Proposal: add full complement of support for decreasing things in Data.Map

[wren romano]

On Thu, May 19, 2016 at 10:00 AM, David Feuer <david.feuer at gmail.com> wrote:
> Data.Map offers functions to convert from ascending lists to maps, and also
> offers a function to map an increasing function over the keys of a map.
> Equivalents for descending lists and decreasing functions are missing. I
> think we should add them. Any objections?

+1.

They're a lot more performant to do directly rather than (a) reversing
the ascending lists, or (b) constructing the mirror image (Map (Down
k) a) so that "ascending" is in the right order.

-- 
Live well,
~wren