Open Grid Forum: Data Format Description Language Working Group OGF DFDL Working Group Call, Aug-26-2009 Attendees Steve Hanson (IBM) Alan Powell (IBM) Suman Kalia (IBM) Mike Beckerle (Oco) Apologies Peter Lambros (IBM) 1. Actions discussed and updated below. 2. New occursCountKind for when number of occurrences can be resolved by parsing. Need to decide semantics - Find as many repeating elements as possible then validate against minOccurs and maxOccurs - Find up to maxOccurs repeating elements. If less than nimOccurs found then processing error. The spec currently implies the later semantic Not discussed on call There is no call next week Next call 10 September 14:00 UK Meeting closed, 15:00 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 24/06: no progress 01/07: no progress 15/07: no progress 29/07: no progress 05/08: no progress 12/08: no progress 19/08: Inconsistencies are being found in ICU behaviour so Calendars need reviewing again. 26/08: Specific three character short time zones may not be maintained during round tripping when there is more than one short form for a time zone offset. Because dates and datetimes in the infoset only maintain a time zone offset so on unparsing it isn't possible to say which short form will be selected for a particular offset when there is more than one possible. Need to document. 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) .... 19/08: No Progress (lower priority) 26/08: 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) 29/07: No Progress (lower priority) 05/08: No Progress (lower priority) 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) 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. 15/07: No Progress 29/07: No Progress 05/08: SH and others had commented on Variables [Draft proposal - 20090715].doc. SH stated that fixOnMatch is not needed in dfdl v1.0 MB will document how to implement fixOnMatch behaviour with existing function. PL to update proposal 12/08: PL to update proposal with SKK examples. 17/08: Chase PL for update 26/08: PL distributed updated proposal. Agreement in principle but some parts need clarification - Clearer description of only one setVariable allowed even when default specified. State table is correct though. - Should document that there is no implied order of defineVariable and other annotations such as defineFormat which might refer to a variable - Should not in the table that it is not an schema error to have multiple setVariables for the same variable defined in the schema but only one should be execute. For example a setVariable in each component of a choice. Although this can only be detected at runtime it is still a schema definition error. - Send further comments to PL 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 29/07: No Progress 05/08: AP has been in touch with IBM bidi experts. 12/08: No Progress 17/09: AP has been in touch with WTX and IBM experts. Support will cover 1) Specifying bidi string in DFDL schema, 2) Representaion in the infoset 3) bidi propeties to describe instance data, including applicability to syntax elements 26/08: Initial proposal publish. General agreement. Send comments to AP 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 19/08: No Progress 26/08: No Progress 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. ..... 19/08: No Progress (lower priority) 26/08: No Progress (lower priority) 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. 29/07: No Progress 05/08: No Progress 12/08: No Progress 19/08: AP will document new syntax rules. 26/08: No Progress 054 ICU DecimalNumber/ Calendar behaviour 15/07: No progress 29/07: No Progress. 05/08: No Progress. This action is to discover and document ICU behaviour. DFDL will do whatever ICU does. 12/08: No Progress 19/09: More examples of inconsistent behaviour discovered 055 Document which properties can take an expression 12/08: AP has distributed proposed list of properties and wording 19/08: SH to review proposal 26/08: SH agrees with proposal. Others to review. 056 resolve lenghtUnit=bits including fillbytes 12/08: No Progress 19/08: No Progress 26/08: No Progress 057 Decide semantics and enumeration for 'parsed' occursCountKind 26/08: Subsequent discussion agreed on 'parsed' Need to agree semantics 058 Should dfdl:initiatedContent be discriminating? 26/08: Agreed that it should and will only be on groups Closed actions: 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 051 052 add entity for 'one or more white space characters' 036 053 name, baseFormat, selector, escapeSchemeRef, textNumberFormatRef, textCalendarFormatRef, binaryCalendarFormatRef attributes only 036 054 Add occureCountKind='parsed' 036 055 Make dfdl:initiatedConet discriminating 036 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