B.2 Ancestral cuts
- prolog_cut_to(+Choice)
 - Prunes all choice points created since Choice. Can be used 
together with prolog_current_choice/1 
to implement ancestral cuts. This predicate is in the hackers 
corner because it should not be used in normal Prolog code. It may be 
used to create new high level control structures, particularly for 
compatibility purposes.
Note that in the current implementation, the pruned choice points and environment frames are not reclaimed. As a consequence, where predicates that are deterministic due to clause indexing, normal cuts or
(if\send{then};else)and and tail recursive run in bounded local stack space, predicates using prolog_cut_to/1 will run out of stack.