On Thu, Jul 5, 2012 at 8:01 AM, Milan Straka
Agreed. These indexing methods work only for OrderededSet and OrderedMap, not for HashMap and HashSet.
If the Data.Set and Data.Map modules were called Data.OrdSet and Data.OrdMap, then there would be no problem including the indexing API in them. Personally I consider Data.Set to be Data.OrdSet, not a generic Set API. If we every create a Set class, the indexing API will definitely _not_ be part of it.
I've also considered Map and Set to be OrdMap and OrdSet for quite a while. If we ever add a type class to abstract over e.g. HashMap and Map we'd probably call it Data.Map.Class or something. A potential downside to adding these functions is that I don't know if we can support them efficiently with a different implementation of ordered trees than the size-balanced ones. I still think we should add them though. -- Johan