[XSLT 2.0] Is it possible to display the type of a node / value / variable?

Having spent a great deal of time today trying to work out where a typing 
problem was going wrong (my coding, Saxon 7.5 support of what I wanted to do, 
etc) I would really have liked to be able to display the type of (in my case) 
a variable at various points in the code - in order to see what was and what 
wasn't working.

Is there a function to do that? As far as I can see the data() function which 
is said to return the "typed value" doesn't actually return the type, at 
least not in a form that I could serialize, which I would need to do in this 
debugging scenario.

If not, it seems to me that a function to display the type of a node, an 
atomic value and a variable would be useful for debugging XSLT 2.0 
stylesheets as people grapple with the "interesting" aspects of typing in 
XSLT 2.0 not behaving quite as expected.

Andrew Watt