[dfdl-wg] Notes from Face to Face day 2 and 3

[Westhead, Martin (Martin)]

Present


Martin Westhead

Steve Hanson

Suman Kalia

Geoff Judd

 


Actions


The following actions were assigned:

*          Scoping and context [guards and tests] (Mike)

*          Properties and conversions (Steve)

*          Revisit conversions [Steve's questions, type matching,
position, speculative parsing, where are we?](Martin)

*          Uncertainty [wildcards, substitution groups, choices,
optionality] (Geoff)

*          Defaults and nulls (Geoff)

*          DFDL Schema (Suman)

 

Open issues:

*          syntax (sequences, markup)

*          identifying core properties and conversions (if any)

*          round tripping

*          embedded XML

 


Day 2 Notes


Properties/conversions/grouping - Steve/Suman


      (Suman took notes on this topic)

 

      Steve will be re-writing the current document to take on board
proposals from this meeting and to start the process (with Martin) of
trying to converge the properties with the conversions material.

            


Choices and wildcards - Geoff 


We explored several ideas around the framework that Geoff has. Geoff
will be writing these up. Comments included:

*         Possible use of binhex to represent "deferred" choices

*         Modeled uncertainty with "any" should be treated as a choice

*         Substitution groups should be treated as a choice

*         Wildcards will be handled here and "open" wildcards (unmodeled
uncertainty) could be handled by dropping in a string/binhex

*         Schematron-like assertions could be used as choice guards such
assertions could also make general statements about data validity

*         Use of XML Schema validation to resolve speculative parsing
raises issues. (Either all DFDL parsers must validate or would get
different results)

 

 


Which XML Schema constructs are supported - Steve


We reviewed Steves slides made various modifications key decisions:

*	Attributes - wait and see

 

 


Final documents


We had an inconclusive discussion on the structure of the final
documents.

 

 


Day 3 Notes


Instance Validation


-          Efficiency of XML Schema validation

-          Implementation difficult of XML Schema validation

-          Therefore cannot force the use of full DFDL parsing

-          so we cannot use XML Schema validation to resolve speculative
parsing

-          property to state validation to be used could allow parser to
produce a warning error if not available

-          possibility: could use require just facet/value checks (not
structure)

 

-          XPath evaluation required

-          Therefore XPath assertions for choice discrimination possible

-          And XPath assertions for describing valid data possible

-          EDI community has strong requirement for such assertions to
be available (such as coexistance rules)

 

-          Is there a requirement for content validation (since
construction is driven by model)

-          Might be useful to have standard names for classes of error

 


DFDL Schema Validation 


-          XML Schema valid

-          Syntax and semantics of annotations (annotations must be
consistent with schema)

-          XPath references are valid

 

(standard should describe ways validation can be done and features that
can be validated, validation should not be mandated).

 

 

 

 

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