zadr

internal extension SequenceType where Element: Hashable {
	/**
	Returns a modified djb hash of all of the elements in a list.
	Reference: http://www.eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
	*/
	internal var hashValue: Int {
		get {
			return reduce(0) { (x, element) -> Int in
				return 33 * x ^ element.hashValue
			}