Open Grid Forum: Data Format Description Language Working Group
OGF DFDL Working Group Call, October-28-2009
Attendees
Alan Powell (IBM)
Steve Marting (Progeny)
Stephanie Fetzer(IBM)
Apologies
Mike Beckerle (Oco)
Suman Kalia (IBM)
Steve Hanson (IBM)
Peter Lambros (IBM)
1. 051 Scoping Rules
Reviewed latest draft v7.
"It is a schema definition error if more that one format annotation occurs
at the same annotation point, except when selectors are used, or if the
same property is defined in long and short form."
Agreed thaht multiple annotations should not be allowed. Wording on
selectors is not clear. Will remove from this sentence ad add sentence to
say that selectors have been applied already.
Need better definition of 'applicable' and 'required' properties. Refer to
property precedence section
2. Resolving points of uncertainty and parsing rules
Discussed Alan's proposal for describing variable arrays.
"An alternative might be to consider an array as two points of
uncertainty. On point is for the array and the other, which is nested
inside the first, for the element. We can then have the rule that the
discriminator resolves the element uncertainty only which always exists so
doesn't need to be 'potential'.
The array uncertainty is resolved when minOccurs have been found."
Needs further discussion
3. UTC timezone 'Z'
There is a conflict between the ZZZU calendar pattern and the
calendarUseZForUTC property
ZU time zone (RFC 822) (Number) Z
with output "Z" if the
time zone is +00:00)
calendarUseZForUTC
Enum
Valid values ?always?, ?never?, ?onInput?, ?onOutput?
Applies when a time zone appears in the data with pattern ZZZ (that is,
+hh:mm) and the time zone is UTC (that is, GMT+00:00). Specifies whether
?Z? or ?+00:00? should be used.
Annotation: dfdl:calendarFormat
I suggest we drop the property and have the following
ZZZ (strict) => accept +00:00 only on input, use +00:00 on output
ZZZU (strict) => accept Z only on input, use Z on output
ZZZ (lax) => accept +00:00 & Z on input, use +00:00 on output
ZZZU (lax) => accept +00:00 & Z on input, use Z on output
Agreed to drop calendarUseZForUTC but need to add symbols IU and TU
4. Go through remaining actions
Actions updated below
5. Plan to finish DFDL v1
Next call 04 November 13:00 UK (8:00 ET)
Meeting closed, 14:15
Next action: 063
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
30/09: no progress
07/10: no progress
14/10: no progress
21/10: Will produce a list of known issues.
28/10: Discussed ICU farctional seconds behaviour. SF to send latest
understanding.
033
MB: Need for scope indicator on discriminator
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
30/09: no progress
07/10: no progress
14/10: Action re-titled and assigned to Mike B
21/10: no progress
28/10: 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
30/09: no progress
07/10: no progress
14/10: no progress
21/10: no progress
28/10: 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
30/09: AP distributed proposal and others commented. Brief discussion AP
to incorporate update and reissue
07/10: Updated proposal was discussed.Comments will be incorporated into
the next version.
14/10: Alan to update proposal to include array scenario where minOccurs >
0
21/10: Updated proposal reviewed
28/10: Updated proposal reviewed see minutes
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
30/09: no progress
07/10: no progress
14/10: no progress
21/10: Discussed the real need for this being in the specification. It
seemed that the main value is it define a schema location for downloading
'known' defaults from the web.
28/10: 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
30/09: Significant dissatisfaction with proposed new rules. New proposal
developed during call. AP to document.
07/10: New proposal was refined. Details in minutes.
14/10: Discussed at length. Details in minutes.
21/10: Discussed at length. Details in minutes.
056
resolve lenghtUnit=bits including fillbytes
12/08: No Progress
19/08: No Progress
26/08: No Progress
09/09: no progress
30/09: no progress
07/10: no progress
14/10: no progress
21/10: no progress
28/10: no progress
059
9/9: define how encoding, byteorder and floating point format externally
16/09: no progress
07/10: no progress
14/10: no progress
21/10: SH to investigate
28/10: no progress
061
Refactor dfdl:textNumberFormat to remove dfdl:numberBase.
14/10: Base 2, 8, 16 numbers are invariably integers without formatting,
use of pattern etc is overkill
21/10: no progress
28/10: no progress
062
SH investigate technical writer support.
28/10: SH had contacted S Gao to understand the W3 process and support.
Closed actions:
Work items:
No
Item
target version
status
005
Improvements on property descriptions
not started
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)
037
ensure all behaviour documented
036
Update dfdl schema with change properties
ongoing
038
Improve length section including bit handling
some improvement in 036
042
Mapping of the DFDL infoset to XDM
none
not required for V1 specification
051
Revised scoping rules (from action 051)
037
awaiting completion of action 051
058
textPadCharacter %#rxx limitation and split to textxxxxPadCharacter
037
059
limit terminatorCanBeMissing to last element in schema. Ignore elsewhere.
037
060
New empty string semantic for dfdl:binaryBooleanTrueRep
037
061
Change maxOccurs violations from processing error to validation error (if
not 'fixed')
037
062
Drop calendarUseZForUTC. describe zU, IU and TU symbols
037
ã Copyright IBM Corp. 1998, 2007 All Rights Reserved
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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