[cap-talk] "Composite", was "Same" key

David Hopwood david.nospam.hopwood at blueyonder.co.uk
Fri Feb 16 23:52:24 CST 2007

Mark S. Miller wrote:
> David Hopwood wrote:
>> What composite does the set of zero objects implement? If there were some
>> technical advantage in including the null set, that would be fine, but I
>> don't see any.
> I am thinking in terms of descriptions like
>     Say Alice is one of Bob's clients. Let's describe the set of all of
>     Bob's other clients as the composite Rest.

Oh. Right. You really do mean a composite to allow an *arbitrary* set of objects.

In that case I think that "composite" is a *highly* misleading name.

I suggest something like "group" instead. Then an "abstraction" would be a
special case of a group, where all the objects in the group share state and
are working together to provide some specific functionality.

>     If Alice uses Bob correctly and Bob is defensively consistent, then,
>     no matter what action is taken by Rest, Bob will never give bad service
>     to Alice.
> In this description, the composite Rest "implements" a potentially
> misbehaving client of Bob. Since, in an object-capability system, Bob
> can't sense which client makes a request, for some purposes, we might as
> well aggregate all potentially misbehaving clients of Bob into a single
> descriptive composite.

It seems quite a stretch to use the term "composite" for this.

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

More information about the cap-talk mailing list