In Objective-C, every class is an instance of its metaclass.

What about Swift? If you've looked closely at the Swift Language Reference you'll see two short paragraphs describing SomeClass.self and SomeClass.Type, a short example (that doesn't address Type at all), and that's it.

Meta

In Swift, all types have metatypes, not just classes.

Let's use let object:Any = "beep boop". I'm using Any here to force the compiler to forget what it knows about the type, otherwise it is too smart and flags the test below as always returning true.

Watch out for AnyObject. If I had declared object that way then it would hold an Objective-C NSString cluster instance! This is part of the automatic Objective-C bridging system that also automatically converts true or 0.0 into NSNumber instances in similar cases.

We can ask if object is an instance of String:

let isString = object is String //true

We can use reflection to figure out the type of object (and cast to Any.Type here to again defeat the smartypants compiler).

let mirror = Mirror(reflecting: object)
let typeOfObject:Any.Type = mirror.subjectType

Now how can we ask whether typeOfObject is String? You might try this code:

let isStringType = typeOfObject is String
//warning:Cast from 'Any.Type' to unrelated type 'String' always fails

It doesn't work because we are operating abstractly. typeOfObject is not an instance of String, it's an instance of the String.Type metatype. (I like to think of String.self as being the String struct.) Now we've found a use for the String.Type metatype:

//Swift 1.2
let isStringType = typeOfObject is String.Type

As of Swift 2 you can also directly compare metatypes for equality:

let isStringType = typeOfObject == String.self

tl;dr

• "beep boop" is an instance of the struct String
• We can get a reference to the String struct via String.self
• String.self is an instance of the String.Type metatype
• The String.Type metatype is an instance of the Any.Type metatype