Open Grid Forum: Data Format Description Language Working Group

OGF DFDL Working Group Call, May 26-2010

Attendees
Steve Hanson (IBM)
Alan Powell (IBM)
Suman Kalia (IBM)
Stephanie Fetzer (IBM)
Mike Beckerle (Oco)

Apologies
Tim Kimber(IBM)

1 Nils, defaults
The whole call was spent discussing the proposed changes to the nils and defaults sections including Stephanie's comments.

Definition of 'has default value'
Minor clarifications to simple element. For complex element it is an 'effective' default value.
Clarified default for choices.

Definition:'required'
Clarified that required is in terms of the infoset.

Didn't like the used of 'index' in the definition of variable occurrence elements.

Agreed that ASSERTs do not make an element required. Stephanie to consider examples to confirm this is correct.

Suggest introducing 'required context' to explain defaulting in complex elements.

Discussed the restriction that choice branches may noy have minOccurs = 0 and whether that was sufficient. The was introduced to prevent the empty string being implicitly a valid choice but Mike pointed out that making all the children of a choice branch optional has the same effect. Not resolved.

Discussed whether anonymous sequences and choices were required. Concluded that it wasn't a valid question when required is in terms of the infoset. Thus if anonymous sequences and choices have an initiator or terminator they will always be present in the data stream. If they need to be optional then the seq/choice has to be wrapped in an element.

Suggest removing the definition of success.

Largely agreed on the definition of missing.

2 OGF 29
Chicago, June 20-22
Not discussed

3 Current Actions
Not discussed

4 Trailing alignment with lengthKind delimited or endOfParent
Is it sensible to allow Trailing skip bytes with LK delimited

The grammar says that trailing alignment is applied before the separator

So the parser must search for the separator then remove the trailing bytes from the value and length.

@Data1 *Data2*# - Test1 value=Data1 length=5

@Data1*Data2*# - Test1 value=Da length=2 (do we require that the trailing data must be the fillByte?)

But bear in mind that the grammar effectively says:

RightFraming = Terminator TrailingSkipBytes

So the combination of dfdl:lengthKind="delimited" & dfdl:trailingSkipBytes would work when the delimiter is a terminator.
Not discussed

Meeting closed, 16:30

Next call Wednesday 02 June 2010 15:00 UK (10:00 ET)

Next action: 092

Actions raised at this meeting

No
Action

Current Actions:

No
Action

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
...
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'
24/03: No progress
03/03: Discussions have been taking place on the subset of tests that will be provided.
10/03: work is progressing
17/03: work is progressing
31/03: work is progressing
14/04: And XML test case format has been defined and is being tested.
21/04. Schema for TDML defined. Need to define how this and the test cases will be made public
05/05: Work still progressing
12/05: Work still progressing

084
Check behaviour of dfdl:inputValueCalc and outputValueCalc.
14/04: no prorgess
21/04: no progress
05/05: no progress
26/05: Alan has looked at the precedence tables and the look OK. Suggest closing.

085
ALL: publicize Public comments phase to ensure a good review..
14/04: see minutes
21/04: Press release, OMG and other standards bodies.
05/05: Alan and Steve H have contacted other standards bodies. Will ask them to add comments on spec
15/05: still no public comments

086
AP: Nils and Defaults during unparsing - update table
31/03: TK to documetn use cases for parsing
14/04: Investigate new property to control empty string behaviour.
21/04: After investigation a new property is not required. New rules developed and tables updated.
Need examples of complexTypes to confirm tables apply.
Review Nils, defaulting spec section.
05/05: Discussed defaulting complex elements. Tables updated but need to add terminator.
SH; to confirm WMD behaviour when infoset item has no value on unparsing
Need to describe defaulting choices.
15/05: More discussion. Alan updating sections
26/05: Discussed draft updates. Stephanie to confirm asserts do not make an element required.
Alan will update draft.. All: review rest of draft.

088
define semantics of choiceKind 'fixedLength'
31/03: TK to provide definition of calculable length.
Investigate PL/I varchars and Cobol occurs dependingon.
14/04Tim had distributed a document starting the definition of calculable length for the longest choice member.
Alan had done some investigation of COBOL occurs depending on and when used in the working section of a program then the maximum storage was reserved but when used in the linkage section the dependent number was uses. We need to understand how the WMB COBOL importer deals with ODO.
21/04: Need to define 'calculable length' and WMB importer ODO behaviour.
05/05: TK: Still need definition of calculable length.
SKK: WMB COBOL imported behaviour with ODO
15/05: Suman sent an expmle of an imported Cobol ODo which suggested that the maximum space was reserved. He will extend the example.

091
The IBM team had questioned whether timezones should be just UTC+/- offset or should GMT and other short time zones be allowed. Alan to investigate
15/05: Alan to talk to Ruth.
26/05: Ruth confirmed that it was only the offset from UTC or GMT. For DFDL purposes thates are the same. Suggest closing.

Closed actions

No
Action

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

070
Write DFDL primer

071
Write test cases.

083
Implement RFC2116

097
Remove functions that returns duration

098
occursCountKind="expression" is parsing only

099
nilValue and OccuresStopValue cannot have an expression.
On unparsing only outputValueCalc can have a forward reference.

100
Need to state in 4.1.2 Infoset that value is optional.

101
When dfdl:textNumberRep is ‘zoned’ only the pattern for positive numbers is used. Only the following pattern characters may be used:

'+' MUST BE present at the beginning or end of the pattern to indicate whether the leading or trailing digit carries the overpunched sign, if the logical type is signed
'+' MAY BE present at the beginning or end of the pattern to indicate whether the leading or trailing digit carries the overpunched sign, if the logical type is unsigned
'V' MAY BE used to indicate the location of an implied decimal point
'0' indicates the number of required digits (including overpunched).
'#' indicates the number optional digits.

102
Also textNumberPolicy implies it applies to zoned, but doesn't state what zoned behaviour it covers. I think it should be consistent with binaryNumberCheckPolicy for packed, and control whether positive punched data is accepted or rejected when parsing an unsigned type, and whether unpunched data is accepted or rejected when parsing a signed type.

103
- textStandardBase
- textStandardGroupSeparator
- textStandardExponentCharacter
- textStandardInfinityRep
- textStandardNanRep
- textStandardZeroRep
- textZonedSignStyle

104
4 Unsigned decimal
Proposed solution:
- Allow xs:nonNegativeInteger which enables unsigned unbounded integers to be modelled. The problem to solve is then just for xs:decimal.
- Call the new property dfdl:decimalSigned. It only applies to xs:decimal or user defined restrictions thereof. It applies to all physical decimals, as its name implies (not just zoned or packed).

Regards

Alan Powell

Development - MQSeries, Message Broker, ESB
IBM Software Group, Application and Integration Middleware Software
-------------------------------------------------------------------------------------------------------------------------------------------
IBM
MP211, Hursley Park
Hursley, SO21 2JN
United Kingdom
Phone: +44-1962-815073
e-mail: alan_powell@uk.ibm.com

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

No	Action
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 ... 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' 24/03: No progress 03/03: Discussions have been taking place on the subset of tests that will be provided. 10/03: work is progressing 17/03: work is progressing 31/03: work is progressing 14/04: And XML test case format has been defined and is being tested. 21/04. Schema for TDML defined. Need to define how this and the test cases will be made public 05/05: Work still progressing 12/05: Work still progressing
084	Check behaviour of dfdl:inputValueCalc and outputValueCalc. 14/04: no prorgess 21/04: no progress 05/05: no progress 26/05: Alan has looked at the precedence tables and the look OK. Suggest closing.
085	ALL: publicize Public comments phase to ensure a good review.. 14/04: see minutes 21/04: Press release, OMG and other standards bodies. 05/05: Alan and Steve H have contacted other standards bodies. Will ask them to add comments on spec 15/05: still no public comments
086	AP: Nils and Defaults during unparsing - update table 31/03: TK to documetn use cases for parsing 14/04: Investigate new property to control empty string behaviour. 21/04: After investigation a new property is not required. New rules developed and tables updated. Need examples of complexTypes to confirm tables apply. Review Nils, defaulting spec section. 05/05: Discussed defaulting complex elements. Tables updated but need to add terminator. SH; to confirm WMD behaviour when infoset item has no value on unparsing Need to describe defaulting choices. 15/05: More discussion. Alan updating sections 26/05: Discussed draft updates. Stephanie to confirm asserts do not make an element required. Alan will update draft.. All: review rest of draft.
088	define semantics of choiceKind 'fixedLength' 31/03: TK to provide definition of calculable length. Investigate PL/I varchars and Cobol occurs dependingon. 14/04Tim had distributed a document starting the definition of calculable length for the longest choice member. Alan had done some investigation of COBOL occurs depending on and when used in the working section of a program then the maximum storage was reserved but when used in the linkage section the dependent number was uses. We need to understand how the WMB COBOL importer deals with ODO. 21/04: Need to define 'calculable length' and WMB importer ODO behaviour. 05/05: TK: Still need definition of calculable length. SKK: WMB COBOL imported behaviour with ODO 15/05: Suman sent an expmle of an imported Cobol ODo which suggested that the maximum space was reserved. He will extend the example.
091	The IBM team had questioned whether timezones should be just UTC+/- offset or should GMT and other short time zones be allowed. Alan to investigate 15/05: Alan to talk to Ruth. 26/05: Ruth confirmed that it was only the offset from UTC or GMT. For DFDL purposes thates are the same. Suggest closing.

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
070	Write DFDL primer
071	Write test cases.
083	Implement RFC2116
097	Remove functions that returns duration
098	occursCountKind="expression" is parsing only
099	nilValue and OccuresStopValue cannot have an expression. On unparsing only outputValueCalc can have a forward reference.
100	Need to state in 4.1.2 Infoset that value is optional.
101	When dfdl:textNumberRep is ‘zoned’ only the pattern for positive numbers is used. Only the following pattern characters may be used: '+' MUST BE present at the beginning or end of the pattern to indicate whether the leading or trailing digit carries the overpunched sign, if the logical type is signed '+' MAY BE present at the beginning or end of the pattern to indicate whether the leading or trailing digit carries the overpunched sign, if the logical type is unsigned 'V' MAY BE used to indicate the location of an implied decimal point '0' indicates the number of required digits (including overpunched). '#' indicates the number optional digits.
102	Also textNumberPolicy implies it applies to zoned, but doesn't state what zoned behaviour it covers. I think it should be consistent with binaryNumberCheckPolicy for packed, and control whether positive punched data is accepted or rejected when parsing an unsigned type, and whether unpunched data is accepted or rejected when parsing a signed type.
103	- textStandardBase - textStandardGroupSeparator - textStandardExponentCharacter - textStandardInfinityRep - textStandardNanRep - textStandardZeroRep - textZonedSignStyle
104	4 Unsigned decimal Proposed solution: - Allow xs:nonNegativeInteger which enables unsigned unbounded integers to be modelled. The problem to solve is then just for xs:decimal. - Call the new property dfdl:decimalSigned. It only applies to xs:decimal or user defined restrictions thereof. It applies to all physical decimals, as its name implies (not just zoned or packed).