class Mixin < ActiveRecord::Base end class TreeMixin < Mixin acts_as_tree :foreign_key => "parent_id", :order => "id" end class ListMixin < Mixin acts_as_list :column => "pos", :scope => :parent def self.table_name() "mixins" end end class ListWithStringScopeMixin < ActiveRecord::Base acts_as_list :column => "pos", :scope => 'parent_id = #{parent_id}' def self.table_name() "mixins" end end