A couple other issues: Once you have "one piece on a board" representations and you want to start combining them, it's important to think about how you will distinguish the pieces at the end. Maintaining these as a list of "piece on board" data structures is one way of doing that (since you can use "position in that ultimate list as a way of recovering piece identity).
Another issue has to do with the way fanout works. I think the best approach is to pair up "pieces on boards", along the lines of: _2 combine\^:4 piecepossibilities but probably hard coded, to tailor some of the cleanup and book keeping between steps. The first pass seems fairly straightforward, but after that you might need to start optimizing to save space at the expense of time (depending on how much you can toss immediately as non-viable). -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
