这是微软研究院软件工程研究组开发的，一套代码，可以用于iPad, iPhone, Android, Windows, Mac, Linux。（注意这个原样从其GitHub描述里复制的顺序，微软同学现在心态很好的。）
所用语言看上去有点像BASIC，也有Scratch和AppInventor那样的色块拖拽环境，很适合教孩子编程。而且有云的支持，也有社会化编程。
相比GitHub页和项目网站，研究院的项目主页讲得更清楚：
In the TouchDevelop programming environment you write scripts by
tapping on the screen. You do not need a separate PC or keyboard.
Scripts can perform various tasks similar to regular apps. Any
TouchDevelop user can install, run, edit, publish scripts. You can share
scripts with other people by publishing them to the TouchDevelop script
bazaar
不用键盘就可以编程。 | 
