Hi Alan

To be precise:

b) Case insensitivity of markup (eg, hdr & HDR for initiator)
The same new property that indicates the case sensitivity of all  markup on a component.


Regards

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



Alan Powell/UK/IBM@IBMGB
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[DFDL-WG] Minutes for OGF DFDL Working Group Calls, June 16-17 2009






Open Grid Forum: Data Format Description Language Working Group

OGF DFDL Working Group Calls, June 16-17 2009


These minutes cover the series of meetings and calls which took place June 16-17 2009


Meeting opened, 14:00 UK


Attendees

Steve Hanson (IBM)

Mike Beckerle (Oco)

Suman Kalia (IBM)

Alan Powell (IBM)

Peter Lambros (IBM)


Apologies




Agenda:


Actions updated below



Action 028 Variable Markup/ Recursive use of DFDL


As decided on last calls recursive use of DFDL will not be supported in DFDL v1


The uses cases are satisfied as follows:

a) Case insensitivity of data (eg, true & TRUE for text boolean)

A new property that indicates the case sensitivity of  representation data values. Note: this property will not effect calendar values, such as Monday,  which will always be case insensitive.


b) Case insensitivity of markup (eg, hdr & HDR for initiator)

A new property that indicates the case sensitivity of all  markup on a component.


c) Different possible values for non-white space markup (eg, @ and # for separator)
Markup properties will allow a list of values


d) Different possible values for data (eg, true & yes for text boolean)

Value properties will allow a list of values


e) Encoding of markup different to encoding of data (eg, initiator and terminator different to data)
The markup properties must be put on a wrapping xs:sequence and controlled by the xs:sequence's encoding property.




Action 042 Variables.


The uses cases for variables are

1.        Extracting syntax data fields
2.        As an indicator to identify Payload
3.        As an easier way to set bits in bitmap
4.        As the way dfdl properties can be set from outside the parser.

And the following aspects need to be defined

SKK documented his proposal to define the scope of variables by defining them in a defineFormat annotation. Variables are in scope when the defineFormat is referenced in addition to existing scoping rules. While it seems attractive to group variable definitions there was concern that it is changing the semantics of defineFormat and making it incompatible with the other definexxx annotations. SKK to refine proposal.

Other aspects of variable still to be resolved.


Action 051 Implement concerns with current scoping rules.


MB proposed a new syntax for defining parameters that identified which properties can be overridden. Concern at the complexity. SH proposed using existing variables.


Discussion on how overriding should work with simple types. Options :

1.  Existing rules. Simple types must be completely valid

2. Disallow dfdl annotations on simple types.

3. Only allow 'value representation' properties which must be completely valid.



Next call 23 and 24th June 14:00 UK   Scheduled for 2 hours


Meeting closed, 16:00 UK


Actions raised at this meeting
No
Action

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
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
027
SH: Property precedence tables
08/04: Not discussed

22/04: Two things missing from the existing precedence trees. Firstly, does not show alternates (eg, initiator v initiatorkind). Secondly, need a tree per concrete DFDL object (eg, element). SH to update.

29/04: No progress

06/05: SH is updating tables which will be ready for next call

13/05: SH emailed updated version. AP commented.. See minutes for issues and property changes.

20/05: Updated version circulated. Review before next call and be ready for vote.

27/05: Updated version circulated. more comments raised.
03/06: Further updates to clarify 'core'. Also identified missing design for outputMinLength

17/06: Being updated to include outputMinlength
028
SH: Variable markup
08/04: Discussed briefly at end of call, IBM to see whether there any use cases that require recursive use of DFDL.

15/04: Use case was distributed and will be discussed on next call.

22/04: The use case in question is EDI where the terminating markup for the payload segments is defined in the ISA envelope segment. The markup is modelled as an element of simple type where the allowable markup values are defined as enums on the type. But we need to handle two cases - firstly where the envelope is present, so the value used by the payload is taken from the envelope. Secondly where only the payload is present. Here we need a way of scanning for all the enum values, and adopting the one we actually find, when parsing. And using a default when unparsing. SH to explore use of a DFDL variable, where the variable has a default, but also has a type that is the same as the markup element - that way we get to use the enums without defining everything twice.

29/04: SH and AP working on proposal.

06/05: No progress

13/05: No progress

20/05: No Progress

27/05: Progress made and will tie to other actions

03/06: General desire to avoid having to introduce variable markup in V1.

Proposed having a property to control case behaviour of all syntax (initiator, terminator,separator) rather than separate ones for each. Similar property to 'values' (textZeroRep, textBooleanTrueRep, etc). and allowing lists of values. SH need to solve remaining uses case as described in action 026

09/06: SH proposal discussed. ICU questions to be researched

17/06: ICU is always case insensitive. SH to update proposal.
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.
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)
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
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
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.
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
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
049
20/05 AP Built-in specification description and schemas
03/06: not discussed
050
27/05: xs:any currently limited to initiated text element. Is this sufficient? Should xs:any in its current form be deferred?
03/06: not discussed

09/06: Proposed dropping xs:any support

17:06: Agreed to defer from DFDL v1 subject to final checks that IBM do not need function.
051
Scoping rules.
MB: to document change to scoping rules to satisfy implementation concerns

17/06: MB and SH proposals discussed. Needs further discussion

Closed actions:
043
13/05:  Types in the infoset.  Currently infoset types have defined value space but that implies a parser would have to validate input. Is this correct?
20/05: SH No progress

27/05: No Progress

03/06: No Progress

09/06: SH proposed staying with XML built-in types. Closed

17/06 closed
047
20/05 AP: Scoping for non-format annotations
27/05: Discussed briefly. AP to distribute

03/06: Proposal discussed briefly. Will be updated.

09/06: Doc emailed. Awaiting outcome of variable to define/setvariable rules.

17/06: Closed. Move to work item. Will be updated when variables resolved.
048
20/05: AP investigate Restart
27/05: Suggest RESTART is not part of the scope for DFDL.

03/06: not discussed

09/06: Closed

Work items:
No
Item target version status
003
Variables - ??, 2008 (Mike)
005
Improvements on property descriptions - ??, 2008 (All - split TBD)
006
Envelopes and Payloads (Steve) - Apr 30, 2008
007
(from draft 32) valueCalc (Mike) - ??, 2008   mostly
complete
008
(from draft 32) Property precedence for writing (Steve) - under review
009
(from draft 32) Variable markup (Steve) - Mar 31, 2008   proposal needs writing up
011
(from draft 32) How speculative parsing works (combining choice and variable-occurence - currently these are separate) ??, 2008 (IBM)  in progress
012
(from draft 32) Reordering the properties discussion: move representation earlier, improve flow of topics ??, 2008 (Alan) not started
027 Calendar schemes 034
032 Floating components
033 Changes from action 020 and 027 - renaming properties etc
035 Remove unorderedInitiated, add initiated content (a041)
036 Update dfdl schema with change properties (Suman)
037 Infoset text codepage
038 Improve length section
039 Change scoping of simple types (A 046)
040 Document outputMinLength  (A027)
042 mapping of the dfdl infoset to XDM Not required for V1 specification
043 Document infoset data types (A043)
044 non-format scoping rules (A047)






Alan Powell

MP 211, IBM UK Labs, Hursley,  Winchester, SO21 2JN, England
Notes Id: Alan Powell/UK/IBM     email: alan_powell@uk.ibm.com  
Tel: +44 (0)1962 815073                  Fax: +44 (0)1962 816898





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