think\Route::parseVar PHP Method

    private static function parseVar($rule)
    {
        // 提取路由规则中的变量
        $var = [];
        foreach (explode('/', $rule) as $val) {
            $optional = false;
            if (false !== strpos($val, '<') && preg_match_all('/<(\\w+(\\??))>/', $val, $matches)) {
                foreach ($matches[1] as $name) {
                    if (strpos($name, '?')) {
                        $name = substr($name, 0, -1);
                        $optional = true;
                    } else {
                        $optional = false;
                    }
                    $var[$name] = $optional ? 2 : 1;
                }
            }
            if (0 === strpos($val, '[:')) {
                // 可选参数
                $optional = true;
                $val = substr($val, 1, -1);
            }
            if (0 === strpos($val, ':')) {
                // URL变量
                $name = substr($val, 1);
                $var[$name] = $optional ? 2 : 1;
            }
        }
        return $var;
    }