OCaml |>操作员 [英] OCaml |> operator

问题描述

有人可以解释|>运算符的作用吗?此代码摘自参考文献此处:

Could someone explain what the |> operator does? This code was taken from the reference here:

let m = PairsMap.(empty |> add (0,1) "hello" |> add (1,0) "world")

我可以看到它的作用，但是不知道如何应用|>运算符.

I can see what it does, but I wouldn't know how to apply the |> operator otherwise.

对此，我也不知道Module.()的语法在做什么.对此的解释也很好.

For that matter, I have no idea what the Module.() syntax is doing either. An explanation on that would be nice too.

推荐答案

Module.(e)等同于let open Module in e.在范围内介绍事物是一种简便的语法.

Module.(e) is equivalent to let open Module in e. It is a shorthand syntax to introduce things in scope.

运算符|>在模块Pervasives中定义为let (|>) x f = f x. (实际上，它被定义为外部基元，易于编译.在这里这并不重要.)反向应用程序函数使链接后续调用更加容易.没有它，您将需要写

The operator |> is defined in module Pervasives as let (|>) x f = f x. (In fact, it is defined as an external primitive, easier to compile. This is unimportant here.) It is the reverse application function, that makes it easier to chain successive calls. Without it, you would need to write

let m = PairsMap.(add (1,0) "world" (add (0,1) "hello" empty))

需要更多的括号.

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