XSLT manipulate text scattered across various nodes - xslt

Question

Input file as follows:
<?xml version="1.0" encoding="UTF-8"?>
<!-- lower UPPER case -->
<document>
<rubbish> rubbish </rubbish>
<span class='lower'>
lower
<span class='upper'> upper </span>
case
</span>
</document>
Wanted output:
lower UPPER case
I know how to get the text included in the outer span with value-of, but this also
includes the string "upper" unchanged which is not what I want. I do not know how
to manipulate the text in the inner span and insert it in the middle of
the other text.
Failed attempt:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
<xsl:output method="text" indent="no"/>
<xsl:template match="/">
<xsl:for-each select="//span[#class = 'lower']">
<xsl:if test="span/#class = 'upper'">
<xsl:text>do something</xsl:text> <!--TO DO -->
</xsl:if>
<xsl:value-of select="."/>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>

Answer 1

You need to take a recursive approach here, for example:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xsl:output method="text" encoding="UTF-8"/>
<xsl:template match="text()[parent::span]">
<xsl:choose>
<xsl:when test="../#class='upper'">
<xsl:value-of select="translate(., 'abcdefghijklmnopqrstuvwxyz', 'ABCDEFGHIJKLMNOPQRSTUVWXYZ')" />
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="." />
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<xsl:template match="text()"/>
</xsl:stylesheet>
To understand how this works, read up on built-in template rules: http://www.w3.org/TR/xslt/#built-in-rule

Answer 2

The following approach does away with the <choose> and completely pushes the problem down to the match expression:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet
version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes" />
<xsl:template match="text()"/>
<xsl:template match="text()[parent::span[#class = 'upper']]">
<xsl:value-of select="translate(., 'abcdefghijklmnopqrstuvwxyz', 'ABCDEFGHIJKLMNOPQRSTUVWXYZ')"/>
</xsl:template>
<xsl:template match="text()[parent::span[#class = 'lower']]">
<xsl:value-of select="translate(., 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz')"/>
</xsl:template>
</xsl:stylesheet>