Virtual attributes #2

virtual_attributes.rb

module VirtualAttributes
  extend ActiveSupport::Concern

  class VirtualAttribute < Struct.new(:klass); end

  module ClassMethods
    def attr_virtual(*attrs)
      options = attrs.extract_options!

      attrs.each do |attr|
        virtual_attributes[attr] = VirtualAttribute.new(options[:klass])

        class_eval do
          send("attr_accessor", attr)
        end
      end
    end
  
    def virtual_attributes
      @virtual_attributes ||= {}
    end
  end
end