Returns the name of the function identified by a function item.
fn:function-name
( $func
as function(*)
xs:QName?
If $func
refers to a named function, fn:function-name($func)
returns the name of that function.
Otherwise ($func
refers to an anonymous function),
fn:function-name($func)
returns an empty sequence.
The prefix part of the returned QName is implementation-dependent.
The expression fn:function-name(fn:substring#2)
returns fn:QName("http://www.w3.org/2005/xpath-functions",
"fn:substring")
.
The expression fn:function-name(function($node){count($node/*)})
returns ()
.