[Exist-open] trying to figure out what is wrong with sequence in (my ?) map objects ...

[christophe g. <chr...@e-...>]

Hi all

I am trying to find a flexible way to scan xml documents (while keeping a
ref to the nodes being scanned) with the help of the (very welcomed -
thanks !) xQuery 3.0 facilities, and am getting a lot of very funny stuff
when using map objects (2.1, rev 17278) ...

Can somebody test the xquery below that simply goes through each node of
the $test element and apply a function stored in a map object to each child
element node, and please tell me why I do see the results I see.

With the function defined in $map-ok, everything seems all right.
$map-double (note the slight difference from  "at" := ($node/@*), to  "at"
:= $node/@*)  returns a somehow dupplicated version of the provided $test
node, while $map-error fails to run (stackoverflow error).

using util:expand($test) doesn't help.

My impression is that something goes wrong somewhere, but I am really not
getting the why nor the where ...
Thanks for the help and cheers,

Christophe


xquery version "3.0";
declare function local:scan($content as node()*, $model) {
  let $scan-map := map{
            "scan.true" := function($node, $model, $test) {$node},
            "scan.default" := function($node, $model) {$node}
        }
    let $model:= map:new(($scan-map, $model))
    return for $root in $content return local:process-scan($root, $model)
};

declare function local:process-scan($node as node(), $model) {
      typeswitch ($node)
         case document-node() return
             for $child in $node/node() return local:process-scan($child,
$model)
         case element() return
            let $return := $model("scan.true")($node,$model, ())
            return
                typeswitch($return)
                case map(*) return
                    element {if($return("na") instance of xs:QName) then
 local-name-from-QName($return("na")) else $return("na")} {
                        $return("at"),
                        for $child in $return("ct") return
local:process-scan($child, $model)
                        }
                default return
                    $model("scan.default")($node,$model)
        default return ()
};


let $test :=
<a>
    <b ns="b">
        <c ns="c"/>
    </b>
</a>
let $map-ok:= map{
        "scan.true" := function($node, $model, $test) {
            map {
                "na" := name($node),
                "at" := ($node/@*),
                "ct" := ($node/node())
        }
    }
}
let $map-double:= map{
        "scan.true" := function($node, $model, $test) {
            map {
                "na" := name($node),
                "at" := $node/@*,
                "ct" := ($node/node())
        }
    }
}
let $map-error:= map{
        "scan.true" := function($node, $model, $test) {
            map {
                "na" := name($node),
                "at" := ($node/@*),
                "ct" := $node/node()
        }
    }
}
return
   ( local:scan($test,$map-ok) (:returns what it should:) ,
    local:scan($test,$map-double) (:returns all element nodes twice:) )
   (: local:scan($test,$map-error) stackoverflow error  :)