public void InspectTheObjectAndCalcualteAResult()
{
var shoppingCart = new WebShoppingCart();
var discount = Pattern.Match <ShoppingCart, decimal>(shoppingCart).
Case(cart => cart.Customer is ClubMember, cart => cart.OrderValue * 0.05m).
Case(cart => cart.Customer is FirstTimeCustomer, cart => cart.OrderValue * 0.04m).
Case(cart => cart.Customer is StandardCustomer, cart => cart.OrderValue * 0.02m).
Default(cart => cart.OrderValue).
Result;
}
public void ShopingCardTest()
{
ShoppingCart shoppingCart = new WebShoppingCart();
//sub-type matching with conditions on the sub-type
var specialFrontendOffers = Pattern.Match <ShoppingCart, decimal>(shoppingCart).
Case <AppShoppingCart>(appShopingCart => appShopingCart.IsFirstRunExperience, 0.05m). //5% off for the first time order with the app
Case <WebShoppingCart>(webShopingCart => webShopingCart.PromoCode == "WebSpecial", 0.04m). //4% off for the newsletter promotion code (only supported by the web interface)
Default(0.0m).
Result;
//matching on a condition and nested pattern matching
var cartDiscounts = Pattern.Match <ShoppingCart, decimal>(shoppingCart).
Case(cart => cart.OrderValue > 100, cart => Pattern.Match <Customer, decimal>(cart.Customer). // if the order value is bigger than 100 the discount depends on the customer status
Case <ClubMember>(0.1m). // Club member always get 10%
Case <StandardCustomer>(standardCustomer => !standardCustomer.HasOutstandingDebts, 0.05m). // standardCustomers get 5% if there are no outstanding debts
Default(0.0m).
Result).
Case(cart => cart.OrderValue > 50, 0.02m). // between 50 and 100, the discount is 2% without further conditions
Default(0.0m).
Result;
//after the first match all the other matches are ignored
var shipping = Pattern.Match <Address, decimal>(shoppingCart.ShippingAddress).
Case(address => address.ShippingDistance > 1000, 7m).
Case(address => address.ShippingDistance > 500, 5m).
Case(address => address.ShippingDistance > 50, 3m).
Default(2m);
var overallPrice = shoppingCart.OrderValue +
(shoppingCart.OrderValue * specialFrontendOffers) +
(shoppingCart.OrderValue * cartDiscounts) +
shipping;
//Start check out process
Pattern.Match(shoppingCart.PayMethod).
Case <CreditCard>(creditCard => CheckoutPerCreditcard(shoppingCart, overallPrice)).
Case <AdvancePayment>(advancePayment => CheckoutPerAdvancePayment(shoppingCart, overallPrice)).
Default(() => { throw new NotSupportedException(); });
}
