From: Robert Klemme <shortcutter@...>
Date: 2009-11-18T05:00:16+09:00
Subject: Re: How to dynamically include a module and update top level?

On 17.11.2009 00:30, Alexandre Mutel wrote:
> 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?

Apparently:

irb(main):001:0> module A; end
=> nil
irb(main):002:0> c=Class.new { include A }
=> #<Class:0x1021d37c>
irb(main):003:0> c.ancestors
=> [#<Class:0x1021d37c>, A, Object, PP::ObjectMixin, Kernel, BasicObject]
irb(main):004:0> module B; end
=> nil
irb(main):005:0> module A; include B; end
=> A
irb(main):006:0> c.ancestors
=> [#<Class:0x1021d37c>, A, Object, PP::ObjectMixin, Kernel, BasicObject]
irb(main):007:0> c.class_eval { include A }
=> #<Class:0x1021d37c>
irb(main):008:0> c.ancestors
=> [#<Class:0x1021d37c>, A, B, Object, PP::ObjectMixin, Kernel, BasicObject]
irb(main):009:0>

> 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!

Personally I find that the more interesting question.  Do you want to 
have the side effect of updating potentially many classes (and objects 
via their class and #extend)?  Maybe there is a better design choice?  I 
don't know your use case or what you need that behavior for.  Generally 
Matz pics _very_ reasonable choices so I tend to assume that the 
aforementioned side effect is usually not wanted.  Which does not mean 
that there is no use case for this.

Kind regards

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/