Lazy Proxy

lazy_proxy.rb

class LazyProxy
  
  # blank slate... (use BasicObject in Ruby 1.9)
  instance_methods.each do |method| 
    undef_method(method) unless method =~ /^__/
  end
  
  def initialize(&lazy_proxy_block)
    @lazy_proxy_block = lazy_proxy_block
  end
  
  def method_missing(method, *args, &block)
    @lazy_proxy_obj ||= @lazy_proxy_block.call # evaluate the real receiver
    @lazy_proxy_obj.send(method, *args, &block) # delegate unknown methods to the real receiver
  end
  
end