xsl:for-each-group Questions

kwilliams · July 22nd, 2005, 10:17 AM

I have a list of FAQ's in an XML doc (see example below), and the tags within the "answer" node use <p>, <ol> and other standard tags. I want to use an XSLT stylesheet to convert these child nodes to liternal HTML tags after an XHTML transformation.

So here's an example XML doc:

Code:

<?xml version="1.0" encoding="UTF-8"?>
<faq>
    <question>This is where the question would be placed?</question>
        <answer>
            <p>This is where the answer would be placed:</p>
                <ol>
                    <li>This would be the first point.</li>
                    <li>This would be the second point.</li>
                    <li>This would be the third point.</li>
            <p>This is where a sub sentence would be placed.</p>
        </answer>
</faq>

...and this is the XSLT stylesheet that I created to display these tags literally in the transformation to XHTML:

Code:

<xsl:template match="answer">

    <xsl:for-each-group select="p" group-by="p">
        <p><xsl:value-of select="current-grouping-key()"/></p>
    </xsl:for-each-group>


    <xsl:for-each-group select="em" group-by="p">
        <em><xsl:value-of select="current-grouping-key()"/></em>
    </xsl:for-each-group>


    <xsl:for-each-group select="u" group-by="p">
        [u]<xsl:value-of select="current-grouping-key()"/></u>
    </xsl:for-each-group>


    <xsl:for-each-group select="ol" group-by="p">
        <ol><xsl:value-of select="current-grouping-key()"/></ol>
    </xsl:for-each-group>


    <xsl:for-each-group select="ul" group-by="p">
        [list]<xsl:value-of select="current-grouping-key()"/></ul>
    </xsl:for-each-group>


    <xsl:for-each-group select="li" group-by="p">
        <li><xsl:value-of select="current-grouping-key()"/></li>
    </xsl:for-each-group>

</xsl:template>

But I keep receiving this error message:
System.Runtime.InteropServices.COMException: Keyword xsl:for-each-group may not be used here.

So I reviewed several online resources on XSLT Grouping, including http://www.xml.com/lpt/a/2003/11/05/tr.html and http://www.w3.org/TR/xslt20/#grouping-examples. I'm following the rules that were set in the examples included in these examples, but I'm still getting that message.

I even copied & pasted this example directly from the xml.com site:
XML:

Code:

<html><body>
<h1>Loomings</h1>
<p>par 1</p>
<p>par 2</p>
<p>par 3</p>
<h1>The Whiteness of the Whale</h1>
<p>par 4</p>
<p>par 5</p>
<p>par 6</p>
</body>
</html>

XSLT:

Code:

<xsl:template match="body">
  <body>
    <xsl:for-each-group select="*" group-starting-with="h1">
      <chapter>
      <xsl:for-each select="current-group()">
        <xsl:copy>
          <xsl:apply-templates/>
        </xsl:copy>
      </xsl:for-each>
      </chapter>
    </xsl:for-each-group>
  </body>
</xsl:template>

Resulting XHTML:
[code]<html>
   <body>
      <chapter>
         <h1>Loomings</h1>
         <p>par 1</p>
         <p>par 2</p>
         <p>par 3</p>
      </chapter>
      <chapter>
         <h1>The Whiteness of the Whale</h1>
         <p>par 4</p>
         <p>par 5</p>
         <p>par 6</p>
      </chapter>
   </body>
</html>[code]
... but still received the error. So if anyone could let me know what I'm missing, it would be greatly appreciated. Thanks.

KWilliams

mhkay · July 22nd, 2005, 01:23 PM

xsl:for-each-group is an XSLT 2.0 instruction, and you will get an error if you try to use it with an XSLT 1.0 processor.

For an XSLT 2.0 processor, try Saxon 8 from http://saxon.sf.net/

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

kwilliams · July 22nd, 2005, 03:16 PM

Very good. Thanks for another quick and thorough reply.

KWilliams

kwilliams · July 25th, 2005, 02:20 PM

Hello Michael,

Sorry about this, but I had to ask a few more questions about XSLT 1.0 vs. 2.0:

1) Am I correct in thinking that most browsers support 1.0 but not 2.0 yet?

2) If not, what is the current status of browser compatability with 1.0 & 2.0?

If so:
3) Wouldn't it be more wise for me to develop my site using 1.0 for now until 2.0 is accepted by more if not all browsers?
4) What methods exist with 1.0 that display tags within an XML tag as literal HTML?
Example:
<root>
<element>
  <child>
   <h1>TEST</h1>
   <p>This is a test</p>
   <p>This is only a test</p>
  </child>
</element>
</root>

transforms to this using an XSLT stylesheet:

<html>
<body>
<h1>TEST</h1>
  <p>This is a test</p>
  <p>This is only a test</p>
</body>
</html>

Thanks for your input Michael.

KWilliams

mhkay · July 25th, 2005, 04:14 PM

Yes, there is no browser support for XSLT 2.0 yet, and it will be some time before there is. If you want to do the transformations client-side, you have to use XSLT 1.0.

But many people are using XSLT on the server, and there you do have a choice.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

mhkay · July 25th, 2005, 04:16 PM

Concerning your question 4:

<xsl:template match="child">
<xsl:copy-of select="*"/>
</xsl:template>

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

kwilliams · July 25th, 2005, 04:20 PM

Ok, now I understand. Since I'm doing the transformation server-side and not client-side, I can download XSLT 2.0 through the link that you provided directly on the server. Am I correct?

Also, concerning your answer to question #4, thank you for that information. I'll make sure to give it a try asap. Thanks again for the quick and thorough responses.

KWilliams