I wrote:
[1] Balancing can be done with the information in the blueprint, and mapping back is easily done by doing the transformation on the tree in reverse.
I should add that this possibility was the main reason for dealing with blueprints at all. As Ross Paterson's solution shows, it's possible to get simpler code without balancing the tree. regards, Bertram _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
