code: protected function findController($object)
      {
          // Get the next URL argument
          $urlargs = $this->arguments;
          $arg = $urlargs->shift();
  
          // Store it as controller name
          $controller = $arg;
          
          // Strip any suffix
          if (($pos = strpos($controller, '.')) !== false)
              $controller = substr($controller, 0, $pos);
          
          // Check if the method exists
          if (!method_exists($object, $controller))
          {
              // Fall back to an index method
              if (method_exists($object, "index"))
              {
                  if ($controller !== null)
                      $urlargs->unshift($arg);
                  $controller = "index";
              }
              else
                  throw new HTTPError(404, "Unknown controller: " . $controller);
          }
          return $controller;
      }
docs: Find the correct method in a controller to execute for the current request.
  The route led to this controller, so the method is the first following URL argument.
  Any suffix is stripped - method names may not contain dots anyway.
  @param object $object The object from which to find a method to call.
  @return callable A callable method in this object