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Re: New feature tag registration drafts available

From: Graham Klyne <GK@acm.org>
Date: Tue, 15 Jul 1997 20:53:21 +0100
Message-Id: <>
To: Koen Holtman <koen@win.tue.nl>
Cc: koen@win.tue.nl, http-wg@cuckoo.hpl.hp.com
X-Mailing-List: <http-wg@cuckoo.hpl.hp.com> archive/latest/3758
At 08:00 PM 7/14/97 +0200, Koen Holtman wrote:
>>> draft-ietf-http-feature-scenarios-00.txt 
>>>     `Feature Tag Scenarios' 
>>>     Discusses why we need feature tag registration.

>>* Section 4.3, item t+2.5:
>>This implies another requirement:  it must be possible for content authors
>>to specify feature tags and associated values in authored content (this has
>>possible implications for representability within HTML, for example).
>Yes.  This is why < and > are not allowed in feature tags, and why
>feature predicates have the syntax paper!=A4, not paper<>A4.

Isn't there a conflict here with <draft-mutz-http-attributes-02.txt>?

>>* Section 4.4, para 2:
>>I think there is a potential problem more pernicious than 'dead' tags,
>>etc., which is use of different tags by different vendors to mean the same
>>thing.  This could cause unecessary negotiation failures -- maybe some
>>alias mecchanism could be defined within the registration procedures?
>TCN takes the viewpoint that, in the end, it is up to the content
>authors do decide whether A and B are interchangeable in a particular
>case at hand.  See section 19.1 in draft-ietf-http-negotiation-02.txt.
>Like with dead tags, I do not assume that content authors will directly
>go to the registry, but that there will be third parties who make
>lists of useful aliases, describing for each alias the necessary
>boundary conditions under which the alias relationship holds.

OK -- I accept that an alias mechanism is probably not a Good Idea.

I think your comment suggests a possible requirement on a generic
negotiation framework is the ability to treat some set of features as
interchangeable in the context of some specific negotiation exchange, as
your 'fpred-bag' does for  indicating the quality of a variant.


Graham Klyne
Received on Tuesday, 15 July 1997 12:58:31 UTC

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