Open Grid Forum: Data Format Description Language Working Group OGF DFDL Working Group Call, April-15-2009 Attendees Suman Kalia (IBM) Steve Hanson (IBM) Mike Beckerle (Oco) Alan Powell (IBM) Dave Glick (drac) Apologies 1. Escape Schemes Alan has mailed latest refinement (V2) just before the call. MB sent comments Agreed to drop escapeKind='escapeBlock2' as it was quite resctrictive and was primarily intended for XML style escaping which should be covered by representation='XML'. We got bogged down in individual use cases so AP agreed to document a set of use cases 2. 'Floating' definitions SH had sent out an example of need for floating definitions. The NTE segment in older X12 formats can appear multiple times anywhere within a transaction. This could be modelled in dfdl using - an array of choices which has all the possible fields as choices. This would mean that the fields other than the NTE segment could appear in any order so the document could not be validated using just the schema. - Inserting an optional NTE segment between every other segment. Such a schema would violate UPA rules if any other segments were optional. SH will investigate further to find out if this is used in versions of X12 that should be supported by DFDL v1. 3. Recursive use of DFDL for variable markup SH has sent a use case which WTX solved using 'variable markup'. The use case is from EDI. EDI transactions consist of an initial header segment which defines, among other things, the separator that is used by the data segments that follow. The problem is that EDI transactions may be processed in their entirety, or individual data segments may be processed without the header segment. For the former case, DFDL supports this fine, using an XPath expression to locate the separator, which is defined as an element, the simple type of which enumerates the allowable values, enabling validation. But for the latter case, the XPath expression won't resolve, as there is no header. An explicit dfdl:separator property could be used instead, being a space separated list of all the allowable values - but that then duplicates the separator element enums, leaving a maintenance problem. To be discussed on next call. 4. AOB Issues to be discussed - Suman has identified a identified that the short and long form properties require all dfdl properties to be defined at least twice in the schema for DFDL. - The scoping rules for annotations other than dfdl:format are not specified and need to be clarified. Actions updated below. Next call 22 April 14:00 UK Meeting closed, 15:15 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 020 SH: Resolve packedDecimalSignCodes behaviour depends on NumberCheckPolicy 22/10: No progress 10/12: added how to decide to overpunch and sign position 11/02: proposal largely agreed. SH to make minor changes 18/02: AP to document unsigned type behaviour 25/02: no progress 08/04: Not discussed 023 MB: Review Schema 1.1 29/1: AP and SH to talk to Sandy Gao 04/02 Call arranged for Friday 11/02: Call took place. Identified useful changes. Consolidate with previous list. 04/03: decided to stay on Schema 1.0. 08/04: Not discussed 024 String XML type 08/04: Not discussed 025 Escape schemes 21/1: discussed requirements 04/02: AP/SH to describe behaviour for known length text fields. Need to discuss if comment escapes should be supported. 11/02 new draft distributed: 18/02: SH up document concerns 25/02: SH and AP have refined proposal ready for approval. 04/03: SH and AP have further refined proposal. 11/03: discussed. suggested a simplified proposal be evaluated. 18/03: SH and AP had further discussions on simplified proposal 08/04: See minutes, review in detail for next call 15/04: See minutes, review for next call 026 SH: Envelopes and Payloads 08/04: Not discussed explicity, but recursive use of DFDL is tied up with this 027 Property precedence tables 08/04: Not discussed 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: Used case was distributed and will be discussed on next call. 029 valueCalc (output length calculation) 08/04: Not discussed 032 DG: Investigate compatibility between DFDL infoset and XDM 08/04: No update 033 AP/TK: Assert/Discriminator semantics. AP to document. TK to check uses of discriminator besides choice. 08/04: In progress within IBM 034 AP: Remove redundant properties, correct old examples 08/04: No update 035 AP: Add validation ranges to spec, update specialized annotations in spec. 08/04: Raised. For draft 0.34 036 SH: Provide use case for floating component in a sequence 08/04: Raised 15/04: Use case sent and discussed. SH to do further investigation Closed actions: Work items: No Item 001 String XML type (Ian P) - Apr 30, 2008 002 Escape schemes (Ian P) - Apr 30, 2008 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 010 (from draft 32) Assertions, discriminators and choice, including discussion of timing option (Suman) - Mar 31, 2008 * in progress * 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 * 025 Augmented infoset and unparsing (Alan) added but needs work 026 Remove duration ã Copyright IBM Corp. 1998, 2007 All Rights Reserved 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. 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