compareBy :: (Ord b) => (a -> b) -> (a -> a -> Ordering)
compareBy f = (\ a1 a2 -> compare (f a1) (f a2))
compareBy :: (Ord b) => (a -> b) -> (a -> a -> Ordering)
compareBy f = (\ a1 a2 -> compare (f a1) (f a2))
compareBy f = (\ a1 a2 -> compare (f a1) (f a2))