Ordering Semigroup instance

ordering-semigroup.hs

class Eq a => Ord a where
  compare :: a -> a -> Ordering

class Semigroup a where
  (<>) :: a -> a -> a

instance Semigroup Ordering where
  (<>) = undefined

func :: (Ord u, Ord v) => (u, u) -> (v, v) -> Ordering
func (a, b) (x, y) = compare a b <> compare x y