April 2021 - dfdl-wg - lists.ogf.org

Confirming expected behavior of separatorSuppressionPolicy 'never'
by Mike Beckerle 21 Apr '21

21 Apr '21

An earlier email I sent had this schema: <xs:element name="file1"> <xs:complexType> <xs:sequence dfdl:separator="," dfdl:separatorPosition="infix" dfdl:separatorSuppressionPolicy="never"> <xs:element name="given-name" type="xs:string" minOccurs="0" maxOccurs="3" /> <xs:element name="surname" type="xs:string" minOccurs="0"/> <xs:element name="phone" type="xs:string" minOccurs="0" maxOccurs="6" /> </xs:sequence> </xs:complexType> </xs:element> Given that, and a default dfd:format with occursCountKind='implicit' I expect this data: "madonna,,,,,,,,," To produce this DFDL Infoset (cast as XML): <file1> <given-name>madonna</given-name> </file1> I don't expect to see any empty elements like <given-name></given-name> because all elements are optional, so a zero-length representation for a xs:string is the Empty representation, and optional empty is never added to the infoset. Furthermore, this should "round trip" i.e., unparse back to the original input data. Am I correct here? Mike Beckerle | OGF DFDL Workgroup Co-Chair | Owl Cyber Defense | www.owlcyberdefense.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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example/use-case wanted - separatorSuppressionPolicy 'trailingEmptyStrict' and 'never'
by Mike Beckerle 20 Apr '21

20 Apr '21

Users of Apache Daffodil have asked what these property values are for, i.e., what are idiomatic uses of this property for actual formats, or in other words, what kind of data are these properties needed for? I'd like to provide them examples of this if anyone can recall the kinds of specific use cases for these property values. I've been searching through the example DFDL schemas I can find, and none use trailingEmptyStrict or never for this property. Mike Beckerle | OGF DFDL Workgroup Co-Chair | Owl Cyber Defense | www.owlcyberdefense.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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Latest OGF DFDL WG Call Minutes
by Steve Hanson 15 Apr '21

15 Apr '21

Please find minutes from the latest call at https://github.com/OpenGridForum/DFDL/wiki/DFDL-Workgroup-News Steve Hanson IBM Hybrid Integration, Hursley, UK Architect, IBM DFDL Co-Chair, OGF DFDL Working Group smh(a)uk.ibm.com tel:+44-1962-815848 mob:+44-7717-378890 Note: I work Tuesday to Friday

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Agenda for OGF DFDL WG Call
by Steve Hanson 14 Apr '21

14 Apr '21

Please find agenda for next call on GitHub at https://github.com/OpenGridForum/DFDL/blob/master/calls/2021-04-15_DFDL-WG-… Regards Steve Hanson IBM Hybrid Integration, Hursley, UK Architect, IBM DFDL Co-Chair, OGF DFDL Working Group smh(a)uk.ibm.com tel:+44-1962-815848 mob:+44-7717-378890 Note: I work Tuesday to Friday

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newVariableInstance direction property discussion - PCAP example
by Mike Beckerle 13 Apr '21

13 Apr '21

For our next conference call, I said I would walk through the Apache Daffodil newVariableInstance feature, and how for unparsing we had to add a direction property to variables so they can be evaluated with forward referencing for unparsing. The code I'd like to discuss is here: https://github.com/DFDLSchemas/PCAP/blob/cb9ee66aa565d982f01130918bcd785def… The defineVariable that is the best motivating example is defined at line 104, and is used at line 213. This is a simple common-subexpression elimination, but it is used to avoid redundant calls to dfdl:valueLength in the dfdl:outputValueCalc of the stored length field named InclLen. There is a second example of using newVariableInstance at unparse time in this schema also, with the variable definitions starting at line 115, and usage in the group defined starting at line 320. This usage is far more complex, and in hindsight I think a DFDL parse of PCAP data should not be creating IP addresses in the Infoset that look like "1.2.3.4", because it requires all this complexity to unparse from that back to the binary representation. However, it is a good exercise in how the newVariableInstance feature works. -mikeb Mike Beckerle | OGF DFDL Workgroup Co-Chair | Owl Cyber Defense | www.owlcyberdefense.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 Working Group Call
by Steve Hanson 13 Apr '21

13 Apr '21

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