[Haskell-cafe] deriving instances of Enum for tuples of bounded,
enumerable types (useful for generating QuickCheck.Arbitrary
instances for collection of collection types)
Luke Palmer
lrpalmer at gmail.com
Sat Mar 8 23:32:58 EST 2008
On Sun, Mar 9, 2008 at 3:23 AM, Brandon S. Allbery KF8NH
<allbery at ece.cmu.edu> wrote:
> myFunc :: (forall a. (Bounded a, Enum a) => a) ->
> (forall a. (Bounded a, Enum a) => a) ->
> (forall a. (Bounded a, Enum a) => a)
>
> which is a rather useless declaration (I think the only inhabitant of
> that type is _|_).
Just to nitpick: this function type is quite specific, and there are
many non _|_ implementations.
myFunc a b = a
myFunc a b = b
myFunc a b = toEnum (f a b)
where f :: Int -> Int -> Int
...
Luke
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