On Wed, 11 Sep 2013, Duncan Coutts wrote:
For mapM etc, personally I think a better solution would be if ByteString and Text and other specialised containers could be an instance of Foldable/Traversable. Those classes define mapM etc but currently they only work for containers that are polymorphic in their elements, so all specialised containers are excluded. I'm sure there must be a solution to that (I'd guess with type families) and that would be much nicer than adding mapM etc to bytestring itself. We would then just provide efficient instances for Foldable/Traversable.
I'd prefer to keep bytestring simple with respect to the number of type extensions. Since you must implement ByteString.mapM anyway, you can plug this into an instance definition of Traversable ByteString.