Draft widget nodes and wire interaction

web/src/element.rs

@@ -1,4 +1,7 @@
-use crate::{Color, Widget};
+use crate::{Bus, Color, Widget};
+
+use dodrio::bumpalo;
+use std::rc::Rc;
 
 pub struct Element<'a, Message> {
     pub(crate) widget: Box<dyn Widget<Message> + 'a>,
@@ -11,7 +14,7 @@ impl<'a, Message> Element<'a, Message> {
         }
     }
 
-    pub fn explain(self, color: Color) -> Element<'a, Message> {
+    pub fn explain(self, _color: Color) -> Element<'a, Message> {
         self
     }
 
@@ -29,7 +32,7 @@ impl<'a, Message> Element<'a, Message> {
 
 struct Map<'a, A, B> {
     widget: Box<dyn Widget<A> + 'a>,
-    mapper: Box<dyn Fn(A) -> B>,
+    mapper: Rc<Box<dyn Fn(A) -> B>>,
 }
 
 impl<'a, A, B> Map<'a, A, B> {
@@ -39,9 +42,21 @@ impl<'a, A, B> Map<'a, A, B> {
     {
         Map {
             widget,
-            mapper: Box::new(mapper),
+            mapper: Rc::new(Box::new(mapper)),
         }
     }
 }
 
-impl<'a, A, B> Widget<B> for Map<'a, A, B> {}
+impl<'a, A, B> Widget<B> for Map<'a, A, B>
+where
+    A: 'static,
+    B: 'static,
+{
+    fn node<'b>(
+        &self,
+        bump: &'b bumpalo::Bump,
+        bus: &Bus<B>,
+    ) -> dodrio::Node<'b> {
+        self.widget.node(bump, &bus.map(self.mapper.clone()))
+    }
+}