Ruby 发送与 __send__ [英] Ruby send vs __send__

问题描述

我理解 some_instance.send 的概念，但我想弄清楚为什么你可以同时调用它.Ruby Koans 暗示除了提供许多不同的方法来做同样的事情之外，还有一些原因.以下是两个用法示例:

I understand the concept of some_instance.send but I'm trying to figure out why you can call this both ways. The Ruby Koans imply that there is some reason beyond providing lots of different ways to do the same thing. Here are the two examples of usage:

class Foo
  def bar?
    true
  end
end

foo = Foo.new
foo.send(:bar?)
foo.__send__(:bar?)

有人对此有任何想法吗?

Anyone have any idea about this?

推荐答案

某些类(例如标准库的套接字类)定义了自己的 send 方法，该方法与 Object 无关#发送.所以如果你想处理任何类的对象，你需要使用 __send__ 以确保安全.

Some classes (for example the standard library's socket class) define their own send method which has nothing to do with Object#send. So if you want to work with objects of any class, you need to use __send__ to be on the safe side.

现在剩下的问题是，为什么有 send 而不仅仅是 __send__.如果只有 __send__ 名称 send 可以被其他类使用而不会产生任何混淆.原因是 send 首先存在，直到后来才意识到名称 send 也可能在其他上下文中有用，所以 __send__ 已添加(顺便说一下，这与 id 和 object_id 发生的事情相同).

Now that leaves the question, why there is send and not just __send__. If there were only __send__ the name send could be used by other classes without any confusion. The reason for that is that send existed first and only later it was realized that the name send might also usefully be used in other contexts, so __send__ was added (that's the same thing that happened with id and object_id by the way).

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