Kotlin Programming: The Big Nerd Ranch Guide, First Edition

Writing Your Own Functions

Now that you have organized NyetHack’s logic in functions, you can proceed as planned to implement the new fireball spell. At the bottom of Game.kt, define a function called castFireball that takes no parameters. Make its visibility private. castFireball should have no return statement, but it should print the results of casting the spell.

Listing 4.1  Adding a castFireball function (Game.kt)

...
private fun auraColor(isBlessed: Boolean,
                      healthPoints: Int,
                      isImmortal: Boolean): String {
    val auraVisible = isBlessed && healthPoints > 50 || isImmortal
    val auraColor = if (auraVisible) "GREEN" else "NONE"
    return auraColor
}

private fun castFireball() {
    println("A glass of Fireball springs into existence.") ...