Sorting algorithms/Cocktail sort

func cocktailsort(a) {
    var swapped = false
    func cmpsw(i) {
        if (a[i] > a[i+1]) {
            a[i, i+1] = a[i+1, i]
            swapped = true
        }
    }
    var max = a.end
    do {
        {|i| cmpsw(i) } << ^max
        swapped.not! && break
        {|i| cmpsw(max-i) } << 1..max
    } while (swapped)
    return a
}

Test:

var numbers = [7,6,5,9,8,4,3,1,2,0]
say cocktailsort(numbers)

var strs = ["John", "Kate", "Zerg", "Alice", "Joe", "Jane"]
say cocktailsort(strs)

Output:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
['Alice', 'Jane', 'Joe', 'John', 'Kate', 'Zerg']