IRC log of xproc on 2009-05-28

Timestamps are in UTC.

14:47:59 [RRSAgent]
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logging to
14:48:00 [Zakim]
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14:48:04 [Norm]
Zakim, this will be xproc
14:48:04 [Zakim]
ok, Norm; I see XML_PMWG()11:00AM scheduled to start in 12 minutes
14:48:15 [Norm]
Meeting: XML Processing Model WG
14:48:15 [Norm]
Date: 28 May 2009
14:48:15 [Norm]
14:48:15 [Norm]
Meeting: 145
14:48:15 [Norm]
Chair: Norm
14:48:16 [Norm]
Scribe: Norm
14:48:18 [Norm]
ScribeNick: Norm
14:53:41 [MoZ]
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14:56:03 [PGrosso]
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14:59:51 [MoZ]
Zakim, this will be xproc
14:59:51 [Zakim]
ok, MoZ; I see XML_PMWG()11:00AM scheduled to start in 1 minute
14:59:57 [MoZ]
Zakim, what is the code ?
14:59:57 [Zakim]
the conference code is 97762 (tel:+1.617.761.6200 tel:+ tel:+44.117.370.6152), MoZ
15:00:43 [ht_gone_home]
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15:01:00 [ht]
zakim, please call ht-781
15:01:00 [Zakim]
ok, ht; the call is being made
15:01:01 [Zakim]
XML_PMWG()11:00AM has now started
15:01:02 [Zakim]
15:01:30 [Zakim]
15:01:45 [Zakim]
15:03:12 [Norm]
ht, can you run through the administrivia while I struggle to get off this other call?
15:03:23 [ht]
15:03:25 [Norm]
15:03:39 [ht]
zakim, who is on the call?
15:03:39 [Zakim]
On the phone I see Ht, PGrosso, Vojtech
15:03:52 [ht]
Moz, you calling in?
15:05:39 [Zakim]
15:06:03 [Norm]
Regrets: Alex
15:06:09 [Norm]
Zakim, who's on the phone?
15:06:09 [Zakim]
On the phone I see Ht, PGrosso, Vojtech, Norm
15:06:19 [Norm]
Present: Henry, Paul, Vojtech, Norm
15:06:26 [Norm]
Topic: Accept this agenda?
15:06:26 [Norm]
15:06:38 [Norm]
15:06:53 [Norm]
Topic: Accept minutes from the previous meeting?
15:06:53 [Norm]
15:07:02 [Zakim]
15:07:06 [Norm]
15:07:12 [Norm]
Present: Henry, Paul, Vojtech, Norm, Mohamed
15:07:28 [Norm]
Topic: Next meeting: telcon 4 June 2009
15:07:56 [Norm]
Paul is at risk, so is Norm
15:08:18 [Norm]
Henry gives regrets for 11 June
15:08:23 [Norm]
Henry to chair 4 June in Norm's absence
15:09:16 [Norm]
Topic: New public draft
15:09:18 [Norm]
Is expected today.
15:11:11 [Norm]
Topic: Face-to-face meeting
15:11:30 [Norm]
Is expected in Santa Clara at the upcoming W3C Technical Plenary meeting during the first week of November, 2009.
15:11:39 [Norm]
Topic: The question of unbound options
15:11:58 [Norm]
15:12:13 [Norm]
Norm: I think I've mostly come to terms with the fact that there's no pretty way out of this in V1.
15:12:31 [Norm]
Henry: I agree; so the question is which of the ugly ways do we move forward.
15:13:02 [Norm]
Norm: I think Vojtech's observation that try/catch conflates this case with other errors motivates me.
15:13:09 [Norm]
Henry: I'm motivated too.
15:13:31 [Norm]
Norm: I think the lowest hanging fruit solution is a new XPath extension function, p:option-available.
15:14:33 [Norm]
Norm summarizes
15:14:43 [Norm]
Henry: I don't have any problem with p:option-avaialable.
15:15:01 [Norm]
Henry: I'm prepared to make the case that we don't need to go back to last call if we add this as a "feature at risk"
15:15:07 [PGrosso]
15:15:31 [Norm]
Norm/Vojtech: This is easy to implement.
15:16:34 [Norm]
Henry: We haven't heard from James Fuller, but we haven't heard from him about anything recently.
15:17:20 [Norm]
Norm: Proposal: add this new extension function?
15:17:28 [Norm]
15:17:50 [Norm]
Norm: The other proposal was Mohamed's bound-like-this-option attribute on p:with-option
15:18:18 [Norm]
Henry: I couldn't see how that didn't just push the problem one level down.
15:20:32 [Norm]
Norm attempts to explain
15:22:06 [Norm]
Mohamed: It's a very particular use case that this covers.
15:22:54 [Norm]
Vojtech: In Mohamed's proposal, it takes the name of the option. What if we say that it takes an XPath expression and if that expression raises an error then the step will get an undefined value.
15:23:33 [Norm]
Norm: That will also mask other sorts of errors, like wrong number of function arguments
15:24:07 [Norm]
Henry: If we go that far, I want two additional attributes on p:with-option, @protected and @fallback.
15:24:21 [Norm]
...@protected is a boolean, if it's true then XPath errors in the select expression don't blow the pipeline.
15:24:48 [Norm]
...If @protected is true and there's no @fallback, you get undefined
15:24:57 [Norm]
...If @protected is true and there's an @fallback, you get the fallback.
15:25:08 [Norm]
...If @protected is false, you get the current behavior.
15:25:33 [Norm]
Henry: So to get what Mohamed proposes you write "protected=true' select='$foo'"
15:26:04 [Norm]
Norm: I'm a little more comfortable that way.
15:26:19 [Norm]
Vojtech: I don't think people will be using this feature a lot.
15:27:12 [Norm]
Norm argues that maybe we don't want to go *this* far in V1.
15:28:02 [Norm]
Henry: All this adds up to is: I think we should only do the p:option-available() and not Mohamed's suggestion or any of its refinements.
15:28:15 [Norm]
Norm: I agree.
15:28:52 [Norm]
Norm: Does anyone want to argue for more than p:option-available in V1?
15:28:56 [Norm]
None heard
15:29:08 [Norm]
Norm: Let's nail down the semantics just a little bit.
15:29:23 [Norm]
1. p:option-available() takes a single QName argument
15:29:44 [Norm]
2. It returns true if and only if there is an option with that name and that option has a value
15:29:51 [Norm]
s/a value/an in-scope value/
15:31:32 [Norm]
Henry: It should be p:value-available() or p:reference-valid or something like that if it works for any option/variable in scope.
15:31:54 [Norm]
Norm: I see. I guess value-available works for me.
15:32:12 [Norm]
15:33:18 [Norm]
Norm: I think the last question is...
15:33:36 [ht]
scribenick: ht
15:33:57 [ht]
Norm: does this return 'false' or throw an error if the supplied QName is not in scope at all?
15:34:17 [ht]
HST: Hunh? Oh yes, right -- well, helps the user more if it is an error
15:34:26 [ht]
... How hard is that?
15:35:24 [ht]
Vojtech: It's easy for me, but is it right?
15:35:51 [ht]
Mohamed: I think an error is the right thing . . .
15:36:16 [ht]
... Being consistent with other ...-available would be good
15:36:28 [ht]
... step-available doesn't support this distinction
15:37:15 [ht]
Vojtech: value-available would do more, because it checks a) if there is a var/opt and b) if it has a value
15:37:25 [ht]
Mohamed: OK, so, two functions?
15:37:59 [ht]
Vojtech: Perhaps, or perhaps a second argument to control the error . . .
15:38:28 [ht]
HST: I'm happy with all three options: hard semantics, two functions or a 2nd argument
15:38:37 [ht]
Vojtech: I'd prefer a 2nd argument
15:38:46 [ht]
Mohamed: Fine with me. . .
15:39:10 [ht]
HST: So, what is the 2nd argument called?
15:39:57 [ht]
HST: Do we have optional args in XPath
15:40:09 [ht]
15:40:23 [ht]
I want that to work
15:40:39 [ht]
... with whatever semantics we agree for the 2nd arg
15:41:18 [ht]
... So I guess I propose to call the 2nd arg 'allow-unknowns', with default False
15:42:35 [ht]
Vojtech: We've used fail-if-... elsewhere
15:42:50 [ht]
Mohamed: So 'fail-if-unknown' with default True
15:42:57 [ht]
HST: Works for me
15:45:37 [ht]
Norm: I don't fully see why this is necessary, but I can live with it
15:46:08 [ht]
Vojtech: I had some sense of dynamically-generated option names being tested
15:46:16 [Norm]
scribenick: norm
15:46:18 [ht]
Norm: I guess I would have just had it be 'soft'
15:46:45 [Norm]
Vojtech: I also wonder if the function throws an error, if we need a special error code.
15:46:54 [Norm]
Henry: We should be able to reuse an existing error.
15:47:18 [ht]
15:47:54 [Norm]
Norm: I'm happy either way.
15:48:03 [Norm]
Mohamed: I think the existing error is fine.
15:48:42 [Norm]
Vojtech: If we went this far, maybe there would be value in having a unique error code.
15:48:52 [Norm]
Mohamed: I'm ok either way.
15:49:01 [Norm]
Norm: Error codes are cheap, let's give it a new one.
15:49:49 [Norm]
Vojtech: There was another bug reported on xproc-dev.
15:50:24 [Norm]
...If an unused option refers to an unbound option, is that ok?
15:51:57 [Norm]
Norm: If you put a select expression is used in an option declaration, it's not evaluated then, it's evaluated when a step of that type is instantiated.
15:52:06 [Norm]
Norm: We don't have lazy eval of options and I don't think we need to add it.
15:52:09 [Norm]
Vojtech/Henry: No!
15:52:39 [Norm]
ACTION: Norm to clarify "is needed" in 5.7.2
15:53:22 [Norm]
Topic: Any other business
15:53:28 [Norm]
Norm: Our new draft has been publish.
15:53:45 [Norm]
15:53:50 [Zakim]
15:53:51 [Zakim]
15:53:51 [Zakim]
15:53:53 [Zakim]
15:53:53 [Zakim]
XML_PMWG()11:00AM has ended
15:53:54 [Zakim]
Attendees were Ht, PGrosso, Vojtech, Norm, MoZ
15:53:57 [Norm]
RRSAgent, set logs world-visible
15:54:00 [Norm]
RRSAgent, draft minutes
15:54:00 [RRSAgent]
I have made the request to generate Norm
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