Polymorphic DB Model

Hello!

I've been cracking my head on this for a bit, and I'm ready to plead for help.

I'm trying to create a Polymorphic model for Effects in my RoR card game. My original idea was to structure it like this:

class Card < ActiveRecord::Base     has_many :effects, :through => :is_effect

class Effect < ActiveRecord::Base     belongs_to :card     belongs_to :is_effect, :polymorphic => true

class AddSubtractEffect < Effect

Am I going about this the wrong way?

Thanks in advance,

dan

A little more information. I'm using edge rails.

I've updated a few models to look like so:

class Card < ActiveRecord::Base     has_many :is_effect, :dependent => :destroy     has_many :effects, :through => :is_effect

class Effect < ActiveRecord::Base     belongs_to :card     belongs_to :is_effect, :polymorphic => true

class AddSubtractEffect < Effect

when I try adding an effect to a Card object, this is what I get:

ArgumentError: ./script/../config/../config/../vendor/rails/activerecord/lib/../../activesupport/lib/active_support/dependencies.rb:399:in `to_constant_name': Anonymous modules have no name to be referenced by         from ./script/../config/../config/../vendor/rails/activerecord/lib/active_record/base.rb:1359:in `compute_type'         from ./script/../config/../config/../vendor/rails/activerecord/lib/../../activesupport/lib/active_support/dependencies.rb:211:in `qualified_name_for'         from ./script/../config/../config/../vendor/rails/activerecord/lib/../../activesupport/lib/active_support/dependencies.rb:470:in `const_missing'         from (eval):1:in `compute_type'         from ./script/../config/../config/../vendor/rails/activerecord/lib/active_record/reflection.rb:112:in `klass'         from ./script/../config/../config/../vendor/rails/activerecord/lib/active_record/reflection.rb:163:in `source_reflection'         from ./script/../config/../config/../vendor/rails/activerecord/lib/active_record/reflection.rb:163:in `source_reflection'         from ./script/../config/../config/../vendor/rails/activerecord/lib/active_record/reflection.rb:172:in `check_validity!'         from ./script/../config/../config/../vendor/rails/activerecord/lib/active_record/associations/has_many_through_association.rb:6:in `initialize'         from ./script/../config/../config/../vendor/rails/activerecord/lib/active_record/associations.rb:920:in `effects'         from (irb):5