[xsl] XQuery/XPath 3.1: Node List to Node Set ("distinct nodes")

I couldn’t find an answer in my google and markmail searching so I thought I’d 
ask here:

Given an arbitrary list of nodes that may contain duplicates, what is the most 
efficient way to reduce the node list to a set?

The solution I came up with is a recursive function:

(:
Get the unique nodes from the supplied sequence
@param nodes The sequence of nodes to evaluate
@return A sequence of nodes such that each node in $nodes exists exactly once.
:)
declare function dutils:distinctNodes($nodes as node()*) as node()* {
  dutils:_getDistinctNodes($nodes, ())
};

declare function dutils:_getDistinctNodes($nodes as node()*, $resultList as 
node()*) as node()* {
  if (exists($nodes))
  then
  let $node := head($nodes)
  return dutils:_getDistinctNodes(tail($nodes), ($resultList | $node))
  else $resultList

};

Which works but I feel like I’m missing some obvious way to do this more 
directly, but I’m not seeing it.

Am I missing a better solution?

Thanks,

Eliot

_____________________________________________
Eliot Kimber
Sr Staff Content Engineer
O: 512 554 9368
M: 512 554 9368
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