Agenda for OGF DFDL WG call 09 Decemberer 2009 - 13:00 UK (8:00 ET)

1. 045 - Disciminators Continued discussion of semantics of discriminators and arrays. 2. Clarification of postfix separators, terminators,finalTerminatorCanBeMissing Agree semantics 3. Arrays occursCountKind="useAvailableSpace". On unparsing, unused space should be padded with dfdl:fillByte (added below). But if the number in the infoset is a lot less than the box can hold, how do you know when re-parsing how many are in the box? Also, if we are trying to fit things into a box, does it matter if items are left over? I suggested this was an error below. Need Mike's input as he has seen the use cases for this. Additional thoughts on occursCountKind="useAvailableSpace". I had been thinking that occursCountKind="useAvailableSpace" was for all 'box' use cases but during discussions with Steve I realised that it does not cover the 2 use cases I had in mind. 1. COBOL occurs dependingOn with maximum occurrences allocated. Array complex element dfdl:lengthKind='explicit' dfdl:length='{MaxOccur * Length(row)}' Sequence dfdl:occursCountKind = 'expression' dfdl:occursCount = '{./NoOfOccurs}' Row dfdl:lengthKind='...........' 2. StopValue Array complex element dfdl:lengthKind='explicit' dfdl:length='{MaxOccur * Length(Row)}' Sequence dfdl:occursCountKind = 'StopValue' Row dfdl:lengthKind='...........' We need to articulate the use case for occursCountKind="useAvailableSpace". 4. Does the parser/serializer have to start on a global element? - Should the root global elements be designated in DFDL? - Is the SCD syntax usable to indicate 'starting' element to dfdl processor - Does the 'starting' element need to be a global element 5. Semantics of dfdl:lengthKind 'delimited' Current definition: 'delimited' means the item is delimited by the item?s terminator (if specified) or an enclosing construct?s separator or terminator. Does it need to be extended to cover 'infix' separators where last item can also be delimited by the end of the bitstream or the end of a fixed-length parent elemen 6. UPA checks Discuss Steve H email 7. Go through remaining actions 8. Plan to finish DFDL v1 Agree terminology Reworked plan Activity Schedule Who Complete Action items - 18 Dec 2009 WG Complete Spec Write up work items ? 23 Dec 2009 AP Restructure and complete specification - 23 Dec 2009 AP Issue Draft 038 23 Dec 2009 WG review WG review 7 Dec ? 08 Jan 2010 WG Incorporate review comments 4 Jan - 29 Jan 2010 AP + Issue Draft 039 15 Jan 2010 Incorporate review comments 4 Jan - 29 Jan 2010 AP + Issue Draft 040 29 Jan 2010 Initial OGF Editor Review Initial Editor review 1 Feb - 1 Mar 2010 OGF Initial GFSG review 1 Feb - 1 Mar 2010 Issue Draft 041 1 Mar 2010 OGF Public Comment period (60 days) 1 Mar - 30 Apr 2010 OGF OGF 28 Munich 15-19 March 2010 Incorporate comments Incorporate comments 28 May 2010 Issue Draft 042 28 May 2010 Final OGF Editor Review Final Editor review June 2010 OGF final GFSG review June 2010 Issue Final specification 30 June 2010 Publish proposed recommendation 1 July 2010 Grid recommendation process 1 Jan - 1 April 2011 Current Actions: No Action 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 progress ... 12/08: No Progress (lower priority) 19/08: Clarify that this action is to go through the XML UPA checks to assess impact on dfdl schemas and advice best practice. Name clashes is just one example. SH or SKK 26/08: No Progress (lower priority) 09/09: no progress ... 04/11: no progress 11/11: Steve has started to look at this. He has requested a 'consumable' definition of the UPA rules from the XSD WG members. Even non-normative Appendix H in the XSD 1.0 spec is hard to consume. 18/11: no update 25/11: Steve H has not found simpler definition so may just go through them. 04/12: Steve has received a simpler description from S Gao and will go though each check. 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. 29/07: No Progress 05/08: No Progress. Will document behaviour as a set of rules. 12/08: No Progress ... 16/09: no progress 30/09: AP distributed proposal and others commented. Brief discussion AP to incorporate update and reissue 07/10: Updated proposal was discussed.Comments will be incorporated into the next version. 14/10: Alan to update proposal to include array scenario where minOccurs > 0 21/10: Updated proposal reviewed 28/10: Updated proposal reviewed see minutes 04/11: Discussed semantics of disciminators on arrays. MB to produce examples 11/11: Absorbing action 033 into 045. Maybe decorated discrminator kinds are needed after all. MB and SF to continue with examples. 18/11: Went through WTX implementation of example. SF to gather more documentation about WTX discriminator rules. 25/11: Further discussion. Will get more WTX documentation. Need to confirm that no changes need to Resolving Uncertainty doc. 04/11: Further discussion about arrays. 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. ... 14/10: no progress 21/10: Discussed the real need for this being in the specification. It seemed that the main value is it define a schema location for downloading 'known' defaults from the web. 28/10: no progress 04/11: no progress 11/11: no update 18/11: no update 25/11: Agreed to try to produce for CSV and fixed formats 04/12: no update 056 MB Resolve lengthUnits=bits including fillbytes 12/08: No Progress ... 28/10: no progress 04/11: MB to look at lengthUnits = bits 11/11: no update 18/11: no update 25/11: no update 04/12: no update. ALan will set up a separate call to progress this action. 064 MB/SH Request WG presentation at OGF 28 25/11: Session requested 04/12: no update 065 Resolve parsing rules for various lengthKinds 25/11: Agreed dfdl:lengthKind define how to extract the data. Didn'r t discuss if this changes escaping. 04/12: Closed 066 Investigate format for defining test cases 25/11:IBM to see if it is possible to publish its test case format. 04/12: no update 068 Should the roots of messages be designated.? 069 Is the SCD syntax usable as a DFDL external. 070 Clarification of postfix separators, terminators,finalTerminatorCanBeMissing 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 Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
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Alan Powell