Macro nano_ecs::entity_ids

macro_rules! entity_ids {
    ($world:ident, $iter:expr, $id:ident, |$($x:ty),*| $e:expr) => { ... };
    ($world:ident, $id:ident, |$($x:ty),*| $e:expr) => { ... };
}

Enumerates indices of entities only.

Pre-processes a mask map from component index to entity slice. This is the same for any signature, no matter which order arguments are preserved.