(:
    Find the first author per parent.
    Over bibliography.xml.
    parke godfrey 2013-11-05

    Our query finding first authors again, but wrapped as a full-fledged
    XQuery query.  After the IN in a FOR clause comes the generator,
    which is an XPath expression.

      * All variables in XQuery start with a "$".
      * "at" provides a counter (starting with "1"!) for the FOR iterator.
      * "data(...)" extracts the data content of the node.
      * The query includes a start tag <authors> and its end tag </authors>
        in this case.  This makes the query results a proper XML document
        of its own.
      * The "{...}" is used as an EVAL: evaluate the contents and return
        the results.
      * Note I wrap the results in the "return" to have the tags I decided
        I wanted.
:)

<authors>
{
    for $first at $i in doc("bibliography.xml")//author[1]
    return <first>{$i}. {data($first)}</first>
}
</authors>