Optional protocol methods in Swift

In Swift it’s kind of unsupported to implemented optional protocol methods.

You can, which is ugly, use the @objc syntax:

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@objc protocol MyProtocol {
    optional func doSomething();
}

class MyClass : MyProtocol {
    // no error
}

Another disadvantage here is that structs are unsupported, as you’re bridging for Objc.

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Using protocol extensions to create optional protocol methods

However, with Swift 2.0 it’s possible to define protocol extension. This allows you to create optional methods for your protocol easily:

protocol MyProtocol {
    func doSomethingNonOptionalMethod()
    func doSomethingOptionalMethod()
}

extension MyProtocol {
    func doSomethingOptionalMethod(){ 
        // leaving this empty 
    }
}

As stated in this thread, many people are asking this feature:
http://stackoverflow.com/questions/24032754/how-to-define-optional-methods-in-swift-protocol