sumtree in Parallel Gibbon

module Main where

data Tree = Leaf Int
          | Node Int Tree Tree

mkTree :: Int -> Tree
mkTree i =
  if i <= 0
  then Leaf 1
  else
      let x = (mkTree (i-1))
          y = (mkTree (i-1))
      in Node i x y

sumTree :: Tree -> Int
sumTree foo =
  case foo of
    Leaf i     -> i
    Node i a b ->
      let tup = par (sumTree a) (sumTree b)
          x = fst tup
          y = snd tup
      in x + y

gibbon_main = sumTree (mkTree 27)