// Try to find the appropriate attribute
public override object Exec(InterfaceType d, object arg)
{
UnconstrainedDotOperation uo = new UnconstrainedDotOperation(this.memberName, this.previousDot);
TypeExpression member = (TypeExpression)d.AcceptOperation(uo, arg);
if (member == null)
{
// * Otherwise, error
ErrorManager.Instance.NotifyError(new UnknownMemberError(this.memberName, this.location));
}
return(member);
}
public override object Exec(InterfaceType firstOperand, object arg)
{
int aux, less = -1;
// * Equivalent types
if ((bool)firstOperand.AcceptOperation(new EquivalentOperation(this.secondOperand), arg))
{
less = 0;
}
// * WriteType variable
TypeVariable typeVariable = this.secondOperand as TypeVariable;
if (typeVariable != null)
{
if (typeVariable.Substitution != null)
{
// * If the variable is bounded, the promotion is the one of its substitution
return(firstOperand.AcceptOperation(new PromotionLevelOperation(typeVariable.EquivalenceClass.Substitution), arg));
}
// * A free variable is complete promotion
return(0);
}
// * Field type and bounded type variable
FieldType fieldType = TypeExpression.As <FieldType>(this.secondOperand);
if (fieldType != null)
{
return(firstOperand.AcceptOperation(new PromotionLevelOperation(fieldType.FieldTypeExpression), arg));
}
// * Interface List
if (firstOperand.InterfaceList.Count != 0)
{
for (int i = 0; i < firstOperand.InterfaceList.Count; i++)
{
if ((bool)firstOperand.InterfaceList[i].AcceptOperation(new EquivalentOperation(this.secondOperand), arg))
{
if ((less > 1) || (less == -1))
{
less = 1;
}
}
else
{
aux = (int)firstOperand.InterfaceList[i].AcceptOperation(this, arg);
if (aux != -1)
{
if (less > aux + 1 || less == -1)
{
less = aux + 1;
}
}
}
}
}
if (less != -1)
{
return(less);
}
// * Union type
UnionType unionType = TypeExpression.As <UnionType>(this.secondOperand);
if (unionType != null)
{
return(unionType.SuperType(firstOperand));
}
// * No promotion
return(-1);
}
