Proposal: more general unionWith for Data.Map - Summary

[Milan Straka]

Hi all,

> > Feedback indicated it is worth to unify the existing mess with an abstract
> > foundation, with otherwise no negative reactions. As such, I propose to go
> > through with this.
> 
> 
> My memory is a bit hazy here, but I thought Milan was working on merging
> this in. Milan?

Yes, I am working on merging mergeWith and mergeWithKey with the type
you specified, in Map and IntMap.

Hopefully, IntMap.{union*, difference*, intersecion*} and
Map.intersection* will be implemented using mergeWith*, depending what
the benchmarks reveal. I am not sure about Map.{union*, difference*}, as
they use different algorithm -- I am waiting for the benchmarks.

Cheers,
Milan