/// <summary>
/// Visits and evaluates exists expression.
/// </summary>
/// <param name="expression">Exists expression.</param>
/// <returns>True if the specified expression evaluates as true, false otherwise.</returns>
public bool Visit(ExistsExpression expression)
{
IEnumerable <ISubstitution> localSubstitutions = GroundingManager.GenerateAllLocalSubstitutions(expression.Parameters);
foreach (var localSubstitution in localSubstitutions)
{
Substitution.AddLocalSubstitution(localSubstitution);
bool subExpressionResult = expression.Child.Accept(this);
Substitution.RemoveLocalSubstitution(localSubstitution);
if (subExpressionResult)
{
return(true);
}
}
return(false);
}
/// <summary>
/// Visits and performs a property count on exists expression.
/// </summary>
/// <param name="expression">Exists expression.</param>
/// <returns>Tuple (property satisfied count, property not satisfied count).</returns>
public Tuple <double, double> Visit(ExistsExpression expression)
{
double positiveValue = 0.0;
double negativeValue = 0.0;
IEnumerable <ISubstitution> localSubstitutions = GroundingManager.GenerateAllLocalSubstitutions(expression.Parameters);
foreach (var localSubstitution in localSubstitutions)
{
Substitution.AddLocalSubstitution(localSubstitution);
var childPropertyCounts = expression.Child.Accept(this);
Substitution.RemoveLocalSubstitution(localSubstitution);
positiveValue = Math.Max(positiveValue, childPropertyCounts.Item1);
negativeValue = Math.Max(negativeValue, childPropertyCounts.Item2);
}
return(Tuple.Create(positiveValue, negativeValue));
}
/// <summary>
/// Visits and performs a property count on exists expression.
/// </summary>
/// <param name="expression">Exists expression.</param>
/// <returns>Tuple (property satisfied count, property not satisfied count).</returns>
public Tuple <int, int> Visit(ExistsExpression expression)
{
int minFulfilled = int.MaxValue;
int minNotFulfilled = int.MaxValue;
IEnumerable <ISubstitution> localSubstitutions = GroundingManager.GenerateAllLocalSubstitutions(expression.Parameters);
foreach (var localSubstitution in localSubstitutions)
{
Substitution.AddLocalSubstitution(localSubstitution);
var childPropertyCounts = expression.Child.Accept(this);
Substitution.RemoveLocalSubstitution(localSubstitution);
minFulfilled = Math.Min(minFulfilled, childPropertyCounts.Item1);
minNotFulfilled = Math.Min(minNotFulfilled, childPropertyCounts.Item2);
}
return(Tuple.Create(minFulfilled, minNotFulfilled));
}
/// <summary>
/// Visits and transforms the expression.
/// </summary>
/// <param name="expression">Source expression.</param>
/// <returns>Transformed expression.</returns>
public override IExpression Visit(ExistsExpression expression)
{
return(new ExistsExpression(expression.Parameters, expression.Child.Accept(this)));
}