From: Xavier Shay <contact@...>
Date: 2008-10-10T01:03:37+09:00
Subject: Re: Enumerating constants in anonymous modules

David A. Black wrote:
> Hi --
> 
> On Fri, 10 Oct 2008, Xavier Shay wrote:
> 
>> How can I enumerate all the constants inside the module in the second
>> example?
>> Notice that #constants array is empty
> 
> See comments in code, below.
> 
>> For bonus points, which is the "correct" eval method to use to define a
>> class inside the module (they all seem to work)
> 
> module_eval and class_eval are synonyms for each other. I'd use
> module_eval over instance_eval, unless you specifically need instance
> methods to be singleton methods on the module object (which is
> unlikely, and can be achieved by other means under module_eval).

I'm not really sure what I need, I'll do some more reading and come back 
if I have any further questions. Using module_eval for now.

> Try this:
> 
>    m = Module.new
>    m.module_eval do
>      class self::B    # forces Ruby to wait to bind the constant
>      end
>    end
>    puts m.constants.inspect         #   ["B"]
>    puts m.const_get('B').inspect    #   #<Module:0x220164>::B

This does what I want, cheers
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