Module state

This module provides trailed named values.

The following state predicates are provided.

b_setval(K, W):
The predicate assigns the value W to the key K. The assignment is automatically un-done upon backtracking.
nb_current(K, W):
The predicate succeeds for the value W of the key K.
The predicate de-assigns the key K. The de-assignment is automatically undone upon backtracking.