How is a global variable set to private understood in swift?

Question

I\'m working through a Core Data exercise from a book and it starts out creating a helper class which is a singleton. I understand that global variables can be created outside

Answer 1

A private global variable in Swift is a global that is only accessible from the file in which it is declared.

The book you are using isn't following current best-practice as far as creating singletons in Swift (perhaps it is a little out-dated?).

There is no need for the private global variable. You can just say:

class CDHelper: NSObject {
// MARK: - SHARED INSTANCE
    static let shared = CDHelper()
}