Some QuickCheck Instances

[Dominic Steinitz]

I often find I need to use QuickCheck & SmallCheck with e.g. Word8 but
there don't seem to be standard instances. Would these be worth adding?
If so, what would I need to do? Just send a patch to the maintainers?

Thanks, Dominic.

> 
> instance Serial Word8 where
>    series d = drawnFrom (map fromIntegral [0..d])

> instance Arbitrary Word8 where
>    arbitrary =
>       do n <- choose ((fromIntegral (minBound::Word8))::Int,
>                       (fromIntegral (maxBound::Word8))::Int)
>          return (fromIntegral n)
> 
> instance Arbitrary Word64 where
>    arbitrary =
>       do n <- choose ((fromIntegral (minBound::Word64))::Integer,
>                       (fromIntegral (maxBound::Word64))::Integer)
>          return (fromIntegral n)
> 
> instance Arbitrary Word128 where
>    arbitrary =
>       do n <- choose ((fromIntegral (minBound::Word128))::Integer,
>                       (fromIntegral (maxBound::Word128))::Integer)
>          return (fromIntegral n)
>