Re: Proposal: Add conspicuously missing Functor instances for tuples

On Thu, 18 Feb 2016, Edward Kmett wrote:

Traversable's sequence gives you canonical distributive law for this functor. 

sequence :: (e, f a) -> f (e, a)

I have my own functions Func.mapFst, Func.mapSnd. This seems to better reflect the symmetry of the pair members. They only need (Functor f), not (Applicative f) like 'sequence' does. http://code.haskell.org/~thielema/utility/src/Control/Functor/HT.hs