path-utils.xsl

<?xml version="1.0"?>

<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:template name="dirname">
    <xsl:param name="reldir" />
    <xsl:param name="path" />
    <xsl:choose>
      <xsl:when test="contains($path,'/')">
        <xsl:variable name="pathel" select="substring-before($path,'/')" />
        <xsl:call-template name="dirname">
          <xsl:with-param name="reldir" select="concat($reldir,$pathel,'/')" />
          <xsl:with-param name="path"
                          select="substring($path,string-length($pathel)+2)" />
        </xsl:call-template>
      </xsl:when>
      <xsl:otherwise>
        <xsl:value-of select="$reldir" />
      </xsl:otherwise>
    </xsl:choose>
  </xsl:template>

</xsl:stylesheet>