start on typed IR

src/frontend.rs

@@ -9,6 +9,7 @@ pub use types::{Type, TypeStruct};
 
 mod callable;
 pub mod types;
+pub mod typed_ir;
 
 /// lots of code is still not width-aware, this constant keeps track of that
 const TODO_WIDTH: u32 = 1;

src/frontend/typed_ir.rs

@@ -0,0 +1,16 @@
+use super::types::Type;
+
+/// an abstract element that performs some kind of computation on a value
+struct Element<'ty> {
+    pub id: u32,
+    pub inputs: Vec<Element<'ty>>,
+    pub typ: Type<'ty>,
+}
+
+struct Signal<'ty> {
+    pub id: u32,
+    pub typ: Type<'ty>
+}
+
+struct Expression {
+}