+-- | Looks up all pairs of old state, new state signals, together with
+-- the state id they represent.
+makeStatePairs :: FlatFunction -> [(StateId, SignalInfo, SignalInfo)]
+makeStatePairs flatfunc =
+ [(Maybe.fromJust $ oldStateId $ sigUse old_info, old_info, new_info)
+ | old_info <- map snd (flat_sigs flatfunc)
+ , new_info <- map snd (flat_sigs flatfunc)
+ -- old_info must be an old state (and, because of the next equality,
+ -- new_info must be a new state).
+ , Maybe.isJust $ oldStateId $ sigUse old_info
+ -- And the state numbers must match
+ , (oldStateId $ sigUse old_info) == (newStateId $ sigUse new_info)]
+
+ -- Replace the second tuple element with the corresponding SignalInfo
+ --args_states = map (Arrow.second $ signalInfo sigs) args