Hands-On Object-Oriented Programming with Kotlin

Function as an expression

In Kotlin, a function can behave as an expression. Let's take the example of the add function from the previous section and convert it into an expression:

fun addValues(i: Int, j: Int): Int {     return i + j }

This function takes two parameters, adds them, and returns an integer value. When the function contains only one line of code, it can be written as an expression.

Create a new function as an expression:

fun addValuesEx(a : Int, b : Int) : Int = a + b

The explicit declaration of the function return type can be removed as follows:

fun addValuesEx(a : Int, b : Int) = a + b

Now add an equals operator, remove the curly brackets, and remove the explicit type declaration of the return type along with the return keyword ...