Haskell QuickCheck2 using ByteString?

Question

The RWH books says that to get ByteString support, I need to add:

instance Arbitrary B.ByteString where
    arbitrary   = fmap B.pack arbitrary
    coarbitrary = coarbitrary . B.unpack

But my GHC 7.2 with QuickCheck 2.4.1.1 tells me:

`coarbitrary' is not a (visible) method of class `Arbitrary'

Any pointers?

Loki

Answer 1

coarbitrary has moved to it's own typeclass CoAbritary in QC 2.0, so simply just remove the equation for coarbitrary.

Also see the latest documentation.

Gadson

Thanks. I'm afraid the latest API documentation hasn't helped me much. It is all mumbo-jumbo without some higher level context. A lot of other documentation is also out of date. Very curious for what is supposedly a very popular test package. – Loki