Now I know why I get confused sometimes. The operators _do_ work on nodesets, but functions _don't_..

This has nothing to do with operators/functions -- just the way XPath
1.0 and XPath 2.0 react to a sequence of more than one item when just
one is expected.

Of course, the picture is a little bit more complicated, because we
have backwards compatibility (version="1" in scope) and calculating
the EBV (Effective Boolean Values), that cause XPath 2.0 to behave
(almost) as XPath 1.0.

Grtz,
Geert