{- |

Module : $EmptyHeader$

Description : <optional short description entry>

Copyright : (c) <Authors or Affiliations>

License : GPLv2 or higher

Maintainer : <email>

Stability : unstable | experimental | provisional | stable | frozen

Portability : portable | non-portable (<reason>)

<optional description>

-}

data Natx a = Zx | Sx a (Natx a)

fun1 :: Natx Int -> (Natx Int, Int)

fun1 x = case x of

Zx -> (Zx, 0)

Sx n k -> (Sx n (fst (fun1 k)), n * (fun2 k))

fun2 :: Natx Int -> Int

fun2 x = case x of

Zx -> 0

Sx n k -> (snd (fun1 k)) + n