unrolling forests without recursion
darcs-hash:
20060603085136-5007d-
aa958aa60d5a0d884aa02a8de46c7307d5fb54bc.gz
tentative checkpoint ROLL THIS BACK BUT INCLUDES CRUCIAL FIX
darcs-hash:
20060529074808-5007d-
be65fd987295ef194773dbf20d0fe87af05fc760.gz