[Haskell-cafe] Partial instance of a class

[Tom Ellis]

On Tue, Feb 27, 2018 at 01:46:49PM +0000, Tom Ellis wrote:
> In fact Unpickler is a Monad (isomorphic to an EitherT of a State) so "PU' a"
> is an Applicative and PU is what I call a "product profunctor".
> 
>     https://hackage.haskell.org/package/product-profunctors

(Oh, we also need Pickler to be Data.Functor.Contravariant.Divisible, which
it indeed is.)