From: Heesob Park <phasis@...>
Date: 2008-05-19T22:49:04+09:00
Subject: Re: How to use a class_variable into a Module

Hi,

I単aki Baz Castillo wrote:
> Hi, I want to declare a class_variable in class A.
> Class A includes a Module M and I want some methods in M using the
> class_variable but I get some problem:
> 
> -------------------
> module M
>        def kk
>                #puts (eval %{ #{send('class').class_variables[0]} })
>                puts @@class_var
>        end
> end
> 
> class A
>        include M
>        @@class_var = "kaka1"
> end
> 
> a = A.new
> a.kk
> NameError: uninitialized class variable @@class_var in M
>        from ./class_attr1.rb:4:in `kk'
> -------------------
> 
> 
> I understand the problem. Because the nature of class variables when
> the Module M uses @@ it looks into a class variable defined in same
> class/module.
> 
> Is there any way I could use a class A @class_var into a included M
> module methods? If not then I'll use a normal attribute but I don't
> like it since it's a constant value that could perfectly be a class
> variable instead of initialiting it in each A instance creation.
> 
Here is a working code:

module M
      @@class_var = nil
      def kk
              puts @@class_var
      end
end

class A
      include M
      @@class_var = "kaka1"
end

a = A.new
a.kk


Regards,

Park Heesob
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