MonadZip for Data.Tree

[wren romano]

On Thu, Dec 29, 2016 at 10:54 PM, Edward Kmett <ekmett at gmail.com> wrote:
> As for what I have against munzip as a member, it is a boring, unnecessary
> member with no interesting definitions. It has to be equivalent to fmap fst
> &&& fmap snd to pass the laws and free theorems involved.

The one nice thing is that munzip can perform (fmap fst &&& fmap snd)
in a single pass, rather than taking two passes. This is why we have
all those combined functions in containers like insertLookup,
updateLookup, etc. Though, yes, I'd much rather have a more generic
version which works for any pair/set of functions rather than
hardcoding (fst,snd).

-- 
Live well,
~wren