Separation of function declaration and definition in Swift

Question

I\'m having a look at the new Swift. I come from C, C++, Objective-C... I notice that in swift is not possible (?) to separate the declaration and the definition of function

Answer 1

Just a crazy way to have public API and private implementation:

crazy - stands for factory method create() which I do not like to see in swift without real need.

In AClass.swift file:

// Public API
class AClass {

    private init() {

    }

    class func create() -> AClass {
        return AClassPrivateImplementation()
    }

    // Only method declaration
    func sayHello() {}
}

// Private implementation
private class AClassPrivateImplementation: AClass {

    override func sayHello() {
        privateImplementation()
    }

    func privateImplementation() {
        println("Hello")
    }
}

Usage:

let a = AClass.create()
a.sayHello()

Why it works: private modifier makes things visible only within source file.

Advantages: you can define more than one implementation hence additional createOther() will be needed.

Disadvantages: it looks like Java or C#, not a Swift way :)