1 reply to this topic

[kutasek]

Hello.
I must do following exercise, but i don't know how. Have anybody an idea?

class Enum a where
toEnum :: a  Int
fromEnum :: Int  a

Is it possible to declare (a,b) as a member of
class Enum, given that both a and b are instances
of Enum?

[ZekeDragon]

class Enum a where

    toEnum :: a -> Int

    fromEnum :: Int -> a

    takeTwoEnums :: Enum b => (a, b) -> Int

Don't know what you're trying to do but there you go. I think you're trying to look at this from a far too OOP standpoint, what do you mean by "member"? Type classes have no guaranteed data members, only functions which are guaranteed to work on the passed data values. It's far superior to clumping data together in inefficient and thread-unsafe class objects.