Referencing attribute value in xsl:param xsl:if test condition - xslt

Question

I'm trying to retrieve the attribute value from an xsl:param and use it in an xsl:if test condition.
So given the following xml
<product>
<title>The Maze / Jane Evans</title>
</product>
and the xsl
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:param name="test" select="Jane"/>
<xsl:template match="title[contains(., (REFERENCE THE SELECT ATTRIBUTE IN PARAM))]">
<h2>
<xsl:value-of select="substring-before(., '/')"/>
</h2>
<p>
<xsl:value-of select="substring-after(., '/')"/>
</p>
</xsl:template>
<xsl:template match="title">
<h2><xsl:value-of select="."/></h2>
</xsl:template>
</xsl:stylesheet>
I would like to get back
The Maze
Jane Evans

Answer 1

You have a problem in this line:
<xsl:param name="test" select="Jane"/>
This defines an xsl:param named test, whose value is the child element of the current node ('/') named Jane. As the top element is <product> and not <Jane>, the test parameter has the value of an empty node-set (and a string value -- the empty string).
You want (notice the surrounding apostrophes):
<xsl:param name="test" select="'Jane'"/>
The whole processing task can be implemented rather easily:
This XSLT 1.0 transformation:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:param name="pTest" select="'Jane'"/>
<xsl:template match="title">
<xsl:choose>
<xsl:when test="contains(., $pTest)">
<h2>
<xsl:value-of select="substring-before(., '/')"/>
</h2>
<p>
<xsl:value-of select="substring-after(., '/')"/>
</p>
</xsl:when>
<xsl:otherwise>
<h2><xsl:value-of select="."/></h2>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
when applied on the provided XML document:
<product>
<title>The Maze / Jane Evans</title>
</product>
produces the wanted, correct result:
<h2>The Maze </h2>
<p> Jane Evans</p>
Explanation:
The XSLT 1.0 syntax forbids variable/parameter references in a match pattern. This is why we have a single template matching any title and we specify inside the template the conditions for processing in a specific, wanted way.
An XSLT 2.0 solution:
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:param name="pTest" select="'Jane'"/>
<xsl:template match="title[contains(., $pTest)]">
<h2>
<xsl:value-of select="substring-before(., '/')"/>
</h2>
<p>
<xsl:value-of select="substring-after(., '/')"/>
</p>
</xsl:template>
<xsl:template match="title">
<h2><xsl:value-of select="."/></h2>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on the provided XML document (above), again the same wanted, correct result is produced:
<h2>The Maze </h2>
<p> Jane Evans</p>
Explanation:
XSLT 2.0 doesn't have the limitations of XSLT 1.0 and variable/parameter references can be used within a match pattern.

Answer 2

The term $test refers to the value of the test parameter. Use $test
eg:
<xsl:template match="title[contains(., $test)]">
<h2>
<xsl:value-of select="substring-before(., '/')"/>
</h2>
<p>
<xsl:value-of select="substring-after(., '/')"/>
</p>
</xsl:template>