rosstulloch

if let refURL = (a as NSURL).perform(#selector(NSURL.fileReferenceURL))?.takeUnretainedValue() as? NSURL {
    print(refURL)
}

rosstulloch

func typecast<T,U>(_ a:T) -> U {
    var _a = a
    return withUnsafePointer(to: &_a) { (ptr:UnsafePointer<T>) -> U in
        return UnsafeRawPointer(ptr).load(as: U.self)
    }
}

func typecast_inplace<T,U>(_ a:inout T) -> U {
    return withUnsafePointer(to: &a) { (ptr:UnsafePointer<T>) -> U in
        return UnsafeRawPointer(ptr).load(as: U.self)

rosstulloch

class YourClass {
    required init() {
    }
    func saySomething() {
        print("Hi!")
    }
}

if let classType = NSClassFromString("APPNAMEORMODULE.YourClass") as? YourClass.Type {

rosstulloch

protocol HasInit {
    init()
    func sayHi()
}

extension HasInit {
    func sayHi() { print("Hi from an instance of \(type(of: self))") }
}