Please see below for a proposal to make an additional set of DFDL features optional. The goal is to make it considerably easier to create a minimal conforming DFDL processor for binary data. 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 11/05/2012 12:50 ----- Feature Detection Text representation for types other than String dfdl:representation="text" for Number, Calendar or Boolean types Delimiters dfdl:separator <> "" or dfdl:initiator <> "" or dfdl:terminator <> "" or dfdl:lengthKind="delimited" BCD calendars dfdl:binaryCalendarRep="bcd" Multiple schemas xs:include or xs:import in xsd Named Formats dfdl:defineFormat or dfdl:ref Choices xs:choice in xsd ** Arrays where size not known in advance dfdl:occursCountKind 'implicit', 'parsed', 'stopValue' ** Advanced expressions Advanced features of the DFDL expression language (tbd) ** Including one of these features mean that speculative parsing is needed. Remaining questions: 1) What about lengthKind 'endOfParent' ? 2) Is leaving out choices too restrictive? 3) Expression language subset The result is that a minimal conformant DFDL implementation just needs to support the following annotations and properties, and does not need speculative parsing. dfdl:element dfdl:sequence dfdl:format byteOrder encoding utf16width alignment alignmentUnits (bytes) fillByte leadingSkip trailingSkip lengthKind (explicit, implicit) length lengthUnits (bytes, characters) representation (binary) textPadKind textTrimKind textStringJustification textStringPadCharacter truncateSpecifiedLengthString decimalSigned binaryNumberRep binaryVirtualDecimalPoint binaryFloatRep (ieee) binaryBooleanTrueRep binaryBooleanFalseRep binaryCalendarRep (binarySeconds, binaryMilliseconds) binaryCalendarEpoch sequenceKind (ordered) occursCountKind (fixed, expression) occursCount 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 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