<?xml version="1.0"?>
<!-- Delivers the fragment between two milestones. Takes no care about namespaces. -->

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fn="local-function">

<xsl:function name="fn:contains">
  <xsl:param name="sequence" as="node()*"/> 
  <xsl:param name="node" as="node()?"/> 
  <xsl:sequence select="some $nodeInSequence in $sequence satisfies $nodeInSequence is $node"/>
</xsl:function>

<xsl:output method="xml" encoding="utf-8"/>

<!-- ms1Name and ms2Name have to be given without namespace: e.g. "pb" -->
<xsl:param name="ms1Name"></xsl:param>
<xsl:param name="ms1Position"></xsl:param>
<xsl:param name="ms2Name"></xsl:param>
<xsl:param name="ms2Position"></xsl:param>

<xsl:variable name="ms1XPath" select="concat('subsequence(//*:', $ms1Name, ', ', $ms1Position, ', 1)')"/>
<xsl:variable name="ms2XPath" select="concat('subsequence(//*:', $ms2Name, ', ', $ms2Position, ', 1)')"/>
<xsl:variable name="ms1" select="saxon:evaluate($ms1XPath)" xmlns:saxon="http://saxon.sf.net/"/>
<xsl:variable name="ms2" select="saxon:evaluate($ms2XPath)" xmlns:saxon="http://saxon.sf.net/"/>
<xsl:variable name="ms1Ancestors" select="$ms1/ancestor::*"/>
<xsl:variable name="ms2Ancestors" select="$ms2/ancestor::*"/>

<!-- all elements between the milestone elements and also the ancestor elements (for filling the node path to the root) -->
<xsl:template match="element()[local-name() != $ms1Name and local-name() != $ms2Name]">
  <xsl:choose>
    <xsl:when test="(. >> $ms1 or fn:contains($ms1Ancestors, .)) and ($ms2 >> . or fn:contains($ms2Ancestors, .))">
      <xsl:element name="{local-name(.)}"><xsl:copy-of select="@*"></xsl:copy-of><xsl:apply-templates/></xsl:element>
    </xsl:when>
    <xsl:otherwise><xsl:apply-templates/></xsl:otherwise>
  </xsl:choose>
</xsl:template>

<!-- the two milestone elements -->
<xsl:template match="element()[local-name() = $ms1Name or local-name() = $ms2Name]">
  <xsl:choose>
    <xsl:when test=". is $ms1">
      <xsl:element name="{local-name(.)}"><xsl:copy-of select="@*"></xsl:copy-of></xsl:element>
    </xsl:when>
    <xsl:when test=". is $ms2">
      <xsl:element name="{local-name(.)}"><xsl:copy-of select="@*"></xsl:copy-of></xsl:element>
    </xsl:when>
    <xsl:otherwise></xsl:otherwise>
  </xsl:choose>
</xsl:template>

<xsl:template match="attribute()|text()|comment()|processing-instruction()">
  <xsl:choose>
    <xsl:when test=". >> $ms1 and $ms2 >> .">
      <xsl:copy><xsl:apply-templates/></xsl:copy>
    </xsl:when>
    <xsl:otherwise><xsl:apply-templates/></xsl:otherwise>
  </xsl:choose>
</xsl:template>

</xsl:stylesheet>