Experiences?

Hi Robert, that's what I intended to do but without unions I at least have to seperate-out my types, no big deal as they can be derived from a common type, but then I need to determine each "nodes" type on the fly, hmmm, still looking for a solution. BM certainly appears capable but the more I read/search the more lacking the documentation looks.

LeisureSuitLurie: looks promising but I get an error expanding the dl.