From: Mark Hubbart <discord@...>
Date: 2004-05-15T03:53:15+09:00
Subject: problems with literals and replacing classes

Hi all,

I've been trying to get some code working that restores original 
versions of classes after they have been modified. I ran into a strange 
problem, though; it seems that when you use literals, they don't 
respect which class is actually assigned to their class constant. 
Here's an example of the basic concept I'm looking at, which shows my 
problem:

   # Add a method to String; returns nil
   class String; def foo() end end

   # Backup a copy of String class
   str = String.dup

   # Modify String#foo to return 23 instead of nil
   class String; def foo() 23 end end

   # Test #foo method; should return nil
   String.new.foo #=> 23
   "".foo         #=> 23

   # Restore String class from backup copy
   String = str

   # Test #foo method. The first String class
   # doesn't have it, so it should raise an error.
   String.new.foo #=> nil
   "".foo         #=> 23

Why does the string literal use the old, modified version of the String 
class? I did various tests, "".class and String.new.class both return 
String; but the two String classes have different ids. I can't seem to 
get the literals to use the new class; they *always* use the original 
class.

Is this a bug? Is there any way around it? Am I doing something stupid?

cheers,
--Mark