Thinkphp模版多层继承

打开ThinkPHP/Library/Think/Template.class.php

找到parseExtend方法，
在$content = $this->replaceBlock($content);后面
添加$content = $this->parseExtend($content);

看下面的注释：
protected function parseExtend($content) {
        $begin      =   $this->config['taglib_begin'];
        $end        =   $this->config['taglib_end'];        

        $find       =   preg_match('/'.$begin.'extend\s(.+?)\s*?\/'.$end.'/is',$content,$matches);
        if($find) {

            $content    =   str_replace($matches[0],'',$content);

            preg_replace_callback('/'.$begin.'block\sname=[\'"](.+?)[\'"]\s*?'.$end.'(.*?)'.$begin.'\/block'.$end.'/is', array($this, 'parseBlock'),$content);

            $array      =   $this->parseXmlAttrs($matches[1]);
            $content    =   $this->parseTemplateName($array['name']);
            $content    =   $this->parseInclude($content, false); 

            $content = $this->replaceBlock($content);
            $content = $this->parseExtend($content);    //添加了这行
        }else{
            $content    =   preg_replace_callback('/'.$begin.'block\sname=[\'"](.+?)[\'"]\s*?'.$end.'(.*?)'.$begin.'\/block'.$end.'/is', function($match){return stripslashes($match[2]);}, $content);
        }
        return $content;
    }

再找到replaceBlock方法，
把$content = $content[3];
改成$content = $content[0];

看下面的注释：
private function replaceBlock($content){
        static $parse = 0;
        $begin = $this->config['taglib_begin'];
        $end   = $this->config['taglib_end'];
        $reg   = '/('.$begin.'block\sname=[\'"](.+?)[\'"]\s*?'.$end.')(.*?)'.$begin.'\/block'.$end.'/is';
        if(is_string($content)){
            do{
                $content = preg_replace_callback($reg, array($this, 'replaceBlock'), $content);
            } while ($parse && $parse--);
            return $content;
        } elseif(is_array($content)){
            if(preg_match('/'.$begin.'block\sname=[\'"](.+?)[\'"]\s*?'.$end.'/is', $content[3])){ 
                $parse = 1;
                $content[3] = preg_replace_callback($reg, array($this, 'replaceBlock'), "{$content[3]}{$begin}/block{$end}");
                return $content[1] . $content[3];
            } else {
                $name    = $content[2];
                $content = $content[0];    //这里原来是$content = $content[3];把3改为0
                $content = isset($this->block[$name]) ? $this->block[$name] : $content;
                return $content;
            }
        }
    }