Usage Details

• SuperModule must always be included at the top of a module's body at code-time
• SuperModule inclusion can be optionally followed by other basic or super module inclusions
• A super module can only be included in a class or another super module
• SuperModule adds zero cost to instantiation of including classes and invocation of included methods (both class and instance)

IRB Example

Create a ruby file called super_module_irb_example.rb with the following content:

require 'rubygems' # to be backwards compatible with Ruby 1.8.7
require 'super_module'

module RequiresAttributes
  include SuperModule

  def self.requires(*attributes)
    attributes.each {|attribute| required_attributes << attribute}
  end

  def self.required_attributes
    @required_attributes ||= []
  end
  
  def requirements_satisfied?
    !!self.class.required_attributes.reduce(true) { |result, required_attribute| result && send(required_attribute) }
  end
end

class MediaAuthorization
  include RequiresAttributes
  attr_accessor :user_id, :credit_card_id
  requires :user_id, :credit_card_id
end

Open irb (Interactive Ruby) and paste the following code snippets in. You should get the output denoted by the rockets (=>).

require './super_module_irb_example.rb'

=> true

MediaAuthorization.required_attributes

=> [:user_id, :credit_card_id]

media_authorization = MediaAuthorization.new # resulting object print-out varies

=> #MediaAuthorization:0x832b36be1

media_authorization.requirements_satisfied?

=> false

media_authorization.user_id = 387

=> 387

media_authorization.requirements_satisfied?

=> false

media_authorization.credit_card_id = 37

=> 37

media_authorization.requirements_satisfied?

=> true