ez-roguelike/ch5/src/components.rs

use specs::prelude::*;

#[derive(Component)]
pub struct Renderable {
    pub glyph: carpet::CP437,
    pub color: carpet::Color,
}

#[derive(Component)]
pub struct Player;

impl Player {
    fn get_entity(world: &mut specs::World) -> Entity {
        let storage = (&world.read_component::<Player>(), &world.entities());
        storage
            .join()
            .next()
            .expect("No entities tagged as Player")
            .1
    }
}

#[derive(Component)]
pub struct Motion {
    pub down: i8,
    pub right: i8,
}

impl Motion {
    pub fn move_player(world: &mut specs::World, down: i8, right: i8) {
        let player = Player::get_entity(world);
        world
            .write_component::<Motion>()
            .insert(player, Motion { down, right })
            .unwrap();
    }
}