Hi Marco,
I've also taken a look at the code and I think the observed behaviour is in
accordance with the logic of the accumulator function (local:stand-totaal),
while this logic is probably not really what. First - why do you get the result
which you get?
(1) The logic of local:stand-totaal(a) Accept the new item only if its ID is
not found among the accumulated items (before filtering these for the status,
see b))(b) Retain only those accumulated items which do not have a certain
status
The input sequence is objects 3, 2, 1(1) Process object 3: Object accepted, as
the accumulator is still empty, so the object ID is "new"; the fact that the
new object has a <status> element is ignored.(2) Process object 2: The object
is rejected, as its ID is found in the accumulator; the accumulator is then
filtered, discarding object 3 because of its status; result: the accumulator is
again empty (nothing added, and what was there has been removed)(3) Process
object 1: The object is accepted, as the accumulator is again empty, so the
item ID is "new"
>From your expectations I gather that you want to exclude later reuse of an ID
>possessed by an object with status "beeindigen". Therefore I suggest the
>following simple solution of the problem:(a) Extract all IDs of an object with
>that status(b) Before fold-left, filter the sequence of objects, discarding
>any object with such an ID(c) Process the filtered sequence, not thinking
>about the status any more, just checking the ID
This processing is best encapsulated in a function (e.g. update-stand()).
With kind regards,Hans-Jürgen
PS: Code snippet for the suggestion:
declare function local:update-stand($objects as element()*) as
element()* { let $idsIGN := $objects[.//*:status =
'beëindigen']//*:identificatie => distinct-values() let $objectsF :=
$objects[not(.//*:identificatie = $idsIGN)] return
fold-left($objectsF, (), local:stand-totaal#2) }; declare function
local:stand-totaal (: returns an object by comparing new to old :) (:
newest should be returned, except when
<ow:status>beëindigen</ow:status> then no object should be returned :)
($new as item()*, $old as item()*) as item()* { let
$new_ids := $new//*:identificatie => distinct-values() return ($new,
$old[not(.//*:identificatie = $new_ids)]) };
Am Dienstag, 19. Dezember 2023 um 10:38:49 MEZ hat Martin Honnen
<martin.hon...@gmx.de> Folgendes geschrieben:
On 19/12/2023 09:53, Marco Duiker - LandGoed wrote:
Please help me with the following problem:
I try to construct the current status of a series of objects along the
following simple rules:
- the current status of on object with a certain `identificatie` (id) is
the newest version of that object
- except when the newest object has the property
`<status>beëindigen</status>` then the object stops existing.
I use a fold-left to proces these rules with a simple function implementing
those rules. This gives me unexpected results.
I've reduced the problem to a single stand alone query in which the last
object (`obj3`) has the property `<status>beëindigen</status>`.
So I would expect this line:
`let $stand4 := fold-left(($obj3, $obj2, $obj1), (), function($stand,
$obj) { local:stand-totaal($stand, $obj) })`
to give me an empty result as `obj3` has the property
<status>beëindigen</status>
but I am getting `obj1` as demonstrated in the following stand alone query.
When running the stand alone query I would expect:
declare function local:stand-totaal
(: returns an object by comparing new to old :)
(: newest should be returned, except when
<ow:status>beëindigen</ow:status>
then no object should be returned :)
($new as item()*,
$old as item()*) as item()* {
let $new_ids := local:id($new)
let $stand_deel1 :=
for $obj_oud in $old//*:owObject
where not(local:id($obj_oud) = $new_ids)
return <sl:stand>{ $obj_oud }</sl:stand>
let $stand_deel2 :=
for $obj_new in $new//*:owObject[not(.//*:status)]
return <sl:stand>{ $obj_new }</sl:stand>
return ($stand_deel1, $stand_deel2)
};
>From your comment and explanation I kind of would expect a check for that
>particular value
<ow:status>beëindigen</ow:status>
but that value is not checked for or mentioned at all in the XQuery code.
