fix f = f (fix f)

fact = (\f -> (\x -> if x == 0 then 1
                     else x * f (x - 1)))

test = (fix fact) 5


-- This will not type
-- y = (\f -> (\g -> f (g g)) (\g -> f (g g)))

-- This works on some versions of GHC, and in Hugs
-- newtype Mu a = Roll { unroll :: Mu a -> a }
-- fix2 f = (\x -> f ((unroll x) x)) (Roll (\x -> f ((unroll x) x)))

-- test2 = (fix2 fact) 3