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Minutes for OGF DFDL Working Group Call, Oct-07-2009
by Alan Powell 08 Oct '09

08 Oct '09

Open Grid Forum: Data Format Description Language Working Group OGF DFDL Working Group Call, Oct-07-2009 Attendees Mike Beckerle (Oco) Alan Powell (IBM) Steve Hanson (IBM) Peter Lambros (IBM) Stephanie Fetzer(IBM) Apologies Steve Marting (Progeny) Suman Kalia (IBM) 051 - New scoping rules A number of emails have pointed out minor flaws in the proposal from last week so we spent most of the call refining the proposal. 1. Top level xs:schema elements MAY have a dfdl:format annotation (but only one) 2. The top level xs:schema format annotation provides defaults for the dfdl properties for every DFDL-annotatable construct in the schema. 3. local dfdl annotations on a construct of the schema take precedence over properties coming from the lexically enclosing top-level schema format annotation (if there is one) 4. when a property binding appears explicitly on a reference (element, type, or group), the same property binding cannot appear explicitly on the referenced global definition or declaration. (Schema definition error) 5. The merged explicitly defined properties from the reference and declaration/definition take precedence over the defaults applied to the declaration/definition, which take precedence over the defaults applied to the reference. 6. The same precedence rules apply to simpleType inheritance 7. There are no dfdl annotations on xs:complexTypes and xs:group declarations 8 Variables can still be used for 'parameterization' but expected to be the exception. Splitting dfdl:element and dfdl:simpleType properties. SH proposed that the dfdl:properties on an xs:element and xs:simpleType, currently are nearly the same should be separated so that as far as possible the representational properties are on the xs:simpleType and only the instance properties are on the xs:element. That is become more type oriented similar to XML schema. After discussion of the details, particularly where dfdl:length would be allowed we decided delay any decision until next week. It was noted that it will not be possible to change later. 045: Resolving points of uncertainty An updated proposal was distributed and comments received. The comment were largely editorial and will be incorporated into the next version. AOB: Draft 36 was made available but proplems with gridforge prevented it being uploaded. Contact Alan Powell for a copy. Next call 14 October 13:00 UK for 2 hours Meeting closed, 15:05 Actions raised at this meeting No Action 060 Should dfdl become more type oriented and split dfdl:properties between element and simpleType/complexType 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 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 30/09: no progress 07/10: 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 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. 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 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 refind. Details in minutes. 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 30/09: no progress 07/10: no progress 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 059 9/9: define how encoding, byteorder and floating point format externally 16/09: no progress 07/10: no progress 060 Should dfdl bcome more type oriented and split dfdl:properties between eleement and simpleType/complexType Closed actions: 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. 30/09: Closed Work items: No Item target version status 003 Variables (from action 042) 036 done 005 Improvements on property descriptions not started 006 Envelopes and Payloads (from action 026) 036 done 007 valueCalc (from action 029) 036 done 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 some improvement in 036 042 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 done 053 name, baseFormat, selector, escapeSchemeRef, textNumberFormatRef, textCalendarFormatRef, binaryCalendarFormatRef attributes only 036 done 054 Add occureCountKind='parsed' 036 done 055 Make dfdl:initiatedConet discriminating (from action 58) 036 done 056 bidi support (action 044) 036 done 057 Properties that take an expression (action 55) 036 done 058 textPadCharacter %#rxx limitation and split to textxxxxPadCharacter 059 limit terminatorCanBeMissing to last element in schema. Ignore elsewhere. 060 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 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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Validation of min/mxOccurs
by Tim Kimber 08 Oct '09

08 Oct '09

The specification is not entirely clear on a the following points a) If the input document contains too many occurrences of an element, should that be treated as a validation error, or a processing error? Section 5.2.1 says "It is a parse error when an array is found to have a number of occurrences not conforming to the minOccurs and maxOccurs constraints in the absence of a default value specification. Note that specifically, this is not a validation error, it is a processing error" Points to note: - When unparsing, the infoset might omit an element which has minOccurs > 0. Should that be reported as a validation error, or a processing error? - When unparsing, the infoset might omit an entire group. If all of the elements in the omitted group were optional, should this be considered an error ( because groups are implicitly required ) or not? - When parsing an unordered group, if the input document contains more than maxOccurs occurrences of one of the members, is that a processing error or a validation error? The specification seems to imply that it is a validation error, but that seems inconsistent with section 5.2.1 It may be necessary to include a section which specifies how the DFDL processor should perform schema validation. regards, Tim Kimber, Common Transformation Team, Hursley, UK Internet: kimbert(a)uk.ibm.com Tel. 01962-816742 Internal tel. 246742 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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Agenda for OGF DFDL WG call 07 Octobert 2009 - 13:00 UK (8:00 ET),
by Alan Powell 07 Oct '09

07 Oct '09

Go through actions - In particular 051 - Scoping rules Email from Steve suggesting splitting properties between elements and types. 045: Speculative Parsing Updated proposal from Alan and reponses 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 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 30/09: 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 30/09: 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 30/09: AP distributed proposal and others commented. Brief discussion AP to incorporate update and reissue 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 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. 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 30/09: no progress 056 resolve lenghtUnit=bits including fillbytes 12/08: No Progress 19/08: No Progress 26/08: No Progress 09/09: no progress 30/09: no progress 059 9/9: define how encoding, byteorder and floating point format externally 16/09: no progress 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 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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Re: [DFDL-WG] Parsing Rules for resolving points of uncertainty
by Tim Kimber 07 Oct '09

07 Oct '09

- I'd like to see a version in which the comments are addressed and removed. - typo in para 1 : 'neatest' - 'A point of uncertainty is caused'. Probably better to say that it is 'opened' or 'started'. - para which begins 'For an optional element' has a repeated phrase towards the end. - I was assuming that any processing error, of any kind, relating to any physical region, would cause backtracking to the nearest point of uncertainty. If there is any set of processing errors that *doesn't* cause backtracking, that set should be described in this doc. - Should have a statement about how validation errors affect points of uncertainty. I'm assuming that they don't ( either the parse is immediately stopped by the host application, or the validation error is ignored) - Should have a statement about how schema definition errors, if detected by the DFDL parser, affect points of uncertainty. I'm assuming that they are treated exactly like a processsing error, and cause backtracking to occur in the normal way. regards, Tim Kimber, Common Transformation Team, Hursley, UK Internet: kimbert(a)uk.ibm.com Tel. 01962-816742 Internal tel. 246742 From: dfdl-wg-request(a)ogf.org To: dfdl-wg(a)ogf.org Date: 06/10/2009 18:18 Subject: dfdl-wg Digest, Vol 38, Issue 2 Send dfdl-wg mailing list submissions to dfdl-wg(a)ogf.org To subscribe or unsubscribe via the World Wide Web, visit http://www.ogf.org/mailman/listinfo/dfdl-wg or, via email, send a message with subject or body 'help' to dfdl-wg-request(a)ogf.org You can reach the person managing the list at dfdl-wg-owner(a)ogf.org When replying, please edit your Subject line so it is more specific than "Re: Contents of dfdl-wg digest..." Today's Topics: 1. DFDL Specification draft v1.036 available (Alan Powell) 2. Parsing Rules for resolving points of uncertainty V2 (Alan Powell) ----- Message from Alan Powell <alan_powell(a)uk.ibm.com> on Tue, 6 Oct 2009 14:46:36 +0100 ----- To: dfdl-wg(a)ogf.org Subject: [DFDL-WG] DFDL Specification draft v1.036 available Draft 036 of the DFDL Specification V1 is available but unfortunately sourceforge seems to be having problems again so I cannot upload it. If you need a copy please send me an email. 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 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 ----- Message from Alan Powell <alan_powell(a)uk.ibm.com> on Tue, 6 Oct 2009 18:16:59 +0100 ----- To: dfdl-wg(a)ogf.org Subject: [DFDL-WG] Parsing Rules for resolving points of uncertainty V2 Updated proposal based on comments 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 ----- Forwarded by Alan Powell/UK/IBM on 06/10/2009 18:15 ----- From: Steve Hanson/UK/IBM To: Tim Kimber/UK/IBM@IBMGB Cc: Alan Powell/UK/IBM@IBMGB, Suman Kalia/Toronto/IBM@IBMCA, Mike Beckerle <mbeckerle.dfdl(a)gmail.com>, Peter Lambros/UK/IBM@IBMGB, steve.marting(a)progeny.net Date: 30/09/2009 10:31 Subject: Re: Parsing Rules for resolving points of uncertainty (speculative parsing) Some more comments in here. Steve copied in as will be discussed on call today. [attachment "Resolving Uncertainty v1.doc" deleted by Alan Powell/UK/IBM] Regards Steve Hanson Programming Model Architect, WebSphere Message Brokers, OGF DFDL WG Co-Chair, Hursley, UK, Internet: smh(a)uk.ibm.com, Phone (+44)/(0) 1962-815848 From: Tim Kimber/UK/IBM To: Mike Beckerle <mbeckerle.dfdl(a)gmail.com> Cc: Alan Powell/UK/IBM@IBMGB, Suman Kalia <kalia(a)ca.ibm.com>, Peter Lambros/UK/IBM@IBMGB, Robert Connolly <rconnoll(a)us.ibm.com>, Steve Hanson/UK/IBM@IBMGB Date: 28/09/2009 14:20 Subject: Re: Parsing Rules for resolving points of uncertainty (speculative parsing) re: Mike's point, I would suggest - member of a choice group/unordered group/group containing floating elements: scope of uncertainty is the scope of the element - optional occurrence : parser tries first to parse another occurrence, and the scope of uncertainty is the scope of the element. Secondly, parser tries to parse the item following the element ( which may be a group ) and the scope of uncertainty is the scope of that element/group. re: Alan's draft, I think the final para could be replaced with the following two statements: - if a processing error is encountered while parsing an option, the parser will back up and try the next option. If there are no further options, the processing error will propagate out to the next enclosing point of uncertainty. - a dfdl:assert can be used to trigger a processing error. If the expression evaluates to false, the parser will behave exactly as if a normal processing error had been encountered. Wording can probably be improved... regards, Tim Kimber, Common Transformation Team, Hursley, UK Internet: kimbert(a)uk.ibm.com Tel. 01962-816742 Internal tel. 246742 From: Mike Beckerle <mbeckerle.dfdl(a)gmail.com> To: Alan Powell/UK/IBM@IBMGB Cc: Steve Hanson/UK/IBM@IBMGB, Tim Kimber/UK/IBM@IBMGB, Robert Connolly <rconnoll(a)us.ibm.com>, Peter Lambros/UK/IBM@IBMGB, Suman Kalia <kalia(a)ca.ibm.com> Date: 25/09/2009 21:53 Subject: Re: Parsing Rules for resolving points of uncertainty (speculative parsing) Some feedback attached. We need some notion of the region of uncertainty, so we can discuss where assertions and discriminators have effect, and so we can say when the uncertainty ends and we no longer consider backtracking that region just because we finished without processing error. On Fri, Sep 25, 2009 at 11:51 AM, Alan Powell <alan_powell(a)uk.ibm.com> wrote: Guys (limited distribution initially) I have simplified the previous speculative parsing description into a set of simple rules. Discussion points 1. Deemed to be found rule 1 'All the components of the option are found' could severely limit the ability to do partial parsing as it includes everything up to the terminator. 2. Do all/more the processing errors need to be listed for Not Found rule 3? 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 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 [attachment "Resolving Uncertainty v1.doc" deleted by Tim Kimber/UK/IBM] [attachment "Resolving Uncertainty v1.doc" deleted by Steve Hanson/UK/IBM] 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 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 [attachment "Resolving Uncertainty v2.doc" deleted by Tim Kimber/UK/IBM] -- dfdl-wg mailing list dfdl-wg(a)ogf.org http://www.ogf.org/mailman/listinfo/dfdl-wg 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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Parsing Rules for resolving points of uncertainty V2
by Alan Powell 06 Oct '09

06 Oct '09

Updated proposal based on comments 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 ----- Forwarded by Alan Powell/UK/IBM on 06/10/2009 18:15 ----- From: Steve Hanson/UK/IBM To: Tim Kimber/UK/IBM@IBMGB Cc: Alan Powell/UK/IBM@IBMGB, Suman Kalia/Toronto/IBM@IBMCA, Mike Beckerle <mbeckerle.dfdl(a)gmail.com>, Peter Lambros/UK/IBM@IBMGB, steve.marting(a)progeny.net Date: 30/09/2009 10:31 Subject: Re: Parsing Rules for resolving points of uncertainty (speculative parsing) Some more comments in here. Steve copied in as will be discussed on call today. [attachment "Resolving Uncertainty v1.doc" deleted by Alan Powell/UK/IBM] Regards Steve Hanson Programming Model Architect, WebSphere Message Brokers, OGF DFDL WG Co-Chair, Hursley, UK, Internet: smh(a)uk.ibm.com, Phone (+44)/(0) 1962-815848 From: Tim Kimber/UK/IBM To: Mike Beckerle <mbeckerle.dfdl(a)gmail.com> Cc: Alan Powell/UK/IBM@IBMGB, Suman Kalia <kalia(a)ca.ibm.com>, Peter Lambros/UK/IBM@IBMGB, Robert Connolly <rconnoll(a)us.ibm.com>, Steve Hanson/UK/IBM@IBMGB Date: 28/09/2009 14:20 Subject: Re: Parsing Rules for resolving points of uncertainty (speculative parsing) re: Mike's point, I would suggest - member of a choice group/unordered group/group containing floating elements: scope of uncertainty is the scope of the element - optional occurrence : parser tries first to parse another occurrence, and the scope of uncertainty is the scope of the element. Secondly, parser tries to parse the item following the element ( which may be a group ) and the scope of uncertainty is the scope of that element/group. re: Alan's draft, I think the final para could be replaced with the following two statements: - if a processing error is encountered while parsing an option, the parser will back up and try the next option. If there are no further options, the processing error will propagate out to the next enclosing point of uncertainty. - a dfdl:assert can be used to trigger a processing error. If the expression evaluates to false, the parser will behave exactly as if a normal processing error had been encountered. Wording can probably be improved... regards, Tim Kimber, Common Transformation Team, Hursley, UK Internet: kimbert(a)uk.ibm.com Tel. 01962-816742 Internal tel. 246742 From: Mike Beckerle <mbeckerle.dfdl(a)gmail.com> To: Alan Powell/UK/IBM@IBMGB Cc: Steve Hanson/UK/IBM@IBMGB, Tim Kimber/UK/IBM@IBMGB, Robert Connolly <rconnoll(a)us.ibm.com>, Peter Lambros/UK/IBM@IBMGB, Suman Kalia <kalia(a)ca.ibm.com> Date: 25/09/2009 21:53 Subject: Re: Parsing Rules for resolving points of uncertainty (speculative parsing) Some feedback attached. We need some notion of the region of uncertainty, so we can discuss where assertions and discriminators have effect, and so we can say when the uncertainty ends and we no longer consider backtracking that region just because we finished without processing error. On Fri, Sep 25, 2009 at 11:51 AM, Alan Powell <alan_powell(a)uk.ibm.com> wrote: Guys (limited distribution initially) I have simplified the previous speculative parsing description into a set of simple rules. Discussion points 1. Deemed to be found rule 1 'All the components of the option are found' could severely limit the ability to do partial parsing as it includes everything up to the terminator. 2. Do all/more the processing errors need to be listed for Not Found rule 3? 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 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 [attachment "Resolving Uncertainty v1.doc" deleted by Tim Kimber/UK/IBM] [attachment "Resolving Uncertainty v1.doc" deleted by Steve Hanson/UK/IBM] 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 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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DFDL Specification draft v1.036 available
by Alan Powell 06 Oct '09

06 Oct '09

Draft 036 of the DFDL Specification V1 is available but unfortunately sourceforge seems to be having problems again so I cannot upload it. If you need a copy please send me an email. 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 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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Minutes for OGF DFDL Working Group Call, Sept-30-2009
by Alan Powell 01 Oct '09

01 Oct '09

Open Grid Forum: Data Format Description Language Working Group OGF DFDL Working Group Call, Sept-30-2009 Attendees Mike Beckerle (Oco) Alan Powell (IBM) Suman Kalia (IBM) Steve Marting (Progeny) Steve Hanson (IBM) Tim Kimber (IBM) Apologies Peter Lambros (IBM) 1. %#rxx in TextPadCharacter It has been proposed that use of the raw entity should be restricted in textPadCharacter It was agreed that - dfdl:textPadCharacter only one byte raw entity (%#rxx) can be specified - dfdl:textPadCharacter must not be specified as a raw byte value if the code page is a variable-width code page. Also SH proposed that dfdl:textPadCharacter be split to allow a default be specified for each logical type in a similar way to dfdl:textxxxJustification. Approved dfdl:textPadCharacter will be split into dfdl:textStringPadCharacter, dfdl:textNumberPadCharacter, dfdl:textBooloeanPadCharacter, dfdl:textCalendarPadCharacter 2. finalTerminatorCanBeMissing It has been proposed to restrict the use of this property to the last field in a definition as the only known used case is missing terminator (typically <LF>) at end of file MB expressed concern that if the property was only allowed to be specified on the last element in the schema it would make it difficult for that definition to be reused. Agreed that dfdl:finalTerminatorCanBeMissing can be specified on any element but is ignore expect on the last element in the schema. 051 - New scoping rules There had been a number of emails from most of the members of the work group during the week, mostly expressing dissatisfaction with the new rules based on usability and lack of referential transparency. SKK expressed support for the new rules as he felt is was easier to implement tooling. After considerable debate which mainly re-evaluated previously suggested solutions. Need to be able to a. Set defaults for dfdl properties b. Allow the normal use of xs:include and xs:import to build schemas. c. Allow the applicable dfdl:properties on any given component to be easily discoverable. d. Be 'easy' for users to understand. The following proposal evolved. - A way to define dfdl property defaults at a schema level. Probably by a global dfdl:format annotation. The defaults apply to every component in the schema document. - The global defaults belong to the target namespace of the schem so follow normal schema composition rules. - dfdl properties on xs:complexType and xs:group do not put the properties in scope. - dfdl:properties on an element and its referenced simpleType are merged. It is an error if the same property is defined on the element and the referenced simpleType - dfdl:properties on an element do not override properties on its referenced complexType. dfdl:properties on a complex element effectively only apply to the syntax part of the element (initiator terminator, etc), - dfdl:properties on an element reference and its global element declaration are merged. It is an error if the same property is defined on the element reference and the element declaration. - dfdl:properties on an group reference and its global group declaration are merged. It is an error if the same property is defined on the group reference and the group declaration - variables can still be used for 'parameterization' but expected to be the exception. AP to write up proposal 045: Resolving points of uncertainty A brief discussion of AP proposal and subsequent comments. These were mostly clarification and expansions rather than disagreement. AP to incorporate comment and reissue. Next call 7 October 13:00 UK for 2 hours Meeting closed, 15:15 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 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 30/09: 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 30/09: 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 30/09: AP distributed proposal and others commented. Brief discussion AP to incorporate update and reissue 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 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. 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 30/09: no progress 056 resolve lenghtUnit=bits including fillbytes 12/08: No Progress 19/08: No Progress 26/08: No Progress 09/09: no progress 30/09: no progress 059 9/9: define how encoding, byteorder and floating point format externally 16/09: no progress Closed actions: 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. 30/09: Closed Work items: No Item target version status 003 Variables (from action 042) 036 done 005 Improvements on property descriptions not started 006 Envelopes and Payloads (from action 026) 036 done 007 valueCalc (from action 029) 036 done 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 some improvement in 036 042 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 done 053 name, baseFormat, selector, escapeSchemeRef, textNumberFormatRef, textCalendarFormatRef, binaryCalendarFormatRef attributes only 036 054 Add occureCountKind='parsed' 036 done 055 Make dfdl:initiatedConet discriminating (from action 58) 036 done 056 bidi support (action 044) 036 done 057 Properties that take an expression (action 55) 036 done 058 textPadCharacter %#rxx limitation and split to textxxxxPadCharacter 057 limit terminatorCanBeMissing to last element in schema. Ignore elsewhere. 057 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 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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New scoping rules
by Alan Powell 30 Sep '09

30 Sep '09

All Attached is the description of the new DFDL scoping rules. We did not discuss the rules for simpleType derivations so I have assumed that it uses the same rules as simpleType reference, namely that the properties are merged and there must not be any duplicate properties specified. I have removed most of the complicated examples as they no longer apply. 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 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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Agenda for OGF DFDL WG call 30 Septembert 2009 - 13:00 UK (8:00 ET)
by Alan Powell 29 Sep '09

29 Sep '09

Simple ones first 1. %#rxx in TextPadCharacter It has been proposed that use of the raw entity should be restricted in textPadCharacter 2. finalTerminatorCanBeMissing It has been proposed to restrict the use of this property to the last field in a definition as the only known used case is missing <LF> at end of file 3 Go through actions - In particular 051 - scoping rules (email from AP and MB) 045: Speculative Parsing 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 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 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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Minutes for OGF DFDL Working Group Call, Sept-23-2009
by Alan Powell 23 Sep '09

23 Sep '09

Open Grid Forum: Data Format Description Language Working Group OGF DFDL Working Group Call, Sept-23-2009 Attendees Mike Beckerle (Oco) Alan Powell (IBM) Suman Kalia (IBM) Steve Marting (Progeny) Apologies Peter Lambros (IBM) Steve Hanson (IBM) 1 Go through actions - 051 - scoping rules (email from AP) AP had updated SKK element/group reference examples with new scoping rules which highlighted some concerns We haven't really defined the scoping rules for dfdl:ref but they are assumed to be 'merge with local property definitions. Local takes precedence' dfdl:ref to defineFormat blocks are very difficult to use with parameterization. A dfdl:ref on an element/group reference probably has no effect. The properties would need to be converted to dfdl:setVariable . A dfdl:ref on a global element/group declaration is OK but any property that needs to be overridden must be defined locally as a variable. There is no easy way to provide a default for properties on global elements/groups that can be overridden. Suman had done this in his examples. dfdl:lenghtKind does not take an expression so cannot be a parameter. MB concerned that new rules do not allow referential integrity. MB had to leave early. Went through the examples and although they would not pass dfdl validation as the global components do not define all the necessary dfdl properties they do obey the new scoping rules. SKK asked that an example of a global element of complexType be included. Needs more discussion. Following not discussed 2. %#rxx in TextPadCharacter It has been proposed that use of the rew entity should be restricted in textPadCharacter 3. finalTerminatorCanBeMissing It has been proposed to restrict the use of this propoerty to the last field in a definition as the only known used case is missing <LF> at end of file AOB V036 of the DFDL Specification will be published early next week. Next call 23 September 13:00 UK for 2 hours Meeting closed, 14:00 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(a)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. 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