[cap-talk] ... enforcement - hope? Capabilities as clumsy, not

[David Hopwood]

marcs wrote:
>>The most accurate way to state the design principle is 
>>something like: 
>>"An object must not be polymorphic with another object that provides 
>>less authority."
> 
> I could probably twist dean's arm and get him to rephrase this, "an object
> must not be polymorphic with another object that provides different
> authority".

Not sure I agree with that, or at least it needs refinement. Consider a
revoked object: since revocation is dynamic and type systems cannot generally
deal with dynamic interface changes, the type of a revoked object must be
both a subtype and a supertype of (i.e. polymorphically equivalent to) the
type of the corresponding unrevoked object.

-- 
David Hopwood <david.nospam.hopwood at blueyonder.co.uk>