Looping over distinct values - xslt

Question

Given a variable which returns a list of distinct States using the distinct-values() function, is there a way to tokenize the variable in a for-each loop?
<States>
<State>AL</State>
<State>AL</State>
<State>NM</State>
</States>
The following variable returns AL and NM, but I can't iterate over it using for-each. Is there a way around this?
<xsl:variable name="FormStates" select="distinct-values(States/State)"/>
<xsl:for-each select="$FormStates">
XSLT 2.0 ok.

Answer 1

The distinct-values() function returns a sequence of values which you should be able to iterate over. The result is so to speak "tokenized".
fn:distinct-values('AL', 'AL', 'NL') returns the sequence ('AL', 'NL').
If you output the variable with xsl:value-of it will return the string "AL NL" only because the default sequence separator for xsl:value-of is a single space character. This is something you could change with the #separator attribute:
Input
<?xml version="1.0" encoding="UTF-8"?>
<States>
<State>AL</State>
<State>AL</State>
<State>NM</State>
</States>
XSLT
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
<xsl:template match="/">
<xsl:variable name="FormStates" select="distinct-values(States/State)"/>
<xsl:comment>xsl:value-of</xsl:comment>
<xsl:value-of select="$FormStates" separator=":"/>
<xsl:comment>xsl:for-each</xsl:comment>
<xsl:for-each select="$FormStates">
<xsl:value-of select="."/>
<xsl:text>:</xsl:text>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
Output
<?xml version="1.0" encoding="UTF-8"?>
<!--xsl:value-of-->
AL:NM
<!--xsl:for-each-->
AL:NM:

Answer 2

Here's an XSLT 1.0 solution that I've used in the past.
<xsl:template match="/">
<ul>
<xsl:for-each select="//State[not(.=preceding::*)]">
<li>
<xsl:value-of select="."/>
</li>
</xsl:for-each>
</ul>
</xsl:template>
Returns:
<ul xmlns="http://www.w3.org/1999/xhtml">
<li>AL</li>
<li>NM</li>
</ul>

Answer 3

In theory it should work; are you sure the XPath given to the distinct-values function is correct? The code you've given requires that the States element is a sibling of the forms element.
You could insert <xsl:value-of select="count($FormStates)"> immediately after the variable declaration to confirm if it is being set properly.