Mastering Kotlin

Mutable function variables

We can store functions as mutable variables as well. If we wanted to make the previous example a mutable variable, we could update our variable declaration accordingly by replacing val with var as in the following code:

var greetingProvider: () -> String = { "Hello" }

Now, we can reassign the function value being stored within greetingProvider as we would with any other variable type:

fun main(args: Array<String>) {  println(greetingProvider())  greetingProvider = { "Hey" }  println(greetingProvider())}  // output: Hello// output: Hey

In this example, we've logged String provided by the original greetingProvider variable, then assigned a new function to greetingProvider and re-logged the resultant function invocation. ...