think\Template::parsePhp PHP Method

    private function parsePhp(&$content)
    {
        // 短标签的情况要将<?标签用echo方式输出 否则无法正常输出xml标识
        $content = preg_replace('/(<\\?(?!php|=|$))/i', '<?php echo \'\\1\'; ?>' . "\n", $content);
        // PHP语法检查
        if ($this->config['tpl_deny_php'] && false !== strpos($content, '<?php')) {
            throw new Exception('not allow php tag', 11600);
        }
        return;
    }