IRC log of xproc on 2008-03-20

Timestamps are in UTC.

14:37:36 [RRSAgent]
RRSAgent has joined #xproc
14:37:36 [RRSAgent]
logging to
14:39:19 [Norm]
Meeting: XML Processing Model WG
14:39:19 [Norm]
Date: 20 March 2008
14:39:19 [Norm]
14:39:19 [Norm]
Meeting: 104
14:39:19 [Norm]
Chair: Norm
14:39:21 [Norm]
Scribe: Norm
14:39:23 [Norm]
ScribeNick: Norm
14:48:07 [ht]
ht has joined #xproc
14:51:12 [PGrosso]
PGrosso has joined #xproc
14:55:56 [tlr]
tlr has joined #xproc
14:56:05 [tlr]
tlr has left #xproc
14:57:19 [Zakim]
XML_PMWG()11:00AM has now started
14:57:26 [Zakim]
15:00:11 [ht]
zakim, please call ht-781
15:00:12 [Zakim]
ok, ht; the call is being made
15:00:13 [Zakim]
15:00:35 [Norm]
...with-option, with-param, variables, I think that's most of it
15:01:10 [Zakim]
15:01:21 [richard]
richard has joined #xproc
15:01:48 [alexmilowski]
alexmilowski has joined #xproc
15:02:15 [Zakim]
15:02:19 [richard]
zakim, ? is me
15:02:19 [Zakim]
+richard; got it
15:02:39 [Zakim]
+ +1.415.404.aaaa
15:02:52 [Norm]
Zakim, who's on the phone?
15:02:52 [Zakim]
On the phone I see Norm, Ht, PGrosso, richard, +1.415.404.aaaa
15:03:02 [MoZ]
MoZ has joined #xproc
15:03:07 [Norm]
Zakim, aaaa is alexmilowski
15:03:07 [Zakim]
+alexmilowski; got it
15:03:24 [MoZ]
Zakim, what is the code ?
15:03:24 [Zakim]
the conference code is 97762 (tel:+1.617.761.6200 tel:+ tel:+44.117.370.6152), MoZ
15:03:57 [Norm]
Regrets: Michael
15:04:18 [Zakim]
+ +95247aabb
15:04:21 [Zakim]
15:04:27 [MoZ]
Zakim, aabb is MoZ
15:04:27 [Zakim]
+MoZ; got it
15:04:36 [Norm]
Present: Norm, Henry, Paul, Richard, Alex, Mohamed, Murray
15:04:40 [Norm]
Zakim, who's on the phone?
15:04:42 [Zakim]
On the phone I see Norm, Ht, PGrosso, richard, alexmilowski, MoZ, Murray_Maloney
15:04:57 [Norm]
Topic: Accept this agenda?
15:04:57 [Norm]
15:05:05 [Norm]
15:05:11 [Norm]
Topic: Accept minutes from the previous meeting?
15:05:11 [Norm]
15:05:19 [Norm]
15:05:27 [Norm]
Topic: Next meeting: telcon 27 March 2008?
15:05:37 [Norm]
No regrets given.
15:05:48 [Norm]
Topic: Editor's alternate draft
15:06:01 [Norm]
15:06:25 [Norm]
Norm attempts to summarize the alternate draft.
15:08:55 [Norm]
Henry: I think the new draft is a definite step forward.
15:09:14 [Norm]
Alex: I agree too.
15:10:29 [Norm]
Norm: I also added multi-step container
15:10:41 [Norm]
Mohamed: The p:variable looks like a step too.
15:11:58 [Norm]
Mohamed: Between steps we can have p:variable, which means we can have a change in step dependencies
15:12:07 [Norm]
Henry: I don't think it changes step dependencies.
15:13:20 [Norm]
Norm: Momahed is right. Because p:variable can contain p:step.
15:13:25 [Norm]
15:13:34 [Norm]
Henry: We could say, you can't do that.
15:13:43 [Norm]
...Or we could say that the context document must be empty.
15:14:01 [Norm]
Mohamed: I think we can just say that p:variale is a step that exposes values.
15:14:14 [Norm]
Henry: I think that makes the scoping rules to write.
15:15:12 [Norm]
...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 [Norm]
Henry: So we could say that variables can only depend on lexically preceding ports.
15:15:47 [Norm]
...but that doesn't work.
15:16:07 [Norm]
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 [Norm]
...We can leave them where they are, but they can't see sibling output ports.
15:17:24 [MoZ]
15:18:27 [Norm]
Henry: This puts option and variable in complementary distributions.
15:18:43 [Norm]
...So you can have options or variables and perhaps only in pipeline declarations can have both.
15:18:56 [Norm]
Basically, variables need more work.
15:19:58 [Norm]
Mohamed: General opinion is that we've improved things, the alternate draft is definitely an improvement.
15:20:22 [Norm]
Proposed: We'll take the current altnerate draft as the starting point for further development.
15:20:24 [ht]
15:20:36 [Norm]
15:20:46 [ht]
s/rules to write/rules impossible to write/
15:21:18 [ht]
s/doesn't work/doesn't work, because _steps_ don't have to refer in lexical order/
15:21:19 [Norm]
Norm: We need to resolve variable first, so let's skip the second item on the technical agenda for now.
15:21:40 [Norm]
Topic: Comment #129, fallback for compound steps
15:22:13 [Norm]
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 [Norm]
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 [Norm]
...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 [Norm]
...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 [Norm]
15:24:39 [Norm]
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]
Norm: I'm sorry that we're forever closing the door, but I tend to agree with Henry.
15:26:47 [Norm]
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 [Norm]
15:27:26 [Norm]
Norm: I don't think so; you need to know the inputs and outputs in order to build the graph.
15:27:42 [Norm]
Henry concurs.
15:28:32 [Norm]
Henry: There is one more question: what is the answer to p:step-available(p:for-each)
15:28:43 [Norm]
Norm: I think it should be yes
15:28:46 [Norm]
Henry: I agree.
15:29:25 [Norm]
Henry: What about step-available for a pipeline that you've declared in scope.
15:29:31 [Norm]
Norm: I think that should be 'true' too.
15:30:02 [Norm]
Proposed: We won't make any attempt to provide interoperable extension compound steps.
15:30:27 [Norm]
Mohamed: Can't we try to make something possible from inside a when or a try-catch?
15:31:50 [Norm]
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 [Norm]
Returning to the proposal: accepted.
15:32:41 [Norm]
Topic: #128/#126 revised ontology and step names
15:33:51 [Norm]
Norm: I think we need to consider which steps need to have names.
15:34:19 [ht]
15:35:01 [Norm]
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 [Norm]
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]
Norm: They used to need names, but they don't anymore.
15:36:47 [Norm]
Henry: Right, the rule that applies now is the Dan Connolloy rule that important things ought to have names.
15:37:41 [Norm]
Norm: The XProc Media Type comes into play here.
15:38:29 [Norm]
ACTION: Henry to consider the issue of names and the media type in general and come back with a proposal.
15:39:08 [Norm]
Topic: Issue #53, parallelism
15:41:09 [Norm]
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 [Norm]
Henry: Yes, and we should provide an example.
15:41:59 [Norm]
...Branch 1 computes a stylesheet and branch 2 uses it.
15:42:06 [Norm]
...You should plumb them together.
15:43:02 [Norm]
Norm: You can use a variable or option to achieve serial execution.
15:43:56 [Norm]
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 [Norm]
Scribe isn't sure he got this right.
15:44:16 [Norm]
Henry: I don't want to have to dive into the details of the fine structure of step invocation.
15:44:59 [Norm]
Richard: I think there are some things that ensure it, but it isn't simply connecting a pipe.
15:45:44 [Norm]
Henry: I don't think there's anything you can do that will work for every plausible implementation strategy.
15:46:09 [Norm]
Some discussion of an implementation that prefetches all URLs, in order to acheive the XSLT gaurantee.
15:46:25 [Norm]
Murray: If you prefetch, you might get yesterday's answer.
15:46:37 [Norm]
Herny: That was my goal; to make sure that nothing the pipe did could change what I got.
15:47:04 [Norm]
15:47:55 [Norm]
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 [Norm]
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 [Norm]
Henry: No, I don't want to attempt to provide gaurantees about execution order.
15:50:04 [Norm]
Richard: I'm not disagreeing, I'm just exploring the possibilities.
15:50:29 [Norm]
...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 [Norm]
...The steps in a catch can't be started until after the try has failed.
15:51:16 [Norm]
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 [Norm]
Henry: In fact, this proposal has always been wrong.
15:53:49 [Norm]
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 [Norm]
...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 [Norm]
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 [Norm]
...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]
Norm: We probably want to fix p:store
15:57:29 [Norm]
ACTION: Editor to write a chapter or appendix on parallelism.
15:58:10 [Norm]
Henry: I thought something about non-side-effects might usefully go in p:pipeinfo, but I'm not sure anymore.
15:58:34 [Norm]
Topic: Any other business?
15:58:50 [Norm]
15:58:54 [Zakim]
15:58:54 [Zakim]
15:58:55 [Zakim]
15:58:55 [Zakim]
15:59:00 [Zakim]
15:59:01 [Norm]
RRSAgent, set logs world-visible
15:59:01 [Zakim]
15:59:04 [Zakim]
15:59:06 [Zakim]
XML_PMWG()11:00AM has ended
15:59:06 [Norm]
RRSAgent, draft minutes
15:59:06 [RRSAgent]
I have made the request to generate Norm
15:59:07 [Zakim]
Attendees were Norm, Ht, PGrosso, richard, +1.415.404.aaaa, alexmilowski, +95247aabb, Murray_Maloney, MoZ
15:59:48 [PGrosso]
PGrosso has left #xproc
16:02:24 [MoZ]
Norm, I just send something about p:variable
16:02:28 [MoZ]
hope it will help
16:02:45 [Norm]
Cool. Thanks, MoZ
16:13:50 [ht]
ht has joined #xproc
17:20:40 [Zakim]
Zakim has left #xproc
17:57:42 [Norm]
RRSAgent, bye
17:57:42 [RRSAgent]
I see 2 open action items saved in :
17:57:42 [RRSAgent]
ACTION: Henry to consider the issue of names and the media type in general and come back with a proposal. [1]
17:57:42 [RRSAgent]
recorded in
17:57:42 [RRSAgent]
ACTION: Editor to write a chapter or appendix on parallelism. [2]
17:57:42 [RRSAgent]
recorded in