Finding the closest node (was Re: inconsistent Precedi

Jeni Tennison wrote:
[...]

When you collect together all the preceding-siblings of a node, and
handle them in document order the first of those nodes is the first of
the siblings -- the first child of the parent -- not the closest of
those siblings.

If you want to get the *closest* of the siblings then you can use
[last()] as follows:

<xsl:value-of select="(preceding-sibling::person/name)[last()]" />

What if I want to get the closest of some possible (specific) subset of
ancestors? eg (this is Docbook, let us say the current node is an <xref>
in a <para> at some depth within one of the following):

<xsl:variable name="anchor"
            select="ancestor::sidebar |
                    ancestor::warning |
                    ancestor::note |
                    ancestor::orderedlist |
                    ancestor::itemizedlist |
                    ancestor::variablelist |
                    ancestor::varlistentry |
                    ancestor::listitem |
                    ancestor::procedure |
                    ancestor::step |
                    ancestor::footnote"/>

Unfortunately, XPath returns the remotest node (the earliest in document
order). For example, if the current node is in a step in a procedure, I
need a variable set to that step, not to the whole procedure. Ignore for
the moment the possibility of nested lists.