code: function() {
                      if (input.charAt(i) !== '"' && input.charAt(i) !== "'") return;
                      var str = $(/^"((?:[^"\\\r\n]|\\.)*)"|'((?:[^'\\\r\n]|\\.)*)'/);
                      if (str) {
                          return new tree.Quoted(str[1] || str[2]);
                      }
                  }
docs: A string, which supports escaping " and ' "milky way" 'he\'s the one!'