To get the most out of this book

You should be comfortable creating and running Kotlin projects from an IntelliJ-based IDE, installing IDEs such as IntelliJ, Android Studio, and Xcode, and also be familiar with how to run command-line tools on your machines. With the exception of Chapter 15, Introducing Multi-Platform Kotlin, all examples in this book should run regardless of your OS of choice. For Chapter 15, Introducing Multiplatform Kotlin, the portions of the example dedicated to setting up an iOS project require a computer running macOS and Xcode. You should be comfortable using GitHub and downloading or cloning a GitHub repository in order to make use of the examples presented in this book.

Download the example code files

You can download the example code files for this book from your account at www.packt.com. If you purchased this book elsewhere, you can visit www.packt.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packt.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Mastering-Kotlin. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Code in Action

Visit the following link to check out videos of the code being run: http://bit.ly/325fQhz

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Demonstrations of null and non-null types."

A block of code is set as follows:

data class Language(val name: String)

fun main(args: Array<String>) {
  val language = Language("Kotlin")
  println(language.name)
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

fun main(args: Array<String>) {
    var language: String = "Kotlin"
    language = null // Error: Null can not be a value of a non-null type String
}

Any command-line input or output is written as follows:

$ mkdir css
$ cd css

Bold: Indicates a new term, an important word, or words that you see on screen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Next, under the Client section, select Jetty HttpClient Engine and then click on Next."

Warnings or important notes appear like this.

Tips and tricks appear like this.