fn:nilled.xq

fn:nilled.xq

declare namespace xsi = "http://www.w3.org/2001/XMLSchema-instance";

(: 
  Tries to mimic http://www.w3.org/TR/xpath-functions-30/#func-nilled
  If $arg is the empty sequence, the function returns the empty sequence.
:)
declare function local:nilled($arg as node()?) as xs:boolean? {
  if(empty($arg)) then ()
  else (
   not($arg/(text()|node())) and $arg/@xsi:nil eq "true"
   )
};


let $in-xml :=<root >
  <child>12</child>
  <child xsi:nil="true"></child>   <!-- true -->
  <child xsi:nil="true">a</child>  <!-- false, this is non valid XML ;-) -->
  <child></child>                  <!-- false -->
  <child/>                         <!-- false -->
  <child xsi:nil="false"></child>  <!-- false -->
</root>
return $in-xml//child !  <result>
  { local:nilled(.) } : { . }
</result>