original_string: public function on(string $event, $class_or_obj, string $method, array $arguments = []): Core
      {
          $this->registerEventHandler(new EventHandler($event, $class_or_obj, $method, $arguments));
          return $this;
      }
code: public function on(string $event, $class_or_obj, string $method, array $arguments = []): Core
      {
          $this->registerEventHandler(new EventHandler($event, $class_or_obj, $method, $arguments));
          return $this;
      }
code_tokens: public function on ( string $ event , $ class_or_obj , string $ method , array $ arguments = [ ] ) : Core { $ this -> registerEventHandler ( new EventHandler ( $ event , $ class_or_obj , $ method , $ arguments ) ) ; return $ this ; }
docstring: Create an event handler to be called when a specified event is fired by the framework or a library within the
  Framework.
  
  @param string $event        The name of the event to listen for
  @param mixed  $class_or_obj The object or class the method belongs to
  @param string $method       The method to call
  @param array  $arguments    Optional parameters to pass to the method
  
  @return Core
  @throws \Exception
docstring_tokens: Create an event handler to be called when a specified event is fired by the framework or a library within the Framework .