generic_reflection/
generic_reflection.rs

1//! Demonstrates how reflection is used with generic Rust types.
2
3use bevy::prelude::*;
4use std::any::TypeId;
5
6fn main() {
7    App::new()
8        .add_plugins(DefaultPlugins)
9        // You must manually register each instance of a generic type
10        .register_type::<MyType<u32>>()
11        .add_systems(Startup, setup)
12        .run();
13}
14
15/// The `#[derive(Reflect)]` macro will automatically add any required bounds to `T`,
16/// such as `Reflect` and `GetTypeRegistration`.
17#[derive(Reflect)]
18struct MyType<T> {
19    value: T,
20}
21
22fn setup(type_registry: Res<AppTypeRegistry>) {
23    let type_registry = type_registry.read();
24
25    let registration = type_registry.get(TypeId::of::<MyType<u32>>()).unwrap();
26    info!(
27        "Registration for {} exists",
28        registration.type_info().type_path(),
29    );
30
31    // MyType<String> was not manually registered, so it does not exist
32    assert!(type_registry.get(TypeId::of::<MyType<String>>()).is_none());
33}