In Objective-C we have our header files to expose the functionality of our classes. There we lay out the methods and properties that we allow the consumer of the class to use. Even though we can technically call methods which are not exposed in the header, the header acts as a contract between classes and makes development easier.
In Swift we no longer have header files. We have a single .swift file. We can modify access to our classes members with private, internal and public, but having a good clear indication of what you have exposed to external classes is not easy when you have a dozen methods, and a handful of properties with getters and setters.
So how to have those exposed methods clearly visible on a cursory look into that .swift file? The way I'm starting to do it is with protocols.
protocol carProtocol {
var speed : Float { get } //Readonly
var color : UIColor { get set } //Read/write
func accelerate()
func decelerate()
}
class car : carProtocol {
var speed : Float;
var color : UIColor;
init () {
self.speed = 1.0
self.color = UIColor.redColor()
}
func accelerate() { }
func decelerate() { }
}
And then to have a car instance as a property on your class, you declare the property as being an object which conforms to carProtocol, and instantiate the object as a car object.
class clientThing {
let myCar : carProtocol
init () {
self.myCar = car()
}
}
So now to see what you have exposed to other classes, you just glance at the protocol declaration in your class's file.