#!/usr/bin/env ruby
# This code comes from http://ruby-it.org/pages/Soluzione+Aprile+2003+di+Gabriele+Renzi
# Check the page for copyright notice and explanations



 class Memoize
  def initialize(sym)
    @met=method(sym)
    @val=Hash.new
  end
  def call(*args,&block)
   if not @val[[args,block]]
    @val[[args,block]]=@met.call(*args,&block)
   end
    @val[[args,block]]
  end
 end

 class Memoize
  def initialize(sym)
    @met=method(sym)
    @val=Hash.new
  end
  def call(*args)
   if not @val[args]
    @val[args]=@met.call(*args)
   end
    @val[args]
  end
 end

memoized_slowid=Memoize.new('slowid')

memoized_slowid.call(5)
5    (* in 5 secondi)

memoized_slowid.call(5)
5    (istantaneamente)