From: Xavier Noria <fxn@...>
Date: 2007-11-15T09:04:27+09:00
Subject: Re: Module#constants

On Nov 14, 2007, at 9:41 PM, Xavier Noria wrote:

> However, I have seen that even if there something syntactic the name  
> of the constant is not used, I mean this works:
>
>  module M
>    C = 1
>    module N
>    end
>  end
>
>  X = M
>  module X
>    module N
>      C
>    end
>  end

Nah, that didn't add information. When the code is interpreted and we  
arrive to "module X" the X constant is looked up and has a module as  
value, which happens to be the same module object that is stored under  
M. So that example is no different from plain

   module M
     module N
       C
     end
   end

This test brings some light in what I think I don't understand:

   module M
     C = 1
     module N
     end
   end

   class Module
     def const_missing(c)
       puts self
     end
   end

   M::N.module_eval do
     C
     puts self
   end

Gives:

   Object
   M::N

So I think I am narrowing this to how scope works. I know module_eval  
sees stuff from the surrounding scope, but I think I have a  
misunderstanding between "scope" and "evaluating the block in the  
context of M::N".

There's some module that's taken as a starting point to crawl up in  
the namespace for constant resolution (Object), and there's a  
different module to which method definitions _but not constant  
definitions_ apply (the remark about constants is not proven in the  
example).

Can anyone define those "two" modules better?

-- fxn