1 files changed, 56 insertions, 0 deletions
diff --git a/engine-ecs/examples/relationship.rs b/engine-ecs/examples/relationship.rs
new file mode 100644
index 0000000..749c202
--- /dev/null
+++ b/engine-ecs/examples/relationship.rs
@@ -0,0 +1,56 @@
+use engine_ecs::pair::{Pair, Wildcard};
+use engine_ecs::phase::START as START_PHASE;
+use engine_ecs::{Component, Query, World};
+
+#[derive(Component)]
+struct Sword
+{
+    attack_strength: u32,
+}
+
+#[derive(Component)]
+struct Player;
+
+#[derive(Component)]
+struct Health
+{
+    health: u32,
+}
+
+#[derive(Component)]
+struct Holding;
+
+fn print_player_stats(player_query: Query<(&Player, &Health, Pair<Holding, Wildcard>)>)
+{
+    for (_, health, target_sword) in &player_query {
+        println!("Player health: {}", health.health);
+
+        if let Some(sword_ent) = target_sword.get_target_ent() {
+            let sword = sword_ent
+                .get::<Sword>()
+                .expect("Sword entity is missing sword component");
+
+            println!("Player sword attack strength: {}", sword.attack_strength);
+        }
+    }
+}
+
+fn main()
+{
+    let mut world = World::new();
+
+    world.register_system(*START_PHASE, print_player_stats);
+
+    let sword_uid = world.create_entity((Sword { attack_strength: 17 },));
+
+    world.create_entity((
+        Player,
+        Health { health: 180 },
+        Pair::builder()
+            .relation::<Holding>()
+            .target_id(sword_uid)
+            .build(),
+    ));
+
+    world.step();
+}