1 files changed, 36 insertions, 0 deletions
diff --git a/stockton-levels/src/parts/entities.rs b/stockton-levels/src/parts/entities.rs
new file mode 100644
index 0000000..7a5ac74
--- /dev/null
+++ b/stockton-levels/src/parts/entities.rs
@@ -0,0 +1,36 @@
+use std::iter::Iterator;
+
+pub type EntityRef = u32;
+
+/// A game entity
+pub trait IsEntity<C: HasEntities + ?Sized> {
+    fn get_attr(&self, container: &C) -> Option<&str>;
+}
+
+pub trait HasEntities {
+    type Entity: IsEntity<Self>;
+
+    fn get_entity(&self, idx: EntityRef) -> Option<&Self::Entity>;
+    fn iter_entities(&self) -> Entities<Self> {
+        Entities {
+            next: 0,
+            container: self,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct Entities<'a, T: HasEntities + ?Sized> {
+    next: EntityRef,
+    container: &'a T,
+}
+
+impl<'a, T: HasEntities> Iterator for Entities<'a, T> {
+    type Item = &'a T::Entity;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let res = self.container.get_entity(self.next);
+        self.next += 1;
+        res
+    }
+}