slight re-structure

src/extensions/mod.rs

@@ -1 +1,40 @@
 pub mod keypress;
+
+use crate::{events::EventManager, Screen};
+
+pub trait Extension {
+    fn init(&mut self, screen: &mut Screen, events: &mut EventManager);
+    fn tick_start(&mut self, screen: &mut Screen, events: &mut EventManager);
+    fn tick_end(&mut self, screen: &mut Screen, events: &mut EventManager);
+}
+
+pub struct ExtensionManager(Vec<Box<dyn Extension>>);
+
+impl Extension for ExtensionManager {
+    fn init(&mut self, screen: &mut Screen, events: &mut EventManager) {
+        for ext in &mut self.0 {
+            ext.init(screen, events);
+        }
+    }
+
+    fn tick_start(&mut self, screen: &mut Screen, events: &mut EventManager) {
+        for ext in &mut self.0 {
+            ext.tick_start(screen, events);
+        }
+    }
+
+    fn tick_end(&mut self, screen: &mut Screen, events: &mut EventManager) {
+        for ext in &mut self.0 {
+            ext.tick_end(screen, events);
+        }
+    }
+}
+
+impl ExtensionManager {
+    pub fn new() -> ExtensionManager {
+        ExtensionManager(Vec::new())
+    }
+    pub fn add<E: Extension + 'static>(&mut self, extension: E) {
+        self.0.push(Box::new(extension));
+    }
+}