data FSM state input output = FSM        -- Input and output alphabet are constricted at compile time by datatype
  { start  :: state                      -- Start state
  , trans  :: state -> input -> state    -- Transition function
  , accept :: [state]                    -- Set of accept states
  , out    :: OutFunc state input output -- Output function, either Moore or Mealy
  }

data OutFunc state input output
  = Moore (state -> output)
  | Mealy (state -> input -> output)

runFSM :: Eq state => FSM state input output -> [input] -> (state, Bool)
runFSM (FSM start trans accept out) inputs = (finalState, elem finalState accept)
  where
    -- finalState = foldl' trans start input
    finalState = go inputs start

    -- Output only changes when state changes occur
  --go :: [input] -> state -> state
    go []     acc = acc
    go (x:xs) currentState = go xs (trans currentState x)