checks whether a term is member of the blackboard.
Blackboards are collections of (Key,Value) tuples. bb_contains/2 allows to retrieve the Value part of the blackboard.
If Term is not a free variable then bb_contains succeeds if the blackboard Board contains Term as Value at least once.
If Term is a free variable then by backtracing bb_contains/2
lists in an unspecific order all terms which are elements of the blackboard Board.
Board blackboard Term term
Assume there exists a blackboard 'blackboard' with elements (100, abc), (101, element101), (102, abc).
| bb_contains(blackboard,abc). | Succeeds. |
| bb_contains(blackboard, X). | Succeeds three times with substitution
X <- abc X <- element101 X <- abc |
This predicate is not part of the ISO-Prolog Standard.