Book Image

Functional Kotlin

Book Image

Functional Kotlin

Overview of this book

Functional programming makes your application faster, improves performance, and increases your productivity. Kotlin supports many of the popular and advanced functional features of functional languages. This book will cover the A-Z of functional programming in Kotlin. This book bridges the language gap for Kotlin developers by showing you how to create and consume functional constructs in Kotlin. We also bridge the domain gap by showing how functional constructs can be applied in business scenarios. We’ll take you through lambdas, pattern matching, immutability, and help you develop a deep understanding of the concepts and practices of functional programming. If you want learn to address problems using Recursion, Koltin has support for it as well. You’ll also learn how to use the funKtionale library to perform currying and lazy programming and more. Finally, you’ll learn functional design patterns and techniques that will make you a better programmer.By the end of the book, you will be more confident in your functional programming skills and will be able to apply them while programming in Kotlin.
Table of Contents (22 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Lambda


Lambda, which can also be called anonymous functions, has a first-class citizen support in Kotlin. While, in Java, lambda is only supported starting with Java 8, in Kotlin, you can use Kotlin with JVM 6 onwards, so there's really no barrier for lambda in Kotlin.

Now, we were talking about lambda, anonymous classes (or objects) and anonymous functions, but what are they? Let us explore.

To be generic, lambda or lambda expressions generally means anonymous functions, that is, functions without names, which can be assigned to variables, passed as arguments, or returned from another function. It is a kind of nested function, but is more versatile and more flexible. You can also say all the lambda expressions are functions, but not every function is a lambda expression. Being anonymous and unnamed brings a lot of benefits to lambda expressions, which we will discuss soon.

As I mentioned earlier, not all languages support lambda and Kotlin is one of rarest languages, and it provides extensive...