On Thu, May 30, 2013 at 6:34 PM, Ross Paterson
On Thu, May 30, 2013 at 01:12:00PM -0700, Shachaf Ben-Kiki wrote:
This instance should exist. There's been a couple of discussion on libraries@ before. One of them is at http://www.haskell.org/pipermail/libraries/2012-July/018246.html.
The previous one was in January 2011:
http://thread.gmane.org/gmane.comp.lang.haskell.libraries/15196
I've taken the liberty of pushing the previously discussed Foldable and Traversable instances for Either a and (,) a.
Thank you! While you're at it would it be possible to add (trivial) Foldable and Traversable instances for (Const r), for completeness? I think that was also mentioned in one of the discussions. As in my patch, the instances are: instance Foldable (Const m) where foldMap _ _ = mempty instance Traversable (Const m) where traverse f (Const m) = pure (Const m) Shachaf