xml - The return type of <xsl:variable name="pubDate" select="publicationDate" />, a node-set or a string? -

i new xsl , using version 1.0

here xml source

<?xml version="1.0"?> <catalog>     <cd>         <title>empire burlesque</title>         <artist>bob dylan</artist>         <company>columbia</company>         <publicationdate>03/31/1985</publicationdate>     </cd> </catalog> 

from above xml content, set varialbe in xsl code by

 <xsl:variable name="pubdate" select="//publicationdate" /> 

i thought variable 'pubdate' should contain node-set because of '//publicationdate' realized possible apply string function such substring($pubdate, 1, 4) hints 'pubdate' string.

is automatic type cast or else?

in xslt 1.0 $pubdate node-set. if reference in function expects string value parameter, use string value of first node in node set. say, text value of node , descendant nodes. if first node looked this:

<publicationdate><mm>03</mm><dd>31</dd><yy>1985</yy></publicationdate>  

then substring($pubdate, 1, 4) still output 0331.

things different in xslt 2.0 though. contain sequence, if tried same substring expression error "a sequence of more 1 item not allowed first argument of substring()"

edit: now, if had done this...

   <xsl:variable name="pubdate">        <xsl:copy-of select="//publicationdate" />    </xsl:variable> 

then $pubdate contains "result tree fragment". can still use in string function, use string value of entire result tree fragment in case.