15:57:59 RRSAgent has joined #tagmem 15:57:59 logging to http://www.w3.org/2007/04/23-tagmem-irc 15:58:20 Agenda: http://lists.w3.org/Archives/Public/www-tag/2007Apr/0077.html 15:58:27 (that's the archival one) 15:59:36 The link to the minutes works for me: 15:59:38 did we make a new issue near CURIEs? who has the ball, anyone? 15:59:43 http://www.w3.org/2001/tag/2007/04/16-minutes.html 15:59:44 yes, I fixed it, Norm 15:59:46 Ah 16:00:02 I couldn't tell. I think maybe Henry has the ball on CURIEs 16:00:39 16 apr minutes don't have a link to previous minutes. :-/ 16:00:45 +DanC 16:01:59 +Raman 16:02:39 Topic: Convene, review agenda 16:02:52 Regrets: Stuart 16:03:03 ht has joined #tagmem 16:03:18 zakim, please call ht-781 16:03:18 ok, ht; the call is being made 16:03:20 +Ht 16:03:28 +[IBMCambridge] 16:03:33 zakim, [IBMCamrbidge] is me 16:03:33 sorry, noah, I do not recognize a party named '[IBMCamrbidge]' 16:03:58 zakim, [IBMCambridge] is me 16:03:58 +noah; got it 16:04:06 +Norm 16:05:12 Regrets for 30 April - I will be in Nashville 16:05:20 Next Telcon: Propose: 30rd April -- scribe: Rhys? 16:06:24 Hmmm 16:07:15 +DOrchard 16:08:48 dorchard has joined #tagmem 16:09:11 scribenick: dorchard 16:09:15 scribe: dorchard 16:09:45 RESOLVED: to meet next 30 Apr, Rhys to scribe, Stuart to chair. 16:10:07 -> http://www.w3.org/2001/tag/2007/04/16-minutes.html minutes 16 apr 16:10:20 APPROVED: minutes 16 Apr 16:12:26 agenda + HASTAC, DanC and HT 16:13:47 q+ for an agenda item 16:13:57 q+ to add an agendum 16:14:16 http://www.pacificspirit.com/blog/2007/04/19/forwards_compatibility_with_version_s_requires_version_mapping 16:14:46 APPROVED: Agenda as proposed in http://www.w3.org/2001/tag/2007/04/23-agenda.html 16:16:11 ack norm 16:16:11 Norm, you wanted to add an agendum 16:16:42 agenda + TAG May/June ftf agenda input, Nov tech plenary 16:17:19 Topic: Issue XMLVersioning-41 (and TagSoupIntegration-54) 16:17:57 ________________________________________ 16:18:31 "Marc de Graauw wrote an interesting article in XML.com on how to use version numbers in XML." -- http://www.pacificspirit.com/blog/2007/04/19/what_do_version_identifiers_identify 16:18:48 DO: I looked into HTML versionining Marc deGraaw (sp?) wrote an article on xml.com, spurred in part by our earlier discussions. He proposes you give not a single version, but indicate each version that you believe the document conforms to. 16:19:08 q+ to say that if you put a version number in an instance document, that's an assertion that it conforms to that version 16:19:08 DO: I had noted earlier the question of "what does a version number identify." His response gives one answer. 16:19:47 DO: I used an example with a middle name, in which the document conforms to both a version 1 and a version 2. What to do then? Label with v1 as the "oldest" it's compatible with? Version 2? 16:20:15 "The fundamental problem with a version # in a document is that it doesn't provide for a given document to be valid under more than one version." 16:20:25 DO: So, one of the problems with a single version number in a document is that it doesn't give a way to express compatibility with more than one version. 16:21:08 ack norm 16:21:08 Norm, you wanted to say that if you put a version number in an instance document, that's an assertion that it conforms to that version 16:21:14 DO: In XML, I've suggested using a single namespace name as the scope for a (set of?) compatible versions. 16:21:39 Norm: if you put a version number in an instance document, that's an assertion that it conforms to that version 16:21:46 q+ to say we're working our way back from a specific mechanism, to unearthing our assumptions about the languages 16:22:25 DO: My answer is, that all works out great, and is often what is used. 16:22:54 DO: The problem is that if you say "that's docbook v 4.2", what does a receiver that knows about version 4.1 do? How do they know whether your forward version is ok to process? 16:22:54 q+ to concur that much of the value of version identifiers is an implicit claim about other versions 16:23:42 q+ to say, Once you have a namespace, then you can dereference it and pick up information about how the version relates to other namespaces, whatever their version relationships. With ontologies, this can actually define term by term the compatability, so that complete compatible functionality can be boostrapped by client which just looks up the namespace and understands the language (such as OWL or a rules langauge). 16:23:53 q+ to say you have to make rel'ns explicit 16:23:57 DO: In my next article, I wrote about needing to know about the mappings from one version to another. For example, the rules for how we'll lable new version instances to indicate whether you can or cannot safely process wrt/ older rules. 16:25:37 NW: If you have that elaborate mechanism, that's fine, but it's also fine to say "if you don't know the version, process at your own peril". I wouldn't expect that to hold true across the board. 16:26:23 NM: hitting a lot of the right points. Discussion makes me nervous because the discussions focused on mechanisms very early. 16:26:46 NM: We're getting back to the fact that different languages, communities, and the calculus of evolution/versioning is different. 16:27:13 NM; We should expect that different communities are starting to play around with definitions of the language 16:27:28 NM: what WG grabbed version 5. 16:27:36 NM: could easily be very different 16:27:49 s/version 5/version 5, as opposed to version A/ 16:28:08 lost scribing ability. 16:28:15 noted, dorchard . I'll deal. 16:28:51 The versioning system is very much something which depends on pre-agreed conventions across the language family. All kinds of thing are possible, but they must be agreed. Eg for DocBook they could and for HTML they have been defined. XML schema could be* and OWL is used to write the conventins down machine-processably. 16:29:14 NM: for each it will be different 16:29:19 ack danc 16:29:19 DanC, you wanted to concur that much of the value of version identifiers is an implicit claim about other versions 16:29:35 NM: could be single version #, multiple versions, etc. 16:29:48 DC: there are often implicit claims 16:29:51 DC: I concur that much of the value of a version ID is what's implicit in knowing the relationship to other versions. 16:30:05 ack noah 16:30:05 noah, you wanted to say we're working our way back from a specific mechanism, to unearthing our assumptions about the languages 16:30:06 q? 16:30:09 ack timbl_ 16:30:11 timbl_, you wanted to say, Once you have a namespace, then you can dereference it and pick up information about how the version relates to other namespaces, whatever their version 16:30:15 ... relationships. With ontologies, this can actually define term by term the compatability, so that complete compatible functionality can be boostrapped by client which just 16:30:19 ... looks up the namespace and understands the language (such as OWL or a rules langauge). 16:30:53 TBL: I agree, that a lot of what's important about version numbers is what you've agreed about them in advance. 16:31:11 TBL: In HTML, we've agreed about ignoring tags (and something about version numbers that the scribe missed) 16:31:49 Once you have a namespace, then you can dereference it and pick up information about how the version relates to other namespaces, whatever their version relationships. With ontologies, this can actually define term by term the compatability, so that complete compatible functionality can be boostrapped by client which just looks up the namespace and understands the language (such as OWL or a rules langauge). 16:31:52 TBL: If you've got a namespace, then in essence the version number is a URI, which puts you in a different and interesting world. 16:32:07 TBL: You can use the URI to look things up. 16:32:36 TBL: Can express relationships between languages, such as schema, then can do mapping 16:32:37 TBL: You can't necessarily express that the semantics of the two languages are the same, but you can at least go as far as using things like XML Schema to compare the syntaxs. 16:32:45 q+ to report progress on "DanC to ask Mimasa and Mark Birbeck about feasability of using substitution groups in XHTML modularization, cc public-xml-versioning" 16:32:59 TBL: Using OWL, you can exactly explain the relationship between versions. 16:33:01 TBL: OWL gives you a lot of power to express the relationship between two languages. You an find out exactly which pieces of two languages are the same and which not. 16:33:13 q+ 16:33:33 TBL: That's one of the reasons I'd like to get onto semweb in the tag, as it gives us the tools for a more interesting discussion of versioning. 16:33:36 ack ht 16:33:36 ht, you wanted to say you have to make rel'ns explicit 16:33:37 TBL: Why I want to talk more about Semantic Web so we can talk about these powerful mechanisms 16:33:56 HT: What Tim said, but with a different spin: 16:34:23 HT: The only thing you can say reliably given a version in an instance is that, if it's one you know about or expect, you know what to do. 16:35:03 HT: Unless you have an explicit agreement about the version asserted and some other, you can't draw any conclusions. 16:35:09 ack dorchard 16:35:22 HT: I agree with Tim that machine-readable descriptions of the relationship are desirable. 16:35:54 DO: I think people have an implicit belief about what version markers identify. If that were made more explicit, users would have clearer idea of what was being conveyed. 16:36:12 q+ to advocate documenting version patterns, e.g. "we only make incompatible changes in major versions" 16:36:38 DO: Consider XML. In the XML declaration, it says that if you see version="1.0" you'll be able to parse it. Maybe you would have better forwards compatibility if it had said you could ignore what you didn't understand. 16:37:19 DO: There's a general language issue here. We've talked about defined and accept sets for languages. That's about content. Hasn't addressed the issue of how software will deal with it. 16:37:40 ack danc 16:37:40 DanC, you wanted to report progress on "DanC to ask Mimasa and Mark Birbeck about feasability of using substitution groups in XHTML modularization, cc public-xml-versioning" and to 16:37:43 ... advocate documenting version patterns, e.g. "we only make incompatible changes in major versions" 16:38:11 And if XML had said "if you see version=1.*" you will be able to parse the document 16:38:14 I think what I said is consistent with what DO just said 16:38:26 DC: Regarding the fact that there's a versioning architecture for HTML that doesn't apply more general. True I suppose, but our audience is looking for advice on general good practice. 16:38:46 DC: Perhaps giving a name to the "major version changes imply incompatible" idiom. 16:39:00 q+ to mention that people do version mapping with Schema *a lot*. 16:39:01 http://lists.w3.org/Archives/Public/public-xml-versioning/2007Feb/0000.html 16:39:09 DC: Regarding people not using XML Schema, substitution groups were mentioned awhile ago. I took that to the XML Versioning mailing list. 16:39:20 HT: I followed that thread. Was disappointed. 16:39:50 HT: Seemed like Dan asked "could you tell me about X". The answer (from Chris Lilley?) was "well, we used Y". 16:40:55 http://lists.w3.org/Archives/Public/public-schemata-users/ 16:41:11 DC: There's a list http://lists.w3.org/Archives/Public/public-schemata-users/ 16:41:47 NM: I hadn't known about that. As far as I know, http://lists.w3.org/Archives/Public/xmlschema-dev/ is where users are discussing W3C XML Schemas. 16:42:09 HT: Robin Berjon wrote a note about why schema doesn't work for versioning, and I answered. I need to unearth the thread. 16:42:30 q? 16:42:31 ACTION: Henry to unearth thread in which he and Robin Berjon discussed XML versioning 16:43:05 DC: Trying to decide what priority to give this. I don't think CDF is using substitution groups, perhaps not W3C XML Schema. 16:43:34 DO: I think it's high priority. How to use the mechanisms comes up repeatedly. 16:43:43 DO: That's what part 2 of the draft finding is about. 16:43:55 DC: How to do versioning with XML Schema? 16:43:58 DO: Yes. 16:44:04 DC: Did you look at CDF? 16:44:13 DO: Looked at, but didn't do much with. Perhaps should go back to it. 16:44:34 DO: I did note that substitution groups cause some issues for decentralized versioning. 16:44:50 DC: CDF says they're finished with Last Call. We didn't comment. 16:45:51 NM: Subst groups is interesting, perhaps TBL asked a question at a lunch, multiple inheritance not in v1.0 but in v1.1 16:46:12 s/v1/W3C XML Schema v1/g 16:47:06 NM: don't want to focus too much on W3C XML Schema Subst groups in TAG finding 16:47:07 q+ 16:47:15 DC: did anybody review this? 16:47:30 NM: I looked at CDF about a year ago, but not with XML Schema considerations in mind. 16:47:30 ack dorchard 16:47:30 dorchard, you wanted to mention that people do version mapping with Schema *a lot*. 16:47:48 NM: reviewed for TAG last year, but not specifically about subst groups 16:47:48 NM: reviewed for TAG last year, but not specifically about subst groups 16:48:20 NM: My point is that substitution groups are just one of the XML Schema mechanisms that can be used for some styles of versioning. The schema WG has studied many others. 16:49:13 DO: There's a lot work going on in my company and others to produce tools that start with an instance authored to one version of a language and help you map to use for other purposes. Lots of drag n drop, auto complete, etc. 16:49:16 q+ to suggest substitution groups may have special properties which make them architecturally unique, and so we should push them rather than other methods. being able to add extensions retrospectively (like adding SVG to HTML) , using URIs to name compatability bridges between grammars, etc. 16:49:17 q? 16:49:19 ack timbl_ 16:49:19 timbl_, you wanted to suggest substitution groups may have special properties which make them architecturally unique, and so we should push them rather than other methods. being 16:49:22 ... able to add extensions retrospectively (like adding SVG to HTML) , using URIs to name compatability bridges between grammars, etc. 16:49:33 DO: Customers are using these tools. 16:50:14 TBL: Pushing back on Noah's suggestion that "there are lots of people out there doing these things and we should be even handed." 16:51:01 TBL: I feel we invented some useful things in the TAG and substition groups turned out to be the XML Schema mechanism you needed to describe the particular idiom the TAG was advocating. 16:51:27 TBL: That's Web-like extensibility. We should push for it. 16:52:34 NM: That makes sense. As long as the motivation is "The TAG thinks this is a good way to use XML on the Web, and by the way subtitution groups are a good way to capture it in schemas." 16:54:07 HT: Maybe we should encourage the CDF and Schema WGs to come to consensus on the applicablity of substition groups for CDF. 16:55:57 TVR: Kevin Kelly is not only the WG chair, I know he did some work with schemas and WG. 16:56:08 DC: Dave or Noah, can you take the lead in contacting Kevin. 16:56:33 HT: Question is, are they using substitution groups, and why yes or no? Secondly, are there possibilities for discussion. 16:56:45 DC: Maybe better to just ask "what are you doing about versioning" 16:57:15 DO: The TAG's been working on versioning and has a draft of an XML-related part of the finding. We solicit input on how part 2 of the draft finding stacks up with respect to what CDF is doing. 16:57:26 DC: Is the substitution group pattern in there? 16:57:39 DO: Substitution groups, yes. The pattern I'm not sure about. 16:57:42 DC: URI please? 16:58:15 http://www.w3.org/2001/tag/doc/versioning-xml#iddiv263689376 16:58:40 http://www.w3.org/2001/tag/2006/10/04-tagmem-minutes#item05 16:58:47 DO: The part 2 draft is at http://www.w3.org/2001/tag/doc/versioning-xml#iddiv263689376 16:58:51 "This can only be used for incompatible extensions as the consumer must understand the new element and the schema that contains the substitution type." 16:59:10 DC: See also Vancouver minutes at http://www.w3.org/2001/tag/2006/10/04-tagmem-minutes#item05 17:00:32 q? 17:00:36 q+ to talk about schema 1.1 17:01:04 HT: This is not the pattern. It's usefull, but not the pattern we've been talking about. 17:01:46 HT: The Vancouver pattern was (what's the old TEI name?). Instead of writing content model for

as mixed over ,, etc. 17:02:27 HT: You write a schema that says

is mixed over abstract element , with etc being in the substitution group for . Anyone can add themselves to the group for . 17:02:32 TBL: What's the difference? 17:03:01 (I think my msg http://lists.w3.org/Archives/Public/public-xml-versioning/2007Feb/0000.html captures the pattern HT just spoke of, to the resolution of 1 or 2 paragraphs) 17:03:01 HT: Examples 24 and 25 are taking an element that has a wildcard and making a new one that makes it more explicit. 17:03:37 HT: The case

content model case is one in which the focus is upwards. I.e. what can you put into

. Another good example is data. 17:04:23 HT: You could make
as abstract? 17:04:49 TBL: That's not substitution groups. 17:05:13 HT: It's another style of using substitution groups. 17:05:26 DO: I need to get that into the finding. Would like to respond to this on the XML Versioning list. 17:06:06 ACTION: Dave Orchard to draft discussion of using substitution groups for examples like HTML

mixed content and/or

content. 17:06:30 DC: We will not have formal action on communicating with Kevin. 17:06:37 ack noah 17:06:37 noah, you wanted to talk about schema 1.1 17:07:41 NM: there's some stuff coming in schema 1.1 that pertains, directly and indirectly: (a) multiple inheritance with substitution groups, (b) changes to wildcards [missed example. darn.] 17:08:09 DC: Are the pertinent drafts public? 17:08:11 HT: Yes. 17:09:39 s/[missed example. darn.]/choice between subst. group head and lax wildcard is now possible, so you can get detailed evaluation of things added to the subst. group., but still allow other things/ 17:09:43 NM and DO discussion details of schema 1.1 wildcard/subst and example 24/25... 17:10:07 q+ 17:10:28 ack dorchard 17:11:00 DO: I was wondering about reviewing the versioning drafts. I'd like to talk about these the F2F. 17:11:15 TVR: About the F2F. I need the names so we can have badges made. 17:11:33 HT: Since I can now tell you that I'm coming, I think that completes our group. I believe everyone is coming. 17:12:36 ****SCRIBE NOTE TO SELF: MOVE DISCUSSION OF F2F BADGES TO THE END OF THE MINUTES **** 17:13:01 DC: I have an action to review definitions of backwards/forwards compatible. You can expect me to do that. 17:13:12 ACTION DanC: Review definitions of partial understanding, backward compatible, and forward compatible. [CONTINUES] 17:13:17 DC: I'll read more than that, but probably not a comprehensive review of the whole thing. 17:13:44 DC: How many pages to review? 17:14:37 Zakim, pick a victim\ 17:14:37 I don't understand 'pick a victim\', DanC 17:14:38 Zakim, pick a victim 17:14:38 Not knowing who is chairing or who scribed recently, I propose Norm 17:14:39 DO: I get 20 pages for part 2. 17:14:47 NM: My fonts are a bit larger. I get 30 pages for part 2. 17:15:13 DC: Norm, can you review the 2nd part? 17:15:23 NW: Yes, I'll do it. 17:15:39 DC: F2F starts May 31 and material is available now? 17:15:42 DO: Yes. 17:15:54 NW: I will review in time for telcon on 14 May. 17:16:14 NW: F2F is 30th of May? 17:16:19 DC: Yes, 30 May to 1 June. 17:16:48 http://www.w3.org/2001/tag/doc/versioning 17:16:51 http://www.w3.org/2001/tag/doc/versioning-xml 17:17:09 http://www.w3.org/2001/tag/doc/versioning-xml 26 March 2007 17:17:14 ACTION: Norm to review http://www.w3.org/2001/tag/doc/versioning-xml for discussion on 14 April telcon. 17:17:33 DO: Note that I've given undated URIs, so these may change out from under us. 17:17:39 DC: I encourage you to keep a change log. 17:17:42 DO: OK, starting now. 17:19:48 DC: Noah, have you commented recently? 17:20:20 NM: I think it's been awhile. I did read recently, but honestly feel I've commented a lot the past 2 years and would like to hear from others. 17:20:26 NM: Still, I'll do it if you like. 17:20:39 DC: What's up with the comments from Rhys? 17:20:56 DO: I have not gotten them. 17:21:23 DO: He sent me something privately on Thursday 12 April, and I suggested he respond to public list. 17:21:31 DC: I see, he said he had comments, but did not include them. 17:21:44 DO: I replied on 23 April. 17:21:50 DC: Today? 17:21:52 DO: Yes. 17:22:51 NM: Is there a problem with using proprietary formats? I'll be glad to help convert to PDF. 17:23:34 Zakim, pick a victim 17:23:34 Not knowing who is chairing or who scribed recently, I propose noah 17:23:38 Zakim, pick a victim 17:23:38 Not knowing who is chairing or who scribed recently, I propose DOrchard 17:23:41 Zakim, pick a victim 17:23:41 Not knowing who is chairing or who scribed recently, I propose noah 17:23:43 Zakim, pick a victim 17:23:43 Not knowing who is chairing or who scribed recently, I propose Ht 17:25:15 DO: I've been thinking some on version ids in HTML and XHTML. I've been thinking that the version mapping is critical to forwards compatibility. Backwards is easier, because you can code to recognize old stuff. 17:25:50 DO: What seems to be the status quo is to use the letters "HTML" in the doctype. Leads me to wonder how a 5.1 or 6 would be identified. 17:26:09 DO: That's one of the reasons I've been thinking about this issue of version mapping. 17:26:28 DO: Dan, can you help me understand if they're worrying about forwards compatibility. 17:27:34 DC: Yes, it's very important, but it's also the sort of hard problem that is not going to be easy for the group to drive to consensus. There are strong pros and cons on both the "identify versions" and the "don't identify" sides. 17:27:53 TVR: I think there should be some sort of identifier in the DOM, and that it should be serialized. 17:28:20 DO: Has the mapping discussion come up in terms of making statements in advance about 5.1 and future versions. 17:28:48 DC: Yes, indeed debating such compatibility mechansisms is a central focus of the group, though the terminology used might not always be the same we use in the TAG. 17:28:59 DO: How do I find the discussion. 17:29:13 DC: See thread starting with a Chris Wilson message. It's pointed to from the WG homepage. 17:29:17 DO: I'll look. 17:29:21 Zakim, next item 17:29:21 agendum 1. "HASTAC, DanC and HT" taken up [from DanC] 17:29:36 Zakim, close item 1 17:29:37 agendum 1, HASTAC, DanC and HT, closed 17:29:38 I see 1 item remaining on the agenda: 17:29:40 2. TAG May/June ftf agenda input, Nov tech plenary [from DanC] 17:30:18 -noah 17:30:20 -Ht 17:30:21 -Norm 17:30:22 DC: We will meet in one week with Rhys as scribe and Stuart as chair 17:30:23 -DOrchard 17:30:24 -DanC 17:30:26 DC: adjourned 17:30:36 -Raman 17:32:07 -TimBL 17:32:08 TAG_Weekly()12:00PM has ended 17:32:10 Attendees were TimBL, DanC, Raman, Ht, noah, Norm, DOrchard