Re: XPath context evaluation

BTW, where would I register my own functions?

There are many ways in Saxon to incorporate your own functions if they are
in your own namespace (you'll have to dig around the Javadoc and probably
the code to find them though!) - essentially Saxon's XPath parser searches
in a set of FunctionLibrary objects, each of which is given the opportunity
to grab a function reference and bind it to some implementation; you can add
your own FunctionLibrary at various levels of the system either globally in
the Configuration or in a particular static context.

To add a function that's in the standard namespace is not really approved of
but I can see why you want to do it (there's a need for this in XForms as
well). At present, though, it requires code change, or at a minumum a change
to the table of functions in the StandardFunctions module.

If you want more help on this, switch to the Saxon list.