Re: Clean Object Class Design -- What is it?

Bob Badour wrote:
> > To be honest, I cannot see that. For example, the value-returning
> > set expression
> >
> > S = S difference {x}
> >
> > could be enormously inefficient. Suppose the set contains 20,000
> > elements, none of which is x?
>
> What you think the optimizer is for? These are logical operations not
> physical operations..

Sure. Some misunderstanding on my part as first some crucial defs. were omitted, then presented in a way that made me think they were literal algorithms. If they are "logical operations" (which I mentally translate as "assertions") then all makes sense and of course the execution mechanism can be as lazy or eager as it likes without affecting the semantics.

[ I'd still maintain set-level operations as in relational
[ algebra and set operations as in mathematics are different,
[ but it now looks to me like that wasn't a point of contention.

-- 
http://www.mk.dmu.ac.uk/~gperkins/