Open Grid Forum: Data Format Description Language Working Group

Weekly Working Group Conference Call
13:00 GMT, 22 July 2008


Attendees
Mike Beckerle (Oco)
Steve Hanson (IBM)
Alan Powell (IBM)



1. Update to Decimal supplement
Discussed MB comments on SH decimal supplement document.
Agreed
- added zeroSign to  packedDecimalSignCodes which allows zero to be represented as all zero nibble
- Move numberCheckPoicy out of dfdl:DefineNumberFormat (renamed to dfdl:DefineTextNumberFormat) so it can apply to binary representation.
- add numberZeroRep to provide a special value for zero. er 'zero'

2. Discuss lengthKind issues  
Discussed lengthKind/scanability email distributed by AP
Need to add to table truncation,  fill for binary, more logical/physical type combinations such as logical number with text representation.

lengthKind=Implicit
  no pad/ fill for sequences
  Long discussion on what the implicit length should be on unparse for various logical/physical type combinations.  
Decimal/integer with text representations look a problem.  Action: SH to propose algorithm
For number/text decided that min/maxInclusive would only be used for validation and not for any physical attributes.
Action: Check all simple types vs representation and investigate if numberFormat can be used.                                                              .
LengthKind=explicit
Decided for choice dfdl=length will be used, choiceKind is only used for lengthKind=implicit
Discussion of truncation is logical length is too big.
Decided that truncation is only valid for fixed length strings and we need a new property to control whether it is valid or not.
Action: propose new fixed length string truncation property.

For text numbers if numberpattern produces a text string that is too long at runtime then it is a runtime error.

lengthKind=prefixed
Decided that there is no padding for variable length lengthKinds

Will carry on discussion on next call


3. Hidden proposal
Not discussed

4. Unresolved WTX issues
Not discussed

5. AOB
Next weeks (30 July) call will start at 13:00 UK for 2 hours in stead of an additional call.


Meeting closed, 14:30 GMT

Actions raised at this meeting
No
Action
009
SH: propose algorithm unparse length lengthKind=implicit decimal type/binary representation
010
AP: Document Fixed length string truncation property
011
SH: Update decimal supplement

Current Actions:
No
Action
003
AP: Update spec from WTX document
16/7: in progress
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
006
SH: Distribute hidden proposal
16/7: Done. MB to review
007
AP: enum + expression wording
16/7: no progress

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) - 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)
017
(IBM WTX review) Minor agreed updates (Alan)
018
(IBM WTX review) Review generateNewLine (Alan)
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
023
(IBM WTX review) separatorKind=’prefix’ ‘infix’ or ‘postfix’ (Alan)
024
(IBM WTX review)  StopValue clarification (Alan)
025
Augmented infoset and unparsing (Alan)



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



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