/// <summary>
/// Evaluates the expression.
/// </summary>
/// <param name="expression">Expression.</param>
/// <returns>True if the expression is logically true, false otherwise.</returns>
public virtual bool Visit(PredicateLiteralCNF expression)
{
IAtom groundedPredicateAtom = GroundingManager.GroundAtomDeep(expression.PredicateAtom, Substitution, ReferenceState);
bool evaluationResult = (RigidRelations.Contains(groundedPredicateAtom) || ReferenceState.HasPredicate(groundedPredicateAtom));
return(!expression.IsNegated == evaluationResult);
}
/// <summary>
/// Visits and evaluates predicate expression.
/// </summary>
/// <param name="expression">Predicate expression.</param>
/// <returns>True if the specified expression evaluates as true, false otherwise.</returns>
public bool Visit(PredicateExpression expression)
{
// if the predicate is a rigid relation, then check whether it has the correct value
if (RigidRelations.IsPredicateRigidRelation(expression.PredicateAtom))
{
IAtom predicateAtom = GroundingManager.GroundAtom(expression.PredicateAtom, Substitution);
return(RigidRelations.Contains(predicateAtom));
}
return(true);
}
/// <summary>
/// Evaluates the expression.
/// </summary>
/// <param name="expression">Expression.</param>
/// <returns>True if the expression is logically true, false otherwise.</returns>
public override bool Visit(PredicateLiteralCNF expression)
{
IAtom groundedPredicateAtom = GroundingManager.GroundAtomDeep(expression.PredicateAtom, Substitution, ReferenceState);
if (RigidRelations.Contains(groundedPredicateAtom))
{
// satisfied or failed by rigid relation
return(!expression.IsNegated);
}
bool hasPredicate = ReferenceState.HasPredicate(groundedPredicateAtom);
if (hasPredicate == expression.IsNegated)
{
// failed by state predicate
return(false);
}
// satisfied by state predicate -> store this atom
Atoms.Add(groundedPredicateAtom);
return(true);
}
/// <summary>
/// Visits and evaluates predicate expression.
/// </summary>
/// <param name="expression">Predicate expression.</param>
/// <returns>True if the specified expression evaluates as true, false otherwise.</returns>
public bool Visit(PredicateExpression expression)
{
IAtom groundedPredicateAtom = GroundingManager.GroundAtomDeep(expression.PredicateAtom, Substitution, ReferenceState);
return(RigidRelations.Contains(groundedPredicateAtom) || ReferenceState.HasPredicate(groundedPredicateAtom));
}
