tc.tel

-- returns whether the ascii value of a character is even
isEven = \n -> { \i -> left i -- test for if a recursive call should be made, or the base case should be called
               , \recur i -> recur (left (left i), not (right i)) -- function that will be made recursive, where recur is the continuation
               , \i -> right i -- base case call
               } (n, 1)

-- limit the input space. This is necessary, because it's impossible to find limits to recursive functions operating on unbounded data
validAscii = \x -> assert (not ($127 left x)) "!"

main = \input -> let userInput = left input
                     firstChar = left userInput
                     limInput : validAscii = firstChar
                     oldState = right input

                     output = concat ["R "
                                     , if isEven limInput then "EV" else "O" -- breaks
                                     -- , if isEven limInput then "E" else "O" -- works
                                     ]
                 in if not input
                    then (" ", 1)
                    else (output, 0)