From: "Thomas B." <tpreal@...>
Date: 2008-09-02T18:50:10+09:00
Subject: Re: Self and Current Class

David A. Black wrote:
>> In fact, most of the time this is the way to check the current class.
> 
> I don't think so. Most of the time you're likely to be inside a method
> definition body, where the singleton class is not relevant unless you
> invoke it more or less explicitly.

You're right. That was my sort of inaccurate concept.

> I think you're over-complicating this by using instance_eval as your
> starting point and then describing the behavior of class definitions
> as an exception to a rule. Most of the purpose of class definition
> blocks is to define instance methods, so it's easier just to look at
> it that way directly. If anything, I'd look at instance_eval as having
> the exceptional behavior -- but really, there are so few different
> permutations that it's probably easiest just to learn them and not
> worry about which is the rule and which the exception.

Here I can't fully agree, as I showed it in the previous post there are 
some more cases, not all of which equally obvious. But it's true that 
you can call a rule and an exception whichever case you want, for me 
it's more natural to think that I'm inside instance_eval, because then 
I'm adding methods to an already existing instance, and not to all the 
instances potentially existing in the future.

> The only really weird one is the top level :-)

There's no top level in fact. In the top level, you're inside some 
instance of Object, you're

class<<Object::new
  # here.
end

or

Object::new.instance_eval{
#here
}

or, even more precisely,

eval("#here.",Object::new.instance_eval{binding})

So when you def a method, it goes just to this sole instance. Also the 
method to_s of this object is changed to display "main", and in irb some 
irb-specific methods are added to the instance.

TPR
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