[DFDL-WG] Notes from 2007-05-09 WG call.

[Mike Beckerle]

Notes from DFDL call 2007-05-09

Mike Beckerle
Simon Parker
Martin Westhead
Suman Kalia
Geoff Judd
Steve Hanson
Alan Powell

Notes: 

Simon Parker of PolarLake was introduced. Welcome Simon!

Report from OGF 20 

approximately 12 attendees at session

Notes from session are posted/sent by email.

We discussed the notes:

pointers - not core for v1.0, . A supplement would be ok.

multi-dim arrays - pointed out that we can do these via nesting, though 
there are some drawbacks about storage order variation.

support for versioning - we agreed that we want to be compatible with 
versioning approaches of DFDL schemas by users, but not address the 
problem in the standard. It's not different for DFDL from XML Schema.

we need to revisit "selectors" topic since these could be used to mix 
versions of a format into the same DFDL schema.

ISO CGM - common graphics metafile - suggested as a use case.

New floating point number formats, e..g., small ones like 14 bit ones used 
in graphics and such. 

We discussed whether there should be special DFDL-based annotations that 
DFDL processors would provide visibility to for applications. 
Alternative is "just look for the annotation on the schema", i.e., leave 
it up to the applications to reach into the schema themselves. DFDL stays 
out of this.

2nd point was that spec. needs to specify how various supported floating 
point formats are approximated when converted to the XML types float and 
double. 

We decided that advanced floating point could be a supplement.

Validation: decided to mention in spec that streaming validation is an 
allowed behavior for DFDL processors, and that if XML-schema or schematron 
validation is performed by a DFDL processor that it must be consistent 
with an XML Schema validator operating on an XML document as described by 
the implied XML schema for the DFDL schema.

Issue raised - need "arbitrary whitespace" as delmiter. How to specify.

Issue raised - need arbitrary sized binary integer (or even decimal), 
Bignums. Financial communities use these.

Selectors - need to revisit in a future call.


Mike Beckerle
STSM, Architect, Scalable Computing
IBM Software Group
Information Platform and Solutions
Westborough, MA 01581
direct: voice and FAX 508-599-7148
assistant: Pam Riordan 
                  priordan at us.ibm.com 
                  508-599-7046

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