Multiple unnamed parameters in Swift methods

Question

As far as I can tell, Swift functions have unnamed parameters by default, but Swift methods do not (excluding the first parameter). For example, given the following definitions:

func foo(a: Int, b: Int) -> Int {
    return a + b
}

class MyClass {
    func bar(a: Int, b: Int) -> Int {
        return a + b
    }
}

I have to call foo with unnamed parameters:

foo(10, 20) // fine

foo(a: 10, 20) // error
foo(10, b: 20) // error
foo(a: 10, b: 20) // error

and I have to call bar with the first argument unnamed, and the second argument named:

MyClass().bar(10, b: 20) // fine

MyClass().bar(10, 20) // error
MyClass().bar(a: 10, b: 20) // error
MyClass().bar(a: 10, 20) // error

I understand that I can make any unnamed parameter named by using the # symbol, but my question is: is there any way I can make both arguments to bar unnamed?

In other words, I would like to declare bar in such a way that I can call it like an ordinary function:

MyClass().bar(10, 20)

Is this possible in Swift? If so, how?

Answer 1

Yes, you prefix the second parameter name with _ to have it be anonymous:

class MyClass {
    func bar(a: Int, _ b: Int) -> Int {
        return a + b
    }
}