If you're writing a one line function, whose sole purpose in life is addition, and, clearly, this is about addition, well, then it's, in fact, A reasonable to use a shorter symbol like A, but I do have to specify it's type.

如果你在写一个一行的函数，它唯一的目的是,做加法，显然这是关于加法的，好的，实际上，用一个短的标识符是合理的，像，但是我必须指明它的类型。

哈佛公开课 - 计算机科学课程节选

chickens OK, and then once I've got that, well, notice: I can then check to see, did I return that special symbol none?

第二部分是：,现在一旦我获得了这两个值，注意，我将再检查一下？

麻省理工公开课 - 计算机科学及编程导论课程节选

So, the two most elementary ideas you learn are what is the average velocity of an object, as then ordered by the symbol v-bar.

你们学过的两个最基本的概念是,物体的平均速度,用"v拔"表示

耶鲁公开课 - 基础物理课程节选