Illuminate\Routing\UrlGenerator::buildCompleteUrl PHP Method

    protected function buildCompleteUrl($root, $path, $tail = '')
    {
        $path = '/' . trim($path . '/' . $tail, '/');
        if ($this->formatHostUsing) {
            $root = call_user_func($this->formatHostUsing, $root);
        }
        if ($this->formatPathUsing) {
            $path = call_user_func($this->formatPathUsing, $path);
        }
        return trim($root . $path, '/');
    }