> I've never written or come across (I think...) a runtime 
> created argument to function-available() - are there any 
> common examples / uses or really is it pretty rare?

I used to think it happened only in artificial test cases, but it also
happens in Jesper's stylesheet posted earlier today, where presumably
there's a document containing a list of possible functions names, and he
calls function-available() on each one in turn to compare the coverage in
different processors.

Michael Kay
http://www.saxonica.com/