gistfile1.rb

require 'rubygems'
require 'activesupport'

class Foo
  # Mimic Magic
  cattr_accessor :bar
  class << self
    def set_bar(value)
      @@bar = value
    end
  end
  # User Code
  bar = :tricked_local_var
end

Foo.bar # => nil

class Foo
  set_bar :batz
end

Foo.bar # => :batz

class Foo
  self.bar = :real_class_attr
end

Foo.bar # => :real_class_attr