Kotlin smartcasting example

useThing.kt

interface Animal {
    val name: String
    val noise: String
    fun makeNoise(): String = "$name made a noise: $noise"
}

fun useThing(thing: Any?) {
    if (thing is Animal) {
        println("thing is an animal!! what kind?? ${thing.name}")
        println(thing.makeNoise())
    } else if (thing is Int) {
        println("thing is an Int! if you added 3 to it you would have: ${thing + 3}")
    } else {
        println("i don't really know what that is...")
    }
}