https://ruby-china.org/topics/20291
http://www.zhihu.com/question/23512853
http://ued.taobao.org/blog/tag/%E5%89%8D%E5%90%8E%E7%AB%AF%E5%88%86%E7%A6%BB/
http://ued.taobao.org/blog/2014/04/xtpl/
http://my.oschina.net/ulyn/blog/324196
http://www.qconshanghai.com/node/466