Mike I have been reviewing ch 6 Sequence Groups, Initiators and Separators of proposal-to-simplify-null-default-optional-handling-v4.doc and I am uneasy about the approach of transforming the DFDL. This is because They are examples rather than rules so do not fully explain the syntax. The results are often so convoluted that they do not, at least to me, provide any clarification. So much so that I believe most of the examples are actually wrong. I think that we should either provide proper transformation rules or just stick to explaining original DFDL syntax. Comments added to Ch 6 examples. Alan Powell MP 211, IBM UK Labs, Hursley, Winchester, SO21 2JN, England Notes Id: Alan Powell/UK/IBM email: alan_powell@uk.ibm.com Tel: +44 (0)1962 815073 Fax: +44 (0)1962 816898 Mike Beckerle <beckerle@us.ibm.com> Sent by: dfdl-wg-bounces@ogf.org 23/10/2007 23:03 To dfdl-wg@ogf.org cc Subject [DFDL-WG] Material for Call on 2007-10-24 We had been reviewing the facets and default/null/optional a few weeks back. I said I would make revisions as a number of people had objections. Here are documents based on these comments. Main things I did: (1) strict adherence to minOccurs and maxOccurs. No more notion that these are only for validity checking. (2) simple rule for default values: if it's required and there's a default value, then use the default value. This is for both input and output. I put a bunch of work into illustrating the semantics of things like dfdl:separatorPolicy="suppress" and so forth. I had been trying to simplify this, but gave up. We're back to 3 policies here: keep, suppress, suppressAtEnd. I did figure out a way to express these via DFDL rewriting. ...mikeb 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@us.ibm.com 508-599-7046 [attachment "proposal-on-facets.doc" deleted by Alan Powell/UK/IBM] [attachment "proposal-to-simplify-null-default-optional-handling-v4.doc" deleted by Alan Powell/UK/IBM] -- dfdl-wg mailing list dfdl-wg@ogf.org http://www.ogf.org/mailman/listinfo/dfdl-wg 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