List of methods that can be exported to Godot

[ralpha]

Add a list of methods to the documentation that can be exported to Godot (ex: _input(), _ready(),...) and most importantly the parameter/argument types.
There is the Godot documentation but this is not for the Rust structs. https://docs.godotengine.org/en/stable/classes/class_node.html#method-descriptions

Although not hard now. I was first struggling to find the right types that the parameters should have in Rust. Maybe add something like this to the doc page here:
https://docs.rs/gdnative/0.9.1/gdnative/attr.methods.html
Or links to Godot docs. As searching in rust docs (https://docs.rs/gdnative/0.9.1/gdnative/index.html?search=_input) does not turn of anything (useful).

Created this issue after posting it on Discord.

[jacobsky]

@Bromeon I'll go ahead and work on this one. I think it's a natural extension to the work from documenting the #[export] tag :)

For now, I'll assume that we are primarily interested in virtual methods like _ready() that are lacking documentation and I will also assume that the main point of interest will be documenting things in Node and Control (to mention the _gui_input method). I'll also go ahead and link the relevant documentation so that we don't have to duplicate documenting "what it does" and can focus on "how to call it"

Please feel free to let me know if you have any other points you'd like me to mention. I'll try to get a PR in by early next week.

[Bromeon]

Yes, the focus are Node and Control methods, which are called by the engine. Things like _ready(), _process(), _enter_tree(), _input(), etc.

I agree that the signature, a one-liner explaining what it does and a link to the Godot docs would be good.
For example:

fn _physics_process(&self, owner: &Node, delta: f32);

Called during physics update, with a fixed timestamp.
See Godot docs for more information.

The question is where we want to add these docs?

[jacobsky]

@Bromeon I'll proceed by using that sample as the template for this change.

With regards to where it should be added, I was thinking that the NativeClass docs under #[export] would be the most fitting.

The reason is that I believe the biggest risk to not documenting is that a user may not be aware of which function names are reserved for Godot to call via notifications.

For example: If a user thinks "oh, I need a private method that processes some data occasionally, I'll just call it _process(&mut self, _owner: &Node, data; Instance<MyDataClass>) I'll connect this to the data instance as a signal callback", they will be a bit shocked to see 60+ errors per second as Godot fails to call the method due to incorrect parameter types.

That was just my line of thinking though.