Function objects are an important part of generic programming because they allow abstraction not only over the types of objects, but also over the operations that are being performed.

函数对象是一个重要的普通程序的一部分，因为他们允许抽象比类型对象还要多，而且比它正在执行的操作还要多。

youdao

At the core of functional programming is the function, just as classes are the primary abstraction in object-oriented languages.

函数式编程的核心是函数，就像面向对象语言的主要抽象方法是类。

youdao

Using a function as a function argument, or returning a function as a value, elevates this abstraction into the realm of higher-order functions.

将函数用作函数的参数，或将函数作为值返回，这些概念属于高阶函数的领域。

youdao

Now I got one just simple thing, and I simply have isolated that module inside of that function.What about abstraction?

而现在我只要做一件简单的事，那就是我只需把这个模块,加到函数中去？

麻省理工公开课 - 计算机科学及编程导论课程节选