module test

import StdEnv

:: Zero = Zero
:: Succ a = Succ a
:: Ar3 a b c :== (a -> b -> c)

class succ a ~b :: a -> b
instance succ Zero (Succ Zero) where succ Zero = Succ Zero
instance succ a (Succ a) where succ a = Succ a

class plus a b | succ a b :: a b
instance plus Zero a a
where
	plus a b = b
instance plus (Succ a) b c | plus a (Succ b) c
where
	plus (Succ a) b = plus a (Succ b)

Start :: Int
Start = 42

class fmap t :: (a -> b) (t a) -> t b

instance fmap ((,)a) where fmap f (a, b) = (a, f b)

Start = fmap inc (42, 37)