NSComparisonResult+compare.swift

extension NSComparisonResult {
  init() {
    self = .OrderedSame
  }

  var isAscending: Bool {
    return self == .OrderedAscending
  }

  var isDescending: Bool {
    return self == .OrderedDescending
  }

  var isSame: Bool {
    return self == .OrderedSame
  }

  func compare<T: Comparable>(l: T, with r: T) -> NSComparisonResult {
    if self != .OrderedSame { return self }
    if l < r { return .OrderedAscending }
    if r < l { return .OrderedDescending }
    return .OrderedSame
  }
}