[Haskell-cafe] Comparison between fields of each record

24 Nov 2015

      Dear All.

I'd like to compare fields of each record.

here is my record.

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

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

instance Comparison Person where
    compare Person a b Person a b
         | b1 == b2 = Friend
         | b1 > b2 = Older
         | b1 < b2 = Younger

How can I fit it?

Sincerely,

Jeon-Young Kang