You need to declare the type of the protocol as AnyObject. protocol ProtocolNameDelegate: AnyObject { // Protocol stuff goes here } class SomeClass { weak var delegate: ProtocolNameDelegate? } Using AnyObject you say that only classes can conform to this protocol, whereas structs or enums can’t.
You can do exactly the same call with Swift: Swift 4 & Swift 5 In Swift 4 String is a collection of Character values, it wasn’t like this in Swift 2 and 3, so you can use this more concise code1: let string = “hello Swift” if string.contains(“Swift”) { print(“exists”) } Swift 3.0+ var string … Read more
I just tested it for you, Swift applications compile into standard binaries and can be run on OS X 10.9 and iOS 7. Simple Swift application used for testing: func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool { self.window = UIWindow(frame: UIScreen.mainScreen().bounds) var controller = UIViewController() var view = UIView(frame: CGRectMake(0, 0, 320, 568)) view.backgroundColor … Read more
Swift itself doesn’t use selectors — several design patterns that in Objective-C make use of selectors work differently in Swift. (For example, use optional chaining on protocol types or is/as tests instead of respondsToSelector:, and use closures wherever you can instead of performSelector: for better type/memory safety.) But there are still a number of important … Read more
What I do is say in the Terminal: $ xcrun swift -version Output for Xcode 6.3.2 is: Apple Swift version 1.2 (swiftlang-602.0.53.1 clang-602.0.53) Of course that assumes that your xcrun is pointing at your copy of Xcode correctly. If, like me, you’re juggling several versions of Xcode, that can be a worry! To make sure … Read more
Yes you can do it. In Swift you can still use the “#if/#else/#endif” preprocessor macros (although more constrained), as per Apple docs. Here’s an example: #if DEBUG let a = 2 #else let a = 3 #endif Now, you must set the “DEBUG” symbol elsewhere, though. Set it in the “Swift Compiler – Custom Flags” … Read more
tl;dr Swift 1.0 is now as fast as C by this benchmark using the default release optimisation level [-O]. Here is an in-place quicksort in Swift Beta: func quicksort_swift(inout a:CInt[], start:Int, end:Int) { if (end – start < 2){ return } var p = a[start + (end – start)/2] var l = start var r … Read more
You can use // MARK: There has also been discussion that liberal use of class extensions might be a better practice anyway. Since extensions can implement protocols, you can e.g. put all of your table view delegate methods in an extension and group your code at a more semantic level than #pragma mark is capable … Read more