Kotlin Programming Cookbook

How to do it...

Follow these steps to understand function literals:

1. Let's start with a simple function literal on a String, which returns a string added to the receiver string:

fun main(args: Array<String>) {    var str1 = "The start of a "    val addStr = fun String.(successor: String): String {        return this + successor     }    str1 = str1.addStr("beautiful day.")    println(str1)}

A function literal has access to the receiver it has been called on, and it can access methods associated with that receiver.

2. We can also pass the receiver as a parameter in an ordinary function, where the first parameter is for a receiver. This can be useful in scenarios where we need to use an ordinary function. So String.(String) -> Int is similar to (String, String) -> ...