Open Grid Forum: Data Format Description Language Working Group Weekly Working Group Conference Call 13:00 GMT, 12 November 2008 Attendees Steve Hanson (IBM) Mike Beckerle(Oco) Alan Powell (IBM) 1. Schema Component Designator specification changes. DFDL currently uses as part of the infoset to point to schema item associated with infoset item. Sandy Gao had alerted us to some changes in the SCD spec. MB reviewed these changes and concluded that the changes removed some limitations an so DFDL could now just reference the SCD spec without caveats. 2. Selectors Discussed Suman's comment on last call's decision on selectors. Reconfirmed the decision 3. Moving to XSD 1.1 as base for DFDL MB has done an initial review of the XSD 1.1 changes and identified some new features that might be used instead of DFDL extensions. Such as Alternative types instead of selectors and xpath instead of DFDL expression language. MB to review further. 4. Multi-level semantics. Discussed why schema had use this style and concluded it was not necessary for DFDL as we could build on the schema work. In passing noted the need to standard for examples in the dfdl spec for showing scoped properties Subsequent MB email In the DFDL spec., the problem exists of how to express the behavior of a construct in the situation where there are properties in scope surrounding the construct. I believe this kind of syntax can be used in the spec. to make clear the implications of scope: Properties in scope: lengthKind="implicit" representation="text" <sequence dfdl:separator=?,? dfdl:terminator=?;? dfdl:lengthKind="delimited"> // these are local <element name=?f1? type=?string? /> <element name=?f2? type=?string? /> </sequence> I would suggest the above syntax for the DFDL spec as a way to discuss property semantics. The only way properties can get in scope is by way of an enclosing complexType definition; but using that syntax explicitly begs the question of whether one means true lexical enclosure, can there be other enclosing complexTypes also, etc. The above style eliminates these issues. 5. Action Items/ Work Items. Went through actions. Updated below 6. AOB Next call 18 November Meeting closed, 13:10 GMT Actions raised at this meeting No Action 024 String XML type 025 Escape schemes 026 SH: Envelopes and Payloads 027 Property precedence tables 028 Variable markup 029 valueCalc (output length calculation) Current Actions: No Action 003 AP: Update spec from WTX document 13/8: All resolved issues have been added to spec. Remaining unresolved items need discussion 10/9: Alan will pull out the remaining unresolved items and circulate for discussion next week 17/9: Doc distributed and partially discussed 15/10: All updateds complete except minlength 22/10: No update 12/11: Updates have been sent to wtx to review. Will chase up for comments 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 018 AP: Agree padding to minimum length 15/10: Needs documenting 22/10: No update 020 SH: Resolve packedDecimalSignCodes behaviour depends on NumberCheckPolicy 22/10: No progress 023 MB: Review Schema 1.1 Closed actions: 004 MB: Mike will also author a new section in response to comments from Sandy Gao and Suman Kalia, explicitly connecting syntax with DFDL semantics 16/7: no progress 10/9: Mike not convinced this is necessary. Steve to talk to Sandy to see if it is needed for any IBM implementation that extends the existing XML parsing framework 15/10: SH to talk to Sandy 22/10: SH needs reminding of what this issue is about 12/11: Decided not needed. Closed 007 AP: enum + expression wording 13/8: no progress 10/9: No update 17/9: No update 22/10: No update 12/11: converted to work item 014 SH: Use cases for lengthKind pattern on binary fields. 10/9: Not done 17/9: No update 22/10: SH not sure he can provide a concrete use case 12/11: SH had identified need for pattern of complex structures with binary comtent which already included. Decided to allow patterns on simple binary fields for symetry. Closed 016 AP: Add hidden changes to spec 22/10: No update 12/11:converted to work item 017 All: Review EndOfData changes 22/10: SH response mailed to Mike 5/11: Discussed on call and design agreed 12/11: converted to work item 019 AP: Document defineTextNumber etc 22/10: No update 12/11:converted to work item 021 AP: Document textNumberRepresenation and binaryNumberRepresentation 22/10: No update 12/11:converted to work item 022 SH: Talk to Sandy Gao to assess use of schema 1.1 22/10: Mail sent to Sandy 12/11: track as action 023 033 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) 004 Selectors (Suman/Alan) - Apr 30, 2008 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) - *complete but 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 * 013 (from F2F) New scoping rules 014 (from F2F) Occurs, OccurSeparator changes 015 (from F2F) choices and Output (Mike) 016 (from F2F) xpath forward references (Alan) *complete* 017 (IBM WTX review) Minor agreed updates (Alan) *complete* 018 (IBM WTX review) Review generateNewLine (Alan) *complete* 020 (IBM WTX review) Special value for zero seen eg 'zero'. (Steve) 021 (IBM WTX review) 'EndOfData' changes (Alan) 022 (IBM WTX review) Unresolvable choices - infoset changes *complete* 023 (IBM WTX review) separatorKind=?prefix? ?infix? or ?postfix? (Alan) 024 (IBM WTX review) StopValue clarification (Alan) 025 Augmented infoset and unparsing (Alan) 026 Hidden changes 027 Add decimal supp to main spec 028 Remove extended floats 029 AP: enum + expression wording 030 AP: Add hidden changes to spec 031 All: Document EndOfData changes 032 AP: Document defineTextNumber etc 032 AP: Document textNumberRepresenation and binaryNumberRepresentation 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