什么是“主要"?在Ruby中? [英] What is "main" in Ruby?

问题描述

如果我以"ruby x.rb"的身份运行此文件:

If I run this file as "ruby x.rb":

class X
end
x = X.new

什么叫"X.new"?

是对象/进程/等吗?

推荐答案

Ruby中的一切都发生在某个对象的上下文中.顶层的对象称为主要".基本上，它是具有特殊属性的Object的实例，在那里定义的任何方法都将添加为Object的实例方法(因此它们随处可见).

Everything in Ruby occurs in the context of some object. The object at the top level is called "main". It's basically an instance of Object with the special property that any methods defined there are added as instance methods of Object (so they're available everywhere).

因此我们可以制作一个完全由以下内容组成的脚本:

So we can make a script consisting entirely of:

puts object_id
@a = 'Look, I have instance variables!'
puts @a

它将显示"105640"和看，我有实例变量！".

and it will print "105640" and "Look, I have instance variables!".

这不是您通常需要关注的事情，而是在那里.

It's not something you generally need to concern yourself with, but it is there.

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