Re: [Haskell-beginners] Real world example of Typeclasses > Interfaces

4 Sep 2010


      On 4 September 2010 18:04, Alec Benzer  wrote:
...
What I mean is, if you had a function: something n =
[1..n], and your type was a -> [a], a needs to be declared as (Num a,
Enum a), even though this is sort of redundant, since you can't really
have a number that isn't also enumerable.
Well, you can actually have a Num that isn't Enum.

ghci> :info Num
class (Eq a, Show a) => Num a where
  (+) :: a -> a -> a
  (*) :: a -> a -> a
  (-) :: a -> a -> a
  negate :: a -> a
  abs :: a -> a
  signum :: a -> a
  fromInteger :: Integer -> a


-- 
Ozgur Akgun