- dfdl-wg - lists.ogf.org

Proposal - simplifying opaque types
by Mike Beckerle 10 Aug '07

10 Aug '07

Please review for discussion on a future call. Mike Beckerle STSM, Architect, Scalable Computing IBM Software Group Information Platform and Solutions Westborough, MA 01581 direct: voice and FAX 508-599-7148 assistant: Pam Riordan priordan(a)us.ibm.com 508-599-7046

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Minutes of 2007-07-18 meeting
by Mike Beckerle 08 Aug '07

08 Aug '07

DFDL WG teleconference 2007-07-18 Attendees: Mike Beckerle, Geoff Judd, Simon Parker We reviewed Simon's comments on Draft v019. We got through only a few of course. sp 15 - we recommend globally that the property name "repType" be changed to "representation" sp 18, 19 - Original assertion annotation syntax was based on schematron. We recommend departing from the schematron precedent and making the assertion syntax like so: <dfdl:assert timing="before/after" message="message text">element value is the predicate expression</dfdl:assert> or you can use test="expression string" if the test is simple enough. <dfdl:discriminator ..../> i.e., use an annotation element name to distinguish discriminators from other assertions instead of a discriminator="true" attribute. Simon observed that when using schematron, schematron's choices for assertions seem to be quite awkward to use, requiring clumsy quoting and such whenever the test expression itself contains string literals. We already have the precedent that for property bindings we can put expressions as the values of annotation elements by way of the optional property binding element syntax : <dfdl:property name="propertyName">....property value expression ...</dfdl:property> syntax. Making assertions consistent with this seems better than the schematron way. Note: Simon also suggested a <dfdl:require .../> annotation - will post to wiki example. The purpose of this seems to be to specify constant data (aka "markup" to some people) that is found in the data syntax, but is not part of the logical model. MikeB suggested we already have hidden elements to do this, but couldn't point to the example in the draft spec. We'll debate on the wiki. sp23 - we recommend removing the constraint saying the result must be a single node. Note that where the return result of an expression is constrained, we need to be explicit about it. There will be many contexts where an expression must return a single node value of a specific type, and we need to be clear about those cases. sp24 - we should revisit the constraints on the XPath expressions we allow. The problem here is that we don't need a full XPath 2.0 language expressive power, and since an XPath 2.0 implementation is quite burdensome for implementors, we'd like to make the DFDL spec not simply subsume XPath 2.0, but be easier to implement than that. This is a case where just being consistent with existing standards is probably not the way to go. We can say that we want our language to be consistent with XPath 2.0, but a subset is very reasonable for DFDL. MikeB's example is the flattner, the XPath "**" path component. We simply don't need this. Recommend: we need rationale in the spec here to motivate why it's not just XPath 2.0 in its entirety, and we need to be very precise about the definition of the subset. ------------------------------------------------------------------------

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No WG call on 2007-07-25
by Mike Beckerle 24 Jul '07

24 Jul '07

Many people are already known to be unable to make our approximately weekly call on 7/25 so let's cancel it right now. Next call on 8/1. Tentative agenda: continue review of Simon's comments on draft 019, and wiki discussion of missing/default topic. Mike Beckerle STSM, Architect, Scalable Computing IBM Software Group Information Platform and Solutions Westborough, MA 01581 direct: voice and FAX 508-599-7148 assistant: Pam Riordan priordan(a)us.ibm.com 508-599-7046

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Session at next OGF
by Mike Beckerle 18 Jul '07

18 Jul '07

I requested a 90 min session for us. Deadline is next week and I'll be out then. We have to decide fairly soon, if we want to use this spot, but I didn't want to get excluded by spacing out on the request deadline. ...mikeb Mike Beckerle STSM, Architect, Scalable Computing IBM Software Group Information Platform and Solutions Westborough, MA 01581 direct: voice and FAX 508-599-7148 assistant: Pam Riordan priordan(a)us.ibm.com 508-599-7046

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This week's DFDL WG meeting
by Mike Beckerle 17 Jul '07

17 Jul '07

I will be unable to attend this week's call. Martin said he also would be unable to attend. However, Simon sent a marked up document last week (forwarded in this email) and the comments he made might be discussed this week if there is a quorum. E.g., he suggests reformulating the properties we use for length along the lines originally suggested by Kris Rose, i.e, eliminate the separate lengthUnits property to reduce coupling. Somehow Simon's version seems simpler though. ...mikeb Mike Beckerle STSM, Architect, Scalable Computing IBM Software Group Information Platform and Solutions Westborough, MA 01581 direct: voice and FAX 508-599-7148 assistant: Pam Riordan priordan(a)us.ibm.com 508-599-7046 ----- Forwarded by Mike Beckerle/Worcester/IBM on 06/27/2007 09:56 AM ----- "Simon Parker" <simon.parker(a)polarlake.com> 06/20/2007 09:52 AM To Mike Beckerle/Worcester/IBM@IBMUS, "Martin Westhead" <westhead(a)avaya.com> cc Subject DFDL specification comments Good afternoon. As long promised, I've read the specification and embedded some comments and suggested corrections with 'Track changes' switched on. I have some observations that don't fit well in those little yellow boxes, so I hope to air them on the wiki. I see significant opportunities for simplifying the language and its specification in the area would call 'composability' (encompassing 'Kernel DFDL' and 'Layers'). In short: find a general way to define complex structures as groups of simple fields. I've already offered to try to find an alternative technique for specifying parser semantics, but haven't made much progress with that yet. Some ideas occurred to me as I read about defaults, null values and so on. It's a smaller topic and maybe an easier starting point, so I created a wiki page. Like everyone, I've not much time to devote to this interesting and worthwhile project. My contributions may seem sketchy, terse or ragged, but they're well meant. More later, Simon Simon Parker Software Consultant PolarLake 80 Harcourt Street Dublin 2, Ireland Phone +353 (1) 449-1075 Fax +353 (1) 449-1011 Web http://www.polarlake.com/ The information transmitted in this email is intended for the addressee only and may contain confidential and/or privileged material. Any review, retransmission, dissemination, reliance upon or other use of this information by persons or entities other than the addressee is prohibited. If you think, for any reason, that this message may have been addressed to you in error, we would ask you to notify the sender immediately by return email and delete the material. PolarLake Limited | Registered in Dublin, Ireland | Number 357324 | Registered office as above.

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Can't attend DFDL meeting today 2007-07-11
by Mike Beckerle 11 Jul '07

11 Jul '07

I am sorry I am overcommitted today and cannot attend the OGF DFDL call today. I know other IBMers are also committed to the same meeting, so I suggest we cancel. I just wanted to emphasize that missing a few meetings of late by myself and the other IBMers should not be construed as any loss of enthusiasm about DFDL by IBM. In fact quite the opposite. DFDL is on the agenda of some of the meetings I have today that unfortunately conflict with our OGF call. The problem is just that these mid-day east-coast US hours are very precious because of the way the time zones lay out from California to the UK, and so there are, alas, many conflicts during these times. ...mikeb

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AUTO: Brian Petrini is on vacation in Tibet until July 5th(returning 07/05/2007)
by Brian Petrini 27 Jun '07

27 Jun '07

I am out of the office until 07/05/2007.. Hello, I'm vacation in Tibet from Tuesday June 26 - Thursday July 5, 2007, during which I'm doubtful I'll have any access to email. For anything urgent, please contact my manager Sam Kaipa (kaipa(a)us.ibm.com) I'll respond as soon as I can. Thanks, -Brian Note: This is an automated response to your message dfdl-wg Digest, Vol 10, Issue 4 sent on 6/27/07 6:57:05. This is the only notification you will receive while this person is away.

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DFDL WG
by Westhead, Martin (Martin) 27 Jun '07

27 Jun '07

Hi Folks, I'm afraid I cannot get to this weeks call. Martin *Dial-in Number: 8777602813 *Dial-in Toll Number: 7706595626 *Conference Code: 95697 Helpful Keypad Commands: * *0 Operator Assistance - conference * 00 Operator Assistance - individual * *6 / #6 Mute/Unmute - individual Dr. Martin Westhead | Technical Lead, Assured Networks Group, Milpitas, CA | westhead(a)avaya.com <mailto:westhead@avaya.com> |+1 408-577-7810 | AVAYA

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DFDL Call today
by Westhead, Martin (Martin) 20 Jun '07

20 Jun '07

Hi Folks, I can join the call, but I expect to be half an hour late (sorry). Martin *Dial-in Number: 8777602813 *Dial-in Toll Number: 7706595626 *Conference Code: 95697 Helpful Keypad Commands: * *0 Operator Assistance - conference * 00 Operator Assistance - individual * *6 / #6 Mute/Unmute - individual Dr. Martin Westhead | Technical Lead, Assured Networks Group, Milpitas, CA | westhead(a)avaya.com <mailto:westhead@avaya.com> |+1 408-577-7810 | AVAYA

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Today's DFDL call - sorry cannot attend 2007-06-20
by Mike Beckerle 20 Jun '07

20 Jun '07

I cannot attend the call today due to an unmovable conflicting meeting of high urgency. ...mikeb

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