// *******************
// *** Playground ***
// *******************

import Foundation

internal protocol Initializable: NSObjectProtocol {
 init()
}

internal class BaseClass: NSObject, Initializable {
 required override init() {
 print("Initializing BaseClass.")
 }
}

internal final class SubClass: BaseClass {
 required init() {
 super.init()
 
 print("Initializing SubClass.")
 }
}

let className = "SubClass"

let classNamePrefix = (NSStringFromClass(BaseClass.self) as NSString).components(separatedBy: ".").first ?? ""

let completeClassName = classNamePrefix + (!classNamePrefix.isEmpty ? ".": "") + className

if let type = NSClassFromString(completeClassName) as? Initializable.Type {
 let instance = type.init()
 
 print("type = '\(type)'. instance = '\(instance)'.")
}

*********************************************************************************************
*** Xcode 10.1/Swift 4.2.1 output, without '@objc' before 'internal protocol Initializable': ***
*********************************************************************************************
Initializing BaseClass.
Initializing SubClass.
type = 'SubClass'. instance = '<__lldb_expr_3.SubClass: 0x6000032cc130>'.

 

*********************************************************************************************
*** Xcode 10.1/Swift 4.2.1 output, with '@objc' before 'internal protocol Initializable': ***
*********************************************************************************************
Initializing BaseClass.
Initializing SubClass.
type = 'SubClass'. instance = '<__lldb_expr_1.SubClass: 0x600001c7c2a0>'.

 

********************************************************************************************
*** Xcode 10.2/Swift 5 output, without '@objc' before 'internal protocol Initializable': ***
********************************************************************************************
Initializing BaseClass.
type = 'SubClass'. instance = '<__lldb_expr_1.BaseClass: 0x600003104130>'.

 

*****************************************************************************************
*** Xcode 10.2/Swift 5 output, with '@objc' before 'internal protocol Initializable': ***
*****************************************************************************************
Initializing BaseClass.
Initializing SubClass.
# type = 'SubClass'. instance = '<__lldb_expr_3.SubClass: 0x600001d78110>'.