When we're just interacting with idol, with the interactive editor or sorry, interactive environment if you like, that's what you expect. What's happening is that we're typing in something, an expression it doesn't know how to deal. It's raising the exception, but is this simply bubbling up at the top level saying you've got a problem.

就发生了其中之一是吧，当你在交互数据处理或者是在交互编辑器，抱歉，任何你喜欢的交互式环境中，你可能会遇到这些，如果你在输入什么内容,譬如一个它不知道怎么处理的表达式,它就会报一个异常,但这是否是简单的,把你遇到的问题冒到最顶层呢？

麻省理工公开课 - 计算机科学及编程导论课程节选