From: rubyhacker@...
Date: 2005-10-27T05:07:04+09:00
Subject: Re: how private is private in ruby?


Edward Faulkner wrote:
>
> While it may or may not be a good idea that #send subverts access
> control, your choice of example betrays a misunderstanding of the
> meaning of "private".
>
> "private" is not intended as a security measure.  It's an
> encapsulation technique.  You'll find this is generally true in other
> languages as well.  You can certainly subvert "private" in C++.
>
> "private" exists only to tell other programmers which methods they
> really shouldn't be calling.

Exactly right.

I made an analogy the other day with the movie _Apollo 13_. Remember
when Bacon's character had been awake for many hours and was, as he
said, "a little punchy"? There was a toggle switch which would
separate the two modules (and thus doom to death the other two astro-
nauts who were spending their time in the other one). He taped a
piece of paper over it saying "NO."

That's how "private" works.


Hal