- dfdl-wg - lists.ogf.org

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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GitHub - usage guides
by Mike Beckerle 14 Jan '14

14 Jan '14

Git hub has a brief tutorial on how to set up the account information: https://help.github.com/articles/set-up-git<https://exchange10.columbia.tresys.com/owa/redir.aspx?C=718292ffc47f4cceb75…> And to create a repo and commit to it: https://help.github.com/articles/create-a-repo<https://exchange10.columbia.tresys.com/owa/redir.aspx?C=718292ffc47f4cceb75…> They have the basics. Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com Please note: Contributions to the DFDL Workgroup's email discussions are subject to the OGF Intellectual Property Policy<http://www.ogf.org/About/abt_policies.php>

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OGF DFDL WG Call Agenda 2014-01-14
by Steve Hanson 13 Jan '14

13 Jan '14

Happy New Year to all. Please find agenda for call on Redmine at http://redmine.ogf.org/dmsf_files/13181?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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Next DFDL WG call is Jan 14 2014 @ 4pm UK
by Steve Hanson 01 Jan '14

01 Jan '14

Sorry but can't make Jan 7 call due to hospital appointment. 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

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Cancelled: DFDL Working Group Call
by Steve Hanson 01 Jan '14

01 Jan '14

Steve not available this week

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