Meeting: TAG Teleconference, February 14, 2005 zakim, who is on the phone? Chair: Vincent Quint On the phone I see Hoylen, Vincent, Ed_Rice?, Norm, DanC, Noah, DavidE +Roy_Fielding + +1.856.914.aabb zakim, aabb is Ashok +Ashok; got it zakim, who is on the phone? On the phone I see Hoylen, Vincent, Ed_Rice?, Norm, DanC, Noah, DavidE, Roy_Fielding, Ashok *** dezell has joined #tagmem +TimBL *** Hoylen has joined #tagmem zakim, davide is dezell +dezell; got it scribe: Noah *** Ashok has joined #tagmem +Mary_Holstege *** timbl has joined #tagmem *** MSM has joined #tagmem Present: Noah Mendelsohn, Vincent Quint, Roy Fielding, Tim Berners-Lee, Norm Walsh, Ed Rice, Hoylen Sue, David Ezell, Mary Holstege, Michael Sperberg-McQueen(MSM), Ashok Malhotra, David Orchard(late) * Norm was unable to reach DavidO, let voicemail zakim, please call Michael-Office ok, MSM; the call is being made +Michael Regrets: Henry Thompson zakim, who is here? On the phone I see Hoylen, Vincent, Ed_Rice?, Norm, DanC, Noah, dezell, Roy_Fielding, Ashok, TimBL, Mary_Holstege, Michael On IRC I see MSM, timbl, Ashok, Hoylen, dezell, holstege, Ed, Roy, noah, RRSAgent, Zakim, Vincent, DanC, Norm Topic: Schedules We will have a telcon next week on the 21st Dan Connolly will scribe next week. I'd like to see xml:id/C14N discussions on the agenda for next week Topic: Review of Minutes for 2/7 (ed sent something thursday?) http://www.w3.org/2005/02/07-tagmem-minutes.html VQ: Should we accept minutes of 2/7 that were released on Thursday: http://www.w3.org/2005/02/07-tagmem-minutes.html ? +DOrchard Dan: there is some miscellaneous stuff in there that should be cleaned up. ATTENDANCE: David Orchard joins the call VQ: We will not accept 2/7 minutes now. Will wait for cleaned minutes. ACTION: Ed Rice to clean up 2/7 minutes and either email or commit somewhere in CVS * RRSAgent records action 1 (2/7 is not I18N-happy. it's 7 Feb) ACTION 1=Ed Rice to clean up 7 Feb minutes and either email or commit somewhere in CVS (or 2005-02-07) * RRSAgent records action 1 replaced Topic: Telcon Scheduling VQ: Propose 1PM Eastern Time for future TAG Telcons Various members assent. 22 Feb *** dorchard has joined #tagmem * DanC pats self on back for WBS telcon tiddlywinks VQ: We have decided to schedule TAG telcons on Tuesdays at 1 PM Eastern time, starting Tues 22 Feb Topic: Topic Plenary ACTION Vincent: arrange bridge for 1pET tuesdays starting 22Feb * RRSAgent records action 2 Noah: REGRETS for 22 Feb. s/Topic: Topic/Topic: Tech/ Tim bl sends regrets for Feb 22 Dan: I was asked for input by Paul Downey VQ: work directly with the organizer if you have questions or concerns about the panel * MSM zakim, please mute Michael * Zakim Michael should now be muted VQ: Noah will be on future of XML panel * Norm wonders who's organizing that panel? Norm: I think I'm on the XML futures panel, if it's the same as the XML 2.0 panel (it's not called "XML 2.0" anywhere that I can see, norm. "Session 3: Where XML is Going, and Where it Should (or Shouldn't) Go" Moderator: Rich Salz. http://www.w3.org/2005/03/02-TechPlenAgenda.html ) Noah: FWIW, I don't think I'm specifically representing the TAG on future of XML. I was invited because of lightening talk I gave last year on XML 1.1 issues. VQ: we have been solicted to propose lightening talks at the Plenary. Any candidates? * MSM believes that the XML session is being organized by Liam Quin, but i could be wrong * DanC Zakim, mute me * Zakim DanC should now be muted * DanC brb... * noah I was contacted by Rich Salz on XML Futures. I think he's the one. VQ: OK, nothing specific on lightening talks here. * Norm notes he's already listed as a participat on the XML Futures panel, thanks. Topic: TAG F2F at Plenary VQ: We have TAG meeting on Monday morning of TP, with WS-Addressing meeting at the end of that. VQ: I will work on agendas etc. tomorrow morning. Suggestions welcome. Topic: TAG Liaisons during Plenary Week See: http://www.w3.org/2001/tag/2005/01/TechnicalPlenaryLiaisons.html for list of proposed meetings I am available for all liaison meetings listed. VQ: Propose Thurs. 11 AM for Core WG meeting. * Norm will be there, but I don't really think I count for this purpose :-) Noah: Doublebooked with Schemas Roy: available for all liaisons. Norm: will be there, and is on core. Ed: can attend. VQ: OK, we'll confirm that we will meet with them. ACTION: Vincent to confirm Thurs meeting at 11AM with Core WG * RRSAgent records action 3 VQ: Proposal for joint meeting with XML Schema WG Thurs after lunch DaveO: I will be there Norm: would like to be there, but may conflict with core Noah: will be there, on both groups ditto VQ: Vincent will be there Roy: will be there VQ: Resolved, we will meet with XML Schema on Thurs at 2 PM sorry missed the opportunity -- for how long? 1 hr? 2? VQ: Proposal to meet with QA WG. Discussion with chairs suggests best course is joint calls after the plenary. (I'm bummed about the scheduling of the TAG/WS-Addressing and TAG/CDF meetings. sigh.) (I'm bummed Dan will miss WSA) VQ: Compound Document group proposes to meet with us on Monday at 3PM * noah Dan, do you still want to be muted? I suspect you might be. * dorchard I'm also bummed dan will miss wsa. * DanC Zakim, unmute me * Zakim DanC should no longer be muted I've stepped away to deal with the heating guy. brb. Dan: says he's chairing other WG's Mon & Tues, how about Thurs.? VQ: Well, we already have 3 meetings on Thurs., could be hard Dan: OK, do it without me. Too bad. ACTION: Vincent to figure out whether and when we want to meet with Compound Documents group * RRSAgent records action 4 VQ: If you are interested in CDF meeting and have scheduling constraints, send me mail by tomorrow, 15 Feb. Topic: Extensibility and Versioning Discussion with XML Schema WG * noah Norm, feel like scribing? * noah I'll keep doing for now VQ: Dave, as editor of draft finding, please give us a TAG status report DO: the draft finding has been considerably refined from 2003 version. See http://lists.w3.org/Archives/Public/www-tag/2004Nov/att-0071/versioning-part1.html and http://lists.w3.org/Archives/Public/www-tag/2004Nov/att-0071/versioning-part2.html DO: Discusses some of the decisions a language designer would want to consider, and gives advice on making those decisions. Sample issues: do you want compatible or incompatible extensions, should owners of other Namespaces be able to extend your language. s/Sample/DO: Sample/ DO: which versions of schemas do producers and consumers have? DO: how does a consumer know which particular version a particular component is part of? DO: are you using new namespaces for new constructs? Spectrum of possibilities. DO: Compared to 2003, trying to provide somewhat more formal definitions of terms like language. DO: That was part 1. Part 2 discusses schema-specific issues, and in this case mainly W3C XML Schemas. DO: This cut focusses on W3C XML Schemas. Plan is to include RDF, OWL and Relax NG. Norm has been helping me with Relax NG. Hope is to put that in soon. q+ To update status a bit * Zakim sees noah on the speaker queue DO: Plan to spend a bit more time on this now that I'm back on the TAG VQ: Would someone from schema give us an update on your work. Ezell: We've been looking at this for several years. (this use cases thing is great... I only discovered it minutes before the telcon, though. has everybody else read it in detail? http://www.w3.org/XML/2005/xsd-versioning-use-cases.html) Ezell: Our mandate is to improve things in XML Schema 1.1 * noah Dan, thanks. The attention to use cases is among the reasons I've been encouraging tighter liaison between the two WGs on this issue * DanC q+ to ask if the problems with extensibility also relate to having a PSVI * Zakim sees noah, DanC on the speaker queue * MSM notes that recreating the functionality of DTDs in XSD 1.0 was not just a goal but a requirement. Ezell: XML Schema 1.0 was focussed more on expressing constraints. In Schema 1.1, we plan an explicit focus on frameworks for extensibility and versioning. * noah MSM: suggest you type your comments into IRC on DTDs. Saves me paraphrasing. Ezell: Schema WG has posted a number of documents including Ezell: Use cases http://www.w3.org/XML/2005/xsd-versioning-use-cases.html ack noah noah, you wanted to update status a bit * Zakim sees DanC on the speaker queue ack danc DanC, you wanted to ask if the problems with extensibility also relate to having a PSVI * Zakim sees no one on the speaker queue Noah: yes, just reminding that I am still working on my action to help Dave O. with higher level issues in the draft finding zakim, please unmute Michael Michael should no longer be muted Dan: does having a PSVI make it harder? I think some early Schema WG members thought so. q+ to comment on psvi * Zakim sees noah on the speaker queue ack noah noah, you wanted to comment on psvi * Zakim sees no one on the speaker queue q+ to say that in fact I think the PSVI is the key to support for versioning * Zakim sees MSM on the speaker queue -> An Approach for Evolving XML Vocabularies Using XML Schema http://lists.w3.org/Archives/Public/www-tag/2004Aug/att-0010/NRMVersioningProposal.html ack msm MSM, you wanted to say that in fact I think the PSVI is the key to support for versioning * Zakim sees no one on the speaker queue (what I hear is yes, folks are looking at interactions between PSVI and versioning) Ezell: I can't say much officially on behalf of the wg. PSVI is a fertile area for discussion. Noah: actually, there have been proposals to leverage the PSVI to help applications discover which content was truly expected (validated against explicit declaration) vs. being tolerated for forward compatibility (validated against some sort of wildcard or extensibility hook) ("the finding"=??) q+ to talk about parsers impl of partial validation * Zakim sees dorchard on the speaker queue ack dorchard dorchard, you wanted to talk about parsers impl of partial validation * Zakim sees no one on the speaker queue MSM: I don't share Dan's concern. I think indeed that David's draft findings fail to fully explore some of the positive potential of the PSVI. * noah MSM, did I get that right? DaveO: One reason draft finding doesn't talk much about partial validation is that in practice today's processors don't report the PSVI in detail. * noah MSM: Want to talk about RQ-144? DaveO: I was trying to talk about solutions that were practical today. MSM: one of our requirements (specifically RQ-144) for version 1.1 of XML Schema is to clarify the conformance requirements as to how much of the PSVI processors must support. MSM: We are seriously considering but not yet committed to also naming useful combinations so a processor could claim: "I report the Red subset." BTW, when I specification "optional", I mean both optional in the spec and optional in the impl. Amazingly, in general, not all software implements all required parts of specs. q+ to report on PSVI support * Zakim sees dezell on the speaker queue MSM: you can find pointers to proposals from the Schemas editorial page (http://www.w3.org/XML/Group/2004/06/xsd-ed-pointers.html - W3C Members only). * noah Dave: I think part of the idea is that if we give people a vocabulary for saying what you chose to do, that it becomes low overhead to say what you're doing in a precise way. ack dezell dezell, you wanted to report on PSVI support * Zakim sees no one on the speaker queue * MSM agrees with DO about the amazing behavior of implementers. FYI: link to definition of schema requirement 144 is http://www.w3.org/XML/Group/2002/07/xmlschema-1.1-current-reqs-list.html#WhichPSVIPropertiesReqd (member only) * dorchard Noah, I understand and support that idea. My point is just the reality of what impls do on specs has to be accounted for.. * DanC hopes DavidE meant that for the public record Ezell: At our schema meeting at Redwood shores many implementors were present, and all claimed to support full PSVI. * noah DaveO understood * noah Dan: are you worried that I'm disclosing something controversial? If so, I can check before we publish minutes * MSM does hope very much that DO will review the RQ-144 proposal and comment on the subsets defined DaveO: For the information of new tag members, I've been doing a fair amount of the work on the finding. VQ: How can we best coordinate with the Schema WG on this? * DanC noah I'm not worried about you; you're free to write down anything anybody says (unless they ask otherwise). I just don't know if DavidE is in the habit of publicly-recorded telcons DaveO: for a start, I think the scenarios (what I've called mine) and use cases (what the Schema WG has called theirs) are important * Norm wanders back, apologizes * dezell good point, I'll try to be circumspect. What did I say? * noah Vincent: note that I would like to follow through on the action I took in Cambridge to help push some higher level focus into part 1 of the draft finding. I will work with Dave on that. * noah dezell: if you're asking about Dan's question, I think he was afraid that we were inadvertently disclosing implementation plans for PSVI for particular vendors. Is that public? * noah I'm having a bit of trouble grokking Dave's point here...help in scribing on this one is welcome. q+ to embellish * Zakim sees dezell on the speaker queue DaveO: we need to understand, beyond use cases, which parts of this work the schema WG thinks is its responsibility dorchard: getting agreeement on the scenarios / use cases is really really important. Extensibility is not JUST a question of the schema langauge, or the schema, but systemic DaveO: we need to work together to figure out what behavior should be from a web arch perspective. DaveO: having the schema use cases public helps. DaveO: then there the nuts and bolts of what happens in Schema NG (presumably Schema 1.1 [scribe]), which is mostly the responsibility of the Schema WG DaveO: I think the mandate I've received is to explore many different schema languages. ack dezell dezell, you wanted to embellish * Zakim sees no one on the speaker queue * noah Noah notes that at some point, not necessarily today, he'd like to understand what the mandate really was for this work, and how much of it represents tag consensus as a mandate. I keep hearing conflicting annecdotes on that. Ezell: we agree very much that the use cases are important. Ezell: we've tried hard not to be self selecting in use cases, I.e., to not focus only on things we think we know how to solve or should solve on our own. Ezell: we shouldn't prejudge use cases as to which are the business of W3C XML Schema, per se. Ezell: it's in our charter to make sure that XML Schema 1.1 has a much better story on versioning. (our list of actions is a mess) (but it's worth noting that an action is continued explicitly) Ezell: I keep hearing form people in (my employer's group), the National Assoc. of Convenience stores, that they expect XML to make things simple, but versioning is a big challenge for them. Users do care. VQ: Noah, what was that you volunteered to do? Noah: to indeed fulfill the action I took at the Cambridge to work with Dave Orchard in exploring some higher level issues for the draft findings. VQ: new action? Noah: No, I think it's in the list somewhere. If not, we should add it, but I won't generate a duplicate now. VQ: Anyone with anything else on this topic? MSM: Yes. I think you're focussing on older processors/applications getting data conforming to newer schemas. MSM: Seems that you're worrying mainly about the case where the old processor can't get at the new schema and resulting PSVI. * DanC q+ * Zakim sees DanC on the speaker queue MSM: We think that there are use cases where you can get the new schema and use cases where you can't. DaveO: it seems to me the 80/20 case is where the software that did not evolve is not configured to pull new schemas or similar descriptions dynamically. Could happen, but not 80/20. MSM: are you saying what they have done or should do? * noah Noah wonders whether Dave is focussing unduly on web services use cases? Within an organization, I suspect new schemas do get around. * noah ...even when applications are not rewritten. DaveO: security models are a factor. MSM: we may need to agree to disagree MSM: I think there will be situations where people should fetch the new schema. DaveO: agreed in principle, but I'm not sure it's practical in enough cases to be worth major focus * DanC q+ to suggest findings or chapters list in http://lists.w3.org/Archives/Public/www-tag/2005Feb/0093.html * Zakim sees DanC on the speaker queue MSM: Another point. You seem to be assuming that applications will necessarily roll over and die when data is not valid per a schema. That's only one model. Many applications will fall back after a validation failure. MSM: So, there's a model in which the early schemas do not try to partially validate future extensions, but in which the applications have some other model as to how to proceed when the validation doesn't fully succeed. DaveO: I don't understand. MSM: I'll try again. The draft finding conflatest the set of documents that a given application will accept with those that are valid per its (preferred) schema. the finding seems to me to conflate two distinct notions: (1) the set of documents valid against schema v.N and (2) the set of documents application software will accept and process. * Norm wanders off again for another moment. :-( DaveO: I think you're saying there can be implicit schemas which are larger than (in your example) or smaller than the explicit schema written in a specific schema language. DaveO: I agree with that. Have been trying to figure out how to articulate that. And it's important to note that it's not really hard for parser-generator technology (and thus for code generators) to generate a parser that is more forgiving, more capacious, and accepts partially valid or invalid documents * DanC q? * Zakim sees DanC on the speaker queue * Norm comes back Tim: would the broader schema be for what the application accepts in its "longer lifetime", I.e. for all the future variants that the application will to some degree tolerate? Dave: Java code could add constraints tim, in the ideal case, yes, that larger 'set of all future documents' is what one might plausibly want the application software to accept. Tim: I'm raising the case where constraints are looser than you might think. ack danc DanC, you wanted to suggest findings or chapters list in http://lists.w3.org/Archives/Public/www-tag/2005Feb/0093.html ack DanC * Zakim sees no one on the speaker queue * Zakim sees no one on the speaker queue Noah(nonscribe) notes: we also have to watch for the fact that sometimes people introduce intentionally incompatibilities. Sometimes the v8 flavor of a language is intentionally incompatible with v1 of an application, because we know very old versions are not in use any more. "Extending and Versioning XML Languages Part 2: Schema Languages" Dan: I think your title in part 1 sounds broader than what you actually discuss. q+ * Zakim sees noah on the speaker queue DaveO: originally, this was going to be a one parter on using XML schema language to extend and version. People came back and said, please split it into a general and a specific. Dan: Norm wrote "consider the case of XSLT 2.0". That's a good idea, and I have a list of about 10. Here goes: Dan: XSLT extension functions Dan: Adding to HTML Dan: Adding

to HTML Dan: Adding and