Book Image

Functional Kotlin

By : Mario Arias, Rivu Chakraborty
Book Image

Functional Kotlin

By: Mario Arias, Rivu Chakraborty

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

Class delegation


Class delegation is another interesting feature of Kotlin. How? Just think of the following situation.

You have an interface, I, and two classes, A and B. Both A and B implement I. In your code, you've an instance of A and you want to create an instance of B from that A.

In traditional inheritance, it is not directly possible; you have to write a bunch of nasty codes to achieve that, but class delegation is there to save you.

Go through the following code:

interface Person { 
    fun printName() 
} 
 
class PersonImpl(val name:String):Person { 
    override fun printName() { 
        println(name) 
    } 
} 
 
class User(val person:Person):Person by person { 
    override fun printName() { 
        println("Printing Name:") 
        person.printName() 
    } 
} 
 
fun main(args: Array<String>) { 
    val person = PersonImpl("Mario Arias") 
    person.printName() 
    println() 
    val user = User(person) 
    user.printName() 
} 

In this program, we created the instance...