Proposal: Add bifunctor related classes to base

[Herbert Valerio Riedel]

On 2014-04-25 at 18:02:33 +0200, Dan Doel wrote:
> The previous discussion about methods on Either had some mention of adding
> bifunctors to base, but no one wrote up the details. So I've taken it upon
> myself to do so.
>
>
> The following proposal is to add some modules of the bifunctors [1] package
> to base, namely:
>
>     Data.Bifunctor
>     Data.Bifoldable
>     Data.Bitraversable
>
> These modules contain classes and functions for working with types similar
> to those identified by Functor, Foldable and Traversable, except that there
> are parameterized by two 'element types' so to speak.

[...]

+1 !