anchor.diff:  === DDD and Rails
   
   *http://victorsavkin.com/post/41016739721/building-rich-domain-models-in-rails-separating[Entity Data Repository] - Blog post describing hybrid ActiveRecord/DAO approach to building rich domain models in Rails, implemented in https://github.com/nulogy/edr[EDR library]. Implements restricted version of http://martinfowler.com/eaaCatalog/dataMapper.html[DataMapper pattern]. Datamapper 2 will be implementing the same pattern, but is not production-ready yet (see above)
  -
  -
  +* http://iain.nl/domain-driven-design-building-blocks-in-ruby[DDD in Ruby article] - recommends using to_s for UI concerns and structs for value objects, both of which seem problematic to me.
  +
  
positive.code: * https://github.com/harukizaemon/hamster[Hamster - Efficient, Immutable, Thread-Safe Collection classes for Ruby]
  * https://github.com/tcrayford/values
  * https://github.com/solnic/virtus
  * https://github.com/rouge-lang/rouge[Ruby + Clojure = Rouge]
  
  === Enums in Ruby
  
negative.code: * http://stackoverflow.com/questions/75759/enums-in-ruby
  * http://www.lesismore.co.za/rubyenums.html
  * http://gistflow.com/posts/682-ruby-enums-approaches
  
  === Equality in Ruby
  
  * http://woss.name/2011/01/20/equality-comparison-and-ordering-in-ruby/[Equality, Comparison and Uniqueness in Ruby]
  * http://stackoverflow.com/questions/11247000/which-equality-test-does-rubys-hash-use-when-comparing-keys[SO: Which equality test does Ruby's Hash use when comparing keys?]
  * http://pivotallabs.com/equality-and-sameness-in-ruby/[Equality and sameness in RubyConf]
  * http://kentreis.wordpress.com/2007/02/08/identity-and-equality-in-ruby-and-smalltalk/[Identity and Equality in Ruby and Smalltalk]
  
  == Persistence
  
  