Re: Cannot find extension function using 10.x

The code you've shown us is fine, so there's something wrong in the code you haven't shown us...

I ran this JUnit test based on your code, and it worked fine:

public void testIntegratedExtensionFunctionXslt3() {
    try {
        Processor proc = new Processor(false);
        proc.registerExtensionFunction(new ConstructDocument(proc));
        XsltCompiler comp = proc.newXsltCompiler();
        StringReader sr = new StringReader(
                "<xsl:stylesheet version='2.0' xmlns:xsl='http://www.w3.org/1999/XSL/Transform' xmlns:f='https://w3id.org/atomgraph/client#' xmlns:xs='http://www.w3.org/2001/XMLSchema'>" +
                        "<xsl:template name='go'><a name=\"{f:construct-doc(xs:anyURI('http://a/'), xs:anyURI('http://b/'), xs:anyURI('http://c/'))/*/name()}\"/></xsl:template>" +
                        "</xsl:stylesheet>");
        XsltExecutable exec = comp.compile(new StreamSource(sr));
        XsltTransformer xsl = exec.load();
        xsl.setInitialTemplate(new QName("go"));
        StringWriter sw = new StringWriter();
        Serializer out = proc.newSerializer();
        out.setOutputWriter(sw);
        xsl.setDestination(out);
        xsl.transform();
        assertTrue("out", sw.toString().contains("doc52"));
    } catch (Exception e) {
        e.printStackTrace();
        fail(e.getMessage());
    }
}


public static class ConstructDocument implements ExtensionFunction {

    private final Processor processor;

    public ConstructDocument(Processor processor) {
        this.processor = processor;
    }

    @Override
    public QName getName() {
        return new QName("https://w3id.org/atomgraph/client#", "construct-doc");
    }

    @Override
    public SequenceType getResultType() {
        return SequenceType.makeSequenceType(ItemType.DOCUMENT_NODE,
                                             OccurrenceIndicator.ZERO_OR_MORE);
    }

    @Override
    public SequenceType[] getArgumentTypes() {
        return new SequenceType[]
                {
                        SequenceType.makeSequenceType(ItemType.ANY_URI,
                                                      OccurrenceIndicator.ONE),
                        SequenceType.makeSequenceType(ItemType.ANY_URI,
                                                      OccurrenceIndicator.ZERO_OR_MORE),
                        SequenceType.makeSequenceType(ItemType.ANY_URI,
                                                      OccurrenceIndicator.ONE),
                };
    }

    @Override
    public XdmValue call(XdmValue[] arguments) throws SaxonApiException {
        return processor.newDocumentBuilder().build(new StreamSource(new StringReader("<doc52/>")));
    }

    public Processor getProcessor() {
        return processor;
    }

}
It could be for example that you have more than one Processor and you've registered the function with the wrong one; or perhaps you only registered it after compiling the stylesheet (without seeing all your code I can't rule out these possibilities).

If you still can't get it to work, please provide a complete repro so we can actually reproduce the problem.

The configuration option Feature.TRACE_EXTERNAL_FUNCTIONS can be useful for diagnostics on this kind of problem.

Michael Kay
Saxonica

> On 7 Aug 2020, at 13:06, Martynas Jusevičius <martynas-tyFqBaoSXPC1Z/[email protected]> wrote:
> 
> Hi,
> 
> I've been trying to upgrade to Saxon 10.x and had to implement a few
> (simple) extension functions in the process. I've been following this
> guide:
> https://www.saxonica.com/html/documentation/extensibility/integratedfunctions/ext-simple-J.html
> 
> However I get this error message when attempting to use one of them:
> 
> Error near {...c:forClass, $ldt:base)/rdf:...} at char 0 in
> xsl:apply-templates/@select on line 650 column 135 of layout.xsl:
>  XPST0017: Cannot find a 3-argument function named
>  Q{https://w3id.org/atomgraph/client#}construct-doc()
> 
> I've double-checked the namespaces.
> 
> The function is registered on the Processor:
> 
>        processor.registerExtensionFunction(new ConstructDocument(processor));
> 
> The function itself looks like this:
> 
> public class ConstructDocument implements ExtensionFunction
> {
> 
>    private final Processor processor;
> 
>    public ConstructDocument(Processor processor)
>    {
>        this.processor = processor;
>    }
> 
>    @Override
>    public QName getName()
>    {
>        return new QName("https://w3id.org/atomgraph/client#", "construct-doc");
>   }
> 
>    @Override
>    public SequenceType getResultType()
>    {
>        return SequenceType.makeSequenceType(ItemType.DOCUMENT_NODE,
> OccurrenceIndicator.ZERO_OR_MORE);
>    }
> 
>    @Override
>    public SequenceType[] getArgumentTypes()
>    {
>        return new SequenceType[]
>        {
>            SequenceType.makeSequenceType(ItemType.ANY_URI,
> OccurrenceIndicator.ONE),
>            SequenceType.makeSequenceType(ItemType.ANY_URI,
> OccurrenceIndicator.ZERO_OR_MORE),
>            SequenceType.makeSequenceType(ItemType.ANY_URI,
> OccurrenceIndicator.ONE),
>        };
>    }
> 
>    @Override
>    public XdmValue call(XdmValue[] arguments) throws SaxonApiException
>    {
>        ...
>    }
> 
>    public Processor getProcessor()
>    {
>        return processor;
>    }
> 
> }
> 
> What am I missing here? Thanks.
> 
> 
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