code: function () {
                      var name, curly, index = i;
  
                      if (input.charAt(i) === '@' && (curly = $(/^@\{([\w-]+)\}/))) {
                          return new(tree.Variable)("@" + curly[1], index, env.currentFileInfo);
                      }
                  }
docs: A variable entity useing the protective {} e.g. @{var}