Open Grid Forum: Data Format Description Language Working Group
OGF DFDL Working Group Call, June 02-2010
Attendees
Steve Hanson (IBM)
Alan Powell (IBM)
Stephanie Fetzer (IBM)
Apologies
Tim Kimber(IBM)
Suman Kalia (IBM)
Mike Beckerle (Oco)
1 Nils, defaults and unparsing
Continue review proposal emailed by Alan
The proposal was not discussed on the call. Please send comments to Alan
by next Monday.
Stephanie sent an email discussing whether using discriminators had any
effect on defaulting using a COBOL occursDependingOn example. It seems as
though there is not a problem. However the discussion prompted questions
about how occursCountKind effected defaulting. In particular if the
occureCountKind is expression referring to another field in the data which
doesn't match the number of occurences is it an error should defaulting
occur?. Action raised to follow up.
2 OGF 29
Chicago, June 20-22
Suman was unable to get authorization to attend.
3 Current Actions
Updated below
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
Steve was keen that there was consistent behaviour over different
lengthKinds so that we shouldn't just disallow trailingSkipBytes for
delimited. We discussed allowing TSB when terminator was specified. Alan
to propose wording.
5 More on bit oriented formats
Steve has been looking at a bit oriented format from the space industry
The 'unused' fields could be defined as hidden or as leading/trailing skip
bytes of a nearby field. But LSB and TSB are specified in bytes only.
Steve proposed that LSB and TSB should be renamed leadingSkip and
trailingSkip and can be specified in bits or bytes as specified by
alignmentUnits or a new property skipUnits
6 separatorPolicy with optional fields and variable arrays.
In particular:
- separatorPolicy 'required' with variable arrays
- supressAtEnd with required fields that have defaults.
Meeting closed, 16:00
Next call Wednesday 09 June 2010 15:00 UK (10:00 ET)
Next action: 094
Actions raised at this meeting
No
Action
092
AP: Confirm behaviour of defaulting with various occursCountKinds
093
AP: Describe trailingSkipBytes for delimited formats.
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
02/06: Work still progressing on technical and legal considerations
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
02/06: 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.
02/06: Alan updated description. Please review.
Discussed Stephanie's example using discriminators. Decided no changes
needed.
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.
02/06: no progress
092
AP: Confirm behaviour of defaulting with various occursCountKinds
093
AP: Describe trailingSkipBytes for delimited formats.
Closed actions
No
Action
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.
02/06: Closed
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.
02/06: 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
041
098
occursCountKind="expression" is parsing only
041
099
nilValue and OccuresStopValue cannot have an expression.
On unparsing only outputValueCalc can have a forward reference.
041
100
Need to state in 4.1.2 Infoset that value is optional.
041
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.
041
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.
041
103
- textStandardBase
- textStandardGroupSeparator
- textStandardExponentCharacter
- textStandardInfinityRep
- textStandardNanRep
- textStandardZeroRep
- textZonedSignStyle
041
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).
041
Regards
Alan Powell
Development - MQSeries, Message Broker, ESB
IBM Software Group, Application and Integration Middleware Software
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