January 2014 - dfdl-wg - lists.ogf.org

still no need for fn:error
by Mike Beckerle 03 Aug '16

03 Aug '16

Here's the example as suggested by Jonathan of how to issue an error that I previously was suggesting needed fn:error. I'm convinced this is sufficient and we can avoid the need for fn:error now. <xs:element name="magic_number" type="ex:uint32" dfdl:byteOrder="bigEndian"> <xs:annotation> <xs:appinfo source="*http://www.ogf.org/dfdl/*<http://www.ogf.org/dfdl/dfdl-1.0/> "> <dfdl:assert test="{ (xs:unsignedInt(.) eq *dfdl:hUInt('0xa1b2c3d4')*) | (xs:unsignedInt(.) eq *dfdl:hUInt('0xd4c3b2a1')*) }" message="{ fn:concat( 'Magic number ', dfdl:hexBinary(dfdl:unsignedInt(.)), ' was not 0xA1B2C3D4 (for bigEndian) or 0xD4C3B2A1 (for littleEndian).' }" /> <dfdl:setVariable ref="ex:bOrd">{ xs:unsignedInt(.) }<dfdl:setVariable> </xs:appinfo> </xs:annotation> </xs:element> -- Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com

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Fw: Spec question: 16.6 Forward Progress Requirement
by Tim Kimber 03 Feb '14

03 Feb '14

Proposed revised wording: 16.6 Forward Progress Requirement When parsing an optional occurrence of an array element, if the element is found to have a zero-length representation and its associated separator region is also zero-length then it is a processing error. An optional occurrence is defined as follows: - any occurrence of an element with occursCountKind='implicit' and index > XSDL minOccurs - any occurrence of an element with occursCountKind='parsed' or 'stopValue' If occursCountKind is 'stopValue' then the element will not be a point of uncertainty and the processing error will invalidate the entire array. For occursCountKind='implicit' or 'parsed' the processing error will terminate the array and will thus avoid either redundant processing or an infinite loop ( when XSDL maxOccurs='unbounded'). Feel free to propose better terminology. I'm not sure whether 'optional occurrence' has been used elsewhere in the specification with a different meaning. The final paragraph is conveying important information but can be reworded if necessary. regards, Tim Kimber, DFDL Team, Hursley, UK Internet: kimbert(a)uk.ibm.com Tel. 01962-816742 Internal tel. 37246742 ----- Forwarded by Tim Kimber/UK/IBM on 29/01/2014 14:42 ----- From: Tim Kimber/UK/IBM To: dfdl-wg(a)ogf.org, Date: 28/01/2014 14:24 Subject: Spec question: 16.6 Forward Progress Requirement 16.6 Forward Progress Requirement It is a processing error when an array is potentially unbounded and the position in the data does not move during the parsing of an occurrence of the element including any associated separator. This is to prevent an infinite loop. An array is potentially unbounded if any of the following are true: * dfdl:occursCountKind is 'parsed' or 'stopValue' * dfdl:occursCountKind is 'implicit' and XSDL maxOccurs is 'unbounded' Q1: Is this paragraph intended to a) safely terminate the parsing of the array, allowing the parser to proceed with whatever follows in the DFDL schema or b) cause the parser to discard the entire array along with everything that was parsed within the nearest point of uncertainty? If b) then I think a Schema Definition Error would be more appropriate ( because backing out the entire array implies that none of the occurrences were well-formed and some later branch might be the correct option ). Although... Q2: If the array has occursCountKind='stopValue' then none of the occurrences is an actual point of uncertainty because only stopValue can terminate the array. If paragraph 16.1 is invoked then a processing error will be thrown. But the occurrence is not a point of uncertainty so the entire array will be treated as badly-formed. In other words, behaviour will be as described in option b) above. I think that is correct in this case because the array's stopValue was never found. Q3: Should this infinite-loop detection be performed only after at least minOccurs occurrences of the array have been processed successfully? Until then, I think an empty occurrence should cause the default value to be put into the info set. regards, Tim Kimber, DFDL Team, Hursley, UK Internet: kimbert(a)uk.ibm.com Tel. 01962-816742 Internal tel. 37246742 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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Rescheduled: DFDL Working Group Call (5 Feb 15:00 GMT in DE3S09)
by Steve Hanson 29 Jan '14

29 Jan '14

Rescheduled: DFDL Working Group Call 05/02/2014 - (Repeats) Location: DE3S09 Steve Hanson has rescheduled this meeting. You have not yet responded. Repeats This entry repeats Required: jcranford(a)mitre.org, mbeckerle(a)tresys.com, Suman Kalia/Toronto/IBM@IBMCA, Tim Kimber/UK/IBM@IBMGB Optional: dfdl-wg(a)ogf.org, jonathan.w.cranford(a)gmail.com, mbeckerle.dfdl(a)gmail.com, Stephanie Fetzer/Charlotte/IBM@IBMUS OGF DFDL WG weekly call dial-in details. Passcode for Participants: 5381214 Canada Toll-Free 888-426-6840 China Toll-Free 10-800-711-1071 CHINA NETCOM GROUP USERS China Toll-Free 10-800-110-0996 CHINA TELECOM SOUTH USERS France Toll-Free 0800-94-0558 Germany Toll-Free 0800-000-1018 India Toll-Free 000-800-100-1176 Ireland Toll-Free 1-800-943-427 Israel Toll-Free 1-809-417-783 United Kingdom Caller Paid 0-20-30596451 United Kingdom Toll-Free 0800-368-0638 USA Caller Paid 215-861-6239 USA Toll-Free 888-426-6840 Other international numbers available - e-mail smh(a)uk.ibm.com. OGF DFDL Home: http://www.ogf.org/dfdl Redmine DFDL: http://redmine.ogf.org/projects/dfdl-wg

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OGF DFDL WG Call Minutes 2014-01-28
by Steve Hanson 29 Jan '14

29 Jan '14

Please find minutes from the above call at http://redmine.ogf.org/dmsf_files/13202?download= Note next week's call is Wed 3pm UK (10am Eastern). Regards Steve Hanson Architect, IBM DFDL, Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh(a)uk.ibm.com tel:+44-1962-815848

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Spec question: 16.6 Forward Progress Requirement
by Tim Kimber 28 Jan '14

28 Jan '14

16.6 Forward Progress Requirement It is a processing error when an array is potentially unbounded and the position in the data does not move during the parsing of an occurrence of the element including any associated separator. This is to prevent an infinite loop. An array is potentially unbounded if any of the following are true: * dfdl:occursCountKind is 'parsed' or 'stopValue' * dfdl:occursCountKind is 'implicit' and XSDL maxOccurs is 'unbounded' Q1: Is this paragraph intended to a) safely terminate the parsing of the array, allowing the parser to proceed with whatever follows in the DFDL schema or b) cause the parser to discard the entire array along with everything that was parsed within the nearest point of uncertainty? If b) then I think a Schema Definition Error would be more appropriate ( because backing out the entire array implies that none of the occurrences were well-formed and some later branch might be the correct option ). Although... Q2: If the array has occursCountKind='stopValue' then none of the occurrences is an actual point of uncertainty because only stopValue can terminate the array. If paragraph 16.1 is invoked then a processing error will be thrown. But the occurrence is not a point of uncertainty so the entire array will be treated as badly-formed. In other words, behaviour will be as described in option b) above. I think that is correct in this case because the array's stopValue was never found. Q3: Should this infinite-loop detection be performed only after at least minOccurs occurrences of the array have been processed successfully? Until then, I think an empty occurrence should cause the default value to be put into the info set. regards, Tim Kimber, DFDL Team, Hursley, UK Internet: kimbert(a)uk.ibm.com Tel. 01962-816742 Internal tel. 37246742 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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OGF DFDL WG Call Agenda 2014-01-28
by Steve Hanson 27 Jan '14

27 Jan '14

Please find agenda for call on Redmine at http://redmine.ogf.org/dmsf_files/13202?download= Regards Steve Hanson Architect, IBM Data Format Description Language (DFDL) Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh(a)uk.ibm.com tel:+44-1962-815848

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Fw: Thoughts on a discriminator scenario
by Steve Hanson 27 Jan '14

27 Jan '14

Been thinking some more on the discriminator scenario below that I mailed out before xmas, and discussing it with the IBM DFDL team. The 'confusing' aspect of the behaviour is that a discriminator within a potential PoU will act on a higher level PoU if the potential PoU is not an actual PoU. In the example, the array element 'Type1' is not an actual PoU for occurrence 1, only for occurrences 2+. So when the discriminator fires for occurrence 1 it will resolve a higher level unresolved PoU if one exists. Perhaps the spec should say that a discriminator can't 'leak' beyond the potential PoU that encloses it ? If so, then for occurrence 1 the discriminator has no effect, and only has an effect for occurrences 2+. This makes for more predictable and robust schemas. We'd need to go through spec section 9.3.3 carefully to see if this does not break any of the potential PoUs that are listed. Regards Steve Hanson Architect, IBM Data Format Description Language (DFDL) Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh(a)uk.ibm.com tel:+44-1962-815848 ----- Forwarded by Steve Hanson/UK/IBM on 16/01/2014 09:55 ----- From: Steve Hanson/UK/IBM To: dfdl-wg(a)ogf.org, Date: 20/12/2013 13:20 Subject: Thoughts on a discriminator scenario Take the following schema (simplified) for element Type1 (1,10) being a loop for elements A,B,C. Type 1 does not have an initiator so I need to use a discriminator to establish the existence of an occurrence of Type1 so that incorrect backtracking does not occur after an error. Because occursCountKind is 'implicit', the 1st occurrence is not a point of uncertainty so the discriminator acts instead on any enclosing point of uncertainty, but for 2nd and subsequent occurrences it acts on Type1. That is all working as designed, but I think users will the 1st occurrence behaviour a bit confusing. There are workarounds to avoid the problem, eg, use occursCountKind 'parsed' or split Type1 into two as (1,1) and (0,9). I think this is worth documenting in a tutorial as this is quite subtle stuff. <xs:element name="Type1" maxOccurs="10" dfdl:occursCountKind="implicit"> <dfdl:discriminator test="{fn:exists(A)}" /> <xs:complexType> <xs:sequence> <xs:element name="A" dfdl:initiator="A:" ... /> <xs:element name="B" dfdl:initiator="B:" ... /> <xs:element name="C" dfdl:initiator="C:"... /> </xs:sequence> </xs:complexType> Regards Steve Hanson Architect, IBM Data Format Description Language (DFDL) Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh(a)uk.ibm.com tel:+44-1962-815848 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 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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OGF DFDL WG Call Minutes 2014-01-21
by Steve Hanson 22 Jan '14

22 Jan '14

Please find minutes from the above call at http://redmine.ogf.org/dmsf_files/13201?download= Regards Steve Hanson Architect, IBM DFDL, Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh(a)uk.ibm.com tel:+44-1962-815848

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OGF DFDL WG Call Agenda 2014-01-21
by Steve Hanson 20 Jan '14

20 Jan '14

Please find agenda for call on Redmine at http://redmine.ogf.org/dmsf_files/13201?download= Any progress on actions 224 and 242 welcomed. Regards Steve Hanson Architect, IBM Data Format Description Language (DFDL) Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh(a)uk.ibm.com tel:+44-1962-815848

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OGF DFDL WG Call Minutes 2014-01-14
by Steve Hanson 15 Jan '14

15 Jan '14

Please find minutes from the above call at http://redmine.ogf.org/dmsf_files/13181?download= Public Comment for the revised DFDL 1.0 specification is now finished. Regards Steve Hanson Architect, IBM DFDL, Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh(a)uk.ibm.com tel:+44-1962-815848

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