DFDL's count function does not operate on any "node set", but on specific
named array elements only.
In your case, the array is the row element, so { fn:count(/Document/row) +
1 } should give the value you want.
On Wed, Dec 27, 2023 at 8:44 AM Roger L Costello <coste...@mitre.org> wrote:
> Hi Folks,
>
>
>
> My input file has a field containing the number of “words” in the file,
> where the “words” are the child elements of the root element. Here’s the
> XML that parsing produces:
>
>
>
> <Document>
> <initial_word>
> <message_length>3</message_length>
> </initial_word>
> <row>...</row>
> <row>...</row>
> </Document>
>
>
>
> The message_length is the initial_word + number of <row> elements, i.e., 1
> + 2 = 3
>
>
>
> I would like to hide message_length because it provides no meaningful
> information in the XML (after all, if you want to know the message length
> simply count the child elements of <Document>).
>
>
>
> To hide message_length, I will need a hidden group in my DFDL schema:
>
>
>
> <xs:group name="hidden-MESSAGE_LENGTH ">
> <xs:sequence>
> <xs:element name="hidden" type="unsignedint3"
> dfdl:outputValueCalc="{????}"/>
> </xs:sequence>
> </xs:group>
>
>
>
> The challenge that I am having is what XPath to use in
> dfdl:outputValueCalc. Initially, I used this:
>
>
>
> dfdl:outputValueCalc="{fn:count(/Document/*)}
>
>
>
> Daffodil complained: *Wildcard * is not supported.*
>
>
>
> Then I tried this:
>
>
>
> dfdl:outputValueCalc="{fn:count(../following-sibling::row)+1}
>
>
>
> Daffodil complained: *following-sibling axis is not supported.*
>
>
>
> Eek!
>
>
>
> I don’t know what else to try. Any suggestions?
>
>
>
> /Roger
>
>
>
