Add note about Nodes

schala-lang/language/src/eval.rs

@@ -269,6 +269,7 @@ impl<'a> State<'a> {
     }
   }
 
+  //TODO to make builtins work, need to change this concept of Node
   fn apply_builtin(&mut self, builtin: Builtin, args: Vec<Expr>) -> EvalResult<Expr> {
     use self::Expr::*;
     use self::Lit::*;