Laravel中str_slug()的疑问

<code>app('translug')->translate('如何安装 Laravel'); // or Translug::translate('如何安装 Laravel');
//How to install the Laravel

app('translug')->translug('如何安装 Laravel'); // or Translug::translug('如何安装 Laravel');
//how-to-install-the-laravel

//或者你只想要 slug 的话

translug('如何安装 Laravel');
//how-to-install-the-laravel

translug('怎么理解 laravel 关联模型');
//how-to-understand-the-laravel-associated-model

//針對繁體,翻譯會有一點不一樣
translug('怎麼理解 laravel 關聯模型');
//how-to-understand-the-laravel-correlation-model</code>

<code>public static function slug($title, $separator = '-')
{
    $title = static::ascii($title);
    // Convert all dashes/underscores into separator
    $flip = $separator == '-' ? '_' : '-';
    $title = preg_replace('!['.preg_quote($flip).']+!u', $separator, $title);
    // Remove all characters that are not the separator, letters, numbers, or whitespace.
    $title = preg_replace('![^'.preg_quote($separator).'\pL\pN\s]+!u', '', mb_strtolower($title));
    // Replace all separator characters and whitespace by a single separator
    $title = preg_replace('!['.preg_quote($separator).'\s]+!u', $separator, $title);
    return trim($title, $separator);
}</code>