EXCELLENT!!! That fits the bill...
<xs:element name="fields" minOccurs="1" maxOccurs="1">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="[0-9]{1,2}"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
<xs:element name="field" maxOccurs="unbounded"
dfdl:occursCount="{ *xs:unsignedInt(../fields)* }"
dfdl:occursCountKind="expression">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:pattern value="[a-zA-Z0-9+=]{0,64}"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
Thx again... after the fact.
Attila
On Fri, Jul 30, 2021 at 12:55 PM Beckerle, Mike <
mbecke...@owlcyberdefense.com> wrote:
> Model the length field as a string so its characters are perfectly
> preserved.
>
> Where you need to use its value in the number of occurrences, call the
> xs:unsignedInt(...) function on the string value.
>
>
> ------------------------------
> *From:* Attila Horvath <attila.j.horv...@gmail.com>
> *Sent:* Friday, July 30, 2021 12:48 PM
> *To:* users@daffodil.apache.org <users@daffodil.apache.org>
> *Subject:* Re: variable length CSV records via 'lengthKind' property
>
> Thx to all responses. Got variable length record w/ variable number of
> 'specified' fields working EXCEPT unparsing does not yield "lossless"
> reconstituted data.
>
> Per...
> <xs:element name="fields" type="xs:unsignedInt"/>
>
> "fields" specifies number of fields in record. When "fields" has value
> "1", unparse yields lossless result. However, when "fields" has value "01",
> unparse yields lossful "1" result dropping the leading zero.
>
> Suggestions to resolve? Our solution MUST be lossless.
>
> Thx in advance
>
> Attila
>
> On 2021/07/21 14:01:12, "Beckerle, Mike" <mbecke...@owlcyberdefense.com>
> wrote:
> > There is an example of doing dfdl:occursCountKind 'expression' on github
> in the CSV example here:
> >
> >
> https://github.com/DFDLSchemas/CSV/blob/master/src/main/resources/com/tresys/csv/xsd/csvHeaderEnforced.dfdl.xsd
> >
> > Line 75 of this file, it uses this technique to ensure each row has the
> same number of items as there were titles in the initial header row. Your
> case you want a different expression to pick out the exact count from an
> earlier element, but the example may help.
> >
> >
> >
> > ________________________________
> > From: Steve Lawrence <slawre...@apache.org>
> > Sent: Wednesday, July 21, 2021 9:52 AM
> > To: users@daffodil.apache.org <users@daffodil.apache.org>
> > Subject: Re: variable length CSV records via 'lengthKind' property
> >
> > You cannot dynamically set maxOccurs--that has to be either a static
> > number or "unbounded". This is a restriction of XML Schema that DFDL is
> > based off of.
> >
> > But Daffodil does support what you're trying to do . First, you'll want
> > to set maxOccurs="unbounded" (since we don't know how many parameter
> > instances there might be). Bbut then we can use the
> > dfdl:occursCountKind="expression" and dfdl:occursCount properties to
> > evaluate an expression at parse time to set the number of occurrences to
> > the value of the third field. For example:
> >
> > ...
> > <xs:element name="field3" type="xs:int" ... />
> > <xs:element name="parameters" type="..." maxOccurs="unbounded"
> > dfdl:occursCountKind="expression"
> > dfdl:occursCount="{ ../field3 }" ... />
> > ...
> >
> > So we parse field3 to an integer and then use that value in an
> > expression to determine the number of occurrences of the parameters
> array.
> >
> >
> > On 7/21/21 8:04 AM, Horvath, Attila J CTR (USA) wrote:
> > > ALCON - see attached PDF version of this message
> > >
> > > I have a Character Separated Values [CSV] ASCII input file where:
> > >
> > > - fields are ASCII STX character [0x02] separated
> > >
> > > - variable number of fields per below
> > >
> > > - records are ASCII DC4 character [0x14] terminated
> > >
> > > - file is ASCII EOT character [0x04] terminated
> > >
> > > In following sample excerpt, highlighted in YELLOW is last record of
> data file.
> > >
> > > 3rd field [31 30] specifies 10 fields to follow each STX [0x02]
> delimited,
> > >
> > > followed by record and file terminators [0x14 0x04] respectively...
> > >
> > > Is it possible to read the 3rd field ['10'], save it via
> [*_dfdl:lengthKind_*
> > > and/or *_dfdl:defineVariable_*] as "NUM_FIELDS" and pass that value to
> > > 'maxOccurs' attribute on per record basis?
> > >
> > > EG:...
> > >
> > > <xs:element name="parameters" maxOccurs=NUM_FIELDS minOccurs="1">
> > >
> > > ...
> > >
> > > </xs:element>
> > >
> > > Thx in advance
> > >
> > > Attila
> > >
> >
> >
>
