public override void Evaluate(Stack state, FormulaEngine engine)
{
var namedRef = (Reference)engine.ReferenceFactory.Named(_name);
Formula target = engine.GetFormulaAt(namedRef);
if (target != null)
{
var selfRef = (NamedReference)target.SelfReference;
IOperand op = selfRef.ValueOperand;
state.Push(op);
}
else
{
state.Push(new ErrorValueOperand(ErrorValueType.Name));
}
}