Re: Constraints on definition of `length` should be strengthened

Already done mate. https://hackage.haskell.org/package/hask-0/docs/Hask-Category.html#t:Either https://hackage.haskell.org/package/hask-0/docs/Hask-Category.html#t:Functor Note the multiple Functor instances for Either and Coproduct. e.g. - Functor * (* -> *) Either - Functor * * (Either a) etc etc On 09/04/17 10:29, Henrik Nilsson wrote:

And of course, if, in a hypothetical future version of Haskell where we could make all possible functor instances for tuples, the question becomes: which one do we pick? The answer might well be "none" (in the prelude, at least).