From: Alexandre Mutel <alexandre_mutel@...>
Date: 2009-12-01T07:35:14+09:00
Subject: Re: Problem trying to get a constant with correct scope

pharrington wrote:
> On Nov 30, 4:15�pm, Alexandre Mutel <alexandre_mu...@yahoo.fr> wrote:
>> How to get constant B from inside C but executed from outside first
>> declaration?
>> After module A is declared, trying :
>>
>> >>> puts A::C.class_eval("B")
>>
>> failed and const_get is not working too.
> Your goal is confusing. module A contains the "B" constant, not class
> C. How does "A::B" not satisfy your needs? What exactly are you trying
> to do?

Sorry for the shortcut in my explanation. In fact, my test case is a bit 
more dynamic. I'm developing a DSL that evaluate blocks that can contain 
a line like this:
A_CONSTANT  some,args,...etc.

So i'm trying to get the constant dynamically and not statically :

I have something like :
class ConstSearcher
   def self.method_missing(sym,*args)
        puts const_get(sym)
   end
end

module A
   class B
   end
   class C < ConstSearcher
       puts B           # << static constant lookup is working
   end
end

But performing a dynamic lookup is not : A::C.instance_eval("B 11111") 
:
NameError: (irb):3:in `const_get': uninitialized constant A::C::B
  from (irb):13
  from (irb):3:in `method_missing'
  from (eval):1
  from :0

i tried several methods (eval with binding...etc.) without any success. 
Does i have to loop through parent modules and perform a const_get on 
each module ? (generating a huge performance penalty).
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