From: dblack@...
Date: 2006-01-21T08:23:02+09:00
Subject: Re: Inserting

Hi --

On Sat, 21 Jan 2006, James Hughes wrote:

> On 1/19/06, Paul Brannan <pbrannan@atdesk.com> wrote:
>>
>> You can also create a mixin and extend Foo::Bar with the mixin.  If you
>> do this, instance methods in the mixin will be available as class
>> methods in Foo::Bar and derived classes.
>
> Ok, I'm doing something like the following:
>
> module FooBarHelper
>
>  class << Foo::Bar
>     # some instance methods, which reference class vars from Foo::Bar
>  end
> end
>
> Then, in classes A and B I do "include FooBarHelper".  When I run this
> I get "uninitialized class variable" errors for the Foo::Bar's class
> vars.
>
> So, to state my question again, how can I extend the functionality of
> the Foo::Bar library (short of hacking it's source directly), while
> still maintaining access to the class variables defined in Foo::Bar?
> Is this even possible?

Does this help at all?

   module Foo
     class Bar
       def self.meth
         puts "Class method of Foo::Bar"
       end
       X = "Constant of Foo::Bar"
     end
   end

   module Needed
     def self.const_missing(c)
       Foo::Bar.const_get(c)
     end
     def needed_method
       puts "This is a needed method"
       puts X
     end
   end

   class A < Foo::Bar
     extend Needed
   end

   puts A::X
   A.meth
   A.needed_method


David

-- 
David A. Black
dblack@wobblini.net

"Ruby for Rails", from Manning Publications, coming April 2006!
http://www.manning.com/books/black