Converting milestone tags

Hi everybody,

I am new to this list and apologize, if my question is an FAQ. I scanned
the archives, but did not find a solution. The question arises in a TEI
project where we have to switch from a chapter hierarchy to a page
oriented form. The XSLT is done in multiple steps (a cocoon pipeline)
and I use Saxon9.

Here is a simplified example of an infile:

<root>
 <p>text <span order="start"/>text<span order="end"/> text</p>
 <p>text <span order="start"/>text<span order="end"/> text
    text <span order="start"/>text<span order="end"/> text</p>
 <p>text text text <span order="start"/>text<span order="end"/></p>
 <p><span order="start"/>text<span order="end"/> text text text</p>
</root>

which should result in the following output:

<root>
 <p>text <span>text</span> text</p>
 <p>text <span>text</span> text
    text <span>text</span> text</p>
 <p>text text text <span>text</span></p>
 <p><span>text</span> text text text</p>
</root>

There my be an arbitrary number of <span order="begin"/> (and
corresponding end milestone tags) in a p element. Furthermore, any
"text" node may again contain markup which should be preserved in the
output. I tried various approaches but I failed. Here is one of my
attempts using sibling recursion ...

<xsl:stylesheet version="2.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:template match="/">
  <xsl:apply-templates/>
 </xsl:template>
	
 <xsl:template match="root">
  <root><xsl:apply-templates/></root>
 </xsl:template>
	
 <xsl:template match="p">
  <p>
   <xsl:apply-templates select="child::node()" mode="procp"/>
  </p>
 </xsl:template>
	
 <xsl:template match="span[@order='start']" mode="procp">
  <span>
   <xsl:apply-templates
     select="following-sibling::node()[1][not(self::span)]"
     mode="procp"/>
  </span>
  <xsl:apply-templates select="following-sibling::node()[1]"/>
 </xsl:template>
	
 <xsl:template match="node()" mode="procp">
  <xsl:copy-of select="."/>
   <xsl:apply-templates
      select="following-sibling::node()[1][not(self::span)]"
      mode="procp"/>
 </xsl:template>
</xsl:stylesheet>

Any help would be greatly appreciated. Josef

-- 
Josef Schneeberger
josef@xxxxxxxxxxxxxxxxxx
Nuernberg, Germany