Open Grid Forum: Data Format Description Language Working Group

OGF DFDL Working Group Call, February 17-2010

Attendees
Steve Hanson (IBM)
Alan Powell (IBM)  
Steve Marting (Progeny)  
Peter Lambros (IBM)  
Stephanie Fetzer (IBM)

Apologies
Mike Beckerle (Oco)
Suman Kalia (IBM)
Tim Kimber(IBM)  


1. Comments of latest discriminators doc v5.

Steve questioned:   It is a processing error if none of the choice branches are known to exist
Steve: I know we agreed on this but I’m concerned that I am now unable to model the situation where I have a header, a footer, and in between either nothing or exactly 1 of a choice of n records

It was agreed that the body could be an optional complex element with the choice as its content.

Also confirmed

dfdl:discriminator can be an annotation on
·        a local xs:element declaration

·        an xs:element reference

·        an xs:group reference (when the top level of a choice branch)

·        an xs:sequence (when the top level of a choice branch)

·        an xs:choice (when the top level of a choice branch)

Action 045 will be closed.


2. Remaining 037 review issues

16.2 scannablility with lengthKind pattern:  
Confirm that this is what we agreed
In summary, you can use a data pattern on any element (complex, simple text, simple binary) as long as the bytes are legal in the stated encoding, which where binary data is involved in practice means an 8-bit ASCII encoding.

By 8-bit ASCII we really mean an encoding where all the codepoints from 0-255 map to the equivalent value. Subsequent investigation indicates that 'all' 8-bit ASCII encodings have gaps so there isn't a valid character.
Mike has suggested
1) for all ascii-based character sets, we say that bytes 0x00 to 0xFF all map to exactly those codepoints in ISO 10646 for the infoset, and vice versa.

2) define dfdl:encoding="bytes" as a special character set name which has the above property.

Briefly discussed but no conclusion.



3. Go through Actions
Updated below

4. Biztalk comparison
Short discussion which noted that DFDL could match Biztalk representation properties but was missing support for attributes and some simple types. Decided that we don't need to do anything in DFDL v1.

5 DFDL v1 Specification completion.
It was agreed that the spec should be in the OGF review process by OGF 28 in March.
Alan stated it needed 2 more drafts.
Draft 39 with all the updates completed for a final WG review - available 24 Feb
Comments by 3 March
Draft 40 with updates for OGF submission - available 5 March

Meeting closed, 14:00

Next call  Wednesday 24 February January 2010  13:00 UK

Next action: 083

Actions raised at this meeting
No
Action

Current Actions:
No
Action
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
23/12: no update
06/01: no progress. If there is no resource to complete this action it can be deferred
13/01:no progress
20/01: no progress
27/01: no progress
29/01: No progress.  The predefined formats do not need to be available when the spec is published.
Suman said that he had been mapping COBOL structures to DFDL and it didn't look as though the way text numbers are define is very usable. He will document for next call
03/02: No progress
10/02: No progress
17/03: No progress
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
23/12: SH will send another reminder.
06/01: Another reminder will be sent
13/01: no update
20/01: no update
27/01: no progress
29/01: no progress
03/02: IBM is still investigating
10/02: IBM is still investigating
17/02: IBM is willing in principle to publish the test case format and some of the test cases. May need some time to build a 'compliance suite'
079
MB:Encoding for binary fields when lenghtkind is pattern
17/02: Discussed but no conclusion
080
AP:Clarify semantics of fn:poisition and fn:count
17/02: no progress
081
AP: Inf and Nan
The description is the way ICU behaves but need clarification. It isn't clear how inf and Nan are represented in the infoset. Need to investigate if XML allows these values
17/02: XML allows Nan and inf for float and double Dfdl will do the same. Requires more investigation of ICU.

Closed 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.
23/12: SF to provide better description of WTX behaviour and invite B Connolley to next call
06/01:B Connolly not available. SF to provide more complete description.
13/01: Stephaine took us through a description of WTX identifiers. Mike agreed to write up in DFDL terms.
20/01: Mike will write up
27/01: further discussion of discriminators
29/01: Alan had  emailed both proposals but not enough time to discuss
02/02: Agreed to adopt 'component exists' semantics for discriminators
10/02: 'component exists' proposal updated. comments by next call.
17/02: reviewed needs minor updates.
Closed
082
MB: Should alignment be 0 or 1 based
17/02: Mike has reworded the section to be 1 based and Agreed this was OK
Closed

Work items:
No
Item target version status
005
Improvements on property descriptions not started
012
Reordering the properties discussion: move representation earlier, improve flow of topics not started
036
Update dfdl schema with change properties ongoing
042
Mapping of the DFDL infoset to XDM none not required for V1 specification
069
ICU fractional seconds 039
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 039
073
Rename dfdl:separatorPolicy="required" to "always". 039 Defferred untilaction 071 agreed
078
document UPA checks 039
079
Semantics of length=0, nil handling and defaults. (A071) 039
080
Tlog: Allow LengthKind delimited for packed/bcd (A074) 039
081
Update empty sequence section (A075) 039
082
semantics of minOccurs= 0 on choice branches (A076) 039
083
Implement RFC2116
084
Length|Kind pattern scanability rules
085
Invalid character substitution
086
infoset round tripi: Rephrase sentence 'It is possible to define a schema so that when infoset unparsed and the datastream reparsed, the same infoset will be produced'
087
Clarify use of relative paths in global components.
088
'DFDL expression'
089
Ageed that dfdl:represetnation 'text' is implied for strings and dfdl:represetnation 'binary' is implied for hexbinary
091
textStringPadCharacter textNumberPadCharacter  must be a 1 byte character if the char set encoding is variable width?
092
 finalDocumentTerminatorCanBeMissing and  finalDocumentSeparatorCanBeMissing allowed only in 'default' format
093
 remove textNumberFormat and textCalendarFormat.
094
Alignment should be  1 based



 
Regards
 
Alan Powell
 
Development - MQSeries, Message Broker, ESB
IBM Software Group, Application and Integration Middleware Software
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