protected function registerEngines()
    {
        $app = $this->app;
        $config = $app['config'];
        $resolver = $app['view.engine.resolver'];

        if ($config['markdown.tags']) {
            $this->registerBladeEngine($resolver);
        }

        if ($config['markdown.views']) {
            $this->registerMarkdownEngine($resolver);
            $this->registerMarkdownPhpEngine($resolver);
            $this->registerMarkdownBladeEngine($resolver);
        }
    }