For discussion on today's call Regards Steve Hanson Architect, Data Format Description Language (DFDL) Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh@uk.ibm.com tel:+44-1962-815848 ----- Forwarded by Steve Hanson/UK/IBM on 16/10/2012 13:13 ----- From: Mike Beckerle <mbeckerle.dfdl@gmail.com> To: Steve Hanson/UK/IBM@IBMGB Date: 02/10/2012 18:41 Subject: One email or a flock or... - re: 10.03 draft - open review items Steve, I've got the issues below left after your review pass on 10.03, minus 2 I send emails to you about separately. Should I issue this email to the WG, or do you want me to decompose this into separate emails, or do you just want to list these as agenda topics for next call? I think it is good if people get to look at them in advance of a call. ...mikeb -------------------------------------------------------- This is a list of items left open after a review pass by SMH(on draft in preparation r010.03). These items need specific WG discussion on a call. They may be small enough to resolve there, or may be escalated into action items. (A couple issues already clearly action-item related are not listed here.) Note: please Ignore the identifiers like SMH107 or m236 I'm tagging these with. Those are just for me editing the text. (Those change ...grrr... if someone inserts a comment into the document, so they're not good issue identifiers). 1. SMH107 Spec says: When the separator and terminator on a group have the same value, then at a point where either separator or terminator could be found, the separator is tried first. Issue is that this language still feels ambiguous. E.g., So it tries the separator first, let’s say it finds it. Will a subsequent processing error cause it to backtrack and revisit this and try the terminator? Or does finding the separator confirm that it IS a separator, resolve forever that point of uncertainty? I believe the latter is what was intended (delimiter decisions drive parsing and are not revisited), but we need to state this (or do we somewhere else already?) 2. SMH169 - Some numeric types are signed, others unsigned. Some representations are sign-capable, some are not (BCD specifically). Right now spec draft says you can't have bcd as rep for signed integer types long, int, short, byte. But you CAN have bcd for rep of decimal, integer. We could allow bcd only for nonNegativeInteger type, but there is no nonNegativeDecimal type, so....how to resolve? I would suggest that we simply allow bcd as rep for both signed and unsigned types, and it's a processing error to unparse a negative value into bcd rep. 3. m229 - textStandardZeroRep - should this allow %ES; as one of the list of possibles? 4. m236 - is V (virtual decimal point position) and also P allowed in the textNumberPattern for double and float types? 5. m237 - Do we check that the various symbols used for infinity, digits, grouping separators, decimal separators are properly distinct to allow parsing? E.g., that the decimal separator and grouping separator aren't the same, and that the positive and negative pattern variants are distinguishable? ICU library supposedly doesn't do this checking. Do we state this is an SDE in DFDL. If so then is this checking required? Can we make it possible for implementations to not check somehow? Other grammar ambiguity situations like separator and terminator being ambiguous are specifically NOT checked for, because determining if a grammar is ambiguous is hard or undecidable, and would have to be done at runtime because delimiters can be run-time computed. Buf for the syntax components of text numbers do we require checking or not? 6. m370 - multiple PoU resolutions: If you have initiatedContent, AND a choiceBranchRef, AND a discriminator all on the same element, and there are 3 enclosing nested PoU, which one controls which? Precedence is the issue. Or..... do we really need to allow this? Why don’t we just disallow this kind of piling-on of complexity and make the user choose which PoU resolution technique they want? 7. m396 - is BCD representation a mandatory feature, or optional? 8. m398 - portability at risk if subset processors ignore properties they don't implement. We relaxed this from a more rigid policy, and now allow subsets to not validate properties they don't implement. However, is there a better compromise, e.g., require a warning about all unimplemented/unrecognized properties? E.g., dfdl:textBiDi='no' yields SDE "unrecognized property 'textBiDi' with value 'no'. -- Mike Beckerle | OGF DFDL WG Co-Chair Tel: 781-330-0412 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