I want to convert a list of attributes to a comma-separated list

a variable $choiceNode contains a tree fragment:
<xsd:choice maxOccurs="unbounded">
  <xsd:element ref="referential"/>
  <xsd:element ref="temporal"/>
  <xsd:element ref="privacy"/>
</xsd:choice>

when i use the syntax:
<xsl:value-of select="string-join($choiceNode/node()/xsd:element/string(@ref),',')"/>
 the output is "referential,temporal,privacy"
but when i want to put this in a variable, the variable stays empty. How come???????
I use the syntax:
<xsl:variable name="choicelist" select="string-join($choiceNode/node()/xsd:element/string(@ref),',')"/>
or
<xsl:variable name="choicelist">
<xsl:value-of select="string-join($choiceNode/node()/xsd:element/string(@ref),',')"/></xsl:variable>
The debugger in oxygen displays the value but doesn't recognise it as a string

even this doesn't return a variable with a value:
<xsl:variable name="choiceList" select="string-join(('a','b'),'|')" />
when using
<xsl:value-of select="string-join(('a','b'),'|')"/> this returns "a,b" but I can't seem to fill the variable with this value

I think it's one of those cases where the problem is in the part of the code that you haven't shown us. Try to construct a complete but minimal working example that illustrates the problem.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

I got it working by replacing it to another part where i use the variable.

the problem I did not know was that the variables created with xsl:variables last only inside the tag it is called even inside a xsl:if tag and when placed under the param tags and not using it right away, the variable is not set.

I did not add a line directly under the variable that did something with the variable.
It seems that if I put the xsl:variable inside a <xsl:if > tag, the variable only is present inside the <xsl:if></xsl:if> tags. I thought the local variables added under the param of a template would last everywhere inside the template tags (like in scripting languages)but it doesn't

This doesn't work:
<xsl:template name="rule">
    <xsl:param name="choiceNode" select="node()" />
    <xsl:variable name="choiceList" select="string-join($choiceNode/node()/xsd:element[1]/@ref,'|')" />
    <xsl:element name="sch:pattern">..using $choiceList here doesnt work choiceList is empty here...</xsl:element>
</xsl:template>

This does:
<xsl:template name="rule">
    <xsl:param name="choiceNode" select="node()" />
    <xsl:element name="sch:pattern">
    <xsl:if test="$choiceNode/node()">
        <xsl:variable name="choiceList" select="string-join($choiceNode/node()/xsd:element[1]/@ref,'|')" />
        <xsl:if test="replace(.,'{$choiceList}','x') = 'x'">
            found in list ...
        </xsl:if>
    </xsl:if>

</xsl:element>
</xsl:template>

Yes, that's the way XSLT defines the scope of variables.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference