class Object
  def lazy(&block)
    Lazy.new(self, &block)
  end
end

class Lazy
  undef_method(*(instance_methods - %w/__id__ __send__ respond_to? debugger/))

  def initialize(obj, &block)
    @obj, @block = obj, block
    @args = @done = nil
  end

  def method_missing(*args, &block)
    unless @done
      if !@args && !@block
        @args, @block = args, @block
        return self
      end

      @res = @args ?  @obj.send(*@args, &@block) : @block.call(@obj)
      @done = true
    end
    
    @res.send(*args, &block)
  end
end