Open Grid Forum: Data Format Description Language Working Group

OGF DFDL Working Group Call, July-15-2009

Attendees

Suman Kalia (IBM)
Steve Hanson (IBM)
Mike Beckerle (Oco)

Apologies
Alan Powell (IBM)
Peter Lambros (IBM)

Actions discussed and updated below.

Work items tidied up to reflect issue of draft 0.35.

Next call 22 July 14:00 UK

Meeting closed, 14:40

Current Actions:
No
Action
012
AP/SH: Update decimalCalendarScheme
10/9: Not allocated yet
17/9: No update
24/9: Add calendar binary formats to actions
22/10: No progress
16/1: proposal distributed and discussed. Will be redistributed
21/1: add locale,
04/02: changed from locale to specific properties
18/2: Need more investigation of ICU strict/lax behaviour.
08/04: Not discussed
22/04: AP to complete asap once the ICU strict/lax behaviour is understood.
29/04: No progress
06/05: No progress
13/05: Calendar has been added to latest spec version v034 but still a few details to clarify.
20/05: No Progress
27/05: No Progress
03/06: No Progress (low priority)
09/06: No Progress (low priority)
17/06: SH to check ICU code for lax calendar behaviour
24/06: no progress
01/07: no progress
15/07: no progress
026
SH: Envelopes and Payloads
08/04: Not discussed explicity, but recursive use of DFDL is tied up with this
22/04: Two aspects. Firstly compositional - do sufficient mechanisms exist to model an envelope with a payload that varies. Secondly markup syntax - this might be defined in the envelope.
The second of these is very much tied up with the variable markup action 028, so will be considered there. SH to verify the composition aspect.
29/04: SH and AP working on proposal. related to Action 028
06/05: No progress
06/05: No progress
20/05: No Progress
27/05:  Still a number of aspects to be decided.
- Compostion - Does the envelope and payload need to be defined in the same schema or should they be dynamically bound at runtime?
- Compostion- How is a variable payload specified. Choice or xs:any; New action raised to discuss xs:any
- extracting dymanic syntax from data. Covered by action 029 valuecalc.
03/06: Dynamic runtime binding will not be supported.
SH investigating use of variables to enable standalone and use in envelope of global element.
09/06: Payload should be specified using a choice rather than xs:any
17/06: SH still working on example using variables
24/06: SH to document how property list satisfies uses cases.
01/07: SH to document how property list satisfies uses cases. PL looking at variable also. MB suggested modelling first separator as data for use case 3.
15/07: Action 042 on variables now includes examples of enevlopes and payloads. SH will also circulate what he has agreed with WTX team.
033
AP/TK: Assert/Discriminator semantics. AP to document. TK to check uses of discriminator besides choice.
08/04: In progress within IBM
22/04: Waiting for TK to return from leave to complete.
29/04: TK has sent examples shown need for discriminators beyond choice. Agreed. MB to respond to TK
06/05: Discussed suggestion of adding type indicator to discriminator. MB to provide examples.
15/03: Semantic documented in v034. MB to provide examples of need for scope indicator on discriminator
20/05: MB to provide examples of need for scope indicator on discriminator (but lower priority than action 029)
27/05: No Progress (lower priority)
03/06: No Progress (lower priority)
09/06: No Progress (lower priority)
24/06: No Progress (lower priority)
01/07: No Progress (lower priority)
15/07: No Progress (lower priority)
037
All: Approach for XML Schema 1.0 UPA checks.
22/04: Several non-XML models, when expressed in their most obvious DFDL Schema form, would fail XML Schema 1.0 Unique Particle Attribution checks that police model ambiguity.  And even re-jigging the model sometimes fails to fix this. Note this is equally applicable to XMl Schema 1.1 and 1.0. While the DFDL parser/unparser can happily resolve the ambiguities, the issue is one of definition. If an XSD editor that implements UPA checks is used to create DFDL Schema, then errors will be flagged. DFDL may have to adopt the position that:
a)DFDL parser/unparser will not implement some/all UPA checks (exact checks tbd)
b) XML Schema editors that implement UPA checks will not be suitable for all DFDL models
c) If DFDL annotations are removed, the resulting pure XSD will not always be valid (ie, the equivalent XML is ambiguous and can't be modelled by XML Schema 1.0)
Ongoing in case another solution can be found.
29/04: Will ask DG and S Gao for opinion before closing
06/05: Discussed S Gao email and suggestions. Decided need to review all XML UPA rules and decide which apply to dfdl.
20/05: SH or SKK to investigate
27/05: No Progress
03/06: The concern is that some dfdl schemas will fail UPA check when validation is turned on or when editted using tooling that enforces UPA checks. Renaming fields will resolve some/most issues. Need documentation  that  describes issue and best practice.
17/06: no change
24/06: no change
01/07: no prgress
15/07: No Progress (lower priority)
042
MB: Complete variable specification.
To include how properties such as encoding can be set externally. Must be a known variable name.
06/05: No progress
20/05: AP to make proposal
27/05: MB proposed differentiating between input and output variables to avoid unnecessary evaluations during parse and unparse. Need to complete rest of variable specification.
03/06: Pointed out problem of declaring variables input or output when used to define syntax which is used both times. MB to update proposal to include how variables are set externally and how specific properties  such as encoding are set.
09/06: SKK to use example to dicument his proposal
17/06: SKK to refine proposal. Other aspects need progress.
24/06: SKK proposal discussed but not accepted. PL to document simpler proposal.
07/01: PL working on proposal
15/07: PL has distributed his proposal. SH, MB and SKK have commented. Broad agreement in principle. Need to agree on better name for dfdl:variable to reflect the annotation's purpose. PL to update proposal.
044
13/05:  Bidi
20/05: AP: will check what IBM products support.
27/05: Bidi is supported so will be needed in dfdl v1
03/06: No Progress
09/06: No Progress
24/06: No Progress
01/07: AP started investigation and documented issues. Suggest do whatever XML does.
15/07: No further progress
045
20/05 AP: Speculative Parsing
27/05: Psuedo code has been circulated. Review for next call
03/06: Comments received and will be incorporated
09/06: Progress but not discussed
17/06: Discussed briefly
24/06: No Progress
01/07: No Progress
15/07: No progress. MB not happy with the way the algorithm is documented, need to find a better way.
049
20/05 AP Built-in specification description and schemas
03/06: not discussed
24/06: No Progress
24/06: No Progress (hope to get these from test cases)
15/07: No progress. Once available, the examples in the spec should use the dfdl:defineFormat annotations they provide.
051
Scoping rules.
MB: to document change to scoping rules to satisfy implementation concerns
17/06: MB and SH proposals discussed. Needs further discussion
24/06: AP to update presentation with latest proosal
24/06: AP had updated presentation. MB to review
08/07: Discussed at length. Simple types will now take annotations. Variables will be used for parameters.
15/07: No further progress. Needs final write up.
054
ICU DecimalNumber behaviour
15/07: No progress.

Closed actions:
029
MB: valueCalc (output length calculation)
08/04: Not discussed
22/04: Action allocated to MB, this is to complete the work started at the Hursley WG F2F meeting.
29/04: No progress
06/05: MB will have update for next call
13/05: MB will have update for next call
20/05: Some progress. will be circulated this week
27/05: MB circulated proposal and got comments. Will update and review on next call
03/06: Discussed proposal. MB to update dealing with uses cases raised. Options include a new lenghtKind='Reference' to make it easier to distinguish from fixed length case. Or use outputLengthCalc to separate calculation of parsing and unparsing length.
09/06: SH/AP proposal discussed and MB to document
17/06: MB to document proposal.
Grammar updated and reviewed. Minor changes needed.
24/06: Grammar description was updated and approved.  Need to describe new function.
01/07: MB to circulate grammar and document new XPATH function
15/07: Closed. MB has documented this. Key points are included in draft 0.35, work item exists to make sure the rest makes draft 0.36.
038
MB: Submit response to OMG RFI for non-XML standardization
22/04: First step is for MB to mail the OGF Data Area chair to say that we want to submit
29/04: MB has been in contact with OMG and will sunbit dfdl.
06/05: MB has prepared response to OMG. Will send DFDL sepc v033
20/05: Response has been sent to OMG based on v034
27/05: Awaiting response from OMG.
03/06: On hold
15/07: Closed. Eventually a response will come back.

Work items:
No
Item target version status
003
Variables (from action 042) 036 awaiting completion of action 042
005
Improvements on property descriptions not started
006
Envelopes and Payloads (from action 026) 036 awaiting completion of actions 026 and 042
007
valueCalc (from action 029) 036 ensure all aspects documented
011
How speculative parsing works (combining choice and variable-occurence - currently these are separate) (from action 045) awaiting completion of actions 045  
012
Reordering the properties discussion: move representation earlier, improve flow of topics not started
033
Numeric data - what physical reps are allowed for what logical types (from action 020) 036 ensure all behaviour documented
036
Update dfdl schema with change properties
038
Improve length section including bit handling not started
042
Mapping of the DFDL infoset to XDM not required for V1 specification
051
Revised scoping rules (from action 051) 036 awaiting completion of action 051


Regards

Steve Hanson
Programming Model Architect
WebSphere Message Brokers
Hursley, UK
Internet: smh@uk.ibm.com
Phone (+44)/(0) 1962-815848





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