From: Lucas Holland <hollandlucas@...>
Date: 2007-05-04T20:50:01+09:00
Subject: Re: Top-level

Brian Candler wrote:
> On Fri, May 04, 2007 at 01:52:21PM +0900, Lucas Holland wrote:
>>    test
>>   end
>> end
>> 
>> I am able to call the test method because of the implicit receiver, 
>> self. In this case, however, self refers to the class MyClass (which is 
>> an instance of Class, as far as I know).
> 
> No. Inside your 'test' method, which is an instance method of MyClass, 
> self
> refers to an object which is one particular instance of MyClass.
> 
> That is, you can't run it like this:
> 
>     MyClass.pub
> 
> Rather, you have to do
> 
>     MyClass.new.pub
> 
> (the receiver of the message is an *instance* of MyClass that you've
> created)
> 
> Outside of 'def test', self does indeed refer to the class.
> 
> class MyClass
>   p self     # self is 'MyClass'
>   def test
>     p self   # self is an instance of MyClass
>   end
> end

Ah, I see. Okay, so I can call puts like a 'standalone function' because 
of the following: When I run a Ruby script, an object called 'main' is 
instanciated. It's an instance of the Object class. The Object class 
includes puts via a mixin from the Kernel module. It's thus like a 
private instance method of Object.

When I call puts, I don't specify a receiver. That's why Ruby takes self 
as the receiver. At the top level, self refers to the main object. So my 
call is basically main.puts

puts is a *private* instance method of Object, so why can I call it from 
an instance (main being the instance in this case)?

Lucas

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