Demonstrates how an obj-c selector can be replaced in Swift

SwiftSelector.swift

import Foundation

class A {
  func call(selector: Selector, on destination: Any) {
    if let object = destination as? NSObject {
      object.performSelector(onMainThread: selector, with: self, waitUntilDone: true)
    } else {
      DispatchQueue.main.async {
        Thread.detachNewThreadSelector(selector, toTarget: destination, with: self)
      }
    }
  }
}


class B: NSObject {
  @objc func tellMe(sender: Any) {
    print("Message received! for B")
  }
}

class C {
  @objc func tellMe(sender: Any) {
    print("Message received! for C")
  }
}

let a = A()

let b = B()
let bSelector = #selector(b.tellMe(sender:))

let c = C()
let cSelector = #selector(c.tellMe(sender:))

a.call(selector: bSelector, on: b)
a.call(selector: cSelector, on: c)