Nette\Routing\Helpers::splitName PHP Method

    public static function splitName($name)
    {
        $pos = strrpos($name, ':');
        return $pos === FALSE ? ['', $name, ''] : [substr($name, 0, $pos), (string) substr($name, $pos + 1), ':'];
    }

 /**
  * @param  array   default values
  * @param  int     flags
  */
 public function __construct($defaults = [], $flags = 0)
 {
     if (is_string($defaults)) {
         list($presenter, $action) = Helpers::splitName($defaults);
         if (!$presenter) {
             throw new Nette\InvalidArgumentException("Argument must be array or string in format Presenter:action, '{$defaults}' given.");
         }
         $defaults = ['presenter' => $presenter, 'action' => $action === '' ? 'default' : $action];
     }
     $this->defaults = $defaults;
     $this->flags = $flags;
     if ($flags & self::SECURED) {
         trigger_error('IRouter::SECURED is deprecated, router by default keeps the used protocol.', E_USER_DEPRECATED);
     }
 }