PersistTheList8.kt

fun <E> dropWhile(list: List<E>, f: (E) -> Boolean): List<E> {

    tailrec fun loop(remaining: List<E>): List<E> =
        when(remaining) {
            is Empty -> remaining
            is Cons -> if (f(remaining.head)) loop(remaining.tail) else remaining
        }

    return loop(list)
}