Quicksort In Swift

// Accompanying documentation on Swift generics at
// http://dev.iachieved.it/iachievedit/?p=375
import Foundation

class Element : NSObject, Comparable, Printable {
    var name:String
    var number:Int
    init(name:String,number:Int) {
        self.name   = name
        self.number = number
    }

    override var description: String {
        return "\(self.name) (\(self.number))"
    }
}

func == (lhs:Element, rhs:Element) -> Bool {
    return lhs.number == rhs.number
}
func < (lhs:Element, rhs:Element) -> Bool {
    return lhs.number < rhs.number
}

/*
 * Quicksort algorithm was taken from the Python version
 * at http://hetland.org/coding/python/quicksort.html
 * and converted to Swift in about 2 minutes.
 */
func partition<T:  Comparable>(list: Array<T>, start:Int, end:Int) -> Int {

    var pivot  = list[end]
    var bottom = start - 1
    var top    = end

    var done:Bool = false
    while (!done) {
        while (!done) {
            bottom += 1
            if (bottom == top) {
                done = true
                break
            }
            if (list[bottom] > pivot) {
                list[top] = list[bottom]
                break
            }
        }

        while (!done) {
            top -= 1
            if (top == bottom) {
                done = true
                break
            }
            if (list[top] < pivot) {
                list[bottom] = list[top]
                break
            }
        }
    }

    list[top] = pivot
    return top

}

func quicksort<T:  Comparable>(list:  Array<T>, start:Int, end:Int) {
    if (start  < end) {
        var split = partition(list, start, end)
        quicksort(list, start, split-1)
        quicksort(list, split+1, end)
    }
}

var listOfNumbers  = [10, 11, 8, 5, 27, 1, 25]
var listOfNames    = ["Joe", "Jane", "Frank", "Marc", "Zach", "Sean"]
var listOfElements = [Element(name:"Gold",      number:79),
                      Element(name:"Silver",    number:47),
                      Element(name:"Zinc",      number:30),
                      Element(name:"Titanium",  number:22),
                      Element(name:"Plutonium", number:94)]

quicksort(listOfNumbers, 0, listOfNumbers.count-1)

println(listOfNumbers)

quicksort(listOfNames, 0, listOfNames.count-1)

println(listOfNames)

quicksort(listOfElements, 0, listOfElements.count-1)

println(listOfElements)