Re: [Haskell-cafe] ANN: signed-multiset-0.1

Stefan Holdermans writes:

This package provides an efficient implementation of so-called signed multisets, which generalise multisets by allowing for negative membership.

SignedMultiset a = Data.Map.Map a Integer so what do I gain by using your library? (what is the API difference?) Perhaps you could state this clearly at the top of the package description (visible on hackage). I sometimes find I want a type "Map with default" (the default value is stored when the Map is constructed, and you never put keys in there that map to this default). Best - J.W.