Alma

func quicksort(array) {
    if array.size() > 1 {
        my pivot = array[0];
        my less = quicksort(array.filter(func (e) { return e < pivot }));
        my equal = array.filter(func (e) { return e == pivot });
        my greater = quicksort(array.filter(func (e) { return e > pivot }));
        array = less.concat(equal.concat(greater));
    }
    return array;
}

my unsorted = (^20).shuffle();
say("Unsorted: ", unsorted);
say("Sorting...");
my sorted = quicksort(unsorted);
say("Sorted: ", sorted);