• BitSet: Seems to be working nice. Needs a benchmark comparing with other implementations. However, replacing IntSet on Pugs doesn't seem to get much improvement (tests were inconclusive, but looks like BitSet is only a little bit better). But the use of this datatype in Pugs is very limited, so BitSet wasn't fully exercised.
• Judy.Map: Did a Map type on top of JudyHS, it uses StablePtr as values and any "Stringable" type as keys. Stringable means that there's a injective function from type to Strings, as JudyHS use Strings as index type. I'm thinking in use some class stuff to deal with values too, so default implementation uses StablePtr, but will be easy to do specialized implementation for Int, for example (don't need SPtr in this case, just save the Int).
• Pugs: I'm trying to figure out how IHash works in Pugs, so I can test Judy.Map in Pugs code. Let's see what happens.
• My next steps: As Bulat, and later AudreyT, suggested I'm working on a CollectionM and MapM classes based on Collections interface. Some benchmark for BitSet and Map will be nice to have too.