In XSLT 1.0, match="g" matches exactly the same elements as
match="//g".
There's a slight difference in 2.0, because match="//g"
will only match g elements that are in a tree with a
document node as its root - which means the processor has
extra checks to do in this case.
Confused. Don't *all* elements exist in a tree with a document
node as its root?
Under what circumstances might an element *not* have such a
root please?
No, XSLT 2.0 (and XQuery) allow you to create free-standing nodes. For
example, there was a question a few days ago (I think on the Saxon list
rather than here) from someone who wanted to write a function that returned
a set of attribute nodes:
<xsl:function name="my:atts" as="attribute()">
<xsl:param name="p"/>
<xsl:attribute name="a" select="{$p+1}"/>
<xsl:attribute name="b" select="{$p+2}"/>
</xsl:function>
(Essentially the same as an attribute-set, except that attribute sets do not
allow parameters.)
You can copy these attributes to an element, like this:
<e>
<xsl:copy-of select="my:atts(17)"/>
</e>
But you can also apply-templates to them:
<xsl:apply-templates select="my:atts(29)"/>
If you try to find the parent of one of these attributes, you find it hasn't
got one:
<xsl:value-of select="count(my:atts(6)/..)"/> displays "0".
And of course the same applies to elements.
Michael Kay