[Haskell-beginners] Re: [Haskell-cafe] Enum and Bounded in generic type

Raeck said:

Hi, how can I make the following code work? (show all the possible values of a type 'a')

...

showAll :: (Eq a, Bounded a, Enum a) => a -> [a] showAll a = [minBound..maxBound]::[a]

What you are really looking for, I think, is a polymorphic value of type [a], where a is some enumerable, bounded type. allValues :: (Enum a, Bounded a) => [a] allValues = [minBound .. maxBound] You can omit the type signature, but then you'll run into the monomorphism restriction (which you'll can turn off with, e.g. -XNoMonomorphismRestriction)