Why no need of parenthesis to access nested class?

Question

Created Mar ’21

Replies 2

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Participants 2

Code Block class One {
  func sayOne() {
    print("from inside One")
  }
   
  class Second {
    func saySecond() {
      print("from inside second")
    }
  }
}
One.Second().saySecond()

Why can I access Second class without instantiating One() with parenthesis, when I can't access member function and variables without instantiation with ()?

Answered by Claude31 in 669047022

You have defined Second inside One.

So, when you call One.Second(), you just create an instance of Second ("prefixed" by One). You don't have to create an instance of One.
You do the same when you call from a framework:

Code Block           let vc = UIKit.UIViewController()

which is equivalent to

Code Block           let vc2 = UIViewController()

One just tells that we look for Second() inside this class.

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Answer 1

Claude31 OP

Mar ’21

Accepted Answer

You have defined Second inside One.

So, when you call One.Second(), you just create an instance of Second ("prefixed" by One). You don't have to create an instance of One.
You do the same when you call from a framework:

Code Block           let vc = UIKit.UIViewController()

which is equivalent to

Code Block           let vc2 = UIViewController()

One just tells that we look for Second() inside this class.

0

Answer 2

Aldariann OP

Mar ’21

Good example with UIKit! Helps sink that in.

0