[DFDL-WG] Minutes for OGF DFDL Working Group Call, Sept-16-2009
Alan Powell
alan_powell at uk.ibm.com
Thu Sep 17 05:46:32 CDT 2009
Open Grid Forum: Data Format Description Language Working Group
OGF DFDL Working Group Call, Sept-16-2009
Attendees
Mike Beckerle (Oco)
Steve Hanson (IBM)
Alan Powell (IBM)
Suman Kalia (IBM)
Steve Marting (Progeny)
Apologies
Peter Lambros (IBM)
1 Go through actions -
042 - Variables.
PL had distributed an updated proposal answering comments from last week.
Although nobody had reviewed it thoroughly it appeared to be satisfactory
so was approved. - Closed
044 - bidi (update emailed yesterday, please review)
AP had distributed an updated proposal which was approved. Closed.
Will be incorporated into normal property section rather than an appendix
055 - Document which properties can take an expression
Proposed list approved
dfdl:byteOrder
dfdl:encoding
dfdl:length
dfdl:initiator
dfdl:terminator
dfdl:separator
dfdl:occursStopValue
dfdl:nilValue
dfdl:textBooleanTrue
dfdl:textBooleanFalse
dfdl:inputValueCalc
dfdl:outputValueCalc
dfdl:niIndicatorPath (path)
Subsequently added
dfdl:binaryFloatRepresentation (can be specified externally in IBM
products)
dfdl:occursCount (see action 57 below)
057 - semantics for occursCountKind ='parsed'
Became a general discussions about arrays and optional elements.
dfdl:occursCountxxx properties should apply to both arrays and optional
elements so can be used to control the existence on optional elements.
dfdl:occursStopValue is always a logical value and applies to simple
elements only. Literal values are specified as a terminator of the array.
Spec needs updating
Enumerations for dfdl:occursCountKind should be:
'fixed' - use xs:maxOccurs which must equal xs:minOccurs
'expression' - use dfdl:occursCount which must be an expression
'stopValue' - logical value to mark end of array
'parse' - use normal speculative parsing rules
'useAvailableSpace' - size deliniated by parent.
The semantics of dfdl:occursCountKind='parsed' are
'parse as many as possible then validate against min/maxOccurs is
validation is on. This is consistent with XML UPA checks as any other
semantic would cause UPA failures.
To be approved on next call
051 - scoping rules (email from AP)
Not discussed but AP agreed to redo SKK element reference samples with new
rules
2. OGF meeting in Banff
Too late for Banff meeting but should aim to present completed spec in
Munich 03/10. MB suggested that we host a webinar in 01/10 to publicise
the spec.
3 Suman has requested a change in the WG call time to either 13:00 UK
(8:00 US ET ). I would also like to reccommend extending the call to 2
hours as we are not getting though the work items.
Agreed calls will be from 13:00 UK (8:00 ET) for 2 hours
Next call 23 September 13:00 UK
Meeting closed, 15:20
Actions raised at this meeting
No
Action
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.
20/05: No Progress
27/05: No Progress
03/06: No Progress (low priority)
09/06: No Progress (low priority)
17/06: SH to check ICU code for lax calendar behaviour
24/06: no progress
01/07: no progress
15/07: no progress
29/07: no progress
05/08: no progress
12/08: no progress
19/08: Inconsistencies are being found in ICU behaviour so Calendars need
reviewing again.
26/08: Specific three character short time zones may not be maintained
during round tripping when there is more than one short form for a time
zone offset. Because dates and datetimes in the infoset only maintain a
time zone offset so on unparsing it isn't possible to say which short form
will be selected for a particular offset when there is more than one
possible. Need to document.
09/09: no progress
16/09: no progress
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
20/05: MB to provide examples of need for scope indicator on discriminator
(but lower priority than action 029)
27/05: No Progress (lower priority)
....
19/08: No Progress (lower priority)
26/08: No Progress (lower priority)
09/09: no progress
16/09: 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.
20/05: SH or SKK to investigate
27/05: No Progress
03/06: The concern is that some dfdl schemas will fail UPA check when
validation is turned on or when editted using tooling that enforces UPA
checks. Renaming fields will resolve some/most issues. Need documentation
that describes issue and best practice.
17/06: no change
24/06: no change
01/07: no prgress
15/07: No Progress (lower priority)
29/07: No Progress (lower priority)
05/08: No Progress (lower priority)
12/08: No Progress (lower priority)
19/08: Clarify that this action is to go through the XML UPA checks to
assess impact on dfdl schemas and advice best practice. Name clashes is
just one example. SH or SKK
26/08: No Progress (lower priority)
09/09: no progress
16/09: no progress
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
19/08: No Progress
26/08: No Progress
09/09: no progress
16/09: no progress
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.
.....
19/08: No Progress (lower priority)
26/08: No Progress (lower priority)
09/09: no progress
051
Scoping rules.
MB: to document change to scoping rules to satisfy implementation concerns
17/06: MB and SH proposals discussed. Needs further discussion
24/06: AP to update presentation with latest proosal
24/06: AP had updated presentation. MB to review
08/07: Discussed at length. Simple types will now take annotations.
Variables will be used for parameters.
15/07: No further progress. Needs final write up.
29/07: No Progress
05/08: No Progress
12/08: No Progress
19/08: AP will document new syntax rules.
26/08: No Progress
09/09: AP has documented new scoping rules. Not discussed
16/09: Not disussed. AP to update element reference examples
054
ICU DecimalNumber/ Calendar behaviour
15/07: No progress
29/07: No Progress.
05/08: No Progress. This action is to discover and document ICU behaviour.
DFDL will do whatever ICU does.
12/08: No Progress
19/09: More examples of inconsistent behaviour discovered
09/09: no progress
16/09: no progress
056
resolve lenghtUnit=bits including fillbytes
12/08: No Progress
19/08: No Progress
26/08: No Progress
09/09: no progress
057
Decide semantics and enumeration for 'parsed' occursCountKind
26/08: Subsequent discussion agreed on 'parsed' Need to agree semantics
09/09: no progress
16/09: occursxxx applies to array and optional elements. occursCountKind
enumeration agreed. Semantics of 'parsed' are 'parse as many as possible.
059
9/9: define how encoding, byteorder and floating point format externally
16/09: no progress
Closed actions:
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
20/05: AP to make proposal
27/05: MB proposed differentiating between input and output variables to
avoid unnecessary evaluations during parse and unparse. Need to complete
rest of variable specification.
03/06: Pointed out problem of declaring variables input or output when
used to define syntax which is used both times. MB to update proposal to
include how variables are set externally and how specific properties such
as encoding are set.
09/06: SKK to use example to dicument his proposal
17/06: SKK to refine proposal. Other aspects need progress.
24/06: SKK proposal discussed but not accepted. PL to document simpler
proposal.
07/01: PL working on proposal
15/07: PL has distributed his proposal. SH, MB and SKK have commented.
Broad agreement in principle. Need to agree on better name for
dfdl:variable to reflect the annotation's purpose. PL to update proposal.
15/07: No Progress
29/07: No Progress
05/08: SH and others had commented on Variables [Draft proposal -
20090715].doc. SH stated that fixOnMatch is not needed in dfdl v1.0
MB will document how to implement fixOnMatch behaviour with existing
function. PL to update proposal
12/08: PL to update proposal with SKK examples.
17/08: Chase PL for update
26/08: PL distributed updated proposal. Agreement in principle but some
parts need clarification
- Clearer description of only one setVariable allowed even when default
specified. State table is correct though.
- Should document that there is no implied order of defineVariable and
other annotations such as defineFormat which might refer to a variable
- Should not in the table that it is not an schema error to have multiple
setVariables for the same variable defined in the schema but only one
should be execute. For example a setVariable in each component of a
choice. Although this can only be detected at runtime it is still a schema
definition error.
- Send further comments to PL
09/09: Discussed comments.PL to update. Created separate action for
externalizing encoding etc.
16/09: Updated proposal approved. Closed
044
13/05: Bidi
20/05: AP: will check what IBM products support.
27/05: Bidi is supported so will be needed in dfdl v1
03/06: No Progress
09/06: No Progress
24/06: No Progress
01/07: AP started investigation and documented issues. Suggest do whatever
XML does.
15/07: No further progress
29/07: No Progress
05/08: AP has been in touch with IBM bidi experts.
12/08: No Progress
17/09: AP has been in touch with WTX and IBM experts. Support will cover
1) Specifying bidi string in DFDL schema,
2) Representaion in the infoset
3) bidi propeties to describe instance data, including applicability
to syntax elements
26/08: Initial proposal publish. General agreement. Send comments to AP
09/09: Discussed comments. AP to update
16/09: Updated proposal approved. Closed
055
Document which properties can take an expression
12/08: AP has distributed proposed list of properties and wording
19/08: SH to review proposal
26/08: SH agrees with proposal. Others to review.
09/09: Agreed
16/09: Closed
Work items:
No
Item
target version
status
003
Variables (from action 042)
036
awaiting completion of action 042
005
Improvements on property descriptions
not started
006
Envelopes and Payloads (from action 026)
036
awaiting completion of actions 026 and 042
007
valueCalc (from action 029)
036
ensure all aspects documented
011
How speculative parsing works (combining choice and variable-occurence -
currently these are separate) (from action 045)
awaiting completion of actions 045
012
Reordering the properties discussion: move representation earlier, improve
flow of topics
not started
033
Numeric data - what physical reps are allowed for what logical types (from
action 020)
036
ensure all behaviour documented
036
Update dfdl schema with change properties
038
Improve length section including bit handling
not started
042
Mapping of the DFDL infoset to XDM
not required for V1 specification
051
Revised scoping rules (from action 051)
036
awaiting completion of action 051
052
add entity for 'one or more white space characters'
036
053
name, baseFormat, selector, escapeSchemeRef, textNumberFormatRef,
textCalendarFormatRef, binaryCalendarFormatRef attributes only
036
054
Add occureCountKind='parsed'
036
055
Make dfdl:initiatedConet discriminating (from action 58)
036
056
bidi support (action 044)
036
057
Properties that take an expression (action 55)
036
Alan Powell
MP 211, IBM UK Labs, Hursley, Winchester, SO21 2JN, England
Notes Id: Alan Powell/UK/IBM email: alan_powell at uk.ibm.com
Tel: +44 (0)1962 815073 Fax: +44 (0)1962 816898
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
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