import "JavaBuiltin" as Java

infixl 6 (+)

class Additive a where 
    (+)  :: a -> a -> a    
    
instance Additive Double where
    x + y = Java.dadd x y

instance Additive Integer where
    x + y = Java.iadd x y
    
instance (Additive a, Additive b) => Additive (a,b) where
    (x1,y1) + (x2,y2) = (x1+x2,y1+y2)
    
main = (1.0::Double,3::Integer) + (2.0::Double,4::Integer)
--
(3.0,7)