compile matches into executable decision trees

examples/protocol.tess

@@ -0,0 +1,8 @@
+data State = Idle | Waiting | Connected
+
+data Message = Hello Int | Data Int | Close
+
+match classify (s : State) (m : Message) : Int =
+  | Idle (Hello n) -> n
+  | Waiting (Data n) -> n
+  | Connected Close -> 0