Re: Distinguishing features and feature sets

At 02:11 PM 2/3/99 +0000, Graham Klyne wrote:
[...]
>Again if I am understanding you correctly, I think the issue is here is the
>extent of new knowledge that is introduced.  In some cases it is sufficient
>for both sender and recipient to know that the capabilities of a
>(SONY-GIZMO) device are asserted;  in other cases, if (ACME-COMMUNICATOR)
>is a rebadged (SONY-GIZMO) they use their own name but indicating the same
>feature set (hence the same hash value), so the features known as
>(ACME-COMMUNICATOR) can be konown to match (SONY-GIZMO) without knowing the
>actual features;  in other cases it will be necessary to actually recover
>the feature set to determine a match.
[hope that's enough summary]

The lazy client that doesn't want to dereference ACME-COMMUNICATOR will
match it with ACME-COMMUNICATOR and treat ACME-COMMUNICATOR and SONY-GIZMO
as values of different tags.  The industrious client will dereference
ACME-COMMUNICATOR and know it matches SONY-GIZMO or the content of SONY-GIZMO.
Yes?

I guess I just missed an earlier turn in the road -- like the motivation
for hashes.
I am not sure you should be messing with hashes.  Use

h.True where URN

for feature sets and make sure that the sets are cleanly mapped to URNs.
And don't bother with less.

Al