code: function Descendent (process) {
      var descendent = this
      this.process = process
      this.children = {}
      this._listeners = {}
      this._counter = 0
      events.EventEmitter.call(this)
  }
docs: TODO Could use `-1` to mean go up one. `0` means root. Or else `-Infinity` means to the root. No, `0` because `-Infinity` is not valid JSON. Overshoot and it stops at the root.