wip: slowly putting it back together

crates/tek_core/src/engine.rs

@@ -0,0 +1,23 @@
+use crate::*;
+
+/// Entry point for main loop
+pub trait App<T: Engine> {
+    fn run (self, context: T) -> Usually<T>;
+}
+
+/// Platform backend.
+pub trait Engine {
+    type Handled;
+    type Rendered;
+    fn setup (&mut self) -> Usually<()> {
+        Ok(())
+    }
+    fn teardown (&mut self) -> Usually<()> {
+        Ok(())
+    }
+    fn handle (&self, _: &mut impl Handle<Self, Self::Handled>)
+        -> Usually<()> where Self: Sized;
+    fn render (&mut self, _: &impl Render<Self, Self::Rendered>)
+        -> Usually<()> where Self: Sized;
+    fn exited (&self) -> bool;
+}