//! Component events.

use std::convert::Infallible;
use std::fmt::Debug;

use crate::Component;

/// Pair relation for events emitted when:
/// a) A entity with the target component is spawned.
/// b) The target component is added to a entity.
#[derive(Debug, Component)]
pub struct Added(Infallible);

/// Pair relation for events emitted when:
/// a) The target component is removed from a entity.
/// b) A entity with the target component is despawned.
#[derive(Debug, Component)]
pub struct Removed(Infallible);