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Re: [XMLVersioning-41] Comments and Suggestions on Draft Extensibility Finding

From: Karl Dubost <karl@w3.org>
Date: Tue, 22 Feb 2005 15:39:58 -0500
Message-Id: <8327e48be637561919bfae04fd8a7568@w3.org>
Cc: www-tag@w3.org, "David Orchard" <dorchard@bea.com>
To: noah_mendelsohn@us.ibm.com

Le 20 févr. 2005, à 12:30, noah_mendelsohn@us.ibm.com a écrit :
> I. Pros and cons of extensibility
> I suspect that similar tradeoffs will apply as XML vocabularies are
> designed for other purposes:  extensibility tends to stand in 
> opposition
> to interoperability, and both are important.  I think the finding 
> would be
> much stronger if it explored such tradeoffs, and gave some more nuanced
> guidance as to when things should be locked down and when they should 
> be
> extensible.

Yes, It has always been the position of the QA WG.

To accommodate changes in technology and information on the Web, a 
specification can be designed for extensibility. A specification is 
extensible when it provides a mechanism to allow an external party to 
create extensions. Extensions incorporate additional features beyond 
what is defined in the specification. However, extensions can 
compromise interoperability if there are too many differences between 
implementations. The impact of extensions can be mitigated through 
features specifically designed to allow new functionality. These 
features provide a 'standard way to be non-standard' by including 
hooks, conformance rules, or other mechanisms by which new 
functionality may be added in a conforming way, designated as 
extensibility mechanism.
]]] -http://www.w3.org/TR/2004/WD-qaframe-spec-20041122/#extensions

>  In fact, such analysis could be one of the essential
> contributions of the finding.  Yes, the answer is often to provide for
> certain forms of extensibility, but we shouldn't recommend that 
> blindly. I
> think this is a subtle question that's particularly appropriate to the
> scope and mission of the TAG.

It's why one of the requirements of QA Specification GL is to address 
the topic of Extensibility in the technology which has been defined. QA 
Specification Guidelines being here a tool to help a working group to 
really think about it and do this cost/benefit analysis.

Karl Dubost - http://www.w3.org/People/karl/
W3C Conformance Manager
*** Be Strict To Be Cool ***

Received on Wednesday, 23 February 2005 00:02:30 UTC

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