#include <x/xml/xpath.H> rlock->get_xpath("body/p[1]")->to_node();
The parameter to a reader or a writer lock's
get_xpath() is an XPath expression.
x::xml::xpathescape()
and x::xml::xpathescapestr()
are available to help with referencing literal strings in the XPath
expression.
get_xpath() returns a
x::xml::xpath
representing the resulting nodeset from evaluating the expression against
the current node the reader, or the writer, lock is positioned to.
to_node() expects the nodeset containing exactly
one node. It positions the lock, that created the
x::xml::xpath, to the node.
Each x::xml::xpath holds an
internal reference on the underlying lock that created it, until the
last reference to the object referred to by the
x::xml::xpath goes out of, and it
gets destroyed.
auto xpath=rlock->get_xpath("body/p"); for (size_t i=1, n=xpath->count(); i<=n; ++i) { xpath->to_node(i); }
count() returns the number of nodes in the
nodeset. Passing an explicit node number to
to_node() positions the lock to the given
node in the nodeset.
Nodes are numbered starting with node #1. A nodeset with three nodes consists of nodes #1, #2, and #3.
to_node() throws an exception if the requested
node no longer exists because
it was remove()d.