KotlinUnlessStatement.kt

fun main(args: Array<String>) {
    var i = 0
    until({ i++ >= 100 }, {
        println(fizz(i))

        if (i == 50) {
            return
        }
    })
}

fun fizz(n: Int): String {
    unless(n % 3 == 0) {
        return "${n}"
    }
    return "fizz"
}

inline fun unless (condition: Boolean, then: () -> Unit) {
    if (! condition) then.invoke()
}

inline fun until (condition: () -> Boolean, body: () -> Unit) {
    while(! condition.invoke() ) body.invoke()
}