[dmaluka]

Also uploaded PR #3245 with fixes for the found bugs of the onSetActive callback.