Re: Design principles and ethics

[Jonathan S. Shapiro]

On Mon, 2006-05-01 at 11:30 +0200, Bas Wijnen wrote:
> In order to guarantee confinement (and encapsulation, as you define it below),
> A. The instantiator must know that there is no unauthorized outward
>    communication.  Unauthorized by the instantiator, that is.
> B. The parent must know that information cannot be extracted from the program
>    without the parent's consent.

Part A is correct. Part B is nonsense. Encapsulation is a policy that is
selected or rejected entirely by the child.

I actually don't think that confinement is what Marcus lost when he
removed constructors. I think what he lost was authentication,
integrity, and separation of concerns. There may be other ways to
re-establish these, but he has not yet examined them.

This needs a broader discussion of the constructor feature set, which I
have promised. We need to understand precisely what is getting lost
before we can sensibly respond to Marcus's challenge question.


shap