Macro slotmap::new_key_type

macro_rules! new_key_type {
    ( $(#[$outer:meta])* $vis:vis struct $name:ident; $($rest:tt)* ) => { ... };
    () => { ... };
}

A helper macro to conveniently create new key types. If you use a new key type for each slot map you create you can entirely prevent using the wrong key on the wrong slot map.

The type constructed by this macro is identical to DefaultKey, just with a different name.

Examples

new_key_type! {
    struct EntityKey;

    /// Key for the Player slot map.
    pub struct PlayerKey;
}

fn main() {
    let mut players = SlotMap::with_key();
    let mut entities: SlotMap<EntityKey, (f64, f64)> = SlotMap::with_key();
    let bob: PlayerKey = players.insert("bobby");
    // Now this is a type error because entities.get expects an EntityKey:
    // entities.get(bob);
}