internal static System.Collections.Generic.IEnumerable<CutState> Retract(object term, PrologContext context)
{
ELNode foundNode;
ELNodeEnumerator enumerator;
if (!TryQuery(term, context, out foundNode, out enumerator))
return CutStateSequencer.Fail();
if (foundNode != null)
{
foundNode.DeleteSelf();
return CutStateSequencer.Succeed();
}
return DeleteSuccessive(enumerator);
}
internal static IEnumerable <CutState> Retract(object term, PrologContext context)
{
ELNode foundNode;
ELNodeEnumerator enumerator;
if (!TryQuery(term, context, out foundNode, out enumerator))
{
return(CutStateSequencer.Fail());
}
if (foundNode != null)
{
foundNode.DeleteSelf();
return(CutStateSequencer.Succeed());
}
return(DeleteSuccessive(enumerator));
}
internal IEnumerable <CutState> FindClauses(Structure head, object body)
{
PredicateInfo i = CheckForPredicateInfo(head.PredicateIndicator);
return((i == null)?CutStateSequencer.Fail():i.FindClauses(head, body));
}
