From: Eugene Scripnik <Eugene.Scripnik@...>
Date: 2003-01-04T03:10:28+09:00
Subject: Re: toplevel modules and classes

Friday, January 3, 2003, 7:23:55 PM, you wrote:

E>> OK, another question. Module#constants return constants accessible
E>> in this module. But Class#constants produces the same output as
E>> Object.constants (Class itself is an Object, right?). How do I get all

t>  no, no you don't have the same output
Oh, sorry. I've tested on some standard classes and they actually
don't have constants inside.

E>> modules and classes defined in this particular class?
t>  but you can't use this directly, because of this problem

t> pigeon% ruby -e 'class A; B = A = 12; end; p (A.constants - Object.constants)'
t> ["B"]
t> pigeon%
Class#constants == self_constants + Object.constants

t>  something like this (it's strange for me to put classes in another class,
t>  why do you want to do this ?)
Well, I just wanted to build classes/modules tree of my application.
This structure is so complicated. And I wanted to do it in generalized
way and also was surprised when I put another class/module into class
and compiler found it OK.
So, both module and class accept defining modules and classes inside
them, but Class#constants and Module#constants behave in different
way. That was second surprise.

t> pigeon% cat b.rb
t> #!/usr/bin/ruby
t> class A
t>    class A; end
t>    class B; end
t> end
t> A.constants.each do |kl|
t>    a = A.const_get(kl)
t>    b = Object.const_defined?(kl) && Object.const_get(kl)
t>    puts a if a != b && a.kind_of?(Module)
t> end
t> pigeon% 

t> pigeon% b.rb
t> A::A
t> A::B
t> pigeon% 

t>  you must adapt it, if it's not a toplevel class

-- 
Best regards,
 Eugene [team Enticla]               mailto:Eugene.Scripnik@itgrp.net