Supported XPath construct as of writing are:
- '/'-axis (child)
- '//'-axis (self-or-descendant)
- node name tests, including namespaces
- predicate test (@ = "")
A state machine is built which the SAX-nodes are tested against. If a node matches, the state machine progresses.
For self-or-descendant-nodes, the state machine is forked and earch fork (including the parent) is tested against the SAX-nodes. This ensures all nodes are matched. See test/saxpath.js and test/inception.xml for an example.