Swift-参数必须符合协议且检查为kindOf的函数

Question

I have an OrderBook with expected and completed orders; both of which are array of Ints.

I want to have an 'add' order function which is generic and works for both the expected and completed class;

Both classes follow a protocol.

I wish to make a function call where the object passed in must conform to a protocol; not only that I want to check that the order is kindOf class.

protocol EntryProtocol {
    var value: Int { get set }
}

class OrderBook {
    var existingOrders: [ExistingOrder] = [ExistingOrder]()
    var completedOrders: [CompletedOrder] = [CompletedOrder]()

    func add<C1: Any>(order: C1) where C1: EntryProtocol {

        print (order is ExistingOrder.Type) // returns false
        print (order is CompletedOrder.Type)  // returns false

        // i want to do a switch here
    }
}

class ExistingOrder: EntryProtocol {
    var value : Int

    init(value: Int) {
        self.value = value
    }

    // .. other methods
}



class CompletedOrder: EntryProtocol {
    var value : Int

    init(value: Int) {
        self.value = value
    }

    // .. other methods
}


var orderBook: OrderBook = OrderBook()

let howMany = 4

for _ in 1...howMany {
    let value = 3 // this is a random number (1-6)
    let order = ExistingOrder.init(value: value)
    orderBook.add(order: order)
}

print (orderBook.existingOrders)
print (orderBook.completedOrders)

In my swift playground, the add() function always returns false when I check to see whether it is a ExistingOrder or CompletedOrder

How do I make a function where the parameter must conform to a protocol; then check that the object passed in via parameter is of a certain type?

Many thanks

Answer 1

the answer is to use order is ExistingOrder , crediting @rmaddy then check the return if let order = order as? ExistingOrder if let order = order as? ExistingOrder , crediting @dan