Trait components_arena::ComponentClass

pub trait ComponentClass {
    fn lock() -> &'static ComponentClassLock
    where
        Self: Sized;
}

An utility trait describing a specific component type.

Normally for a non-generic component type the component type itself implements ComponentClass.

For generic components it would be difficult to have an own ComponentClassLock instance for every specialization because Rust does not have "generic statics" feature.

So, if some component type X is generic, normally you should introduce common non-generic uninhabited type XComponent and implement ComponentClass for this synthetic type.

Correct implementation should return reference to the one and same ComponentClassLock instance from the lock function. Also it should be guaranteed that no other ComponentClass implementation returns same ComponentClassLock instance. This requirements can be easily satisfied with private static:

struct MyComponent { /* ... */ }

impl ComponentClass for MyComponent {
    fn lock() -> &'static ComponentClassLock {
        static LOCK: ComponentClassLock = ComponentClassLock::new();
        &LOCK
    }
}

Required methods

fn lock() -> &'static ComponentClassLock where
    Self: Sized, 

Essential for components arena internal mechanic.

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Implementors

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