Question

I am looking for a solution that will turn

<p>
<hi rend="bold">aa</hi>
<hi rend="bold">bb</hi>
<hi rend="bold">cc</hi>
Perhaps some text.
<hi rend="italic">dd</hi>
<hi rend="italic">ee</hi>
Some more text.
<hi rend="italic">ff</hi>
<hi rend="italic">gg</hi>
Foo.
</p>

into

<p>
<hi rend="bold">aabbcc</hi>
Perhaps some text.
<hi rend="italic">ddee</hi>
Perhaps some text.
<hi rend="italic">ffgg</hi>
Foo. 
</p>

but my solution should _not hardcode elements and the names of the attribute values (italic, bold). The XSLT should really concatenate ALL sibling elements that have the same name and the same attribute value. Everything else should be left untouched.

I have looked at the solutions that already exist out there but none of them seemed to satisfy all of my requirements.

If anybody has a handy XSLT stylesheet for this, I’d be much obliged.

Answer 1

Is the name of that attribute (e.g. rend) known? In that case I think you want

<xsl:template match="p">
  <xsl:copy>
    <xsl:for-each-group select="*" group-adjacent="concat(node-name(.), '|', @rend)">
      <xsl:element name="{name()}" namespace="{namespace-uri()}">
         <xsl:copy-of select="@rend"/>
         <xsl:apply-templates select="current-group()/node()"/>
      </xsl:element>
     </xsl:for-each-group>
  </xsl:copy>
</xsl:template>

[edit]
If there can be text node with content between the elements, as you have shown in the edit of your input, then you need to nest to groupings as in the sample

<xsl:stylesheet
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  version="2.0"
  xmlns:xs="http://www.w3.org/2001/XMLSchema"
  exclude-result-prefixes="xs">

<xsl:template match="p">
  <xsl:copy>
    <xsl:for-each-group select="node() except text()[not(normalize-space())]" group-adjacent="boolean(self::*)">
      <xsl:choose>
        <xsl:when test="current-grouping-key()">
          <xsl:for-each-group select="current-group()" group-by="concat(node-name(.), '|', @rend)">
            <xsl:element name="{name()}" namespace="{namespace-uri()}">
               <xsl:copy-of select="@rend"/>
               <xsl:apply-templates select="current-group()/node()"/>
            </xsl:element>
          </xsl:for-each-group>
        </xsl:when>
        <xsl:otherwise>
          <xsl:apply-templates select="current-group()"/>
        </xsl:otherwise>
      </xsl:choose>
     </xsl:for-each-group>
  </xsl:copy>
</xsl:template>

</xsl:stylesheet>