foo.rb

class AttribBase
  def initialize
    eval($initLine)
  end
end

module ConstExtend
  def const_missing(name)
    const = const_set(name, Class.new(AttribBase))
    const.extend(ConstExtend)
    const
  end
end

class Connectors < AttribBase
  extend ConstExtend

  p External
  p Power::PC
  p PS2::KEYBOARD
end