The Swift Programming Language Companion (16 Part Series)
This article is part of a series on learning Swift by writing code to The Swift Programming Language book from Apple. This is the first article in Section 2 (here is Section 1)
Read each article after you have read the corresponding chapter in the book. This article is a companion to Closures.
If you are jumping around these articles, make sure you read the Introduction to see my recommendation for setting up a reading environment.
To add a new page, in Xcode:
- Choose File > New > Playground Page
- Rename the page to "07-Closures"
At this point, you should have read Closures in The Swift Programming Language. You should have a Playground page for this chapter with code in it that you generated while reading the book.
The chapter covers how to create and call closures and the concept of capturing.
For these exercises, we are going to imagine a simple media playing app.
In your Playground write code to do the following:
- Declare a Boolean variable called
isPlayingand set it to
- Declare a constant called
playthat is a closure type that takes no arguments and returns
Void. Initialize it with a closure that prints the word "Play" and sets
isPlaying(it should be true)
- Make a constant called
stopwhich is like
playbut prints "Stop" and sets
isPlaying, Declare an optional
- Add a
Stringargument to play called
currentSongto it inside the closure.
- Update your call to play pass a
- Declare a
Stringsand initialize it with 5 songs.
- Sort the list by the length of the song name
The next article will provide exercises for the Enumerations chapter.