Using xsl:variable in a xsl:foreach select statement - xslt

Question

I'm trying to iterate through an xml document using xsl:foreach but I need the select=" " to be dynamic so I'm using a variable as the source. Here's what I've tried:
...
<xsl:template name="SetDataPath">
<xsl:param name="Type" />
<xsl:variable name="Path_1">/Rating/Path1/*</xsl:variable>
<xsl:variable name="Path_2">/Rating/Path2/*</xsl:variable>
<xsl:if test="$Type='1'">
<xsl:value-of select="$Path_1"/>
</xsl:if>
<xsl:if test="$Type='2'">
<xsl:value-of select="$Path_2"/>
</xsl:if>
<xsl:template>
...
<!-- Set Data Path according to Type -->
<xsl:variable name="DataPath">
<xsl:call-template name="SetDataPath">
<xsl:with-param name="Type" select="/Rating/Type" />
</xsl:call-template>
</xsl:variable>
...
<xsl:for-each select="$DataPath">
...
The foreach threw an error stating: "XslTransformException - To use a result tree fragment in a path expression, first convert it to a node-set using the msxsl:node-set() function."
When I use the msxsl:node-set() function though, my results are blank.
I'm aware that I'm setting $DataPath to a string, but shouldn't the node-set() function be creating a node set from it? Am I missing something? When I don't use a variable:
<xsl:for-each select="/Rating/Path1/*">
I get the proper results.
Here's the XML data file I'm using:
<Rating>
<Type>1</Type>
<Path1>
<sarah>
<dob>1-3-86</dob>
<user>Sarah</user>
</sarah>
<joe>
<dob>11-12-85</dob>
<user>Joe</user>
</joe>
</Path1>
<Path2>
<jeff>
<dob>11-3-84</dob>
<user>Jeff</user>
</jeff>
<shawn>
<dob>3-5-81</dob>
<user>Shawn</user>
</shawn>
</Path2>
</Rating>
My question is simple, how do you run a foreach on 2 different paths?

Answer 1

Try this:
<xsl:for-each select="/Rating[Type='1']/Path1/*
|
/Rating[Type='2']/Path2/*">

Answer 2

Standard XSLT 1.0 does not support dynamic evaluation of xpaths. However, you can achieve your desired result by restructuring your solution to invoke a named template, passing the node set you want to process as a parameter:
<xsl:variable name="Type" select="/Rating/Type"/>
<xsl:choose>
<xsl:when test="$Type='1'">
<xsl:call-template name="DoStuff">
<xsl:with-param name="Input" select="/Rating/Path1/*"/>
</xsl:call-template>
</xsl:when>
<xsl:when test="$Type='2'">
<xsl:call-template name="DoStuff">
<xsl:with-param name="Input" select="/Rating/Path2/*"/>
</xsl:call-template>
</xsl:when>
</xsl:choose>
...
<xsl:template name="DoStuff">
<xsl:param name="Input"/>
<xsl:for-each select="$Input">
<!-- Do stuff with input -->
</xsl:for-each>
</xsl:template>

Answer 3

The node-set() function you mention can convert result tree fragments into node-sets, that's correct. But: Your XSLT does not produce a result tree fragment.
Your template SetDataPath produces a string, which is then stored into your variable $DataPath. When you do <xsl:for-each select="$DataPath">, the XSLT processor chokes on the fact that DataPath does not contain a node-set, but a string.
Your entire stylesheet seems to be revolve around the idea of dynamically selecting/evaluating XPath expressions. Drop that thought, it is neither possible nor necessary.
Show your XML input and specify the transformation your want to do and I can try to show you a way to do it.