README.rb

# USAGE

class Foo < Struct.new(:name, :address)
  extend HelperMacros

  compare_by :name
  order_by :address, :name
end

helper_macros.rb

module HelperMacros
  def compare_by(*accessors)
    define_method(:==) do |other|
      accessors.all? do |message|
        send(message) == other.send(message)
      end
    end
  end

  def order_by(*accessors)
    define_method(:<=>) do |other|
      accessors.inject(0) do |memo, message|
        if memo.zero?
          result = send(message) <=> other.send(message)
          result <=> memo
        else
          memo
        end
      end
    end
  end
end