From: "David A. Black" <dblack@...>
Date: 2004-08-20T07:11:38+09:00
Subject: Re: Obtaining object in const_missing

Hi --

On Fri, 20 Aug 2004, T. Sawyer wrote:

> I'm stumped. Is there any way to do this?
> 
>   class Object
>     def self.const_missing(name)
>       p self  # => X
>       # Okay, but how do I get at object x?
>       x = ?
>       if x.respond_to?(:myconstant)
>          return "Gotchya"
>       else
>          raise  # proper error?
>       end
>     end
>   end
> 
>   class X
>     def myconstant
>       puts NewConstant
>     end
>   end
> 
>   x = X.new
>   x.myconstant

Sort of thinking it through aloud, so to speak:

I think the problem might be that x has no special status inside
const_missing.  Consider that you could also do:

  class Y
    def otherconstant
      puts X::NewConstant
    end
  end

  y = Y.new
  y.otherconstant

and then y would be playing the role that x is playing in your example.  

So it becomes a pretty general role: the object that received a
message that resulted in a method call during the course of which some
class or module's missing constant was referenced.  I'm not sure that
much history and context is really the business of the class or module
whose constant it is.


David

-- 
David A. Black
dblack@wobblini.net