From: Mike Papper <bodarotech@...>
Date: 2009-12-05T08:37:32+09:00
Subject: Use of extend <module> from within a Class

I would like to include a module into a 'static' class - such that all
the modules methods are class methods. The problem is that code in the
module that uses "self.class.XYZ' breaks and when this code is included,
ruby cannot find the XYZ method.

Here is an example:

module Basic
  def methoda
    puts "AAAAAAAAAAA"
  end

  def mb
    self.class.cee
  end

  module ClassMethods
    attr_writer :cee

    def cee
      puts "CCCCCCCCCCCCC"
    end
  end
end

class Use
  extend Basic

  def self.z
    mb
  end
end

If I do the following:
  Use.z

I get this error:
NoMethodError: undefined method `cee' for Class:Class
        from (irb):100:in `mb'
        from (irb):116:in `z'
        from (irb):119

--------------
The context for this is in Rails, I want to use
ActionController::UrlWriter.url_for outside of the controller. And
within a static class. However, it complains with this error:

NoMethodError: undefined method `default_url_options' for Class:Class

Heres the url_for method in ActionController::UrlWriter
  def url_for(options)
    options = self.class.default_url_options.merge(options) # ERROR
OCCURS HERE

    url = ''
  ...
  ...
  end
--------------

I think my understanding of modules and using extend (or include) is
faulty or at least doesnt cover the subtleties of when a modle uses
"self.class" and its included in another class, then what becomes of
self.class in this case??

Any input into how this stuff works in Ruby is appreciated,

Mike
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