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meeting record: 2009-02-19 RDFa Task Force

From: Ralph R. Swick <swick@w3.org>
Date: Thu, 19 Feb 2009 12:21:44 -0500
Message-Id: <5.1.0.14.2.20090219122004.055ac6e8@127.0.0.1>
To: public-rdf-in-xhtml-tf@w3.org
Cc: public-swd-wg@w3.org
The record of today's RDF-in-XHTML Task Force telecon is available as

  http://www.w3.org/2009/02/19-rdfa-minutes.html

A text snapshot follows.

----

                        RDF-in-XHTML Task Force

19 Feb 2009

   [2]Agenda

      [2] http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2009Feb/0178.html

   See also: [3]IRC log, previous [4]2009-01-22

      [3] http://www.w3.org/2009/02/19-rdfa-irc
      [4] http://www.w3.org/2009/01/22-rdfa-minutes.html

Attendees

   Present
          Manu Sporny, Shane McCarron, Ralph Swick, Ben Adida, Tom
          Baker, Mark Birbeck

   Regrets
          Steven

   Chair
          Ben

   Scribe
          Ralph

Contents

     * Topics
         1. Action Review
         2. @prefix, specifically @prefix on HEAD
     * Summary of Action Items
     _____________________________________________________


   <TomB> just listening (muted)


   <Ralph> [9]previous non-meeting

      [9] http://www.w3.org/2009/02/05-rdfa-minutes.html

   <Ralph> [10]previous 2009-01-22

     [10] http://www.w3.org/2009/01/22-rdfa-minutes.html

Action Review

   ACTION: [DONE] Manu to create design tests for @prefix and @profile.
   [recorded in
   [11]http://www.w3.org/2009/01/22-rdfa-minutes.html#action16]

     [11] http://www.w3.org/2009/01/22-rdfa-minutes.html#action16

   Manu: see [12]my mail
   ... I showed a first pass of three styles of markup

     [12] http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2009Feb/0180.html

   ACTION: [DROPPED] Ben to add public-rdfa examples to wiki and think
   of slightly improved top-level organization [recorded in
   [13]http://www.w3.org/2008/11/06-rdfa-minutes.html#action11]

     [13] http://www.w3.org/2008/11/06-rdfa-minutes.html#action11

   Ben: I did a reorganization of the wiki then Manu added way more
   than this action required

   ACTION: [CONTINUES] Ben to put up information on "how to write RDFa"
   with screencast possibly and instructions on bookmarklet. [recorded
   in [14]http://www.w3.org/2008/11/06-rdfa-minutes.html#action12]

     [14] http://www.w3.org/2008/11/06-rdfa-minutes.html#action12

   ACTION: [CONTINUES] Ralph or Steven fix the .htaccess for the XHTML
   namespace [recorded in
   [15]http://www.w3.org/2009/01/08-rdfa-minutes.html#action01]

     [15] http://www.w3.org/2009/01/08-rdfa-minutes.html#action01

   ACTION: [CONTINUES] Jeremy to demonstrate GRDDL with XHTML/RDFa once
   the NS URI is set up. [recorded in
   [16]http://www.w3.org/2008/09/11-rdfa-minutes.html#action03]

     [16] http://www.w3.org/2008/09/11-rdfa-minutes.html#action03

   Ralph: drop this?

   Ben: I'd like to ping Jeremy; I'd like to see this

   ACTION: [CONTINUES] Manu to create TC to test @resource="[]" does
   not set object based on TC 123. [recorded in
   [17]http://www.w3.org/2009/01/08-rdfa-minutes.html#action14]

     [17] http://www.w3.org/2009/01/08-rdfa-minutes.html#action14

   ACTION: [CONTINUES] Manu to look at
   [18]http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2008D
   ec/0037.html [recorded in
   [19]http://www.w3.org/2009/01/08-rdfa-minutes.html#action15]

     [18] http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2008Dec/0037.html
     [19] http://www.w3.org/2009/01/08-rdfa-minutes.html#action15

   Manu: I sent an email, no response yet

   ACTION: [CONTINUES] Manu to write summary for Semantic Web Use Cases
   for Ivan. [recorded in
   [20]http://www.w3.org/2008/09/11-rdfa-minutes.html#action09]

     [20] http://www.w3.org/2008/09/11-rdfa-minutes.html#action09

   ACTION: [CONTINUES] Mark create base wizard suitable for cloning
   [recorded in
   [21]http://www.w3.org/2008/09/11-rdfa-minutes.html#action12]

     [21] http://www.w3.org/2008/09/11-rdfa-minutes.html#action12

   ACTION: [CONTINUES] Mark to review reasoning on setting explicit
   about="" on HEAD and BODY [recorded in
   [22]http://www.w3.org/2008/12/18-rdfa-irc]

     [22] http://www.w3.org/2008/12/18-rdfa-irc

   ACTION: [CONTINUES] Mark to send Ben ubiquity related wizard stuff
   [recorded in
   [23]http://www.w3.org/2008/11/20-rdfa-minutes.html#action11]

     [23] http://www.w3.org/2008/11/20-rdfa-minutes.html#action11

   ACTION: [CONTINUES] Mark write foaf examples for wiki [recorded in
   [24]http://www.w3.org/2008/09/11-rdfa-minutes.html#action13]

     [24] http://www.w3.org/2008/09/11-rdfa-minutes.html#action13

   ACTION: [CONTINUES] Michael to create 'RDFa for uF users' on RDFa
   Wiki [recorded in
   [25]http://www.w3.org/2008/09/11-rdfa-minutes.html#action14]

     [25] http://www.w3.org/2008/09/11-rdfa-minutes.html#action14

   ACTION: [CONTINUES] Ralph think about RSS+RDFa [recorded in
   [26]http://www.w3.org/2008/09/11-rdfa-minutes.html#action15]

     [26] http://www.w3.org/2008/09/11-rdfa-minutes.html#action15

@prefix, specifically @prefix on HEAD

   Ben: I'd like to talk about this in concert with the test cases

   [[
   I see from the discussion on January 22 that there was talk of
   allowing
   @prefix on HEAD to apply to the BODY, but I think we had clearly
   said in
   prior discussions that this shouldn't happen, because of the
   SAX-based
   processing of documents. We need to clarify this.
   ]]
   -- Ben, in [27]email

     [27] http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2009Feb/0178.html

   Ben: am I correct in my interpretation of that 22-Jan discussion?
   ... @prefix on HEAD would apply to BODY also?

   Manu: yes, that was the discussion
   ... we didn't get too deeply into this
   ... Mark did propose this would be nice

   <msporny> [28]rdfa-test-harness/

     [28] http://rdfa.digitalbazaar.com/rdfa-test-harness/

   Manu: there are 3 variations on @prefix syntax
   ... select 'Design Test Suite' and 'Unreviewed'

   <ShaneM> "We will serve no predicate before its time"

-- test 9001: Establishing @prefix on HTML element

   Manu: the purpose of these tests is just to provide a starting point
   for the design discussion

   <msporny> [29]http://rdfa.info/wiki/design-suite

     [29] http://rdfa.info/wiki/design-suite

   -> [30]explanation of purpose of test 9001

     [30] http://rdfa.info/wiki/Design-suite#9001

   Manu: 9002 shows a CSS-like syntax, 9003 shows an '=' syntax
   ... I prefer the '=' syntax, as does Toby Inkster

   Ben: three decisions; what to call this @ttribute, what's the value
   syntax, what's the parsing model

   Mark: sounds right. the name is the least important

   Ben: the 3 test assume @prefix for the name and the same parsing
   model as @xmlns
   ... they're testing for the value syntax options

   Manu: correct

   Ben: note that none of this discussion is really in scope for this
   Task Force
   ... we're producing some notes on how to proceed
   ... should we make a decision, or should we just note these options
   and leave it to whatever group is chartered to decide?
   ... people who do implement these sorts of things tend to implement
   quickly
   ... Manu's already done something, as has Ivan
   ... if we agree amongst ourselves this is a big step
   ... could be a Note for a year or so
   ... this would at least put it 'there'
   ... already some useful discussions around named graphs
   ... it would be good to converge on a way of approaching these even
   if we don't have a place to put the formal state of this convergence

   <msporny> +1 for going as far as we can with the syntax for @prefix

   Ben: so we might proceed on the understanding that whatever we
   'decide' can be overturned later

   Shane: we're likely to be participants in whatever discussion is
   chartered
   ... the XHTML2 WG can proceed now if it chooses
   ... addition of @profile to the XHTML module would be covered by our
   current WG charter

   Ralph: the SVG folk are pushing on @xmlns support in HTML as well
   ... SVG Tiny has fully incorporated RDFa
   ... and SVG itself uses @xmlns

   <msporny> When Doug and I were talking at WDN09 - I found a wierd
   issue with him using xlink:href to specify hrefs in his SVG - it
   would break a RDFa parser as he marked it up.

   Ralph: so are we diluting our message if we add a syntactic
   alternative?

   Mark: it doesn't hurt to have both @xmlns and @prefix in the same
   document
   ... we consciously left open this scope in the CURIE spec
   ... the wording says that XML documents should support @xmlns
   ... but leaves open the possibility of alternatives

   Shane: CURIE is Candidate Rec
   ... it is correct that alternative mechanisms are permitted by the
   CURIE spec
   ... the CURIE spec itself does not define any attributes
   ... the XHTML2 spec defines the mapping mechanism

   <Zakim> ShaneM, you wanted to discuss xmlns: and XML parsing rules

   Shane: there's been a good argument in the recent days about why
   @xmlns: is not isomorphic w.r.t. processing model between HTML5 and
   XML
   ... if we say that the attribute name "xmlns:foo" should be treated
   as a token,
   ... the truth is that in the XML DOM a real parser should not be
   passing this token through
   ... the actual name of the attribute is 'foo' in the XML namespace,
   not a string 'xmlns:foo'
   ... @xml... is a reserved namespace

   Mark: doesn't the API allow the application to retrieve the full
   name of the attribute?

   Manu: I thought Henri was specifically referring to XOM
   ... the level 1 API would be fine but the level 2 API would filter
   xmlns:foo to something else

   Mark: but the argument was that an HTML5 processor _would_ give
   access to the full xmlns:foo whereas an XML pipeline would not
   ... so why would an application that wants the full string use such
   an XML pipeline?

   Manu: the point was that the cost is not zero as we've claimed

   <msporny> +1 for prefix instead of xmlns:

   <markbirbeck> +10

   Ben: independent of Henri's argument, do we feel that adding @prefix
   would be prefereable

   Ralph: are you just talking about a synonym for @xmlns for CURIE
   prefixes?
   ... or the added features of the value that are under discussion?

   Mark: if we hadn't chosen @xmlns we'd be in deeper trouble

   Ben: there's an argument that @xmlns is working better than
   expected; we _can_ actually get to it in the browsers

   <msporny> me agrees - we needed to use xmlns: for XHTML, but we
   should provide @prefix as an alternative.

   Ben: there's another argument that even if it is working it comes at
   a cost and we should move to @prefix anyway

   Ralph: but what _are_ the costs? I see huge costs in destabilizing a
   spec

   Mark: we're also talking about changing the processing model a bit
   ... currently we don't provide a way to import a bunch of mappings
   ... my main argument in favor of a new attribute is to add a feature
   to come closer to [the simplicity of] microformat

   Ben: I was trying to separate the two issues; new features vs. name

   Ralph: I don't think you can separate these questions now

   Mark: namespaces have never really been resolved in terms of
   attribute contents
   ... so with a new attribute we could avoid some of the mistakes of
   namespaces

   Ben: so if @prefix works exactly like @xmlns, are you leaning to
   preferring it?

   Manu, Shane: yes

   Manu: we're not talking about removing @xmlns; that would
   destabilize it
   ... just adding @prefix as an alternative

   Mark: the RDFa spec says that if @xmlns: is present, it should be
   processed
   ... we'd still process both @xmlns and @prefix
   ... in the CURIE spec I'm pretty sure we require that XML processors
   support @xmlns

   <ShaneM> CURIE spec says "When CURIES are used in an XML-based host
   language, and that host language supports XML Namespaces, prefix
   values MUST be able to be defined using the 'xmlns:' syntax
   specified in [XMLNAMES]. Such host languages MAY also provide
   additional prefix mapping definition mechanisms."

   Ben: in terms of the spec, we don't talk about HTML documents
   currently so I think we're safe adding @prefix
   ... we do have to talk about the precedence of @xmlns and @prefix
   ... if we specified that @xmlns has precedence then we'd have a
   level of backward compatiblity for old XHTML parsers

   Mark: sort-of; new parsers would generate more triples but the
   triples generated by an old parser would match that same subset
   generated by a new parser

   Ben: a note from this TF suggesting that @prefix is a way forward
   would carry some weight

   Mark: we could argue that @prefix is a token substitution before the
   RDFa processing is invoked

   <ShaneM> XHTML 1.2 could introduce @prefix

   Ben: but that would mean that the RDFa Recommendation no longer is
   sufficient to implement an RDFa processor

   <msporny> who's working on XHTML 1.2, Shane?

   Mark: if @prefix is not introduced by some group with some authority
   then the HTML WG [might not give it any attention]
   ... the XHTML2 WG could give this a home and then in the future we
   harmonize the two

   Ben: test cases using @prefix would have to live somewhere

   Mark: could be on a Wiki
   ... a Last Call comment on CURIE would allow the XHTML2 WG to be on
   the record
   ... as supporting it for some future version

   Ben: do we want to say that RDFa parsers should start supporting
   @prefix soon?
   ... if we want @prefix to be supported in both HTML and XHTML
   ... so we'd recommend that new markup use @prefix instead of @xmlns
   ... so some document at some time in the future should say how to
   write such a new RDFa parser

   Mark: given our recent experience of HTML5 discussions, it's asking
   for trouble if we base this on trying to find some accommodation
   ... whereas if we say we really believe this [independently], we
   have a stronger argument

   Ben: sounds like we'd want to update the RDFa specification to add
   @prefix to it

   <ShaneM> I think that we could successfully do this as a "PER"
   second edition of RDFa Syntax 1.0

   Ben: @xmlns would still be supported

   Ralph: it would be harmful for this group to push for XML documents
   that do not conform to the W3C Recommendation
   ... so I am opposed to adding @prefix without updating the
   Recommendation
   ... the cost of updating the Recommendation could be justified if
   the update included new features as well
   ... a possible new feature is the value syntax for @prefix

   Shane: the XHTML2 WG could update the RDFa Recommendation

   Ralph: yes, that's plausible

   Ben: so wiki pages, test cases, etc. should have large disclaimers
   right now saying @prefix is experimental
   ... path forward could be to keep this discussion in the wiki as
   experimental, talk with implementors, work out details in the
   experimental wiki page

   Manu: yes

   Mark: I'm a bit uneasy as there are documents being circulated that
   look like specifications when they should really be blogs
   ... and the wiki might start to look like a specification too
   ... the wiki shouldn't imply that we all agree on the content

   Manu: you want more than the "experimental" note on the wiki pages?
   ... "the existence of this page does not imply ..."

   Mark: might be worth having a higher-level page that links to these

   [adjourned]

Summary of Action Items

   [PENDING] ACTION: Ben to put up information on "how to write RDFa"
   with screencast possibly and instructions on bookmarklet. [recorded
   in [31]http://www.w3.org/2008/11/06-rdfa-minutes.html#action12]
   [PENDING] ACTION: Jeremy to demonstrate GRDDL with XHTML/RDFa once
   the NS URI is set up. [recorded in
   [32]http://www.w3.org/2008/09/11-rdfa-minutes.html#action03]
   [PENDING] ACTION: Manu to create TC to test @resource="[]" does not
   set object based on TC 123. [recorded in
   [33]http://www.w3.org/2009/01/08-rdfa-minutes.html#action14]
   [PENDING] ACTION: Manu to look at
   [34]http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2008D
   ec/0037.html [recorded in
   [35]http://www.w3.org/2009/01/08-rdfa-minutes.html#action15]
   [PENDING] ACTION: Manu to write summary for Semantic Web Use Cases
   for Ivan. [recorded in
   [36]http://www.w3.org/2008/09/11-rdfa-minutes.html#action09]
   [PENDING] ACTION: Mark create base wizard suitable for cloning
   [recorded in
   [37]http://www.w3.org/2008/09/11-rdfa-minutes.html#action12]
   [PENDING] ACTION: Mark to review reasoning on setting explicit
   about="" on HEAD and BODY [recorded in
   [38]http://www.w3.org/2008/12/18-rdfa-irc]
   [PENDING] ACTION: Mark to send Ben ubiquity related wizard stuff
   [recorded in
   [39]http://www.w3.org/2008/11/20-rdfa-minutes.html#action11]
   [PENDING] ACTION: Mark write foaf examples for wiki [recorded in
   [40]http://www.w3.org/2008/09/11-rdfa-minutes.html#action13]
   [PENDING] ACTION: Michael to create 'RDFa for uF users' on RDFa Wiki
   [recorded in
   [41]http://www.w3.org/2008/09/11-rdfa-minutes.html#action14]
   [PENDING] ACTION: Ralph or Steven fix the .htaccess for the XHTML
   namespace [recorded in
   [42]http://www.w3.org/2009/01/08-rdfa-minutes.html#action01]
   [PENDING] ACTION: Ralph think about RSS+RDFa [recorded in
   [43]http://www.w3.org/2008/09/11-rdfa-minutes.html#action15]

     [31] http://www.w3.org/2008/11/06-rdfa-minutes.html#action12
     [32] http://www.w3.org/2008/09/11-rdfa-minutes.html#action03
     [33] http://www.w3.org/2009/01/08-rdfa-minutes.html#action14
     [34] http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2008Dec/0037.html
     [35] http://www.w3.org/2009/01/08-rdfa-minutes.html#action15
     [36] http://www.w3.org/2008/09/11-rdfa-minutes.html#action09
     [37] http://www.w3.org/2008/09/11-rdfa-minutes.html#action12
     [38] http://www.w3.org/2008/12/18-rdfa-irc
     [39] http://www.w3.org/2008/11/20-rdfa-minutes.html#action11
     [40] http://www.w3.org/2008/09/11-rdfa-minutes.html#action13
     [41] http://www.w3.org/2008/09/11-rdfa-minutes.html#action14
     [42] http://www.w3.org/2009/01/08-rdfa-minutes.html#action01
     [43] http://www.w3.org/2008/09/11-rdfa-minutes.html#action15

   [DONE] ACTION: Manu to create design tests for @prefix and @profile.
   [recorded in
   [44]http://www.w3.org/2009/01/22-rdfa-minutes.html#action16]

     [44] http://www.w3.org/2009/01/22-rdfa-minutes.html#action16

   [DROPPED] ACTION: Ben to add public-rdfa examples to wiki and think
   of slightly improved top-level organization [recorded in
   [45]http://www.w3.org/2008/11/06-rdfa-minutes.html#action11]

     [45] http://www.w3.org/2008/11/06-rdfa-minutes.html#action11

   [End of minutes]
     _____________________________________________________


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