HighlandAR
==========

In episode #150 of the Ruby Show podcast[1], Jason jokingly suggested that
someone should write a plugin that adds a .there_can_be_only_one method to
ActiveRecord::Base.

I thought that would be funny.  So I wrote it.

Rather than make this a one liner[2], I decided to implement a random(ish)
selection process. This way, objects with a .there_can_be_only_one association
can accept multiple candidates, who will compete for the one available slot until
only one remains.

Here's a short example:

  class Fight < ActiveRecord::Base
    there_can_be_only_one :winner
  end

  class Man < ActiveRecord::Base
  end

  class String
    def Man
      ::Man.new(:name => titlecase + ' Man')
    end
  end

  particle_man = "Particle".Man  # Doin' the things a particle can
  triangle_man = "Triangle".Man  # Triangle man hates Particle Man
  person_man   = "Person".Man    # Hit on the head with a frying pan

  Fight.new.tap do |fight|
    fight.winner = [triangle_man, particle_man]
    fight.winner # => triangle_man
  end

  Fight.new.tap do |fight|
    fight.winner = [triangle_man, person_man]
    fight.winner # => triangle_man
  end

See the tests or the EXAMPLE file for more details. Oh, and please email me[3] 
if you actually use this in a project, because I think that would be hilarious.

Enjoy,
-Sam

--

[1] http://rubyshow.com/episodes/150
[2] alias :there_can_be_only_one :has_one
[3] eval('%w[geeksam gmail].join("@") + ".com"')

--

Copyright (c) 2011 Sam Livingston-Gray, released under the MIT license