think\Template::parseVar PHP Method

    public function parseVar(&$varStr)
    {
        $varStr = trim($varStr);
        if (preg_match_all('/\\$[a-zA-Z_](?>\\w*)(?:[:\\.][0-9a-zA-Z_](?>\\w*))+/', $varStr, $matches, PREG_OFFSET_CAPTURE)) {
            static $_varParseList = [];
            while ($matches[0]) {
                $match = array_pop($matches[0]);
                //如果已经解析过该变量字串，则直接返回变量值
                if (isset($_varParseList[$match[0]])) {
                    $parseStr = $_varParseList[$match[0]];
                } else {
                    if (strpos($match[0], '.')) {
                        $vars = explode('.', $match[0]);
                        $first = array_shift($vars);
                        if ('$Think' == $first) {
                            // 所有以Think.打头的以特殊变量对待 无需模板赋值就可以输出
                            $parseStr = $this->parseThinkVar($vars);
                        } elseif ('$Request' == $first) {
                            // 获取Request请求对象参数
                            $method = array_shift($vars);
                            if (!empty($vars)) {
                                $params = implode('.', $vars);
                                if ('true' != $params) {
                                    $params = '\'' . $params . '\'';
                                }
                            } else {
                                $params = '';
                            }
                            $parseStr = '\\think\\Request::instance()->' . $method . '(' . $params . ')';
                        } else {
                            switch ($this->config['tpl_var_identify']) {
                                case 'array':
                                    // 识别为数组
                                    $parseStr = $first . '[\'' . implode('\'][\'', $vars) . '\']';
                                    break;
                                case 'obj':
                                    // 识别为对象
                                    $parseStr = $first . '->' . implode('->', $vars);
                                    break;
                                default:
                                    // 自动判断数组或对象
                                    $parseStr = '(is_array(' . $first . ')?' . $first . '[\'' . implode('\'][\'', $vars) . '\']:' . $first . '->' . implode('->', $vars) . ')';
                            }
                        }
                    } else {
                        $parseStr = str_replace(':', '->', $match[0]);
                    }
                    $_varParseList[$match[0]] = $parseStr;
                }
                $varStr = substr_replace($varStr, $parseStr, $match[1], strlen($match[0]));
            }
            unset($matches);
        }
        return;
    }