memoize.rb

module Memoization
  def memoize(name)
    @@lookup ||= Hash.new { |h, k| h[k] = {} }

    fx = instance_method(name)

    define_method(name) do |args|
      return @@lookup[name][args] if @@lookup[name].include?(args)
      @@lookup[name][args] = fx.bind(self).call(args)
    end
  end
end

class Bleh
  extend Memoization

  memoize def saraza(a)
     2*a
  end
end

a = Bleh.new
a.saraza(24)
a.class.class_variable_get(:@@lookup)