From: "Christopher J. Bottaro" <cjbottaro@...>
Date: 2008-07-12T00:18:09+09:00
Subject: instance_eval or class_eval on metaclass?

I was looking at someone's implementation of #meta_eval and I noticed
they used #instance_eval.  I've always been using #class_eval with
metaclasses and getting my desired effect.  So why use #instance_eval
over #class_eval when working with metaclasses?

Furthermore, I can't even tell a difference, as demonstrated by this
code snippet.

class Object
  def metaclass
    class << self
      self
    end
  end
end

class Test

  def f
    metaclass.class_eval do
      puts self.inspect
    end
  end

  def g
    metaclass.instance_eval do
      puts self.inspect
    end
  end

end

t = Test.new
t.f
t.g

#<Class:#<Test:0x8eae4>>
#<Class:#<Test:0x8eae4>>

Using #class_eval and #instance_eval both produce the same result.
Can anyone shed some light on this subject?

Thanks.