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use super::*;
/// Observer mixin implementation
impl World {
/// Upcast entity to an observer.
/// The provided entity must be an observer.
///
/// # Arguments
///
/// * `e` - The entity.
///
/// # Returns
///
/// An observer object.
pub fn observer_from<'a>(&'a self, e: EntityView<'a>) -> Observer<'a> {
Observer::new_from_existing(e)
}
/// Create a new observer.
///
/// # Type Parameters
///
/// * `Components` - The components to match on.
///
/// # Returns
///
/// Observer builder.
///
/// # See also
///
/// * [`World::observer_from()`]
/// * [`World::observer_id()`]
/// * [`World::observer_named()`]
pub fn observer<Event: ComponentId, Components>(&self) -> ObserverBuilder<'_, Event, Components>
where
Components: QueryTuple,
{
ObserverBuilder::<Event, Components>::new(self)
}
pub fn observer_id<Components>(
&self,
event: impl Into<Entity>,
) -> ObserverBuilder<'_, (), Components>
where
Components: QueryTuple,
{
let mut builder = ObserverBuilder::<(), Components>::new_untyped(self);
builder.add_event(event);
builder
}
/// Create a new named observer.
///
/// # Type Parameters
///
/// * `Components` - The components to match on.
///
/// # Arguments
///
/// * `name` - The name of the observer.
///
/// # Returns
///
/// Observer builder.
///
/// # See also
///
/// * [`World::observer_from()`]
/// * [`World::observer()`]
/// * [`World::observer_id()`]
pub fn observer_named<'a, Event: ComponentId, Components>(
&'a self,
name: &str,
) -> ObserverBuilder<'a, Event, Components>
where
Components: QueryTuple,
{
ObserverBuilder::<Event, Components>::new_named(self, name)
}
}