XPath Result Serializer

A standard XSLT module intended to help with XSLT/XPath debugging in combination with the xsl:message instruction and trace() function.

Using two XSLT functions, print() and println(), the result of an XPath expression is converted to a notation similar to JSON.

Note: The standard fn:serialize() function, using the 'adaptive' output method, provides similar functionality:
fn:serialize($n, map{'method':'adaptive'})
The XSLT functions here simply provide more extensibility for features such as coloring and indentation

---

Sample Usage

    <xsl:message expand-text="yes">
      ==== Root element ====
      languages-count:  {node-name() => ext:print(9,'  ')}
      colorNodes:  {ext:print((*,*/@*),9,'  ')}
      
    </xsl:message>
    <xsl:copy>    
      <xsl:message expand-text="yes">
        ==== data====
        context:     {ext:print(.,10,'  ')}
        language:    {ext:print($langItems,10,'  ')}
      </xsl:message>

Screenshot from the xsl:message output shown above in the VS Code terminal using ext:print() and ext:println():

Key Resource Files

• Source XSLT: src/xpath-result-serializer.xsl
• Source XSLT: src/xpath-result-serializer-color.xsl
• Sample: sample/test-serializer.xsl

Colorising of xsl:message Output with Saxon

When using src/xpath-result-serializer.xsl, only if a Saxon version prior to 9.9.0.1 is detected, ANSI escape codes are included in the outputs of ext:print() and ext:println() to provide colorisation (see screenshot).

The src/xpath-result-serializer-color.xsl stylesheeet is a thin wrapper that forces colorising using ANSI escape codes regardless of Saxon version.

These ANSI codes are normally escaped as XML character references by SaxonJ (Java) in the output. In SaxonJ, prior to v9.9.0.2, the command-line option -m:net.sf.saxon.serialize.TEXTEmitter can be used to prevent this XML escaping so xsl:message colors can be seen as intended.

SaxonJ Command-line Wrapper

If you want color output with SaxonJ versions after 9.9.0.1 then you need use the API to add a simple messageListener to ouput text-only. Thin wrappers for the SaxonJ command-line-interface that implement this are maintained on GitHub. There are different branches for Saxon 9.9, 10.0, 11.0 and 12.0.