推奨されてるシングルトンパターンの実装、structのネストの位置を変えても動いた

gistfile1.swift

import UIKit

class Manager {
    struct Singleton {
        static let instance = Manager()
    }
    
    class var sharedInstance: Manager {
        println("sharedInstance called")

//        struct Singleton {
//            static let instance = Manager()
//        }
            
        return Singleton.instance
    }
    
    let name: String
    
    init(name: String = "sample user") {
        self.name = name
    }
}

let instanceA = Manager.sharedInstance
let instanceB = Manager.sharedInstance

if instanceA === instanceB {
    println("singleton pattern")
} else {
    println("not singleton pattern")
}