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

The when expression

The classic switch statement is supported in many languages, including C, C++, and Java, but it is rather restrictive. At the same time, the functional programming concept of pattern matching has become more mainstream. Kotlin blends the two, and offers when, a more powerful alternative to switch while not going quite as far as full pattern matching.

There are two forms of when. The first is similar to switch, accepting an argument, with a series of conditions, each of which is checked, in turn, against the value. The second is without an argument and is used as a replacement for a series of if...else conditions.

When (value)

The simplest example of when is matching against different constants, which will...