April 2013 - dfdl-wg - lists.ogf.org

Implementation limits
by Steve Hanson 11 Jul '13

11 Jul '13

Just checking - did we close on this? Regards Steve Hanson Architect, 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 21/01/2013 18:38 ----- From: Mike Beckerle <mbeckerle.dfdl(a)gmail.com> To: Steve Hanson/UK/IBM@IBMGB, Cc: dfdl-wg(a)ogf.org Date: 19/11/2012 21:08 Subject: Re: [DFDL-WG] proposed clarification/narrowing - no twos-complement decimal, integer or nonNegativeInteger Do we have a section where this goes? There are lots of implied implementation limits. Maximum string length? Maximum hexbinary length? Maximum number of packed digits in various numbers. Maximum length of a delimiter? Maximum length of a fixed attribute? Maximum length of a pattern regex expression? Maximum length of a regular expression? There's also limits on buffering of data for unparsing, etc. There's also limits on lookahead/speculation. I.e., how far an implementation is willing to speculate forward. etc. For some types these are clear: e.g., binary xs:int is 32 bits max. Do we need a numbered section on implementation specific limits. 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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implicit alignment of complex types
by Mike Beckerle 01 May '13

01 May '13

I believe the spec language is unclear here. It says: The 'implicit' alignment of complex elements and groups is the alignment of its child with the greatest alignment. This could be worded more clearly: The 'implicit' alignment of complex elements is the alignment of their model group. The 'implicit' alignment of a model group is the alignment of its child with the greatest alignment. -- Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com

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passing parameters to DFDL?
by Garriss Jr., James P. 29 Apr '13

29 Apr '13

XSLT has an ability to pass an external value to a parameter within the stylesheet, using <xsl:param>. Does DFDL have a similar capability? Does dfdl:defineVariable allow this? TIA

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OGF DFDL WG Call 2013-04-30 - cancelled
by Steve Hanson 28 Apr '13

28 Apr '13

Sorry have to cancel the call as I am at an IBM conference in Las Vegas and the time doesn't work. Regards Steve Hanson Architect, IBM DFDL Co-Chair, OGF DFDL Working Group Hursley, UK smh(a)uk.ibm.com tel:+44-1962-815848

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Cancelled: OGF DFDL WG Call
by Steve Hanson 28 Apr '13

28 Apr '13

Steve is at IBM IMPACT conference

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AUTO: Sunil Dandamudi is out of the office (returning 04/29/2013)
by Sunil Dandamudi 25 Apr '13

25 Apr '13

I am out of the office until 04/29/2013. Note: This is an automated response to your message "dfdl-wg Digest, Vol 82, Issue 17" sent on 04/25/2013 8:00:01. This is the only notification you will receive while this person is away.

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MBTK and Daffodil - Intentioning Violating Property Scoping Rules?
by Garriss Jr., James P. 25 Apr '13

25 Apr '13

(Emotions are hard to convey in email; please trust me when I say that I am writing this email with kindness and friendliness!) In section 8 it says, "The dfdl:format annotation on the top level xs:schema declaration provides defaults for the DFDL representation properties at every DFDL-annotatable component contained in the schema document. They do not apply to any components in any included or imported schema document (these may have their own defaults)." If I understand this, it means that when properties are defined using <dfdl:format> in one DFDL schema file, they are out of scope for any other DFDL schema file. So if schema A defines some properties and includes schema B, the properties are out of scope in schema B. Similarly, if schema A includes schema B and schema B defines some properties, the properties are out of scope in schema A. Is that right? I think so, and I have empirically confirmed this in both tools. Ok, so you know where this going, right? Why does the following line work? <xsd:import namespace="http://www.ibm.com/dfdl/GeneralPurposeFormat" schemaLocation="IBMdefined/GeneralPurposeFormat.xsd"/> According to the spec, it shouldn't. Yet both tools support it. But if you make any changes to the GeneralPurposeFormat, it breaks. You can't rename it. You can't put it in a different folder. Etc. Here's what I suspect: Both MBTK and Daffodil hard-coded this as an undocumented exception to the rule. I think you want to have your cake (properties are out of scope) and eat it, too (except when we want them to be in scope because repeating all the properties in every DFDL file is a pain). If I'm wrong, just let me know. It's entirely possible that I don't really understand what's going here. But if I'm right, then you guys should not do this. * If the spec makes sense, then you should follow the spec. * If the spec doesn't make sense, then you should change the spec. * If the spec needs an exception to the rule for this one case, then add an exception and follow it. To intentionally break the spec in an undocumented fashion seems wrong.

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empty sequences
by Mike Beckerle 24 Apr '13

24 Apr '13

This section of the spec seems wrong: 14.1 Empty Sequences A sequence having no children is syntactically legal in DFDL. In the data stream, such a sequence can have non-zero length LeftFraming and RightFraming regions, but the SequenceContent region in between must be empty. It is a processing error if the SequenceContent region of an empty sequence has non-zero length when parsing. XML schema does not define an empty sequence that is the content model of a complex type definition as effective content so any DFDL annotations on such a construct would be ignored. It is a schema definition error if the empty sequence is the content model of a complex type, or if a complex type has nothing in its content model at all. This seems like it is both legal and useful: <complexType name="headerRowType"> <sequence dfdl:initiator="name%WSP+;address%WSP+;phone" dfdl:terminator="%NL"/> </complexType> So the statement, DFDL annotations on such a construct would be ignored, is not right. And also a complexType sequence might actually have content via dfdl:hiddenGroupRef. <complexType name="hiddenGroupType"> <sequence dfdl:hiddenGroupRef="myHiddenGroup"/> </complexType> So the statement that the region in-between left and right framing must be empty is also not right. Comments? -- Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com

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Fw: DFDL occurs properties on global elements
by Steve Hanson 23 Apr '13

23 Apr '13

Agreed on call that rather than invent different scoping rules for the DFDL occurs properties, we should let them appear on global elements in the usual way. On a global element they won't be validated as a consistent set though, that will only happen on local elements and element references. 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 23/04/2013 19:20 ----- From: Steve Hanson/UK/IBM To: dfdl-wg(a)ogf.org, Date: 17/04/2013 17:44 Subject: DFDL occurs properties on global elements Some more thoughts on this. Even if 4 is changed to a schema definition error, the normal scoping rules would mean that an occurs property could still be picked up from a global element if either the global element use dfdl:ref which pulled in an occurs property, or if the element ref and it's schema were totally silent about an occurs property but a dfdl:format in the global element's schema wasn't silent so the global element picked up a default. As well as the SDE we'd need to make it clear that properties in 4 must not be picked up from the global element's scope. ---------------------------------------------- Errata 3.8 clarifies what action a DFDL processor should take when it encounters an object that explicitly carries properties that are not relevant to the object, as follows: 1 Property not applicable to the object’s kind. Schema definition error. Example is lengthKind on xs:sequence. 2 Property not applicable because of simple type. Warning. Example is calendarPatternKind on xs:string. 3 Property not applicable because of another DFDL property setting. Warning. Example is binaryNumberRep when representation is text 4 Property not applicable because object is global. Warning (optional). Example is occursCountKind on a global xs:element. I am starting to question whether 4 is the correct behaviour. I think this should be a schema definition error and not a warning because the property becomes applicable for an element reference that refers to that global element. It is a different situation from the other warning cases 2 & 3, where the test is made once scoping rules are applied, and the property is therefore not applicable. Thoughts? 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 2013-04-23
by Steve Hanson 23 Apr '13

23 Apr '13

Please find minutes from the above call on Redmine at http://redmine.ogf.org/dmsf_files/13070?download= Errata document is now at v013 here: http://redmine.ogf.org/dmsf_files/8104?download= Action 140 errata addendum at v001 here: http://redmine.ogf.org/dmsf_files/13017?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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