Semigroup instance for Map k v?

Question

Semigroup instance for Map k v?

Closed this issue 11 years ago · 4 comments

hdgarrood commented 11 years ago

with (<>) = union, like Haskell does? I'll prepare a PR if you think this is a good idea.

see https://downloads.haskell.org/~ghc/latest/docs/html/libraries/containers/src/Data-Map-Base.html#line-334

Answer 1 · 2014-12-08T11:58:42.000Z

Oh, sorry, I guess that should be (Ord k) => Semigroup (Map k v)

Answer 2 · 2014-12-08T12:04:38.000Z

Actually I've thought of another potential instance - (Ord k, Semigroup v) => Semigroup (Map k v) where (<>) = unionWith (<>), using the unionWith from Haskell's Data.Map

Answer 3 · 2014-12-08T17:03:10.000Z

Personally, I think the (<>) = union instance is a more natural default, and we can always newtype for other instances.

Answer 4 · 2014-12-08T22:19:35.000Z

resolved via #25