Saxon » SaxonC

Sometimes with XSLT or XQuery you want to run the same transformation or query on a series of input files to aggregate the result into one file e.g. a single .csv file. With SaxonJ or SaxonCS/Saxon.NET I think the API allows that easily, here is one example for SaxonJ using a single FileOutputStream and then having each transformation create a Serializer over that same FileOutputStream:

import net.sf.saxon.s9api.*;

import javax.xml.transform.stream.StreamSource;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class Main {
    public static void main(String[] args) throws SaxonApiException, IOException {
        String sampleDir = "C:\\Users\\marti\\OneDrive\\Documents\\xslt\\blog-xslt-3-by-example\\aggregate-sample-data";
        String[] xmlSamples = new String[] { "sample1.xml", "sample2.xml", "sample3.xml" };

        Processor processor = new Processor(true);

        XsltCompiler xsltCompiler = processor.newXsltCompiler();

        XsltExecutable xsltExecutable = xsltCompiler.compile(new StreamSource(new File(sampleDir, "filter-data.xsl")));

        FileOutputStream fos = new FileOutputStream(new File(sampleDir, "saxonj-result.csv"));

        for (String sample : xmlSamples) {
            Xslt30Transformer xslt30Transformer = xsltExecutable.load30();
            xslt30Transformer.applyTemplates(new StreamSource(new File(sampleDir, sample)), processor.newSerializer(fos));
        }

        fos.close();
    }
}

Now I am wondering whether the SaxonC API (mainly looking at Python currently) would allow me something similar but given that there is only a method like apply_templates_returning_file there doesn't seem to be a similarly simple way like the Java or .NET/CS APIs allow.

Am I left with using apply_templates_returning_string and then using Python to write the string results to the same opened file?

That would for huge results mean having huge intermediary string results in memory.

I understand that of course I could also try to write a wrapper stylesheet that creates a single result processing all input files but that is also forcing me to change my approach and kind of could run into memory problems if all samples files are are built as trees by the same stylesheet.

So I wonder, does SaxonC need some way to write results to a stream or append to a file? Of course I am just wondering whether it would be desirable, I am not sure the architecture and the various target platforms (e.g. C/C++, Python, PHP) would allow that in a consistent and usable way.