module SK where

import Delay
import Control.Monad

i_comb = App (App S_comb K_comb) K_comb

k_run = App i_comb K_comb

-- S (I K I) (K I) S => I
big_i = App (App (App S_comb (App (App i_comb K_comb) i_comb)) (App K_comb i_comb)) S_comb

test1 = run (evalSK k_run) -- K
test2 = run (evalSK big_i) -- S K K

natToInt O = 0
natToInt (S k) = (natToInt k) + 1

instance Show Nat where
    show = show.natToInt

instance Show SK where
    show S_comb = "S"
    show K_comb = "K"
    show (App f a) = "(" ++ show f ++ " " ++ show a ++ ")"

run :: Show a => Delay a -> IO ()
run v = putStrLn $ show (getDelayed v)

getDelayed :: Delay a -> a
getDelayed (Now a) = a
getDelayed (Later x) = getDelayed x