Re: Formulate erratum text on versioning for the web architecture document


The TAG has spent a great deal of time on versioning over the past 7 years.
I have focused on it heavily during 3 terms, as well as a year in between
when I was not on the TAG.  It is extremely difficult to get to consensus on
what I thought were very simple things, like saying "languages intended to
be versioned should be extensible."

I very much agree that there is much much more work that could be done on
versioning and updating the findings.  You may find it difficult to allocate
time to versioning compared to other activities on the TAG.   I applaud your
consideration of the fullness of issues wrt versioning.

This is also directly related to HTML5 WG issue 41, which is that HTML5
currently precludes support for distributed extensibility.


On Tue, Feb 17, 2009 at 11:37 AM, Larry Masinter <> wrote:

> 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
> Larry
> --
> -----Original Message-----
> From: [] On Behalf Of
> John Kemp
> Sent: Tuesday, February 17, 2009 7:47 AM
> To: 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]
> [2]
> [3]
> [4]

Received on Tuesday, 17 February 2009 20:35:27 UTC