Open Grid Forum: Data Format Description Language Working Group OGF DFDL Working Group Call, December-16-2009 Attendees Mike Beckerle (Oco) Steve Hanson (IBM) Alan Powell (IBM) Steve Marting (Progeny) Stephanie Fetzer (IBM) Tim Kimber (IBM) Apologies Suman Kalia (IBM) Peter Lambros (IBM) 1. 045 - Disciminators We went through the examples of discriminator on resolving choices and optional element that Alan had produced in some detail. Noted that all the elements on choice branches should have discriminators to resolve the parent choice not just the simple element, otherwise asymmetry between simple and complex choice branches. Stephanie explained some of the WTX semantics. - an identifier must be on a mandatory item/group (minOccurs > 0) - an identifier has an implicit rule ( exists() ) is no other rule is specified. - identifier is not used on the branches of a choice, but is on a partitioned group. It was suggested that DFDL should adopt the WTX identifier flag with separate rule model rather then distinct assert rules and discriminator rules. Stephanie had to leave so discussion postponed until next call 2. Clarification of postfix separators, terminators,finalTerminatorCanBeMissing Discussion to clarify where dfdl:documentFinalTerminatorCanBeMissing and dfdl:documentFinalSeparatorCanBeMissing apply. It was agreed that they apply on the root element passed to the parser which may not be a global element. 3. Does the parser/serializer have to start on a global element? As part of the discussion of 2 above it was decided after all not to introduce a property to designate global root elements as it was felt that the only sensible options would be for the property to be enforced. ie a specified element MUST have the property, or don't have the property.. But need Stephanie and Suman to agree. 4. LengthUnits = 'bits' Mike will distribute his proposal to mailing list 5. Semantics of length=0 Need to go through each of the lengthKinds to understand the interaction of length=0, nil handling and defaults. ACTION 6. Go through remaining actions Updated below 7. Draft 037 review Please submit comments by Monday 21st Dec Agree terminology Agreed that: -A schema has components which have dfdl annotations .- Dfdl annotations have properties (same as XSDL) but need to distinguish between format/representation properties and other properties such as name, ref, selector. Not discussed. -The data/data stream/message has elements/fields -The infoset has items 7a. Byte Order Mark and Unicode signature Tim stated that the statement that BOM is treated as data is not implementable consistently with ICU. Would prefer it to say that BOM are not allowed. But his use of BOM included both UTF-16 BOM and UTF-8 unicode signature. Not clear that UTF-16 BOM is a problem. Tim will investigate further ICU behaviour. ACTION 8. Plan to finish DFDL v1 Schedule 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 Meeting closed, 15:00 Next call 23 December 13:00 UK Next action: 073 Actions raised at this meeting No Action 071 SH: Semantics of length=0 16/12: Tabular description of semantics for all lengthKinds, including nil handling and defaults. 072 TK: Byte Order Mark and Unicode signature 16/12: Investigate whether the spec's position on UTF-16/32 BOM is implementable Current Actions: No Action 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. 09/12: Reviewed proposed discriminator semantic. 16/12: Reviewed discriminator examples and WTX semantic. 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 09/12: no update 16/12: 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. 09/12: no update. ALan will set up a separate call to progress this action. 16/12: MB, SH and AP had a separate call. MB to distribute proposal 064 MB/SH Request WG presentation at OGF 28 25/11: Session requested 04/12: no update 09/12: no update 16/12: SH has changed request to a general session rather than WG chartered session in the hope of attracting more people. 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 09/12: no update 16/12: reminded dent to project manager 068 Should the roots of messages be designated.? 09/12: Yes. New dfdl:documentRoot property Closed 16/12: reopened and decided to drop property subject to agreement from SKK and SF Closed actions No Action Work items: No Item target version status 005 Improvements on property descriptions not started 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 036 Update dfdl schema with change properties ongoing 038 Improve length section including bit handling some improvement in 036 042 Mapping of the DFDL infoset to XDM none not required for V1 specification 069 ICU fractional seconds 070 Write DFDL primer 071 Write test cases. 072 it is a processing error if the number of occurrences in the data does not match the value of the expression or prefix 073 Rename dfdl:separatorPolicy="required" to "always". 074 - Last 'postFix' separator is not optional - Terminators are mandatory. - dfdl:documentFinalTerminatorCanBeMissing - dfdl:documentFinalSeparatorCanBeMissing (Action (70)) 075 Remove occursCountKind="useAvailableSpace". 076 dfdl:documentRoot, will be defined that can only be on global elements. The DFDL spec does not have to define the format of parameters to the DFDL processor but will indicate that it must be possible to adresss any element. Agreed that ANY element within the schema cane be the starting point for parsing or unparsing. 077 'delimited' means the item is delimited by the item?s terminator (if specified) or an enclosing construct?s separator or end of the enclosing construct designated by its known length or its terminator. The definition of EndOfParent also needs improving. 078 document UPA checks 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