- From: Larry Masinter <masinter@adobe.com>
- Date: Tue, 17 Feb 2009 11:37:14 -0800
- To: John Kemp <john.kemp@nokia.com>, "www-tag@w3.org WG" <www-tag@w3.org>
It's pretty clear to me that the findings on versionings aren't specific enough. I think a full finding on versioning might even include a discussion of the various mechanisms for versioning, MIME types, DOCTYPE, version attributes on root elements, version elements, the relationship between major and minor version numbers, the issues and pros and cons of the various ways of designing languages that are version compatible, and also address the various issues with deployment, difficulties of supporting multiple versions in a single set of software, relationship of scripting to versioning, versioning of languages that are used in compound XML documents from multiple namespaces. Certainly these topics and more are part of the ongoing discussion of versioning in HTML, see http://www.w3.org/html/wg/tracker/issues/4 Larry -- http://larry.masinter.net -----Original Message----- From: www-tag-request@w3.org [mailto:www-tag-request@w3.org] On Behalf Of John Kemp Sent: Tuesday, February 17, 2009 7:47 AM To: www-tag@w3.org WG Subject: Formulate erratum text on versioning for the web architecture document Hello, I acquired an action item [1] to investigate whether the AWWW best practice on versioning [2] should be updated in light of the versioning work done by the TAG. Noah wrote a nice description of the issue on the TAG blog [3] which includes links to the relevant work done by Dave Orchard on versioning. The AWWW currently says this, marked as a best practice: "A data format specification SHOULD provide for version information." My understanding of that line is that when designing a data format specification, the author should provide a mechanism allowing an instance document, conforming to the said specification, to carry information pertaining to the version of the specified format with which the instance complies (where complies _might_ mean 'should validate against the related XML schema' or something else, at the specified discretion of the author). Of course, using XML namespaces in an appropriate manner would be one way by which this best practice could be applied. As Noah described in [3], it is not always necessary for a format author to create an updated version identifier, or require its use in compliant instances. This particular item is also touched on in the AWWW in a section on Versioning and XML Namespace Policy [4] I believe that the best practice is still correct and important - data format specifications should provide a mechanism (where that mechanism might simply be "use XML namespaces") allowing instances to indicate version information. Authors will likely not know whether they will later have to create a new, incompatible version of a format a priori, but should likely assume that they will. I would suggest, however, that perhaps an additional best practice might be warranted, along the lines of Noah's suggestion in [3]: "If a language, or data format, changes in incompatible ways, a new version identifier should be assigned to the updated data format, and allowed in document instances." Regards, - johnk [1] http://www.w3.org/2001/tag/group/track/actions/165 [2] http://www.w3.org/TR/webarch/#ext-version [3] http://www.w3.org/QA/2007/12/version_identifiers_reconsider.html [4] http://www.w3.org/TR/webarch/#versioning-xmlns
Received on Tuesday, 17 February 2009 19:38:03 UTC