data Person = Person {name:: String, age:: Int } deriving (Show)
data Relations = Friend | Older | Younger deriving (Show)

class Comparison a where
    compare:: a -> a -> Relations

instance Comparison Person where
    compare (Person _ b1) (Person _ b2)
         | b1 == b2 = Friend
         | b1 > b2 = Older
         | b1 < b2 = Younger