16 Dec
2010
16 Dec
'10
11:04 p.m.
On Wed, Dec 15, 2010 at 03:38:37PM +0100, Johan Tibell wrote:
My vote is "no", there are already too many fold variants in Data.Map. We have
{left,right} x {non-strict,strict} x {with key, without key} = 8 combinations together.
Adding back the "directionless" version would mean another 4 versions of we want symmetry. This in a module that already has 150 functions.
We need to do something about the large amount of both API (i.e. usability tax) and implementation (maintainer overhead) duplication in the containers library.
Well, once you have withKeys :: Map k a -> Map k (k,a) withKeys = mapWithKey (,) and the Foldable instance, all those fold variants are redundant, as are all the WithKey variants.