Struct EntityFetcher

pub struct EntityFetcher<'w> { /* private fields */ }

Provides a safe interface for non-structural access to the entities in a World.

This cannot add or remove components, or spawn or despawn entities, making it relatively safe to access in concert with other ECS data. This type can be constructed via World::entities_and_commands, or DeferredWorld::entities_and_commands.

Implementations

impl<'w> EntityFetcher<'w>

pub fn get<F: WorldEntityFetch>( &self, entities: F, ) -> Result<F::Ref<'_>, EntityDoesNotExistError>

Returns EntityRefs that expose read-only operations for the given entities, returning Err if any of the given entities do not exist.

This function supports fetching a single entity or multiple entities:

• Pass an Entity to receive a single EntityRef.
• Pass a slice of Entitys to receive a Vec<EntityRef>.
• Pass an array of Entitys to receive an equally-sized array of EntityRefs.
• Pass a reference to a EntityHashSet to receive an EntityHashMap<EntityRef>.

Errors

If any of the given entities do not exist in the world, the first Entity found to be missing will return an EntityDoesNotExistError.

Examples

For examples, see World::entity.

pub fn get_mut<F: WorldEntityFetch>( &mut self, entities: F, ) -> Result<F::DeferredMut<'_>, EntityMutableFetchError>

Returns EntityMuts that expose read and write operations for the given entities, returning Err if any of the given entities do not exist.

This function supports fetching a single entity or multiple entities:

• Pass an Entity to receive a single EntityMut.
  • This reference type allows for structural changes to the entity, such as adding or removing components, or despawning the entity.
• Pass a slice of Entitys to receive a Vec<EntityMut>.
• Pass an array of Entitys to receive an equally-sized array of EntityMuts.
• Pass a reference to a EntityHashSet to receive an EntityHashMap<EntityMut>.

Errors

• Returns EntityMutableFetchError::EntityDoesNotExist if any of the given entities do not exist in the world.
  • Only the first entity found to be missing will be returned.
• Returns EntityMutableFetchError::AliasedMutability if the same entity is requested multiple times.

Examples

For examples, see DeferredWorld::entity_mut.