[DFDL-WG] Action 174: Making DFDL implementations easier
Steve Hanson
smh at uk.ibm.com
Wed May 23 13:25:22 EDT 2012
Agreed on list, just need to answer questions 1) and 3) below.
Regards
Steve Hanson
Architect, Data Format Description Language (DFDL)
Co-Chair, OGF DFDL Working Group
IBM SWG, Hursley, UK
smh at uk.ibm.com
tel:+44-1962-815848
----- Forwarded by Steve Hanson/UK/IBM on 23/05/2012 18:21 -----
From: Steve Hanson/UK/IBM
To: dfdl-wg at ogf.org
Date: 15/05/2012 09:55
Subject: Making DFDL implementations easier
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 at 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 at 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
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
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