public function url($url)
    {
        if (\is_string($url)) {
            if ('/' == $url[0]) {
                return $this->getPathToRoot().ltrim($url, '/');
            } elseif (\is_string($url)) {
                return $url;
            }
        } elseif ($url instanceof ClassDefinition) {
            return $this->url(Documentation::classUrl($url));
        } elseif ($url instanceof CompilerFile) {
            return $this->url(Documentation::classUrl($url->getClassDefinition()));
        }

        return '';
    }