1 files changed, 65 insertions, 0 deletions
diff --git a/ecs/examples/component_relationship.rs b/ecs/examples/component_relationship.rs
new file mode 100644
index 0000000..e07b214
--- /dev/null
+++ b/ecs/examples/component_relationship.rs
@@ -0,0 +1,65 @@
+use ecs::pair::Pair;
+use ecs::phase::START as START_PHASE;
+use ecs::{Component, Query, World};
+
+#[derive(Component)]
+struct Person
+{
+    name: String,
+}
+
+fn print_dog_likers(query: Query<(&Person, Pair<Likes, &Dogs>)>)
+{
+    for (person, liked_dogs) in &query {
+        println!(
+            "{} likes {} dogs!",
+            person.name,
+            if liked_dogs.large { "large" } else { "small" },
+        );
+    }
+}
+
+#[derive(Component)]
+struct Likes;
+
+#[derive(Component)]
+struct Cats;
+
+#[derive(Component)]
+struct Dogs
+{
+    large: bool,
+}
+
+fn main()
+{
+    let mut world = World::new();
+
+    world.register_system(*START_PHASE, print_dog_likers);
+
+    world.create_entity((
+        Person { name: "Irving".to_string() },
+        Pair::builder()
+            .relation::<Likes>()
+            .target_as_data(Dogs { large: true })
+            .build(),
+    ));
+
+    world.create_entity((
+        Person { name: "Mark".to_string() },
+        Pair::builder()
+            .relation::<Likes>()
+            .target_as_data(Cats)
+            .build(),
+    ));
+
+    world.create_entity((
+        Person { name: "Helena".to_string() },
+        Pair::builder()
+            .relation::<Likes>()
+            .target_as_data(Dogs { large: false })
+            .build(),
+    ));
+
+    world.step();
+}