Easy quick sort function writtern in Groovy

quicksort.groovy

def quickSort(List list, beg = 0, end = list.size() - 1) {
    if (list.size() < 2) {
        return
    }

    def beg0 = beg
    def end0 = end

    def marker = list[beg]
    while(true) {
        while (list[beg] < marker) beg++
        while (list[end] > marker) end--

        if (beg < end) {
            def t = list[beg]
            list[beg] = list[end]
            list[end] = t

            beg++
            end--
        }
        else {
            break
        }
    }

    if (beg0 < end) quickSort(list, beg0, end)
    if (end + 1 < end0) quickSort(list, end + 1, end0)
}