Swift 2 internal vs private

Question

I'm confused about the internal and private access modifier.

The docs says:

“Internal access enables entities to be used within any source file from their defining module, but not in any source file outside of that module. You typically use internal access when defining an app’s or a framework’s internal structure.”

How I thought it was, was that with internal you can access everything if you are in your own app. But this is not true, because when I have a viewcontroller what is default internal and I'm having a internal function on that viewcontroller I can't access this from another file in another group (You create these in xCode).

What I tried was having a ViewController that has a method foo in group A then in group B I created a ViewController like this:

let vc: FakeViewController = FakeViewController() vc.foo() 

So is internal restricted to the same group? Or I'm I interpreting it wrong?

Is it useful that in a viewcontroller you create private methods and vars/lets?

Answer 1

@user1007522 Could you post the entire source code for FakeViewController? You should have access to foo() from your vc variable. If you do not, I suspect something else is in play here.

I found the following definitions much easier to understand (copied from UseYourLoaf - Swift 4 Access Levels)

The Five Access Levels of Swift 3/4

Swift 3 has five access levels that control from which source file or module you can access something. In order from most open to most restricted:

• open you can access open classes and class members from any source file in the defining module or any module that imports that module. You can subclass an open class or override an open class member both within their defining module and any module that imports that module.

• public allows the same access as open - any source file in any module - but has more restrictive subclassing and overriding. You can only subclass a public class within the same module. A public class member can only be overriden by subclasses in the same module. This is important if you are writing a framework. If you want a user of that framework to be able to subclass a class or override a method you must make it open.

• internal allows use from any source file in the defining module but not from outside that module. This is generally the default access level.

• fileprivate allows use only within the defining source file.

• private Swift 4: allows use only from the enclosing declaration and new in Swift 4, to any extensions of that declaration in the same source file Swift 3: allows use only from the enclosing declaration.