What you need for this book
The exercises in this book were written and tested for Swift 2.1, which is bundled with Xcode 7.2, and verified against a development build of Swift 2.2. To experiment with Swift, you will need either a Mac OS X or Linux computer that meets the requirements shown at https://swift.org/download/.
To run the exercises involving Xcode in Chapters 2–8, you need to have a Mac OS X computer running 10.9 or above with Xcode 7.2 or above. If newer versions of Swift are released, check the book's GitHub repository or the book's errata page at Packtpub for details about any changes that may affect the book's content.
Note
The Swift playground (described in Chapter 2, Playing with Swift) is only available as part of Xcode on OS X and is not part of the open source version of Swift.
Also, iOS and watchOS development (Chapters 3-8) is only possible on OS X with Xcode; it is not possible to create iOS or watchOS applications on other platforms. Most of the required libraries and modules for iOS development are not available as part of the open source version of Swift.
Xcode can be installed via the App Store as a free download; search for Xcode in the search box. Alternatively, Xcode can be downloaded from https://developer.apple.com/xcode/downloads/, which is referenced from the iOS Developer Center at https://developer.apple.com/devcenter/ios/.
Once Xcode has been installed, it can be launched from /Applications/Xcode.app or from Finder. To run the command line-based exercises, Terminal can be launched from /Applications/Utilities/Terminal.app, and if Xcode is installed successfully, swift can be launched by running xcrun swift.
The iOS applications can be developed and tested in the iOS simulator, which comes bundled with Xcode. It is not necessary to have an iOS device to write or test the code. If you want to run the code on your own iOS device, then you will need an Apple ID to sign in, but the application will be limited to directly connected devices. Similarly, the watch application can be tested in a local simulator or on a local device.
Publishing the application to the AppStore requires that you join the Apple Developer Program. More information is available at https://developer.apple.com/programs/.