As this chapter ends, we end the introduction to the Swift programming language. At this point we have enough knowledge of the Swift language to begin writing our own applications; however, there is still much to learn. In the following chapters we will look in more depth at some of the concepts that we already discussed, such as optionals and subscripts. We will also show how we would perform common tasks with Swift, such as parsing common file formats and handling concurrency. Finally we will also have some chapters that will help us write better code like a sample Swift style guide and a chapter on design patterns.