# Bevy ECS Markers

[![Crates.io](https://img.shields.io/crates/v/bevy_ecs_markers.svg)](https://crates.io/crates/bevy_ecs_markers)
[![MIT/Apache 2.0](https://img.shields.io/badge/license-MIT%2FApache-blue.svg)](https://github.com/ChoppedStudio/bevy_ecs_markers#license)

Adds the support for marking entites and fetching them in queries

## Example

View more examples [here](examples/)

```rust
#[derive(EntityMarker)]
enum Players {
    Red,
    Blue,
    Green,
    Yellow,
}

#[derive(Component)]
struct Player {
    field: usize,
}

fn main() {
    App::new()
        .add_plugins(LogPlugin::default())
        .init_marker::<Players>()
        .add_systems(Startup, (setup, move_red_player).chain())
        .run();
}

fn setup(mut commands: Commands, mut players: MarkerMut<Players>) {
    players[Players::Red].assign(commands.spawn(Player { field: 2 }).id());
    players[Players::Blue].assign(commands.spawn(Player { field: 5 }).id());
    players[Players::Green].assign(commands.spawn(Player { field: 7 }).id());
    players[Players::Yellow].assign(commands.spawn(Player { field: 1 }).id());
}

fn move_red_player(mut query: Query<&mut Player>, current: Marker<Players>) {
    let Ok(mut player) = query.get_mut(current[Players::Red].id()) else {
        warn!("Red Player not set yet!");
        return;
    };

    let old = player.field;
    player.field += 2;
    let new = player.field;

    info!("Player moved from field {old} to field {new}");
}
```

## License

- MIT License ([LICENSE-MIT](LICENSE-MIT) or [http://opensource.org/licenses/MIT](http://opensource.org/licenses/MIT))
- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or [http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0))

at your option.