PaymentMethodPatternMatching.fs

type Order(selectedPaymentMethod: PaymentMethod, 
           discountCode: Option<string>) =

let paymentMethod pm  =
         match pm with
            | x when x =  CashOnDelivery ->
                printfn "Cash on delivery"
            | Paypal id->
                printf "paid by paypal %A" id 
            | Card (cardNumber , cardType) ->
                printf "paid by %A%A" cardNumber  cardType

let printPaymentMethod = paymentMethod (selectedPaymentMethod)

//members
member val PaymentMethod: PaymentMethod = paymentMethod with get

//other members removed for brevity

printfn "%A" printPaymentMethod