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Checkpoint 2.2: Proposal for revised provision regarding XML/SGML content

From: Ian B. Jacobs <ij@w3.org>
Date: Sat, 28 Sep 2002 10:23:41 -0700
Message-ID: <3D95E59D.7030605@w3.org>
To: asgilman@iamdigex.net, w3c-wai-ua@w3.org

Dear UAWG,

This is a proposal to fix a provision of checkpoint 2.2
(text view) in UAAG 1.0. Al, I'm addressing you explicitly
to ask whether the proposal is properly worded.

In the Candidate Recommendation, the checkpoint included:

   "all SGML and XML applications, regardless of
    Internet media type (e.g., HTML 4.01, XHTML 1.1, SMIL, SVG,

Some developers during CR indicated that without Internet media type 
information, one cannot reliably sniff content to determine that a 
piece of content is an instance of an XML application. So in the 
last call draft, we deleted this provision.

Steven Pemberton's last call comments [1] include:

   "I would beef up this definition to at least include XML."

We resolved for issue 548 [3] to include the media type
application/xhtml+xml in this checkpoint. But upon reflection,
I think that's the wrong solution.

I think that my proposal to delete the XML provision was the wrong 
solution to the problem the developers raised in CR.

I now understand the ambiguity in the phrase "any XML application, 
regardless of Internet media type". One could interpret this
to mean "the user agent has to figure out whether this is XML 
content, whatever the media type." I think this ambiguity led
to the comments in CR; I have not confirmed with the reviewers.

I believe the intention of the second provision was to
provide a text view for content identified by media type as
XML and SGML content, even if UAAG 1.0 did not identify
all such media types (hence "regardless of media type").

I would like to reinstate a revised provision as a response
to Steven Pemberton's comments.

For the purposes of this checkpoint, a text format is either:

    1) any media object given an Internet media type of
      "text" (e.g., "text/plain", "text/html", or "text/*"),
       as defined in RFC 2046 [RFC2046], section 4.1., or

    2) any media object identified by Internet media type to
       be an instance of an XML or SGML application.

   Note: As an example, RFC 3023 [2] defines some Internet media
   types for XML content.

I think this proposal:

  a) Would satisfy Steven Pemberton's suggestion to "beef up" the

  b) Is in line with our original intent (pre-last call) to provide
     a text view of XML content. We deleted that requirement thinking
     it was technically unsound, but that discussion was based on

Thank you,

  - Ian

[1] http://lists.w3.org/Archives/Public/w3c-wai-ua/2002JulSep/0149
[2] http://www.ietf.org/rfc/rfc3023.txt
[3] http://www.w3.org/WAI/UA/issues/issues-linear-lc4.html#548

Ian Jacobs (ij@w3.org)   http://www.w3.org/People/Jacobs
Tel:                     +1 718 260-9447
Received on Saturday, 28 September 2002 13:27:52 UTC

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