refactor + not sure whats up with the double padding

crates/tek_core/src/engine.rs

@@ -1,5 +1,12 @@
 use crate::*;
 
+submod! {
+    focus
+    handle
+    keymap
+    layout
+}
+
 /// Entry point for main loop
 pub trait App<T: Engine> {
     fn run (self, context: T) -> Usually<T>;
@@ -31,13 +38,122 @@ pub trait Engine: Send + Sync + Sized {
     ) -> Perhaps<Self::Area>;
 }
 
-submod! {
-    collect
-    component
-    exit
-    focus
-    handle
-    keymap
-    layout
-    //render
+pub trait Widget: Send + Sync {
+    type Engine: Engine;
+    fn layout (&self, to: <<Self as Widget>::Engine as Engine>::Area) ->
+        Perhaps<<<Self as Widget>::Engine as Engine>::Area>
+    {
+        Ok(Some(to))
+    }
+    fn render (&self, to: &mut Self::Engine) ->
+        Perhaps<<<Self as Widget>::Engine as Engine>::Area>;
 }
+impl<'a, E: Engine> Widget for Box<dyn Widget<Engine = E> + 'a> {
+    type Engine = E;
+    fn layout (&self, to: E::Area) -> Perhaps<E::Area> {
+        (**self).layout(to)
+    }
+    fn render (&self, to: &mut E) -> Perhaps<E::Area> {
+        (**self).render(to)
+    }
+}
+impl<E: Engine> Widget for &dyn Widget<Engine = E> {
+    type Engine = E;
+    fn layout (&self, to: E::Area)  -> Perhaps<E::Area> {
+        (*self).layout(to)
+    }
+    fn render (&self, to: &mut E) -> Perhaps<E::Area> {
+        (*self).render(to)
+    }
+}
+impl<E: Engine> Widget for &mut dyn Widget<Engine = E> {
+    type Engine = E;
+    fn layout (&self, to: E::Area) -> Perhaps<E::Area> {
+        (**self).layout(to)
+    }
+    fn render (&self, to: &mut E) -> Perhaps<E::Area> {
+        (**self).render(to)
+    }
+}
+impl<E: Engine, W: Widget<Engine = E>> Widget for Arc<W> {
+    type Engine = E;
+    fn layout (&self, to: E::Area) -> Perhaps<E::Area> {
+        self.as_ref().layout(to)
+    }
+    fn render (&self, to: &mut E) -> Perhaps<E::Area> {
+        self.as_ref().render(to)
+    }
+}
+impl<E: Engine, W: Widget<Engine = E>> Widget for Mutex<W> {
+    type Engine = E;
+    fn layout (&self, to: E::Area) -> Perhaps<E::Area> {
+        self.lock().unwrap().layout(to)
+    }
+    fn render (&self, to: &mut E) -> Perhaps<E::Area> {
+        self.lock().unwrap().render(to)
+    }
+}
+impl<E: Engine, W: Widget<Engine = E>> Widget for RwLock<W> {
+    type Engine = E;
+    fn layout (&self, to: E::Area) -> Perhaps<E::Area> {
+        self.read().unwrap().layout(to)
+    }
+    fn render (&self, to: &mut E) -> Perhaps<E::Area> {
+        self.read().unwrap().render(to)
+    }
+}
+impl<E: Engine, W: Widget<Engine = E>> Widget for Option<W> {
+    type Engine = E;
+    fn layout (&self, to: E::Area) -> Perhaps<E::Area> {
+        Ok(self.as_ref().map(|widget|widget.layout(to)).transpose()?.flatten())
+    }
+    fn render (&self, to: &mut E) -> Perhaps<E::Area> {
+        Ok(self.as_ref().map(|widget|widget.render(to)).transpose()?.flatten())
+    }
+}
+
+pub trait Content: Send + Sync {
+    type Engine: Engine;
+    fn content (&self) -> impl Widget<Engine = <Self as Content>::Engine>;
+}
+//impl<E> Content<E> for () where E: Engine {
+    //fn content (&self) -> impl Widget<E> {
+        //()
+    //}
+//}
+impl<E: Engine, W: Content<Engine = E>> Widget for W {
+    type Engine = E;
+    fn layout (&self, to: E::Area) -> Perhaps<E::Area> {
+        self.content().layout(to)
+    }
+    fn render (&self, to: &mut E) -> Perhaps<E::Area> {
+        match self.layout(to.area())? {
+            Some(area) => to.render_in(area, &self.content()),
+            None => Ok(None)
+        }
+    }
+}
+
+/// A UI component.
+pub trait Component<E: Engine>: Widget<Engine = E> + Handle<E> {}
+
+/// Everything that implements [Render] and [Handle] is a [Component].
+impl<E: Engine, C: Widget<Engine = E> + Handle<E>> Component<E> for C {}
+
+pub trait Exit: Send {
+    fn exited (&self) -> bool;
+    fn exit (&mut self);
+    fn boxed (self) -> Box<dyn Exit> where Self: Sized + 'static {
+        Box::new(self)
+    }
+}
+
+/// Marker trait for [Component]s that can [Exit]
+pub trait ExitableComponent<E>: Exit + Component<E> where E: Engine {
+    /// Perform type erasure for collecting heterogeneous components.
+    fn boxed (self) -> Box<dyn ExitableComponent<E>> where Self: Sized + 'static {
+        Box::new(self)
+    }
+}
+
+impl<E: Engine, C: Component<E> + Exit> ExitableComponent<E> for C {}