Support (or document) downcasting Nodes to scripts

[wyattjsmith1]

I am guessing this is supported and just not documented (or I'm blind), but I would like a way to "cast" a Node to a game script / rust struct. For example:

#[derive(NativeClass)]
#[inherit(Node)]
pub struct TestClass;

#[methods]
impl TestClass{

    fn _init(_owner: Node) -> Self {
        return TestClass;
    }

    pub fn test_method(&self) {
        godot_print!("Method Called");
    }
}

// Then, somewhere in another `impl` where "root/TestClass" is properly implemented by a TestClass.
self.get_node(NodePath::from_str("root/TestClass")).cast_to_test_class().test_method();

I understand that there is a cast() method which sounds great, but doesn't work for me. When I try let result: TestClass= self.get_node(NodePath::from_str("root/TestClass")).unwrap().cast().unwrap();, I get the following error:

error[E0277]: the trait bound `input::TestClass: gdnative_core::object::GodotObject` is not satisfied
  --> godot_utils\src\singleton.rs:20:120
   |
20 |         let result: TestClass= self.get_node(NodePath::from_str("root/TestClass")).expect("").cast().expect("");
   |                                                                                               ^^^^ the trait `gdnative_core::object::GodotObject` is not implemented for `input::TestClass`

From a cpp/oop perspective, this doesn't make sense because TestClass is a Node which extends GodotObject. From a Rust perspective, however, this kinda makes sense because TestClass doesn't actually imelement GodotObject
Ultimately, I understand Rust doesn't have an inheritance tree like most OO languages, but I am not sure how to get the behavior I want. Any help would be appreciated.

[ghost]

Try looking for Instance<T> in rustdoc? It is documented, but admittedly hard to find if you don't know what to look for. There are plans to clean up the top-level namespace in the next release: #304

[wyattjsmith1]

Thanks for the response. Ok, I saw some stuff about Instance. Once I have an Instance, how can I get my struct from it? I see a map function, be I don't really need to map it.

…

On Sun, Apr 19, 2020, 22:21 toasteater ***@***.***> wrote: Try Instance<TestClass>? It is documented, but admittedly hard to find if you don't know what to look for. There are plans to clean up the top-level namespace in the next release: #304 <#304> — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#328 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEFGXF3NLH4HPWRECVJM4D3RNPLUDANCNFSM4MMDJAUA> .

[ghost]

You have to access it using map due to how script storage work. See module-level documentation on user_data for details. Note that type arguments can be () if you don't want a return value.

[ghost]

Superseded by #330.