Book Image

Learn Kotlin Programming - Second Edition

By : Stephen Samuel, Stefan Bocutiu
Book Image

Learn Kotlin Programming - Second Edition

By: Stephen Samuel, Stefan Bocutiu

Overview of this book

Kotlin is a general-purpose programming language used for developing cross-platform applications. Complete with a comprehensive introduction and projects covering the full set of Kotlin programming features, this book will take you through the fundamentals of Kotlin and get you up to speed in no time. Learn Kotlin Programming covers the installation, tools, and how to write basic programs in Kotlin. You'll learn how to implement object-oriented programming in Kotlin and easily reuse your program or parts of it. The book explains DSL construction, serialization, null safety aspects, and type parameterization to help you build robust apps. You'll learn how to destructure expressions and write your own. You'll then get to grips with building scalable apps by exploring advanced topics such as testing, concurrency, microservices, coroutines, and Kotlin DSL builders. Furthermore, you'll be introduced to the kotlinx.serialization framework, which is used to persist objects in JSON, Protobuf, and other formats. By the end of this book, you'll be well versed with all the new features in Kotlin and will be able to build robust applications skillfully.
Table of Contents (21 chapters)
Free Chapter
1
Section 1: Fundamental Concepts in Kotlin
5
Section 2: Practical Concepts in Kotlin
15
Section 3: Advanced Concepts in Kotlin

Destructing types

With the data type, you get the destruction out of the box, but can we achieve the same thing without a data class? The answer is yes. All you have to do is provide the componentN methods. The only requirement is to prefix each method definition with the keyword operator. Let's say we have a Vector3 class that represents the coordinates in a 3D space. For the sake of argument, we will not make this class a data class:

    class Vector3(val x:Double, val y:Double, val z:Double){
      operator fun component1()=x
      operator fun component2()=y
      operator funcomponent3()=z
    }

    for ((x,y,z) in listOf(Vector3(0.2,0.1,0.5), Vector3(-12.0, 3.145,
5.100))){
      println("Coordinates: x=$x, y=$y, z=$z")
    }

As you can see, for each member field, we created the equivalent componentN method. Because of this, the compiler can apply the destruction...