Enums for Ruby

gistfile1.rb

def enum(*values, &class_body)
  Class.new( Class.new(&class_body) ) do
    attr_reader :ordinal

    def initialize(ordinal, *args, &blk)
      super(*args, &blk)
      @ordinal = ordinal
    end

    values.each_with_index do |(name, *parameters), i|
      const_set(name, new(i, *parameters))
    end

    class <<self
      private :new
    end
  end
end

# Usage:
MyEnum = enum([:VALUE1, "Value 1"], [:VALUE2, "Value 2"]) do
  attr_reader :str
  def initialize(str)
    @str = str
  end
end

MyEnum::VALUE1.str #=> "Value 1"
MyEnum::VALUE2.ordinal #=> 1