Open Grid Forum: Data Format Description Language Working Group
OGF DFDL Working Group Call, May-14-2009
Meeting opened, 14:00 UK
Attendees
Steve Hanson (IBM)
Mike Beckerle (Oco)
Suman Kalia (IBM)
Alan Powell (IBM)
Dave Glick (drac)
Apologies
Agenda:
1. Go through actions.
Action 027 Property precedence tables
1) Missing property dfdl:textBooleanJustification --added
2) What is the rule when the same DFDL properties occur on a xs:simpleType
and a xs:element that uses that type? Does this work a) like
element/group references (ie, properties combined with element winning) or
b) like complex element and its sequence (ie, element and simpleType are
considered separate objects)? I don't think section 10 covers this case.
3) Should we allow the DFDL nil & default control properties on a simple
type? Only on element
4) Should we allow DFDL occurs properties on global elements? - No.
5) Missing work item to get BiDi properties into shape and incorporated
into spec. Should these be grouped, like escape scheme, calendar scheme,
etc? Do they apply to calendar and number types? - Action created
6) Should dfdl:integerBooleanXXXRep be renamed dfdl:binaryBooleanXXXRep ?
- agreed
7) We might want to reconsider the name of the new flag dfdl:initiated -
it could be read that the xs:sequence itself is initiated rather than its
children. - renamed initiatedContent
8) Should dfdl:initiated also apply to xs:choice? - yes
9) Draft 33 property precedence had dfdl:outputLengthCalc - was removed.
Action 028 Dfdl infoset and XDM
Discussed DG document. SH commented that document tried to make the dfdl
infoset be XDM rather than be compatible with XDM. DFDL does not need all
the complexity in XDM.
Need a mapping between dfdl infoset and XDM to make sure there are no
uneccessary differences. This needs to consider character sets, validation
(types for unvalidated data) and arrays
2. Check Work items
- add incorporate DG comments on 033
3. Annotations on Top Level element
Not discussed: Please review before next call
4. Scoping rules for assert/discriminator and other annotations
Not discussed: Please review before next call
5. Comments latest version (034)
Not discussed: Please review before next call
6. AOB
Next call 13 May 14:00 UK
Note: Scheduled for 2 hours
Meeting closed, 15:10 UK
Actions raised at this meeting
No
Action
043
13/05: Types in the infoset. Currently infoset types have defined value
space but that implies a parser would have to validate input. Is this
correct?
044
13/05: Bidi
Current Actions:
No
Action
012
AP/SH: Update decimalCalendarScheme
10/9: Not allocated yet
17/9: No update
24/9: Add calendar binary formats to actions
22/10: No progress
16/1: proposal distributed and discussed. Will be redistributed
21/1: add locale,
04/02: changed from locale to specific properties
18/2: Need more investigation of ICU strict/lax behaviour.
08/04: Not discussed
22/04: AP to complete asap once the ICU strict/lax behaviour is
understood.
29/04: No progress
06/05: No progress
13/05: Calendar has been added to latest spec version v034 but still a few
details to clarify.
026
SH: Envelopes and Payloads
08/04: Not discussed explicity, but recursive use of DFDL is tied up with
this
22/04: Two aspects. Firstly compositional - do sufficient mechanisms exist
to model an envelope with a payload that varies. Secondly markup syntax -
this might be defined in the envelope.
The second of these is very much tied up with the variable markup action
028, so will be considered there. SH to verify the composition aspect.
29/04: SH and AP working on proposal. related to Action 028
06/05: No progress
06/05: No progress
027
SH: Property precedence tables
08/04: Not discussed
22/04: Two things missing from the existing precedence trees. Firstly,
does not show alternates (eg, initiator v initiatorkind). Secondly, need a
tree per concrete DFDL object (eg, element). SH to update.
29/04: No progress
06/05: SH is updating tables which will be ready for next call
13/05: SH emailed updated version. AP commented.. See minutes to issues.
028
SH: Variable markup
08/04: Discussed briefly at end of call, IBM to see whether there any use
cases that require recursive use of DFDL.
15/04: Use case was distributed and will be discussed on next call.
22/04: The use case in question is EDI where the terminating markup for
the payload segments is defined in the ISA envelope segment. The markup is
modelled as an element of simple type where the allowable markup values
are defined as enums on the type. But we need to handle two cases -
firstly where the envelope is present, so the value used by the payload is
taken from the envelope. Secondly where only the payload is present. Here
we need a way of scanning for all the enum values, and adopting the one we
actually find, when parsing. And using a default when unparsing. SH to
explore use of a DFDL variable, where the variable has a default, but also
has a type that is the same as the markup element - that way we get to use
the enums without defining everything twice.
29/04: SH and AP working on proposal.
06/05: No progress
13/05: No progress
029
MB: valueCalc (output length calculation)
08/04: Not discussed
22/04: Action allocated to MB, this is to complete the work started at the
Hursley WG F2F meeting.
29/04: No progress
06/05: MB will have update for next call
13/05: MB will have update for next call
032
DG: Investigate compatibility between DFDL infoset and XDM
08/04: No update
22/04: No update
29/04: No update
06/05: DG indicates will have update next week
13/05: see minutes
033
AP/TK: Assert/Discriminator semantics. AP to document. TK to check uses of
discriminator besides choice.
08/04: In progress within IBM
22/04: Waiting for TK to return from leave to complete.
29/04: TK has sent examples shown need for discriminators beyond choice.
Agreed. MB to respond to TK
06/05: Discussed suggestion of adding type indicator to discriminator. MB
to provide examples.
15/03: Semantic documented in v034. MB to provide examples of need for
scope indicator on discriminator
036
SH: Provide use case for floating component in a sequence
08/04: Raised
15/04: Use case sent and discussed. SH to do further investigation
22/04: IBM feedback from WTX team is that alternate suggested ways of
modelling the EDI floating NTE segment have significant usability issues.
The DFDL principle is that for a problem that can be expressed as
two-layered, then two DFDL models are needed. The EDI NTE segment does
not fall into this though, as its use is on a per sequence basis. Ongoing.
29/04: Agreed that need to be in V1. SH to make a proposal
06/05: No progress
037
All: Approach for XML Schema 1.0 UPA checks.
22/04: Several non-XML models, when expressed in their most obvious DFDL
Schema form, would fail XML Schema 1.0 Unique Particle Attribution checks
that police model ambiguity. And even re-jigging the model sometimes
fails to fix this. Note this is equally applicable to XMl Schema 1.1 and
1.0. While the DFDL parser/unparser can happily resolve the ambiguities,
the issue is one of definition. If an XSD editor that implements UPA
checks is used to create DFDL Schema, then errors will be flagged. DFDL
may have to adopt the position that:
a)DFDL parser/unparser will not implement some/all UPA checks (exact
checks tbd)
b) XML Schema editors that implement UPA checks will not be suitable for
all DFDL models
c) If DFDL annotations are removed, the resulting pure XSD will not always
be valid (ie, the equivalent XML is ambiguous and can't be modelled by XML
Schema 1.0)
Ongoing in case another solution can be found.
29/04: Will ask DG and S Gao for opinion before closing
06/05: Discussed S Gao email and suggestions. Decided need to review all
XML UPA rules and decide which apply to dfdl.
038
MB: Submit response to OMG RFI for non-XML standardization
22/04: First step is for MB to mail the OGF Data Area chair to say that we
want to submit
29/04: MB has been in contact with OMG and will sunbit dfdl.
06/05: MB has prepared response to OMG. Will send DFDL sepc v033
039
SKK: Approach for creating Schema-For-DFDL xsds.
22/04: Resolve issue around multiple declarations needed for DFDL
properties, perhaps using MB's meta approach
29/04: Don't like qualified attributes in long form. SKK to check there
are no code gen implications, eg EMF.
06/05: SKK will send update by Friday
040
SH: LengthKind on complex objects.
29/04: All send comment before next call
06/05: See minutes. Agreed to remove lengthKind from sequence and choice.
041
AP: UnorderedInitiated
29/04: All: Review for next call
06/05: See minutes: Agreed to generalize to all sequences
042
MB: Complete variable specification.
To include how properties such as encoding can be set externally. Must be
a known variable name.
06/05: No progress
043
13/05: Types in the infoset. Currently infoset types have defined value
space but that implies a parser would have to validate input. Is this
correct?
044
13/05: Bidi
Closed actions:
020
SH: Resolve packedDecimalSignCodes behaviour depends on NumberCheckPolicy
22/10: No progress
10/12: added how to decide to overpunch and sign position
11/02: proposal largely agreed. SH to make minor changes
18/02: AP to document unsigned type behaviour
25/02: no progress
08/04: Not discussed
22/04: SH to complete last remaining issue, which is the behaviour when
logical type is signed/unsigned and the physical type is unsigned/signed.
29/04: SH had identified a problem with definition values and types in the
infoset and will email proposal. DG to be asked to accelerate action 032
to see if helps
06/05: No progress
13/05: Original problem has been resolved and added to v034. CLOSED
Will open new action for signed/unsigned types in the infoset.
Work items:
No
Item
target version
status
001
String XML type (Ian P) - Apr 30, 2008
deferred
002
Escape schemes (Ian P) - Apr 30, 2008
034
003
Variables - ??, 2008 (Mike)
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) -
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 (A033)
034
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
025
Augmented infoset and unparsing (Alan)
034
added but needs work
026
Remove duration
034
027
Calendar schemes
034
028
Validation ranges (A035)
034
029
Decimals (A020) - document unsigned type behaviour -
packedDecimalSignCodes behaviour depends on NumberCheckPolicy
034
030
Remove redundant properties, fix examples. (A036)
034
031
Specialized annotations
034
032
Floating components
033
Changes from action 020 - renaming properties etc
Alan Powell
MP 211, IBM UK Labs, Hursley, Winchester, SO21 2JN, England
Notes Id: Alan Powell/UK/IBM email: alan_powell(a)uk.ibm.com
Tel: +44 (0)1962 815073 Fax: +44 (0)1962 816898
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