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

I was speaking more generally, not specifically about the Haskell typeclasses Num and Enum (although actually irrational numbers aren't enumerable now that I think of it, but I also guess that's a relatively moot point since you can't really represent irrational numbers in a programming language) On Sat, Sep 4, 2010 at 1:26 PM, Ozgur Akgun wrote:

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