new const trait syntax

src/layout/data.rs

@@ -0,0 +1,27 @@
+use std::any::{Any, TypeId};
+
+use crate::util::{HashMap, Id};
+
+#[derive(Default)]
+pub struct UiData {
+    map: HashMap<TypeId, Box<dyn Any>>,
+}
+
+impl UiData {
+    pub fn get<T: 'static>(&self) -> Option<&T> {
+        self.map
+            .get(&TypeId::of::<T>())
+            .map(|d| d.downcast_ref().unwrap())
+    }
+    pub fn get_mut<T: 'static>(&mut self) -> Option<&mut T> {
+        self.map
+            .get_mut(&TypeId::of::<T>())
+            .map(|d| d.downcast_mut().unwrap())
+    }
+
+    pub fn emit_remove(&mut self, id: &Id) {
+        for (tid, f) in &mut self.on_remove {
+            let data = self.map.get_mut(tid).unwrap().downcast_ref().unwrap();
+        }
+    }
+}