From: "David A. Black" <dblack@...>
Date: 2008-03-26T20:26:50+09:00
Subject: Re: class_eval vs (class << object)

Hi --

On Wed, 26 Mar 2008, Ruby Freak wrote:

> What is the difference between class_eval and "class << object"?
>
> It seems like they are the same. I am thinking that class_eval affects
> the greater class and "class_object" is used on a singleton class. Are
> they mutually exclusive?

class << object is the class keyword, which starts a class definition
block (in this case, on the singleton class of object) and therefore a
new local scope.

class_eval is a method, not a keyword, so it requires a receiver --
namely, a Module or Class object. It takes a block, and the block does
shares the variables of the existing local scope.


David

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