enuma.rb

module Enuma

  def enumerated(type_name, *members, &block)
    @enums      = []
    type_class  = const_set(type_name, Enuma::Type.new(*members))

    instance_eval(&block)

    finalize(@enums, type_class)
  end

  def enum(*values)
    @enums << values
  end

  def finalize(enums, type_class)
    enuma_class = Class.new(Enuma::Types)
    @enuma      = enuma_class.new(enums, type_class)
    all         = const_set("ALL", @enuma.all)

    all.each do |type|
      const_set(type.first.upcase, type.first)
    end
  end

  def method_missing(method, *args, &block)
    @enuma.respond_to?(method) ? @enuma.send(method, *args, &block) : super
  end

  def respond_to_missing?(method, include_private = false)
    @enuma.respond_to?(method, include_private) || super
  end

  class Type < Struct
    alias_method :to_ary, :to_a

    def self.call
      new
    end
  end

  class Types
    def initialize(types, struct)
      @struct = struct
      @all    = [].tap { |all| types.each{ |type| all << @struct.new(*type) } }
    end

    def all
      @all
    end

    def each(&block)
      all.each(&block)
    end

    def find(key)
      all.find(@struct){ |type| type.first == key }
    end
    alias_method :[], :find

  end
end

class Colors
  extend Enuma

  enumerated("Color", :color, :name) do
    enum "red",          "Red"
    enum "blue",         "Blue"
    enum "goldenrod",    "Goldenrod"
    enum "burnt_sienna", "Burnt Sienna"

    def self.colors
      all.map(&:color)
    end

    def self.names
      all.map(&:name)
     end
  end
end


puts Colors::ALL.inspect
#=> [#<struct Colors::Color color="red", name="Red">, #<struct Colors::Color color="blue", name="Blue">, #<struct Colors::Color color="goldenrod", name="Goldenrod">, #<struct Colors::Color color="burnt_sienna", name="Burnt Sienna">]

puts Colors.all.inspect
#=> [#<struct Colors::Color color="red", name="Red">, #<struct Colors::Color color="blue", name="Blue">, #<struct Colors::Color color="goldenrod", name="Goldenrod">, #<struct Colors::Color color="burnt_sienna", name="Burnt Sienna">]

puts Colors.all.first.inspect
#=> #<struct Colors::Color color="red", name="Red">

puts Colors.colors.inspect
#=> ["red", "blue", "goldenrod", "burnt_sienna"]

puts Colors.names.inspect
#=> ["Red", "Blue", "Goldenrod", "Burnt Sienna"]

puts Colors::RED.inspect
#=> "red"

puts Colors::BURNT_SIENNA.inspect
#=> "burnt_sienna"

puts Colors.find("goldenrod").inspect
#=> #<struct Colors::Color color="goldenrod", name="Goldenrod">

puts Colors["blue"].inspect
#=> #<struct Colors::Color color="blue", name="Blue">

puts Colors.find("indigo").inspect
#=> #<struct Colors::Color color=nil, name=nil>

No Toasted Cinnamon??