YET ANOTHER RUBY IMPLEMENTATION for MEMOIZATION based on James Edward Gray II blog (blog.grayproductions.net/articles/caching_and_memoization), however turned to be more problematic than a solution.

YARIM.rb

require 'digest/sha2'
require 'base64'

class HashClod < Hash
  def [](key)
    r = super(key)
    puts r
    if r == nil
       puts "set cache"
    else
       puts "get cache"   
    end
    r
  end
end

module YARIM # YET ANOTHER RUBY IMPLEMENTATION for MEMOIZATION
   def memoize( name, cache = Hash.new )
      original = "__unmemoized_#{name}__"

      ([Class, Module].include?(self.class) ? self : self.class).class_eval do
         alias_method original, name
         private      original
         define_method(name) do |*args| 
            unique_id = self.generate_id args
            cache[unique_id] ||= send(original, *args)             
         end   
      end
           
      def self.generate_id(*args)
         args = args[0]
         args.each do |arg|
            arg.sort! if arg.instance_of? Array
            arg.values.sort! if arg.instance_of? Hash
         end
         
         arguments = Marshal::dump args
         
         unique_id = Base64::encode64(Digest::SHA256.digest(arguments))[0..12].chomp( "=" )
         return unique_id
      end
   end

   def Type(klass = :hash)
      if klass == :hash
         Hash
      else
         Class.new do
            def message
               "place holder go mongodb"
            end
         end
      end
   end
end

extend YARIM

def add(*args)
   2 + args.first
end

memoize :add, HashClod.new

add(1)
add(1)
add(1, 2, 3)
add(1, 2, 3)
add(4, 3, [2, 3])
add(4, 3, [2, 3])
add(4, 3, [3, 2])

add(6, :a => 1, :b => 3)
add(6, :a => 1, :b => 3)
add(6, :b => 3, :a => 1)

puts "done"