[DFDL-WG] Minutes for OGF DFDL Working Group Call, May 05-2010

Thu May 6 12:12:07 CDT 2010

Open Grid Forum: Data Format Description Language Working Group

OGF DFDL Working Group Call, May 05-2010

Attendees
Steve Hanson (IBM) 
Alan Powell (IBM) 
Suman Kalia (IBM)
Stephanie Fetzer (IBM)
Tim Kimber(IBM) 

Apologies
Steve Marting (Progeny) 
Mike Beckerle (Oco)

1. DFDL Specification status 

Alan had contacted an automotive standards body (AIAG) to generate 
interest in getting comments. The request had been forwarded to a number 
of OMG groups some of whom have at least looked at the specification. He 
will encourage them to make comments.

Steve H had commented on the OMG MDMI site that the DFDL spec was 
available

2 Nils, defaults and unparsing   

Alan had distributed tables and examples for defaulting complex elements. 
Steve H had updated the tables.

-  emptyValueDelimiterPolicy does apply to complex elements. 
- on parsing a complex element is empty if its content region is empty. 
That is there no child delimiters or content. 
- on unparsing defaulting occurs if a complex item is missing or present 
present but has no children. 

Defaulting for complex elements on parsing

initiator region
content region

infoset contains
matching
Not empty
default exists for any missing required children
complex element with child elements (real & default values)
matching
empty
default exists for any required children
emptyValueDelimiterPolicy
 must be
initiator or both
complex element with child elements (real & default values)
empty
Not empty
default exists for any missing required children
Initiator must not be specified
complex element with child elements (real & default values)
empty
empty
default exists for any required children
emptyValueDelimiterPolicy
 must be
none
or
Initiator must not be specified
complex element with child elements (real & default values)

Defaulting for complex elements on unparsing

infoset contains

initiator region contains
content region contains
not supplied

supplied but with no children

supplied with some children
default  exist for all missing required children and final representation 
of complex element is empty string 
emptyValueDelimiterPolicy
 none
or
Initiator is not  specified
empty
empty
emptyValueDelimiterPolicy
initiator or both
initiator string
default values exist for all missing required content and final 
representation of complex element is  not empty string
Initiator is not specified
initiator string
 representation of complex element and its children
Initiator is not specified
empty

- The tables need to add terminator which may make them too cluttered
- It was agreed that on unparsing a simple infoset item with no value will 
be treated the same as missing.  Steve H to check WMB behaviour. Need to 
state in 4.1.2 Infoset that value is optional.

- Conformed that emptyValueDelimiterPolicy only applies is initiator or 
terminator is set. 

- Need to describe defaulting of choices.

- Confirmed that a separator is inserted/expected when postfix separator 
and supressedAtEnd.

3. Current Actions: 
Updated below

4 AOB

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

Tim also questioned the teston/off functions. Alan stated that setting 
bits in a array was not possible. Will look at ISO8583 to see if needed.
Meeting closed, 14:10

Next call  Wednesday 12 May  2010  13:00 UK  (8:00 ET)

Next action: 092
Actions raised at this meeting

No
Action 
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

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
084
Check behaviour of dfdl:inputValueCalc and outputValueCalc.
14/04: no prorgess
21/04: no progress
05/05: no progress
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
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.
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
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

Closed actions
No
Action 
090
Semantics of separatorPolicy
14/04: Discussion on detecting when complex types should be defaulted. 
Examples needed.
21/04: Complex defaulting examples needed for new rules
05/05: Subsumed into action 086 defaults.
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
070
Write DFDL primer 

071
Write test cases.

083
Implement RFC2116

097
Remove functions that returns duration

098
occursCountKind 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.

Regards

Alan Powell

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