Entries from 2014-09-01 to 1 day
import Data.Monoid import qualified Data.Foldable as F data Tree a = EmptyTree | Node a (Tree a) (Tree a) deriving (Show) instance F.Foldable Tree where foldMap f EmptyTree = mempty foldMap f (Node x l r) = F.foldMap f l `mappend` f x `map…