- From: Norman Walsh <ndw@nwalsh.com>
- Date: Thu, 29 Oct 2009 12:18:28 -0400
- To: public-xml-processing-model-wg@w3.org
- Message-ID: <m2pr86npgr.fsf@nwalsh.com>
See http://www.w3.org/XML/XProc/2009/10/29-minutes
[1]W3C
- DRAFT -
XML Processing Model WG
29 Oct 2009
[2]Agenda
See also: [3]IRC log
Attendees
Present
Norm, Mohamed, Vojtech, Henry
Regrets
Paul
Chair
Norm
Scribe
Norm
Contents
* [4]Topics
1. [5]Accept this agenda?
2. [6]Accept minutes from the previous meeting?
3. [7]Next meeting: face-to-face 2-3 November, Santa Clara, CA, US
4. [8]Agenda topics for the face-to-face
5. [9]Latest editor's draft
* [10]Summary of Action Items
--------------------------------------------------------------------------
Accept this agenda?
-> [11]http://www.w3.org/XML/XProc/2009/10/29-agenda
Accepted.
Accept minutes from the previous meeting?
-> [12]http://www.w3.org/XML/XProc/2009/10/22-minutes
Accepted.
Next meeting: face-to-face 2-3 November, Santa Clara, CA, US
Henry will be a little bit late on Monday morning.
Agenda topics for the face-to-face
Norm: I think we need consider the state of the draft, the test suite,
coverage, implementation status.
... and beginning to draft our PR request.
... One bit of good news in that regard, Liam noted that it's unheard of
for a spec to go from LC to PR.
... And also the default XML processing model.
... Let's do default XML processing model on Tuesday morning so Mohamed
can participate by phone.
Mohamed: I'll also try to have some ideas in place for not going back to
Last Call.
Latest editor's draft
-> [13]http://www.w3.org/XML/XProc/docs/langspec.html
Norm: Any comments on the latest editor's draft?
Vojtech: I have no big problems with the new versioning scheme, so I'm
fine with that.
... I think relaxing the rules for with-option/with-param is a good thing.
... I think this small change to parameter input ports will also make
things easier.
Norm: Right. With respect to not breaking existing pipelines, we have the
required version attribute issue.
Henry: I don't think the required version attribute has any impact on the
LC to PR question.
... If we can make the argument that there's good interoperability that's
been demonstrated by the end of the LC period then we can go to PR, the
scale of the change isn't relevant.
... Personally, I've changed my mind three times int he last two minutes,
I don't know what the right answer is.
Norm: Does anyone know what the right answer is? Is anyone strongly in
favor of one position or the other?
Vojtech: One breaks existing pipelines, but making it required may be odd.
Moving a pipeline out of a library will require adding the attribute.
Norm: But that cuts both ways, if you don't make it required then a
pipeline from a V2 library silently becomes a V1 pipeline.
Some discussion about whether or not mixing pipelines of different
versions is a problem.
Mohamed: So for example you can have a pipeline A in V1 that imports a
pipeline B in V2.
Norm/Vojtech: Yes
Mohamed: But what's the value of the static context for the version.
Vojtech: It's a static value, it's not dymanic at all.
Mohamed thinks we're rehashing a discussion from several years ago.
Mohamed: What does this mean: <p:pipeline version="1.0"> ... <p:xslt
use-when="p:system-property('p:version') = '2.0'">...
Norm: I think a processor loads that pipeline with the V1 rules: no
unknown steps, no unknown options, etc. But at runtime, if it really is a
V2 processor then the use-when will return true.
... If you want to run a V2 pipeline, you have to specify version="2.0";
if you want it to work in a V1 processor, you have to protect those
regions that aren't fowards-compatible with use-when.
Henry: If I'm a V1 processor and I encounter a V1 pipeline, then I know
what to do. If I'm a V2 processor and I encouter a version="1.0" pipeline
and I encounter a V2 step then...
... So if I encounter a step that I do understand, but isn't in V1, I have
to throw an error. Is that clear?
Norm: No, I think that's probably not clear enough.
Henry: I think we should clarify that: a V2 step is an error in a pipeline
being run in backwards-compatibe V1 mode, even if the processor recognizes
it.
Norm: yes.
Some discussion about what it even means for this spec to have a backwards
compatible section given that there are no preceding versions.
Vojtech: Now that we have this version attribute and the p:version system
property, and something similar for the xpath-version, I wonder if we
shouldn't make p:version a sequence like p:xpath-version.
Norm: Uhm...
... I'm not sure I see the value given that XProc version really only
determines what constitutes a static error
Vojtech: But what about a step you want to have in V1 and V3, but not V2.
Mohamed: What about a future where there's a 2.0 "iso" version and a 2.0
"w3c" version.
Norm: I'm reluctant to go there.
Mohamed: So suppose there's a 1.1 and a 2.0.
... Some implementations only implement 2.0 and 1.0 backwards
compatibility and others implement 1.1
Vojtech: There's a small asymetry between the system properties.
Norm: What do others think about this assymetry?
Vojtech: I think in the use-when you may not have enough information to
decide which part of the pipeline to include.
Norm: How?
Vojtech: I'm not sure, but soemthing like a processor that implements 1.0
and 2.0 but not 1.1. In use-when you can't test this.
Norm: Fair enough.
... XPath "=" comparisons are existential so I guess it wouldn't do any
harm.
Vojtech: Except in XPath 1.0 you'd get only the first one.
Norm: Ah. Yes.
Henry: All of the following are possible: I support V1, V2 and V1 in
backwards compatible mode, and only V2.
... The problem is that we've tied our hands here. We might have been
better off if we'd provided a function p:supports-version that returns
true or false. So you can find out by querying whether a particular
version is supported.
Norm: And a p:supports-xpath-version function?
Mohamed: That's what we proposed on May, 2008.
<MoZ> | Just thinking: Wouldn't it make sense to have an XPath extension
<MoZ> | function p:xpath-version-supported(version), similarly to
<MoZ> | p:psvi-supported()? Some of the processors will support only XPath
1.0,
<MoZ> | some 2.0, but not necessarily 1.0, etc., so perhaps it could be
useful
<MoZ> | to have access to this information in the pipeline.
<MoZ> I thought the resolution from last Thursday used only the system
<MoZ> property, I thought p:psvi-supported() whent away? I've never
<MoZ> understood how the system property and the function would ever be
<MoZ> different.
<MoZ>
[14]http://lists.w3.org/Archives/Public/public-xml-processing-model-wg/2008May/0134.html
Henry: The value of psvi support is a boolean, so there's never any
possibility of confusion.
... But versions aren't booleans. As quoted the answer above doesn't
really answer the question.
Mohamed: I think once you're dealing with an atomic value, there's no
problem. But once you have a sequence, there is a difference.
Norm: Given that implementors have to implement a few functions, I don't
see the harm in adding a few more.
Vojtech: What if you want to know all the versions.
Henry: I think having both the system property and the function is the
right resolution to this issue.
Proposal: The p:version system property returns a space separated list.
Add a p:version-available(xs:decimal) function and a
p:xpath-version-avaialable(xs:decimal) function to query for specific
versions.
Accepted.
Adjourned
Summary of Action Items
[End of minutes]
--------------------------------------------------------------------------
Minutes formatted by David Booth's [15]scribe.perl version 1.135 ([16]CVS
log)
$Date: 2009/10/29 16:17:58 $
References
1. http://www.w3.org/
2. http://www.w3.org/XML/XProc/2009/10/29-agenda
3. http://www.w3.org/2009/10/29-xproc-irc
4. http://www.w3.org/XML/XProc/2009/10/29-minutes#agenda
5. http://www.w3.org/XML/XProc/2009/10/29-minutes#item01
6. http://www.w3.org/XML/XProc/2009/10/29-minutes#item02
7. http://www.w3.org/XML/XProc/2009/10/29-minutes#item03
8. http://www.w3.org/XML/XProc/2009/10/29-minutes#item05
9. http://www.w3.org/XML/XProc/2009/10/29-minutes#item04
10. http://www.w3.org/XML/XProc/2009/10/29-minutes#ActionSummary
11. http://www.w3.org/XML/XProc/2009/10/29-agenda
12. http://www.w3.org/XML/XProc/2009/10/22-minutes
13. http://www.w3.org/XML/XProc/docs/langspec.html
14. http://lists.w3.org/Archives/Public/public-xml-processing-model-wg/2008May/0134.html
15. http://dev.w3.org/cvsweb/~checkout~/2002/scribe/scribedoc.htm
16. http://dev.w3.org/cvsweb/2002/scribe/
Received on Thursday, 29 October 2009 16:19:27 UTC