Functor, Applicative, Monad, Foldable, Traversable instances for (, , ) a b

Fri Mar 31 17:24:03 UTC 2017

On Fri, 31 Mar 2017, Herbert Valerio Riedel wrote:

> On Thu, Mar 30, 2017 at 10:47 PM Bryan Richter <b at chreekat.net> wrote:
>       I just don't know why pairs ever got to Functor. I fear this was an ancient decision... no?
> 
> 
> If you're curious, this happened over 10 years ago:
> 
> http://git.haskell.org/ghc.git/commitdiff/209bf03ac7949c9bcf677561a2b1360b158e3b22

Interesting. The Functor instance for pairs was added together with the 
Functor instance for functions. But the Monad instance for pairs came 
later, right?