Enum for Ruby

enum.rb

# example
#
# States = enum %w(Draft Approved Published Trashed)
# => States {Draft, Approved, Published, Trashed} 
# 
# States::Draft
# => 1
#
# States::Approved
# => 2
#
# States::Published
# => 4
# 
# States::Trashed
# => 8
# 
# States::Approved | States::Draft
# => 3
# 
# States::Approved | States::Published
# => 6

module Enum
  def enum(values)
    Module.new do |mod|
      values.each_with_index{ |v,i| mod.const_set(v.to_s.capitalize, 2**i) }
      def mod.inspect
        "#{self.name} {#{self.constants.join(', ')}}"
      end
    end
  end
end

include Enum