change policy for HTML namespace (ISSUE-60 html5-xhtml-namespace)

I'm interested to get issue-60 closed, but I found
an outstanding concern...

Murray Maloney expressed some concerns about reuse of the 1999

To paraphrase, I think his concern is that once a namespace
is bound to a language, changing the language (adding/removing
elements and attributes, refining their meanings, etc.) invalidates
processing expectations by deployed software.

He also asked if W3C doesn't have a policy regarding that
sort of thing.

Yes, W3C does have a policy:

In short, the policy is that on a case-by-case basis,
some namespaces are bound in an immutable way and others
are not, and the choice between them should available
by following the namespace pointer.

Some examples are given:

The namespace document could contain text along the following lines:

Example 1
        The definitions of names in this namespace will not change from
        those given in the June 13 2007 version of the Foonly spec [ref.
        dated URI]. Subsequent versions of the Foonly spec which make
        any substantive changes will do so in a new namespace.
Example 2
        This namespace URI will be used to refer to this and future
        versions of this specification. The specification defines
        language extension mechanisms and how to handle changes such as
        the addition of new terms to the language. W3C reserves the
        right to determine which changes (backward compatible or not)
        are in the interest of the community at large.

My understanding of the HTML namespace policy is that it's pretty
close to Example 2.

The HTML namespace document currently (last revised 2009/01/08)
gives notice that changes are in progress:

"The charters of the following W3C Working Groups include work on HTML
that may impact this namespace: 

      * Semantic Web Deployment Working Group, chartered July 2006 to
        work on RDFa
      * WAI Protocols and Formats Working Group (PFWG), chartered Dec
        2006 to work on Accessibility of Dynamic Web Content
      * HTML Working Group, chartered March 2007
      * XHTML2 Working Group, chartered March 2007"

Impact on deployed software is very much a factor in the design
of any changes to HTML. This is captured in our design principles
in section 2.2. Degrade Gracefully

Dan Connolly, W3C
gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E

Received on Thursday, 13 August 2009 15:36:17 UTC