I'm very confused by this. The function body contains two recursive calls. The
one inside the typeswitch is certainly not tail-recursive, so you're going to
get recursion depth equal to the maximum tree depth. The other call, as far as
I can see, merely returns its second argument unchanged, which seems totally
pointless.
Michael Kay
Saxonica
> On 15 Sep 2017, at 09:30, Kendall Shaw <ks...@kendallshaw.com> wrote:
>
> I don't remember seeing an xquery function that tries to return it's input
> unchanged.
>
> Can this be improved:
>
> declare function local:id($e as element()?, $acc as element()?) as element() {
> if (empty($e)) then
> $acc
> else
> local:id(()
> , element {node-name($e)} {
> $e/@*
> , for $node in $e/node()
> return typeswitch($node)
> case element() return local:id($node, $acc)
> default return $node
> })
> };
>
> The idea is that functions that do more than return their input could be
> based on the function, and benefit from tail call optimization.
>
> Kendall
>
>
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