Re: SUPPORT FOR DECLARATIVE TRANSITION CONSTRAINTS

Brian wrote:

>Are you assuming that I claim that the system should be able to ensure
>correctness rather than just consistency? Let me assure you that I
>claim no such thing! The system can't detect lies. It can't detect
>mistakes that are consistent with its constraints. It can only detect
>inconsistencies.

Certainly: inconsitencies relative to data that you add. The question is whether adding such data makes sense.

>No matter how you try to disguise it, the objection boils down to the
>objection that a child makes when he is forced to show his work rather
>than just giving the answer: "Why do I have to write down all the
>steps when I already know the answer?"

Nope. The objection boils down to the question whether it is meaningful to regard a statement of fact as mutable. You have this irresistibe urge to regard tuples as mutable, to consider it meaningful to construct a mapping between the tuples before an update and the tuples after. There are certainly contexts of use in which this is meaningful, but it doesn't always make sense. It is even sensible to reject this idea altogether.

But my goldfish story didn't convince you so I'm not going to try again.

-- 
Reinier