April 2010 - dfdl-wg - lists.ogf.org

Action 086: Nils and Defaults for complex elements
by Alan Powell 05 May '10

05 May '10

Part of Action 086 is to apply the clarified Nils and Defaulting rules to complex elements and develop some examples. The tables for parsing and unparsing are simpler because there is no need to consider nillable. I have assumed - emptyValueDelimiterPolicy does apply to complex elements. - on parsing a complex element is empty if its children's content is empty. That is the child delimiters may be present. - on unparsing defaulting occurs if a complex item is missing or present present but has no children. Defaulting for complex elements on parsing initiator region content region Logical Value matching Not empty parsed children matching empty A default is specified emptyValueDelimiterPolicy must be initiator or both default value of children empty Not empty Initiator must not be specified parsed children empty empty A default is specified emptyValueDelimiterPolicy must be none or Initiator must not be specified default value of children Defaulting for complex elements on unparsing Logical Value initiator region contains content region contains Missing or present with no children default of all children is empty string emptyValueDelimiterPolicy none empty empty emptyValueDelimiterPolicy initiator or both initiator string default of any child is not empty string initiator string representation of the child default value. a least on child exists initiator string representation of children Examples Defaulting Complex types ONE:one, TWO: TWOONE:twoone; TWOTWO:twotwo; TWOTHREE:twothree, THREE:three <end> In the following TWO is 'empty' (when relevant dfdl properties are set) ONE:one,THREE:three<end> |separatorPolicy='suppressed', emptyValueDelimiterPolicy='none' ONE:one,,THREE:three<end> separatorPolicy='required', emptyValueDelimiterPolicy='none' ONE:one<end> separatorPolicy='suppressed' or 'suppressedAtEnd', emptyValueDelimiterPolicy='none' <end> separatorPolicy='suppressed' or 'suppressedAtEnd', emptyValueDelimiterPolicy='none' ONE:one,TWO:,THREE:three<end> separatorPolicy= don't care , emptyValueDelimiterPolicy='initiator' ONE:one,TWO:<end> separatorPolicy= 'suppressed' or 'suppressedAtEnd', emptyValueDelimiterPolicy='initiator' ONE:one,TWO:,<end> separatorPosition='postfix' separatorPolicy= 'suppressed' or 'suppressedAtEnd', emptyValueDelimiterPolicy='initiator' *** Should 'postfix' separator be there when 'supressedAtEnd' *** ONE:one,TWO:TWOONE:,THREE:three<end> separatorPolicy= 'suppressed' or 'suppressedAtEnd', (TWO)emptyValueDelimiterPolicy='initiator' (TWOONE)emptyValueDelimiterPolicy='initiator' ONE:one,TWOONE:,THREE:three<end> separatorPolicy= 'suppressed' or 'suppressedAtEnd', (TWO)emptyValueDelimiterPolicy='none' (TWOONE)emptyValueDelimiterPolicy='initiator' *** We should discuss this example. *** 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(a)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

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Cancelled: OGF DFDL Working Group weekly call
by Steve Hanson 28 Apr '10

28 Apr '10

Cancelled: OGF DFDL Working Group weekly call 28/04/2010 - (Repeats) Chair: Steve Hanson/UK/IBM Sent By: Steve_Hanson/UK/IBM%IBMGB Location: Participant Passcode: 8190865 Country Toll Numbers Freephone/Toll Free Number AUSTRIA 43-1-928-9652 BELGIUM 32-2-400-6791 0800-4-9612 DENMARK 45-7014-0237 FRANCE LYON: 33-4-26-69-12-74 080-511-3725 FRANCE MARSEILLE: 33-4-86-06-00-74 080-511-3725 FRANCE PARIS: 33-1-70-70-81-58 080-511-3725 GERMANY 49-69-2222-20363 0800-100-6504 IRELAND 353-1-247-7768 ITALY 39-02-3600-3648 800-985-679 LUXEMBOURG 352-27-000-1312 NETHERLANDS 31-20-713-2741 0800-020-3237 SPAIN 34-91-414-1542 800-099-667 SWEDEN 46-8-566-10-780 SWITZERLAND 41-44-580-3334 0800-000-516 UNITED KINGDOM BIRMINGHAM: 44-121-210-9014 0800-279-9193 UNITED KINGDOM GLASGOW: 44-141-202-3214 0800-279-9193 UNITED KINGDOM LEEDS: 44-113-301-2114 0800-279-9193 UNITED KINGDOM LONDON: 44-20-7019-0808 0800-279-9193 UNITED KINGDOM MANCHESTER: 44-161-601-1414 0800-279-9193 USA 866-505-4412 Steve_Hanson Steve Hanson has cancelled this meeting. Your calendar will be updated to reflect this change. Repeats This entry repeats Required: Akmal Chaudhri, Alan Powell/UK/IBM@IBMGB, mbeckerle.dfdl(a)gmail.com, Stephanie Fetzer/Charlotte/IBM@IBMUS, steve.marting(a)progeny.net, Suman Kalia/Toronto/IBM@IBMCA, Tim Kimber/UK/IBM@IBMGB Optional: alejandr(a)ncsa.illinois.edu, dfdl-wg(a)ogf.org, gary.sikora(a)progeny.net

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OGF DFDL WG call 28 April 20 - Cancelled
by Alan Powell 27 Apr '10

27 Apr '10

All Steve H, Tim and I will not be available for the call so we have cancelled for this week. Please send me any updates to current actions Current Actions: No Action 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 ... 17/02: IBM is willing in principle to publish the test case format and some of the test cases. May need some time to build a 'compliance suite' 24/03: No progress 03/03: Discussions have been taking place on the subset of tests that will be provided. 10/03: work is progressing 17/03: work is progressing 31/03: work is progressing 14/04: And XML test case format has been defined and is being tested. 21/04. Schema for TDML defined. Need to define how this and the test cases will be made public 084 Check behaviour of dfdl:inputValueCalc and outputValueCalc. 14/04: no prorgess 21/04: no progress 085 ALL: publicize Public comments phase to ensure a good review.. 14/04: see minutes 21/04: Press release, OMG and other standards bodies. 086 AP: Nils and Defaults during unparsing - update table 31/03: TK to documetn use cases for parsing 14/04: Investigate new property to control empty string behaviour. 21/04: After investigation a new property is not required. New rules developed and tables updated. Need examples of complexTypes to confirm tables apply. Review Nils, defaulting spec section. 088 define semantics of choiceKind 'fixedLength' 31/03: TK to provide definition of calculable length. Investigate PL/I varchars and Cobol occurs dependingon. 14/04Tim had distributed a document starting the definition of calculable length for the longest choice member. Alan had done some investigation of COBOL occurs depending on and when used in the working section of a program then the maximum storage was reserved but when used in the linkage section the dependent number was uses. We need to understand how the WMB COBOL importer deals with ODO. 21/04: Need to define 'calculable length' and WMB importer ODO behaviour. 090 Semantics of separatorPolicy 14/04: Discussion on detecting when complex types should be defaulted. Examples needed. 21/04: Complex defaulting examples needed for new rules 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(a)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

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Minutes for OGF DFDL Working Group Call, April 21-2010
by Alan Powell 22 Apr '10

22 Apr '10

Open Grid Forum: Data Format Description Language Working Group OGF DFDL Working Group Call, April 21-2010 Attendees Steve Hanson (IBM) Alan Powell (IBM) Mike Beckerle (Oco) Stephanie Fetzer (IBM) Tim Kimber(IBM) Apologies Steve Marting (Progeny) Suman Kalia (IBM) 1. DFDL Specification status There have been no public comments so far but this is not unexpected. Steve H is pursuing a press release from IBM and OCO. Mike will send updated information to the OMG. Alan will pursue contacts from the Athena EU project. 2 Nils, defaults and unparsing Steve H, Tim and Alan have had further discussions and concluded and new property was not required so propose - Elements that are zero length and elements that are 'missing' from the data stream should be treated the same. - missingValueInitiatorPolicy should be renamed to emptyValueInitiatorPolicy to distinguish from a missing infoset value on unparsing - Any 'initiator' policy needs to also include terminators so the enumerations should be extended to "none", "initiator", "terminator", "both". and the properties renamed emptyValueDelimiterPolicy and nilValueDelimiterPolicy . The tables have been reworked Nils and Defaults on Parsing initiator region content region Logical Value matching content content matches nilValue nilValueDelimiterPolicy must be initiator or both nil Content does not match nilValue parse content to get value matching empty empty string is a nil value nilValueDelimiterPolicy must be initiator or both nil A default is specified emptyValueDelimiterPolicy must be initiator or both default value (may be nil, empty space or value) empty content content matches nilValue nilValueDelimiterPolicy must be none nil Content does not match nilValue Initiator must not be specified parse content to get value Initiator is specified ERROR empty empty empty string is a nil value nilValueDelimiterPolicy must be none nil A default is specified emptyValueDelimiterPolicy must be none default value (may be nil, empty space or value) Note. The default value can be the empty space. Nils and Defaults on Unparsing Logical Value initiator region contains content region contains Nil (implies nillable) nilValueDelimiterPolicy none empty representation of nil nilValueDelimiterPolicy initiator or both initiator string "" (empty string) (type is xs:string or xs:hexBinary) emptyValueDelimiterPolicy none empty empty emptyValueDelimiterPolicy initiator or both initiator string missing useNilForDefault nilValueDelimiterPolicy none empty representation of nil nilValueDelimiterPolicy initiator or both initiator string default is empty string (type is xs:string or xs:hexBinary) emptyValueDelimiterPolicy none empty empty emptyValueDelimiterPolicy initiator or both initiator string Other default initiator string representation of the default value. a non-nil non-empty-string value initiator string representation of the logical value The above tables (with minor changes) were agreed. The tables currently apply to simpleTypes, examples are needed to confirm that they are correct for complexTypes as well. Steve questioned whether complexTypes can be nillable as WTX allow this. Stephanie will investigate. Subsequently Stephanie confirmed that this was only needed for XML support in WTX so is not needed in DFDL. The Nils, defaulting section in the spec will be reviewed/rewritten to incorporate the new understanding. 3. Current Actions: Updated below. 4 Expressions during Unparsing. In order to reduce complexity and potential performance problems it is proposed to - nilValue and occursStopValue should NOT be able to take an expression. Agreed - Very few properties should be allowed to have forward references. Table below agreed Here's the list of properties that can take an expression, along with some suggested restrictions on forward referencing: byteOrder backward reference only encoding backward reference only initiator backward reference only terminator backward reference only separator backward reference only outputNewline backward reference only length simple elements : backward reference only. complex elements : forward reference allowed Quote "When unparsing with dfdl:lengthKind="explicit", the calculation of dfdl:representationLength() returns the value of the dfdl:length property." A simple element's length needs to be known in advance, else it cannot be parsed. A complex element's length might get resolved while parsing its content, so a forward reference within the scope of the complex element is possible. Having said that, we might want to impose a restriction in IBM's DFDL processor v1.0 that only backward references are allowed. escapeCharacter backward reference only escapeEscapeCharacter backward reference only textNumberDecimalSeparator backward reference only textNumberGroupSeparator backward reference only textNumberExponentCharacter backward reference only binaryFloatRep backward reference only textBooleanTrueRep backward reference only textBooleanFalseRep backward reference only nilValue backward reference only Not clear why this needs to be specified as an expression. ( may already be on a list of open issues somewhere ) nilIndicatorPath backward reference only occursCount backward reference only occursStopValue Not clear why this needs to be specified as an expression. [inputValueCalc] [Parser only] Backward reference only outputValueCalc Forward or backward reference Meeting closed, 14:10 Next call Wednesday 28 April January 2010 13:00 UK (8:00 ET) Next action: 091 Actions raised at this meeting No Action Current Actions: No Action 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 ... 17/02: IBM is willing in principle to publish the test case format and some of the test cases. May need some time to build a 'compliance suite' 24/03: No progress 03/03: Discussions have been taking place on the subset of tests that will be provided. 10/03: work is progressing 17/03: work is progressing 31/03: work is progressing 14/04: And XML test case format has been defined and is being tested. 21/04. Schema for TDML defined. Need to define how this and the test cases will be made public 084 Check behaviour of dfdl:inputValueCalc and outputValueCalc. 14/04: no prorgess 21/04: no progress 085 ALL: publicize Public comments phase to ensure a good review.. 14/04: see minutes 21/04: Press release, OMG and other standards bodies. 086 AP: Nils and Defaults during unparsing - update table 31/03: TK to documetn use cases for parsing 14/04: Investigate new property to control empty string behaviour. 21/04: After investigation a new property is not required. New rules developed and tables updated. Need examples of complexTypes to confirm tables apply. Review Nils, defaulting spec section. 088 define semantics of choiceKind 'fixedLength' 31/03: TK to provide definition of calculable length. Investigate PL/I varchars and Cobol occurs dependingon. 14/04Tim had distributed a document starting the definition of calculable length for the longest choice member. Alan had done some investigation of COBOL occurs depending on and when used in the working section of a program then the maximum storage was reserved but when used in the linkage section the dependent number was uses. We need to understand how the WMB COBOL importer deals with ODO. 21/04: Need to define 'calculable length' and WMB importer ODO behaviour. 089 Need to be able to define unsigned decimal and integer 31/03: MB to agree proposed solution 14/04: MB to agree proposed solution 21/04: Agreed. Closed 090 Semantics of separatorPolicy 14/04: Discussion on detecting when complex types should be defaulted. Examples needed. 21/04: Complex defaulting examples needed for new 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 070 Write DFDL primer 071 Write test cases. 083 Implement RFC2116 097 Remove functions that returns duration 098 occursCountKind is parsing only 099 nilValue and OccuresStopValue cannot have an expression. On unparsing only outputValueCalc can have a forward reference. 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(a)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

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Agenda for OGF DFDL WG call 21 April 2010- 13:00 UK (8:00 ET)
by Alan Powell 20 Apr '10

20 Apr '10

1. DFDL Specification status 2 Nils, defaults and unparsing 3. Current Actions: 4 Expressions during Unparsing. --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 1. DFDL Specification status 2 Nils, defaults and unparsing Steve H, Tim and Alan have had further discussions and concluded and new property was not required so propose - Elements that are zero length and elements that are 'missing' from the data stream should be treated the same. - missingValueInitiatorPolicy should be renamed to emptyValueInitiatorPolicy to distinguish from a missing infoset value on unparsing - Any 'initiator' policy needs to also include terminators so the enumerations should be extended to "none", "initiator", "terminator", "both". and the properties renamed emptyValueDelimiterPolicy and nilValueDelimiterPolicy . The tables have been reworked Nils and Defaults on Parsing initiator region content region Logical Value matching content content matches nilValue nilValueDelimiterPolicy must be initiator or both nil Content does not match nilValue parse content to get value matching empty empty string is a nil value nilValueDelimiterPolicy must be initiator or both nil A default is specified emptyValueDelimiterPolicy must be initiator or both default value (may be nil, empty space or value) empty content content matches nilValue nilValueDelimiterPolicy must be none nil content does not match nilValue Initiator is not specified parse content to get value Initiator is specified ERROR empty empty empty string is a nil value nilValueDelimiterPolicy must be none nil A default is specified emptyValueDelimiterPolicy must be none default value (may be nil, empty space or value) Nils and Defaults on Unparsing Logical Value initiator region contains content region contains Nil (implies nillable) nilValueDelimiterPolicy none empty representation of nil nilValueDelimiterPolicy initiator or both initiator string "" (empty string) (type is xs:string or xs:hexBinary) emptyValueDelimiterPolicy none empty empty emptyValueDelimiterPolicy initiator or both initiator string missing useNilForDefault nilValueDelimiterPolicy none empty representation of nil nilValueDelimiterPolicy initiator or both initiator string default is empty string (type is xs:string or xs:hexBinary) emptyValueDelimiterPolicy none empty empty emptyValueDelimiterPolicy initiator or both initiator string Other default initiator string representation of the default value. a non-nil non-empty-string value initiator string representation of the logical value 3. Current Actions: No Action 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 ... 17/02: IBM is willing in principle to publish the test case format and some of the test cases. May need some time to build a 'compliance suite' 24/03: No progress 03/03: Discussions have been taking place on the subset of tests that will be provided. 10/03: work is progressing 17/03: work is progressing 31/03: work is progressing 14/04: And XML test case format has been defined and is being tested. 084 Check behaviour of dfdl:inputValueCalc and outputValueCalc. 14/04: no prorgess 085 ALL: publicize Public comments phase to ensure a good review.. 14/04: see minutes 086 AP: Nils and Defaults during unparsing - update table 31/03: TK to documetn use cases for parsing 14/04: Investigate new property to control empty string behaviour. 088 define semantics of choiceKind 'fixedLength' 31/03: TK to provide definition of calculable length. Investigate PL/I varchars and Cobol occurs dependingon. 14/04Tim had distributed a document starting the definition of calculable length for the longest choice member. Alan had done some investigation of COBOL occurs depending on and when used in the working section of a program then the maximum storage was reserved but when used in the linkage section the dependent number was uses. We need to understand how the WMB COBOL importer deals with ODO. 089 Need to be able to define unsigned decimal and integer 31/03: MB to agree proposed solution 14/04: MB to agree proposed solution 090 Semantics of separatorPolicy 14/04: Discussion on detecting when complex types should be defaulted. Examples needed. 4 Expressions during Unparsing. In order to reduce complexity and potential performance problems it is proposed to - nilValue and occursStopValue should NOT be able to take an expression. - Very few properties should be allowed to have forward references. Here's the list of properties that can take an expression, along with some suggested restrictions on forward referencing: byteOrder backward reference only encoding backward reference only initiator backward reference only terminator backward reference only separator backward reference only outputNewline backward reference only length simple elements : backward reference only. complex elements : forward reference allowed Quote "When unparsing with dfdl:lengthKind="explicit", the calculation of dfdl:representationLength() returns the value of the dfdl:length property." A simple element's length needs to be known in advance, else it cannot be parsed. A complex element's length might get resolved while parsing its content, so a forward reference within the scope of the complex element is possible. Having said that, we might want to impose a restriction in IBM's DFDL processor v1.0 that only backward references are allowed. escapeCharacter backward reference only escapeEscapeCharacter backward reference only textNumberDecimalSeparator backward reference only textNumberGroupSeparator backward reference only textNumberExponentCharacter backward reference only binaryFloatRep backward reference only textBooleanTrueRep backward reference only textBooleanFalseRep backward reference only nilValue backward reference only Not clear why this needs to be specified as an expression. ( may already be on a list of open issues somewhere ) nilIndicatorPath backward reference only occursCount backward reference only occursStopValue Not clear why this needs to be specified as an expression. [inputValueCalc] [Parser only] Backward reference only outputValueCalc Forward or backward reference 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(a)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

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Minutes for OGF DFDL Working Group Call, April 14-2010
by Alan Powell 15 Apr '10

15 Apr '10

Open Grid Forum: Data Format Description Language Working Group OGF DFDL Working Group Call, April 14-2010 Attendees Steve Hanson (IBM) Alan Powell (IBM) Steve Marting (Progeny) Stephanie Fetzer (IBM) Suman Kalia (IBM) Tim Kimber(IBM) Apologies Mike Beckerle (Oco) 1. DFDL Specification status After a slight delay the DFDL v1 Specification was opened to public comment on April 15th until June 15th. There was some discussion about publicizing the review. Steve H mentioned he started the process for getting approval for IBM to be included in a press release. Steve M indicated that Progeny may also be willing. Steve M mentioned that Progeny were working on an OMG mediation framework that requires DFDL and theat Progeny will have at least a partial implementation of DFDL that may satisfy the OGF requirement. 2 Nils, defaults and unparsing Tim had distributed some uses cases of fixed and delimited formats with initiated and non-initaited element. The was considerable discussion of the initiated, delimited cases ONE:one,THREE:three<END> ONE:one,,THREE:three<END> The discussion was mainly about whether was any difference in intent between missing and zero length in these examples and whether zero length string or default should be inserted into the infoset, Tim suggested using separatorPolicy required as a trigger. Alan pointed out that the table in the spec used the presence or absence of a default value to decide is the default or empty string should be the result. Eventually concluded that an additional property may be needed and a proposal will be developed. In addition it was noted that the interaction between dfdl:initiatedContent and dfdl:missingValueInitiatorPoilcy may need clarifying. It was also question whether XSDL allows the empty space to be specified as a default value. 3 dfdl:separatorPoilicy. The main discussion was about how to detect when complex types should be defaulted which was similar to the defaulting discussion for simpleTypes. The added complication for complex types is that the content region is the children so should you detect missing by parsing the first child? It was agreed that examples simpler to the ones above would be helpful. Meeting closed, 14:45 Next call Wednesday 21 April January 2010 13:00 UK (8:00 ET) Next action: 091 Actions raised at this meeting No Action Current Actions: No Action 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 ... 17/02: IBM is willing in principle to publish the test case format and some of the test cases. May need some time to build a 'compliance suite' 24/03: No progress 03/03: Discussions have been taking place on the subset of tests that will be provided. 10/03: work is progressing 17/03: work is progressing 31/03: work is progressing 14/04: And XML test case format has been defined and is being tested. 084 Check behaviour of dfdl:inputValueCalc and outputValueCalc. 14/04: no prorgess 085 ALL: publicize Public comments phase to ensure a good review.. 14/04: see minutes 086 AP: Nils and Defaults during unparsing - update table 31/03: TK to documetn use cases for parsing 14/04: Investigate new property to control empty string behaviour. 088 define semantics of choiceKind 'fixedLength' 31/03: TK to provide definition of calculable length. Investigate PL/I varchars and Cobol occurs dependingon. 14/04Tim had distributed a document starting the definition of calculable length for the longest choice member. Alan had done some investigation of COBOL occurs depending on and when used in the working section of a program then the maximum storage was reserved but when used in the linkage section the dependent number was uses. We need to understand how the WMB COBOL importer deals with ODO. 089 Need to be able to define unsigned decimal and integer 31/03: MB to agree proposed solution 14/04: MB to agree proposed solution 090 Semantics of separatorPolicy 14/04: Discussion on detecting when complex types should be defaulted. Examples needed. 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 070 Write DFDL primer 071 Write test cases. 083 Implement RFC2116 097 Remove functions that returns duration 098 occursCountKind is parsing only 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(a)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

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Action 088 - define semantics of choiceKind 'fixedLength'
by Tim Kimber 14 Apr '10

14 Apr '10

More work to do on this, but no time before the meeting. Let's discuss the rules below, and refine afterwards: If dfdl:choiceKind='fixedLength' then there must be at least one branch of the choice for which all of the content has a calculable length. Definition : A DFDL region is a region of the data stream described by the DFDL grammar. Note : we need to define this term - we use the term 'region' without definition throughout the specification. Sometimes we call it a 'grammar region'. Definition: A DFDL region has a calculable length if the length of its representation in units of bytes can be calculated from the DFDL description alone. The leading alignment region has a calculable length if the alignment of the component is the same as the alignment of the parent. The trailing alignment region has a calculable length if the alignment of the component is the same as the alignment of the parent. Q: Is this rule necessary? The initiator region has a calculable length if all of the possible initiator values have a calculable length. An initiator value is a DFDL string literal. It has a calculable length if the DFDL string literal does not contain any variable-length parts. The terminator region has a calculable length if all of the possible terminator values have a calculable length. A terminator value is a DFDL string literal. It has a calculable length if the DFDL string literal does not contain any variable-length parts. A variable-length part is any of the following - a character string in a variable-width encoding - a DFLD entity in a variable-width encoding - a DFDL generic entity which can match a variable number of characters ( NL, WSP+, WSP* ) The simple content region has a calculable length if both of the following are true: - either the encoding is a fixed-width encoding or the representation does not contain characters. - either lengthKind is 'explicit' and the length is not a DFDL expression or lengthKind is 'implicit' and there is an implicit length for the simple type and its dfdl:representation The complex content region has a calculable length if all of the following are true: - either the encoding is a fixed-width encoding or the representation ( recursively ) does not contain characters. - the element has lengthKind='explicit' and dfdl:length is not a DFDL expression - all group members, recursively, are required ( minOccurs=maxOccurs ) 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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Scenarios for action 086 - nils and defaults
by Tim Kimber 14 Apr '10

14 Apr '10

I took an action from the last meeting to document the scenarios relating to nils and defaults, with particular reference to groups that have a separator. The number of combinations is large, but I'll try to do this in an organised way. The variables are: - separatorPolicy ( required / suppressed / suppressedAtEnd ) - element has a zero-length representation / element is missing from the data stream - user wants ( nil / default value / no element ) in the infoset - element is simple / complex Some ground rules: * A group member is missing if the group has initiatedContent="true" and its initiator is not found. * A group member is missing if the group ends before the member has been parsed. * A group member cannot be missing if its parent group has separatorPolicy="required" Scenario 1: Fixed-length elements with initiators, no separators ONE:oneTWO:twoTHREE:three<END> All members are present. ONE:oneTHREE:three<END> 'Two' is missing, and is defaulted if required. ONE:oneTWO:two<END> Group ends early. 'Three' is missing, and is defaulted if required. Scenario 2: Variable-length elements with initiators and infix separators Note how the presence of separators allows a zero-length representation - not possible in scenario 1 ONE:one,TWO:two,THREE:three<END> All members are present. ONE:one,THREE:three<END> If separatorPolicy='suppressed; then 'Two' is missing, and is defaulted if required. If separatorPolicy!='suppressed' then a processing error is reported. ONE:one,,THREE:three<END> If separatorPolicy='required' then 'Two' has a zero-length representation, zero-length is interpreted as 'missing' and 'Two' defaulted if required If separatorPolicy!='required' then 'Two' is present with a zero-length representation. If 'Two' cannot be zero-length, then it is a processing error. The above rules can be discussed, but I believe they have merit. The key point is that 'required' and 'suppressed' really do imply different things about a zero-length member. I'm aware that there may be other lengthKinds where zero-length needs to be interpreted as 'missing'. I think 'pattern' would be one example of that. Not so sure about 'prefixed' and 'explicit-when-length-is-a-DFDL-expression' Note that the next example is the most likely use of defaulting when separatorPolicy='suppress" ONE:one,TWO:,THREE:three<END> 'Two' has a zero-length content region, and is defaulted if missingValueInitiatorPolicy="required". ONE:one,TWO:two,<END> If separatorPolicy='required' then 'Three' has a zero-length representation, zero-length is interpreted as 'missing', and 'Three' is defaulted if required If separatorPolicy='suppressed' then 'Three' has a zero-length representation. If 'Three' cannot be zero-length, then it is a processing error. ONE:one,TWO:two<END> If separatorPolicy='required' then it is a processing error. If separatorPolicy!='required' then the group ends early. 'Three' is missing, and is defaulted if required. Other points: - I think the name 'missingValueInitiatorPolicy' is confusing - the name implies that it is about missing items, and about the presence/absence of the value only The role of this property is actually a) to tell the parser how to recognize a required element that is not missing from the data stream, but does need to be defaulted b) to tell the unparser how to serialize a required element that is missing from the infoset ( or one that is present in the infoset without a value? ) I think the old name 'defaultValueInitiatorPolicy' conveys it a little more accurately (and is consistent with nilValueInitiatorPolicy ), but there were reasons for changing the name. Unfortunately I don't remember what they were. - OccursCountKind: I'm assuming that it is intended to allow variable-length arrays in formats where the array length cannot easily be detected in other ways. Occurences must be contiguous ( so don't try using it for occurrences within an unordered group ). If the data stream ends before all occurences have been parsed, it is a processing error. 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 14 April 2010- 13:00 UK (8:00 ET)
by Alan Powell 13 Apr '10

13 Apr '10

1. DFDL Specification status There has been no announcement of the public comment period so presumably it hasn't started. Chasing email sent. 2 Nils, defaults and unparsing Logical Value initiator region contains content region contains Nil (implies nillable) nilValueInitiatorPolicy 'prohibited' empty representation of nil nilValueInitiatorPolicy 'required' initiator string "" (empty string) (type is xs:string or xs:hexBinary) missingValueInitiatorPolicy 'prohibited' empty empty missingValueInitiatorPolicy 'required' initiator string missing useNilForDefault nilValueInitiatorPolicy 'prohibited' empty representation of nil nilValueInitiatorPolicy 'required' initiator string default is empty string (type is xs:string or xs:hexBinary) missingValueInitiatorPolicy 'prohibited' empty empty missingValueInitiatorPolicy 'required' initiator string Other default initiator string representation of the default value. a non-nil non-empty-string value initiator string representation of the logical value Other changes: missingValueInitiatorPolicy Enum Valid values ?required', ?prohibited' Specifies whether to expect an initiator when an element is missing. Ignored unless dfdl:initiator is specified and is not "" (empty string). 'required'- Indicates that the dfdl:initiator followed by empty content is the required syntax to indicate that the element is missing. ?prohibited' - Indicates that empty content is the required syntax to indicate that the element is missing. The presence of an initiator implies that real content must follow. Use of ?prohibited' implies an ordered sequence. If used on an initiated element of an unordered group it is a schema definition error. If the element is required, defaulting occurs as defined above. This property also applies on unparsing, when the data to be written (after nil value and default value processing) is empty content. Annotation: dfdl:element Need to decide whether there needs to be a differentiation between 'zero length content' and 'missing from the data stream'. Tim will document the parsing use cases so we can verify the parsing table. 3 dfdl:separatorPoilicy. dfdl:separatorPolicy enumeration definitions are not complete as they do not discuss arrays or defaulting. separatorPolicy="required" All the separators must be there. No group member, except for required members with a default, may be omitted from the data stream. Every group member must have a separator in the correct position. Optional members and variable-occurrence arrays will be allowed, separators will be expected for all maxOccurs ** It is a schema definition error if maxOccurs="unbounded" for any member of the group separatorPolicy="suppressed" Any group member ( optional or required with a default) can be omitted from the data stream, in which case its separator must may also be omitted. For prefix and infix, if a separator is found then another group member is expected. For postfix, if enclosing markup is not found immediately after a postfix separator then another group member is expected. Enclosing markup or end of data can occur where an infix or prefix separator is expected. This terminates the group. Enclosing markup or end of data can occur immediately after a postfix separator (if dfdl:documentfinalSeparatorCanBeMissing is 'yes' then the postfix separator may be missing at the end of the datastream). This terminates the group. If the group terminates before all of its members have been parsed then any required members in the remainder of the group must be defaulted into the infoset. The entire group can have a zero-length representation, which is indicated by enclosing markup at the start of the group's content region. If another group member is expected and the next group member is a point of uncertainty then the identity of the next group member must be determined by resolving the point of uncertainty as described in section XXX. If another group member is expected but no group member is found in the data stream then it is a processing error. If another group member is expected but all group members have been parsed then it is a processing error. separatorPolicy="suppressedAtEnd" suppressAtEnd has the same rules as 'required' up to the last required member that does not have a default, then it has the same rules as 'suppressed' Open questions 1. If a group has separatorPolicy='required' and one of its optional members has a zero-length representation, and that member is allowed to have a zero-length representation, what should the parser do? A similar question arises for required, defaultable elements with a zero-length representation when they are based on a type with xs:minLength="0". Should the default value be used, or the empty string? 2. How should the occursXXX properties be applied when there are other ways to determine the number of occurences ( e.g. by counting separators )? 3. What algorithm should the parser use to decide whether to default a complex element or group ( when the element/group is a child of a separated group)? 4. How does unparsing work for separated groups in all of these scenarios? 4 Current Actions: No Action 066 Investigate format for defining test cases 25/11:IBM to see if it is possible to publish its test case format. .... 31/03: work is progressing 084 Check behaviour of dfdl:inputValueCalc and outputValueCalc. 085 ALL: publicize Public comments phase to ensure a good review.. 086 AP: Nils and Defaults during unparsing - update table 31/03: TK to document use cases for parsing 088 define semantics of choiceKind 'fixedLength' 31/03: TK to provide definition of calculable length. Investigate PL/I varchars and Cobol occurs dependingon. 089 Need to be able to define unsigned decimal and integer 31/03: MB to agree proposed solution 090 Semantics of separatorPolicy 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(a)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

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Today's DFDL WG meeting is cancelled
by Steve Hanson 07 Apr '10

07 Apr '10

We have a couple of people missing plus actions from last week are still being progressed. Next call at usual time next week. Regards Steve Hanson Strategy, Common Transformation & DFDL Co-Chair, OGF DFDL WG IBM SWG, Hursley, UK, smh(a)uk.ibm.com, tel +44-(0)1962-815848 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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