From: Alexandre Mutel <alexandre_mutel@...>
Date: 2009-11-17T08:30:45+09:00
Subject: Re: How to dynamically include a module and update top level?

Robert Klemme wrote:
> On 16.11.2009 22:01, Alexandre Mutel wrote:
> Basically "include" behaves as if the inheritance chain at the time of
> inclusion is copied.

Thanks for your response. So it seems that every time a module is 
mixed-in another top-module, i have to reinclude the top-module into its 
includers?

I tried the following "hack" and seems to work, I would be glad to have 
some feedback... not sure it's a good ruby habit... even if it's 
working!

module ModuleIncluderTracker
  def includers()
    @includers
  end

  def included(mod)
    puts "#{self} included in #{mod}"
    if !(@includers.include? mod)
      @includers << mod
    end
    if (mod.respond_to? :reinclude)
      mod.reinclude
    end
  end

  def reinclude()
    @includers.each { |mod| puts "try to reinclude #{self} in #{mod}"; 
mod.module_eval "include #{self}"; }
  end
end

module A
   @includers = []
   extend ModuleIncluderTracker
   def toto()
       "toto"
   end
end

module B
   @includers = []
   extend ModuleIncluderTracker

   def self.late_include(mod)
       module_eval "include #{mod}"
   end
end


irb(main):037:0> include B
B included in Object
=> Object

irb(main):038:0> B.late_include "A"
A included in B
try to reinclude B in Object
B included in Object
=> B

irb(main):039:0> toto
=> "toto"

With this, it keeps all the includers up-to-date with new module 
included (although i have not managed any kind of circular references... 
not sure if it's possible...)
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