[DFDL-WG] Action 174: Making DFDL implementations easier

Fri May 25 08:58:15 EDT 2012

But the expression language is highly restricted in the subset.

On Fri, May 25, 2012 at 7:59 AM, Steve Hanson <smh at uk.ibm.com> wrote:

> Tim
>
> I tend to agree with endOfParent as optional.
>
> Expression language was kept in the core to handle occursCountKind
> 'expression' which is also in the core.  The examples of binary data we
> have seen from NSA and ESA both have occurs counts in the data, in the same
> way as COBOL does. When you have untagged binary data, it's typically the
> way to provide an array size. It was felt that dropping this from the core
> did left us with too little capability.
>
> Regards
>
> Steve Hanson
> Architect, Data Format Description Language (DFDL)
> Co-Chair, *OGF DFDL Working Group* <http://www.ogf.org/dfdl/>
> IBM SWG, Hursley, UK*
> **smh at uk.ibm.com* <smh at uk.ibm.com>
> tel:+44-1962-815848
>
>
>
> From:        Tim Kimber/UK/IBM
> To:        Steve Hanson/UK/IBM at IBMGB
> Cc:        dfdl-wg at ogf.org, dfdl-wg-bounces at ogf.org
> Date:        25/05/2012 10:07
> Subject:        Re: [DFDL-WG] Action 174: Making DFDL implementations
> easier
> ------------------------------
>
>
> 1) I would make endOfParent an optional feature - there are not many
> formats that require it.
>
> 3) There are many formats that do not require the expression language - it
> is only required when a property value or an assert/discriminator needs to
> query already-parsed data. On that basis, I think the entire expression
> language feature should be optional.
>
> regards,
>
> Tim Kimber, Common Transformation Team,
> Hursley, UK
> Internet:  kimbert at uk.ibm.com
> Tel. 01962-816742
> Internal tel. 246742
>
>
>
>
>
> From:        Steve Hanson/UK/IBM at IBMGB
> To:        dfdl-wg at ogf.org
> Date:        25/05/2012 00:08
> Subject:        [DFDL-WG] Action 174: Making DFDL implementations easier
> Sent by:        dfdl-wg-bounces at ogf.org
> ------------------------------
>
>
>
> 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* <http://www.ogf.org/dfdl/>
> IBM SWG, Hursley, UK*
> **smh at uk.ibm.com* <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* <http://www.ogf.org/dfdl/>
> IBM SWG, Hursley, UK*
> **smh at uk.ibm.com* <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* <http://www.ogf.org/dfdl/>
> IBM SWG, Hursley, UK*
> **smh at uk.ibm.com* <smh at uk.ibm.com>
> tel:*+44-1962-815848* <%2B44-1962-815848>
>
>
> 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
> --
>  dfdl-wg mailing list
>  dfdl-wg at ogf.org
>  https://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
>
> --
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-- 
Mike Beckerle | OGF DFDL WG Co-Chair
Tel:  781-330-0412
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