# just "extend" this thing in your modules and/or "include" it if it is a class
module Foo
  def foodef( name, attr_hash, method_name, method_code )
    attr.each { |k,v| instance_variable_set( k, v ) }
    method_name, method_code = foobuild(name)
    # Err, what exactly is the difference between eval and module_eval?
    eval(method_code, binding, __FILE__, __LINE__)
    method(method_name)
  end
end

module BuildCreationMethods

  extend Foo

  def def_assign(name)
    foodef( name, {"@bcm_polymorphic_assoc_name" => 'addressable'}, "#{name}_id=",
    <<-code_end
      def self.#{method_name}(arg)
        self.#{@bcm_polymorphic_assoc_name} = #{name.classify}.find_by_id arg
      end
    code_end
    )
  end

end