14:37:36 RRSAgent has joined #xproc 14:37:36 logging to http://www.w3.org/2008/03/20-xproc-irc 14:39:19 Meeting: XML Processing Model WG 14:39:19 Date: 20 March 2008 14:39:19 Agenda: http://www.w3.org/XML/XProc/2008/03/20-agenda 14:39:19 Meeting: 104 14:39:19 Chair: Norm 14:39:21 Scribe: Norm 14:39:23 ScribeNick: Norm 14:48:07 ht has joined #xproc 14:51:12 PGrosso has joined #xproc 14:55:56 tlr has joined #xproc 14:56:05 tlr has left #xproc 14:57:19 XML_PMWG()11:00AM has now started 14:57:26 +Norm 15:00:11 zakim, please call ht-781 15:00:12 ok, ht; the call is being made 15:00:13 +Ht 15:00:35 ...with-option, with-param, variables, I think that's most of it 15:01:10 +[ArborText] 15:01:21 richard has joined #xproc 15:01:48 alexmilowski has joined #xproc 15:02:15 +??P13 15:02:19 zakim, ? is me 15:02:19 +richard; got it 15:02:39 + +1.415.404.aaaa 15:02:52 Zakim, who's on the phone? 15:02:52 On the phone I see Norm, Ht, PGrosso, richard, +1.415.404.aaaa 15:03:02 MoZ has joined #xproc 15:03:07 Zakim, aaaa is alexmilowski 15:03:07 +alexmilowski; got it 15:03:24 Zakim, what is the code ? 15:03:24 the conference code is 97762 (tel:+1.617.761.6200 tel:+33.4.89.06.34.99 tel:+44.117.370.6152), MoZ 15:03:57 Regrets: Michael 15:04:18 + +95247aabb 15:04:21 +Murray_Maloney 15:04:27 Zakim, aabb is MoZ 15:04:27 +MoZ; got it 15:04:36 Present: Norm, Henry, Paul, Richard, Alex, Mohamed, Murray 15:04:40 Zakim, who's on the phone? 15:04:42 On the phone I see Norm, Ht, PGrosso, richard, alexmilowski, MoZ, Murray_Maloney 15:04:57 Topic: Accept this agenda? 15:04:57 -> http://www.w3.org/XML/XProc/2008/03/20-agenda 15:05:05 Accepted. 15:05:11 Topic: Accept minutes from the previous meeting? 15:05:11 -> http://www.w3.org/XML/XProc/2008/03/06-minutes 15:05:19 Accepted. 15:05:27 Topic: Next meeting: telcon 27 March 2008? 15:05:37 No regrets given. 15:05:48 Topic: Editor's alternate draft 15:06:01 -> http://www.w3.org/XML/XProc/docs/langspec.html 15:06:25 Norm attempts to summarize the alternate draft. 15:08:55 Henry: I think the new draft is a definite step forward. 15:09:14 Alex: I agree too. 15:10:29 Norm: I also added multi-step container 15:10:41 Mohamed: The p:variable looks like a step too. 15:11:58 Mohamed: Between steps we can have p:variable, which means we can have a change in step dependencies 15:12:07 Henry: I don't think it changes step dependencies. 15:13:20 Norm: Momahed is right. Because p:variable can contain p:step. 15:13:25 s/p:step/p:pipe/ 15:13:34 Henry: We could say, you can't do that. 15:13:43 ...Or we could say that the context document must be empty. 15:14:01 Mohamed: I think we can just say that p:variale is a step that exposes values. 15:14:14 Henry: I think that makes the scoping rules to write. 15:15:12 ...There seem to be two ways to think of this. One as a limited kind of step and one like XSLT variables. 15:15:41 Henry: So we could say that variables can only depend on lexically preceding ports. 15:15:47 ...but that doesn't work. 15:16:07 Henry: Very little is lost, and we still get almost all the intended benefit if we push variables back into the prologue. 15:16:35 ...We can leave them where they are, but they can't see sibling output ports. 15:17:24 s/Momahed/Mohamed/g 15:18:27 Henry: This puts option and variable in complementary distributions. 15:18:43 ...So you can have options or variables and perhaps only in pipeline declarations can have both. 15:18:56 Basically, variables need more work. 15:19:58 Mohamed: General opinion is that we've improved things, the alternate draft is definitely an improvement. 15:20:22 Proposed: We'll take the current altnerate draft as the starting point for further development. 15:20:24 s/p:variale/p:variable/ 15:20:36 Accepted. 15:20:46 s/rules to write/rules impossible to write/ 15:21:18 s/doesn't work/doesn't work, because _steps_ don't have to refer in lexical order/ 15:21:19 Norm: We need to resolve variable first, so let's skip the second item on the technical agenda for now. 15:21:40 Topic: Comment #129, fallback for V.next compound steps 15:22:13 Norm: As it stands, I think, an implementor can provide a new compound step, but that pipeline just won't run in any other processor. 15:23:33 Henry: I'm against p:fallback. In XSLT, p:fallback is restricted to instruction elements, the interior of templates. You cannot extend XSLT by defining a new kind of template element. You can't add my:supertemplate. There's no way to do that. 15:23:56 ...For my money, the compound steps and multi-containers are like that for us. There's just no way to do it that's backward compatible or interoperable. 15:24:20 ...The chances that you can define a workaround that are so small, that adding a whole bunch of mechanism to the language, just in case someone can is all out of proportin. 15:24:25 s/portin/portion/ 15:24:39 Henry: I'd like to go less far, I don't think we need to say anything at all about extension compound steps. 15:26:10 Norm: I'm sorry that we're forever closing the door, but I tend to agree with Henry. 15:26:47 Mohamed: We say that we're going to provide a file that contains the atomic step declarations. Can we also provide a small signature for compond steps? 15:26:51 s/compond/compound/ 15:27:26 Norm: I don't think so; you need to know the inputs and outputs in order to build the graph. 15:27:42 Henry concurs. 15:28:32 Henry: There is one more question: what is the answer to p:step-available(p:for-each) 15:28:43 Norm: I think it should be yes 15:28:46 Henry: I agree. 15:29:25 Henry: What about step-available for a pipeline that you've declared in scope. 15:29:31 Norm: I think that should be 'true' too. 15:30:02 Proposed: We won't make any attempt to provide interoperable extension compound steps. 15:30:27 Mohamed: Can't we try to make something possible from inside a when or a try-catch? 15:31:50 Norm: I don't think so, because you wouldn't know the bindings if it occured, for example, as the last step in a p:when subpipeline. 15:32:07 Returning to the proposal: accepted. 15:32:41 Topic: #128/#126 revised ontology and step names 15:33:51 Norm: I think we need to consider which steps need to have names. 15:34:19 http://www.w3.org/XML/XProc/docs/langspec.html#step-names 15:35:01 Henry: In section 2.1.1, do we want to endorse the idea of default names, and if so, what gets a name. 15:35:41 Henry: At the moment, all steps and all containers get names. I think that's fine as long as the odd containers aren't steps. 15:36:24 Norm: They used to need names, but they don't anymore. 15:36:47 Henry: Right, the rule that applies now is the Dan Connolloy rule that important things ought to have names. 15:37:41 Norm: The XProc Media Type comes into play here. 15:38:29 ACTION: Henry to consider the issue of names and the media type in general and come back with a proposal. 15:39:08 Topic: Issue #53, parallelism 15:41:09 Norm: Nokolai asks if we're content with a story that means a pipeline might succeed in parallel and fail in serial. 15:41:41 Henry: Yes, and we should provide an example. 15:41:59 ...Branch 1 computes a stylesheet and branch 2 uses it. 15:42:06 ...You should plumb them together. 15:43:02 Norm: You can use a variable or option to achieve serial execution. 15:43:56 Richard: One thing that wouldn't work would be to have an output that went from the first to the second but not consumed by the step. 15:43:59 Scribe isn't sure he got this right. 15:44:16 Henry: I don't want to have to dive into the details of the fine structure of step invocation. 15:44:59 Richard: I think there are some things that ensure it, but it isn't simply connecting a pipe. 15:45:44 Henry: I don't think there's anything you can do that will work for every plausible implementation strategy. 15:46:09 Some discussion of an implementation that prefetches all URLs, in order to acheive the XSLT gaurantee. 15:46:25 Murray: If you prefetch, you might get yesterday's answer. 15:46:37 Herny: That was my goal; to make sure that nothing the pipe did could change what I got. 15:47:04 s/Herny/Henry/ 15:47:55 Murray: We can say that when things are moving through the pipeline, they're in your control. Anytime you put them on the filesystem, you can get arbitrary results. 15:49:43 Richard: Provided I can constrain the outer environment, I can be sure the C runtime won't mess up the files. Are we going to say the same thing about pipelines. 15:49:53 Henry: No, I don't want to attempt to provide gaurantees about execution order. 15:50:04 Richard: I'm not disagreeing, I'm just exploring the possibilities. 15:50:29 ...There are some things that do gaurantee an order. A step inside a when can't start until the conditional has been evaluated. 15:50:38 ...The steps in a catch can't be started until after the try has failed. 15:51:16 Henry: I note that this is a counter example to my original claim, that the following is a perfectly acceptable implementation strategy: put all the steps in a separate thread and start them all. 15:51:51 Henry: In fact, this proposal has always been wrong. 15:53:49 Henry: Consider the following case: my XSLT step implementation says the minute you get started, look at the pipeline XSLT stylesheet cache and use it or start building an entry in the cache. 15:54:27 ...That's perfectly reasonable. That's sufficient to say that nothing you do that doesn't involve a choose or a try catch can prevent yesterday's stylesheet from being used. 15:54:45 Richard: Let's consider another example: we've got p:store and it writes to a URI and produces a result that contains that URI. 15:55:12 ...Do we expect that there will be any gaurantee that the result will not appear on the output port until the document has been written. 15:55:57 Norm: We probably want to fix p:store 15:57:29 ACTION: Editor to write a chapter or appendix on parallelism. 15:58:10 Henry: I thought something about non-side-effects might usefully go in p:pipeinfo, but I'm not sure anymore. 15:58:34 Topic: Any other business? 15:58:50 None. 15:58:54 -Murray_Maloney 15:58:54 -richard 15:58:55 -Norm 15:58:55 -MoZ 15:59:00 -PGrosso 15:59:01 RRSAgent, set logs world-visible 15:59:01 -alexmilowski 15:59:04 -Ht 15:59:06 XML_PMWG()11:00AM has ended 15:59:06 RRSAgent, draft minutes 15:59:06 I have made the request to generate http://www.w3.org/2008/03/20-xproc-minutes.html Norm 15:59:07 Attendees were Norm, Ht, PGrosso, richard, +1.415.404.aaaa, alexmilowski, +95247aabb, Murray_Maloney, MoZ 15:59:48 PGrosso has left #xproc 16:02:24 Norm, I just send something about p:variable 16:02:28 hope it will help 16:02:45 Cool. Thanks, MoZ 16:13:50 ht has joined #xproc 17:20:40 Zakim has left #xproc 17:57:42 RRSAgent, bye 17:57:42 I see 2 open action items saved in http://www.w3.org/2008/03/20-xproc-actions.rdf : 17:57:42 ACTION: Henry to consider the issue of names and the media type in general and come back with a proposal. [1] 17:57:42 recorded in http://www.w3.org/2008/03/20-xproc-irc#T15-38-29 17:57:42 ACTION: Editor to write a chapter or appendix on parallelism. [2] 17:57:42 recorded in http://www.w3.org/2008/03/20-xproc-irc#T15-57-29