From: Chris Pine <nemo@...>
Date: 2002-12-13T01:23:46+09:00
Subject: Re: deleting a class

I don't understand.  Are you saying there's a temporary reference to the
class?  I was asking why that would be the case when I define a class one
way, but not another?

This code does NOT remove the class Foo:

  class Foo; end
  Object.module_eval { remove_const 'Foo' }
  GC.start

But this DOES remove it:

  eval 'class Foo; end'
  Object.module_eval { remove_const 'Foo' }
  GC.start

To sum up all the ways of defining a class I can think of, the following
ways of defining a class WILL allow the class to be removed (at least by
removing the constant and starting the GC):

-->  eval 'class Foo; end'
-->  Foo = Class.new
-->  load 'foo.rb'
-->  require 'foo.rb'

(foo.rb is simply:  class Foo; end)

And the following WILL NOT allow the class to be removed:

-->  class Foo; end
-->  eval 'Foo = Class.new'  #  How weird is that??

So I just wanted to know why.  If you are saying there's a temporary
reference, why is it avoided by using 'eval' (or sometimes *caused* by using
'eval')?  Is there a way I can get rid of this temporary reference?

Chris