[DFDL-WG] Minutes for OGF DFDL Working Group Call, February 02 & 03-2010
Alan Powell
alan_powell at uk.ibm.com
Thu Feb 4 10:55:56 CST 2010
Open Grid Forum: Data Format Description Language Working Group
OGF DFDL Working Group Call, February 02 & 03-2010
Attendees
Mike Beckerle (Oco)
Steve Hanson (IBM)
Alan Powell (IBM)
Suman Kalia (IBM)
Peter Lambros (IBM)
Tim Kimber(IBM)
Apologies
Stephanie Fetzer (IBM)
Steve Marting (Progeny)
1. Discriminators
Discussed the 'parent exists' and 'component exists' options for
dfdl:discriminator semantics. The WG agreed that DFDL would adopt the
'component exists' semantics where the discriminator indicates that the
component it is on exists and does not say anything about the components
parent.
Examples need minor changes and full syntax. Arrays would be the same as
optional components.
Discriminators are not allowed on
- Global groups and the top level sequence or choice of a global group.
- Global element decalrations
- The top level group of a complex type.
- Anonymous groups other than when it is the top level of a choice branch.
The discriminator timing property was also discussed. It was agreed that a
parser should be able to tell when it is possible to evaluate the
expression so the timing property will be removed.
The following will be added instead 'The expression will be evaluated when
the referenced elements are known to exist or known not to exist.'
Timing on asserts was also mention but deferred for the time being.
Alan will update the 'component exists' proposal.
1. Action 077 Cobol and numberFormats
Suman highlighted a problem using textNumberFormat for COBOL numbers where
a separate textNumberFormat is required for each length. This is because a
different numberPattern is required for each one. It was suggested that
numberPattern was move from textNumberFormat to the standard properties
but it was decided to get rid of textNumberFormat altogether and move all
the properties. Tim pointed out that this meant that is was now not
possible to just vary the number properties so there may be more
definedFormats but this was not felt to be a problem.
For consistency it was agreed that textCalendarFormat would also be
removed. EscapeScheme is different so will be retained.
2. Remaining 037 review issues
2. I agree with the existing comment that the RFC2119 key words should be
upper case. Agreed that the RFC2119 keywords should be in upper case and
wherever possible the spec should be reworded to use the key words.
16.2 scannablility with lengthKind pattern: One use case it to find the
end of of a character element by looking for 'binary' bytes of the
following element.
Discussed whether dfdl:lengthKind pattern should be allowed for binary
elements. Pattern scanning inherently treats the data as characters but
for single byte encodings a binary byte can be specified by its character
codepoint. Agreed that dfdk:lengthKind pattern will be allowed for
binary elements when the encoding is US-ASCII. (why didn't we say any
single byte character set?)
Section 16.2 says that that the children on a complex type must not change
the encoding. This will be relaxed when encoding is US-ASCII.
DFDL raw entities will not be allowed in a pattern.
Tracker Issue: illegal character encodings for parsing and unparsing.
What should DFDL do when it finds illegal bytes when converting strings
during parsing and unparsing? Discussed adding a new property to declare a
substitution character. Discussed what products do and ICU. Decided to
follow ICU.
Conversions to Unicode (during parsing) will substitue characters that
cannot be converted with the unicode substitute character (U+FFFD). When
converting from Unicode (during unparsing) they will be substituted with
the substitute character for that encoding, for example 0x1A (Control-Z)
for ASCII.
Tracker Issue: Processing-time Schema Definition Errors
Mike will reword Section 2.3.1
Tim will supply rules for the order that terminators and separators are
look for in the data stream
Tracker Issue: "round trip" for infoset. Should we omit the whole point?
Rephrase sentence 'It is possible to define a schema so that when infoset
unparsed and the datastream reparsed, the same infoset will be produced'
3. Go through Actions
Meeting closed, 15:00
Next call Tuesday 10 February January 2010 13:00 UK
Next action: 079
Actions raised at this meeting
No
Action
078
MB: Reword section 2.3.1 incorporating markup order rules.
Current Actions:
No
Action
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
...
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
04/11: Discussed semantics of disciminators on arrays. MB to produce
examples
11/11: Absorbing action 033 into 045. Maybe decorated discrminator kinds
are needed after all. MB and SF to continue with examples.
18/11: Went through WTX implementation of example. SF to gather more
documentation about WTX discriminator rules.
25/11: Further discussion. Will get more WTX documentation. Need to
confirm that no changes need to Resolving Uncertainty doc.
04/11: Further discussion about arrays.
09/12: Reviewed proposed discriminator semantic.
16/12: Reviewed discriminator examples and WTX semantic.
23/12: SF to provide better description of WTX behaviour and invite B
Connolley to next call
06/01:B Connolly not available. SF to provide more complete description.
13/01: Stephaine took us through a description of WTX identifiers. Mike
agreed to write up in DFDL terms.
20/01: Mike will write up
27/01: further discussion of discriminators
29/01: Alan had emailed both proposals but not enough time to discuss
02/02: Agreed to adopt 'component exists' semantics for discriminators
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.
...
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
04/11: no progress
11/11: no update
18/11: no update
25/11: Agreed to try to produce for CSV and fixed formats
04/12: no update
09/12: no update
16/12: no update
23/12: no update
06/01: no progress. If there is no resource to complete this action it can
be deferred
13/01:no progress
20/01: no progress
27/01: no progress
29/01: No progress. The predefined formats do not need to be available
when the spec is published.
Suman said that he had been mapping COBOL structures to DFDL and it didn't
look as though the way text numbers are define is very usable. He will
document for next call
03/03: No progress
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
09/12: no update
16/12: reminded dent to project manager
23/12: SH will send another reminder.
06/01: Another reminder will be sent
13/01: no update
20/01: no update
27/01: no progress
29/01: no progress
03/02: IBM is still invetsigating
077
SKK: mapping of COBOL numbers to textNumberFormats.
03/02: Suman documented the problem. Agreed to remove textNumberFormat and
textCalendarFormat.
078
MB: Reword section 2.3.1 incorporating markup order rules.
Closed actions
No
Action
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
069
ICU fractional seconds
039
070
Write DFDL primer
071
Write test cases.
072
it is a processing error if the number of occurrences in the data does not
match the value of the expression or prefix
039
073
Rename dfdl:separatorPolicy="required" to "always".
039
Defferred untilaction 071 agreed
078
document UPA checks
039
079
Semantics of length=0, nil handling and defaults. (A071)
039
080
Tlog: Allow LengthKind delimited for packed/bcd (A074)
039
081
Update empty sequence section (A075)
039
082
semantics of minOccurs= 0 on choice branches (A076)
039
083
Implement RFC2116
084
Length|Kind pattern scanability rules
085
Invalid character substitution
Regards
Alan Powell
Development - MQSeries, Message Broker, ESB
IBM Software Group, Application and Integration Middleware Software
-------------------------------------------------------------------------------------------------------------------------------------------
IBM
MP211, Hursley Park
Hursley, SO21 2JN
United Kingdom
Phone: +44-1962-815073
e-mail: alan_powell at uk.ibm.com
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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.ogf.org/pipermail/dfdl-wg/attachments/20100204/74d68c42/attachment-0001.html
More information about the dfdl-wg
mailing list