On Mon, Feb 7, 2011 at 11:57 PM, John Lato
I think the real problem we have with container classes has a lot more to do with what we would use them for. That is, Haskell already has Monoid, Foldable and Traversable. These three (especially Foldable) cover nearly everything OOP programmers would expect out of generic container operations.
Unfortunately using e.g. Foldable hurts performance a lot. We need to look into inlining and specialization and move some functions (e.g. foldl') into the type class if we want acceptable performance.
What's missing are classes for specific data types. That is, a Map/Dict interface, a Queue interface, and a Heap interface (probably others too, but these are the first that come to mind). But the standard Data.Map and List (for a queue) seem good enough for most people, so there seems to be a lot of inertia to overcome for these to be popular.
I think the missing piece to make this abstraction worthwhile is a second Map/Dict type worth using. Then there's a point in abstracting over which type is actually used. In most OOP languages the two map types are sorted and hashed maps. Johan