Inference Engine: How to use one atom value in another when creating implication. about nxbre HOT 4 CLOSED

    public class Product
    {
        public string Name { get; set; }
        public double Price { get; set; }
        public string Category { get; set; }

        public override string ToString()
        {
            return Name;
        }
    }

    public class Order
    {
        public string CustomerName { get; set; }
        public string Product { get; set; }
        public double Quantity { get; set; }
        public double GrossAmount { get; set; }
        public double Discount { get; set; }
        public double TotalAmount { get; set; }

        public override string ToString()
        {
            return CustomerName;
        }
    }

    class ProductBinder : AbstractBinder
    {
        public ProductBinder() : base(BindingTypes.BeforeAfter) { }

        public override void BeforeProcess()
        {
            foreach (Product p in (ArrayList)BusinessObjects["PRODUCTS"])
            {
                IEF.AssertNewFactOrFail("Price", new object[] { p, p.Price });
            }

            foreach (Order p in (ArrayList)BusinessObjects["ORDERS"])
            {
                IEF.AssertNewFactOrFail("OrderQty", new object[] { p, p.Product, p.Quantity });
            }
        }

        public override void AfterProcess() { }

        public override NewFactEvent OnNewFact
        {
            get
            {
                return new NewFactEvent(NewFactHandler);
            }
        }

        public override object Compute(string operationName, IDictionary arguments)
        {
            switch (operationName)
            {
                case "CalulateTotal":
                    return Convert.ToDouble(arguments["Qty"]) * Convert.ToDouble(arguments["Value"]);
            }

            throw new Exception("Binder can not evaluate " + operationName);
        }

        private void NewFactHandler(NewFactEventArgs nfea)
        {
            if (nfea.Fact.Type == "Category")
                ((Product)nfea.Fact.GetPredicateValue(0)).Category = nfea.Fact.GetPredicateValue(1).ToString();
            if (nfea.Fact.Type == "GrossAmount")
                ((Order)nfea.Fact.GetPredicateValue(0)).GrossAmount = Convert.ToDouble(nfea.Fact.GetPredicateValue(1));
            if (nfea.Fact.Type == "OrderDiscount")
            { 
                ((Order)nfea.Fact.GetPredicateValue(0)).Discount = Convert.ToDouble(nfea.Fact.GetPredicateValue(1));
                Order obj = (Order)nfea.Fact.GetPredicateValue(0);
                obj.TotalAmount = obj.GrossAmount - obj.Discount;
            }
        }
    }

        private ArrayList GetProducts(int nCount)
        {
            ArrayList prods = new ArrayList();
            Random rnd = new Random();

            for (int i = 0; i < nCount; i++)
            {
                prods.Add(new Product() { Name = "PRODUCT-" + (i + 1), Price = rnd.Next(10000) });
            }
            return prods;
        }

        private ArrayList GetOrders(int nCount, ArrayList prods)
        {
            ArrayList orders = new ArrayList();
            Random rnd = new Random();

            for (int i = 0; i < nCount; i++)
            {
                orders.Add(new Order() { CustomerName = "Customer-" + (i + 1), Product = "PRODUCT-"+rnd.Next(1,5), Quantity = rnd.Next(1, 10) });
            }
            return orders;
        }

        public void PerformProductProcess(IBinder binder)
        {
            string ruleBaseFile = Application.StartupPath + "\\productrating2.ruleml";

            // generate dummy business objects
            Hashtable bo = new Hashtable();
            ArrayList prodList = GetProducts(5);
            bo.Add("PRODUCTS", prodList);
            bo.Add("ORDERS", GetOrders(10, prodList));
            IDictionary businessObjects = bo;

            try
            {

                // instantiate an inference engine, bind my data and process the rules
                IInferenceEngine ie = new IEImpl(binder);
                ie.LoadRuleBase(new RuleML09NafDatalogAdapter(ruleBaseFile, System.IO.FileAccess.Read));

                ie.Process(businessObjects);

                RefreshStatus(ie);
                IList<IList<NxBRE.InferenceEngine.Rules.Fact>> op = ie.RunQuery(0);
                //double.Parse()
            }
            catch (Exception e)
            {

            }
        }