Proposal: Add conspicuously missing Functor instances for tuples

Henning Thielemann lemming at
Tue Feb 23 08:16:49 UTC 2016

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.

More information about the Libraries mailing list