-- IB015 binarni stromy
-- funkce na vykresleni stromu BinTree a pomoci externi knihovny Data.Tree

-- externi knihovna Data.Tree pracuje s n-arnymi stromy
-- vice info na http://hackage.haskell.org/packages/archive/containers/latest/doc/html/Data-Tree.html
import qualified Data.Tree as T (Tree(..), drawTree)

-- nase definice binarniho stromu
data BinTree a = Empty | Node a (BinTree a) (BinTree a) deriving (Eq, Show)

-- transformuje nase stromy na typ, se ktorym pracuje knihovna
convertTree :: Show a => BinTree a -> T.Tree String
convertTree Empty = T.Node "Empty" []
convertTree (Node x l r) = T.Node (show x) (map convertTree [l,r])

-- samotna vykreslovaci funkce
drawTree :: Show a => BinTree a -> IO ()
drawTree = putStr . T.drawTree . convertTree