The XSLT recommendation at http://www.w3.org/TR/xslt#element-sort specifies that "When used in xsl:for-each, xsl:sort elements must occur first."
That is generally a good rule, but I suggest an exception should be made for xsl:variable (and possibly others that do not generate content), allowing that element to appear before xsl:sort.
Because the purpose of variables is to avoid having to print similar code many times.
But as seen in the examples, due to the current restricion, you have to print out a long complex search path twice.
In the second (conceptual) example, you could first assign a node to a variable, then use it in the xsl:sort element already.
The result is a much cleaner document, that is easier to maintain.


<xsl:for-each select="/foo/bar">
	<xsl:sort select="document('items.xml')//item[@xml:id = current()/@code]/@label" />
	<xsl:variable name="item" select="document('items.xml')//item[@xml:id = current()/@code]" />  <!-- unnecessary repetion -->
	<xsl:value-of select="$item/@a" />
	...
	<xsl:value-of select="$item/@z" />
</xsl:for-each>


<xsl:for-each select="/foo/bar">
	<xsl:variable name="item" select="document('items.xml')//item[@xml:id = current()/@code]" />  <!-- only written once -->
	<xsl:sort select="$item/@label" />
	<xsl:value-of select="$item/@a" />
	...
	<xsl:value-of select="$item/@z" />
</xsl:for-each>