Functional Programming in Kotlin

 Functional Programming in Kotlin:

Functional Programming in Kotlin is a reworked version of the bestselling Functional Programming in Scala, with all code samples, instructions, and exercises translated into the powerful Kotlin language. In this authoritative guide, you'll take on the challenge of learning functional programming from first principles.

In Functional Programming in Kotlin you will learn:

Functional programming techniques for real-world applications

Write combinator libraries

Common structures and idioms in functional design

Simplicity and modularity (and fewer bugs!)

Functional Programming in Kotlin is a reworked version of the bestselling Functional Programming in Scala, with all code samples, instructions, and exercises translated into the powerful Kotlin language. In this authoritative guide, you’ll take on the challenge of learning functional programming from first principles. Complex concepts are demonstrated through exercises that you’ll love to test yourself against. You’ll start writing Kotlin code that’s easier to read, easier to reuse, better for concurrency, and less prone to bugs and errors.

Is Kotlin purely functional?

Kotlin brings awesome features to Android development. One of those is functional programming. In functional programming, functions are the heart and liver.

Is Kotlin better than Scala?

It was designed by JetBrains, which is known for tools such as Intellij IDEA and ReSharper. Kotlin compiles directly to bytecode, but it does so much more efficiently than Scala does which means it is much more concise and performs better than Scala.

Is Kotlin declarative programming?

A good declarative example can be given using the kotlinx-html library. Both examples are kotlin code, and print the same HTML to the standard out. ... In the end, every declarative framework is implemented on machine code, which is highly imperative mostly.

What is a lambda Kotlin?

Lambda expression is a simplified representation of a function. It can be passed as a parameter, stored in a variable or even returned as a value. Note: If you are new to Android app development or just getting started, you should get a head start from Kotlin for Android: An Introduction.

Is Kotlin functional or OOP?

Is Kotlin an object-oriented language or a functional one?  Kotlin has both object-oriented and functional constructs. You can use it in both OO and FP styles, or mix elements of the two.

Example kotlin function

fun <T, R> Collection<T>.fold(

    initial: R,

    combine: (acc: R, nextElement: T) -> R

): R {

    var accumulator: R = initial

    for (element: T in this) {

        accumulator = combine(accumulator, element)

    }

    return accumulator

}

val items = listOf(1, 2, 3, 4, 5)

// Lambdas are code blocks enclosed in curly braces.

items.fold(0, { 

    // When a lambda has parameters, they go first, followed by '->'

    acc: Int, i: Int -> 

    print("acc = $acc, i = $i, ") 

    val result = acc + i

    println("result = $result")

    // The last expression in a lambda is considered the return value:

    result

})

// Parameter types in a lambda are optional if they can be inferred:

val joinedToString = items.fold("Elements:", { acc, i -> acc + " " + i })

// Function references can also be used for higher-order function calls:

val product = items.fold(1, Int::times)