[ruby-talk:03847] RE: Private variables can be changed outside?

Let me add one more thing (I'm starting to feel Columbo ;).

> every class *can* access every 
> other's instance
> variables!
...
> 2) a method Class#spy, to the class we wanted to inspect, 
>    which calls just created Object#spy

Of course it's easier to spy by creating Class#spy like this:

class Foo
  def spy
    @var = send_and_alter( @var )
  end
end

But the trick is to mess up with object's variables without changing it or
letting it know in any way. 

If only we know any of the class' methods which calls any of Object's
methods, we could alter Object#called_method, intercept the message, peek
what out cute object has eaten today, call the aliased
Object#original_method and return it's value. The object didn't knew it was
fooled.

Even if I've not made any mistake here somewhere (quite unprobable :) and
such spying is possible, I don't think the hole this opens up is really big.
Or it might be, but I don't know *why* to use it. Anyway, the 'private' has
less power.

	- Aleksi