“内核"的目的是什么? [英] What is the purpose of `Kernel`?

问题描述

1. Kernel模块的目的是什么?如果当前在Kernel上定义的所有内容都在Object上定义，并且没有诸如Kernel这样的模块，将会发生什么变化?
2. 当我想定义一个可以在任何对象上调用的方法时，我应该在Kernel还是Object上定义它?

1. What is the purpose of the Kernel module? What would change if all the things currently defined on Kernel were defined on Object, and there were no such module as Kernel?
2. When I want to define a method that can be called on any object, should I define that on Kernel or on Object?

推荐答案

我将从一个问题开始:self在典型的 Array 或 fork .因此，您可以将Kernel视为方法的垃圾场，这些方法或多或少是发给Ruby本身的命令或消息.

I'll start with a question: what would self be inside a typical Kernel method such as puts? The closest thing to a meaningful self inside puts would probably be the Ruby runtime itself. Similarly for other "methods that really want to be functions" like Array or fork. So you can look at Kernel as a dumping ground for methods that are, more or less, commands or messages to Ruby itself.

Kernel也具有诸如 sub 和 chop 仅对一次性ruby -e脚本.这些东西倾向于使用$_作为隐含的self，但是我认为它们可以被视为上述"Ruby运行时命令"的特殊情况.

Kernel also has odd methods like sub and chop that are really only useful for one-off ruby -e scripts. These things tend to use $_ as an implied self but I think they can be considered as special cases of the "commands to the Ruby runtime" as above.

当您希望能够在任何对象上调用该方法时，该方法会去哪儿?我会说它将进入Object.如果该方法确实是伪装的函数并且没有有意义的self，则它将进入Kernel.

Where does a method go when you want to be able to call that method on any object? I'd say that it would go into Object. If the method is really a function in disguise and has no meaningful self, then it would go into Kernel.

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