literally ducks in haskell

Ducks.hs

class Quacks t where
	quack :: t -> String

printQuack :: Quacks a => a -> IO ()
printQuack thing = putStrLn (quack thing)

-- Define your Duck type somewhere
data Duck = {- whatever -}

instance Quacks Duck where
	quack duck = "Quack! Quack, quaaack?"

-- Define some other type
data DuckBucket = DuckBucket {
		bucketName :: String
		bucketSize :: Int
		bucketContents :: [Duck]
	}

instance Quacks DuckBucket where
	quack bucket = "All " ++ (show $ bucketSize bucket) ++ " ducks in " ++ bucketName bucket ++ " say 'Quack!'"

-- Now you can throw either a Duck or a DuckBucket at printQuack: