Thanks Christian, Martin for the explanation and good news! Yes, I've seed BXFiddle, it looks promising! Will switch to the 12th version as soon as you release it.
On Mon, Dec 16, 2024 at 5:18 PM Christian Grün christian.gruen@gmail.com wrote:
Hi Oleksandr,
As Martin has summarized, the the current behavior is not a bug as the XQuery 3.x specification does not define order on maps. It is up to the implementation to choose an internal order for entries (usually realized via an immutable/persistent hash structure) that maximizes access time. With XQuery 4, as indicated, this is about to change. As you may have seen if you have clicked the Fiddle link, a proof-of-concept implementation is available now that demonstrates the new behavior. It is also included in the latest snapshot of BaseX [1]. We will further pursue it in BaseX, no matter how the spec evolves.
As for JavaScript, the JSON specification (RFC 8259) states that the order of key/value pairs is not guaranteed. In ECMAScript, however, orderedness was introduced with ES6.
Hope this helps, Christian
[1] https://files.basex.org/releases/latest/
On Mon, Dec 16, 2024 at 4:01 PM Oleksandr Shpak shadowkin@gmail.com wrote:
Since ECMAScript v5 if I remember correctly object keys are ordered, because under the hood List object should be used to store keys.
On Mon, Dec 16, 2024 at 4:37 PM Martin Honnen martin.honnen@gmx.de wrote:
Am 16.12.2024 um 15:19 schrieb Oleksandr Shpak:
Hi Martin,
I found even more weird situation parse-json('{"1:aa": 1, "2:bb": 2}') returns {"2:bb":2.0e0,"1:aa":1.0e0}
Seems like order is inversed But, parse-json('{"aa": 1, "b": 2, "ab": 3}') returns {"aa":1.0e0,"ab":3.0e0,"b":2.0e0}
and, finally parse-json('{"aa": 1, "b": 2, "ab": 3, "1:aa": 1, "2:bb": 2}') returns {"aa":1.0e0,"ab":3.0e0,"b":2.0e0,"2:bb":2.0e0,"1:aa":1.0e0}
🤯
It seems like a bug to me ;)
As I said, in XPath 3.1 and XQuery 3.1 maps are unordered collections, you might get any order when parsing a particular JSON into an XDM 3.1 map.
If it is any help, in the BaseX fiddle you probably get/see the order preservation you want/expect https://fiddle.basex.org/?share=%28%27query%21%275.**8.A6%21%27%27%7Emode%21%27XQuery+%7BBaseX6Type%21%27xml%27%29*A%7D%2C%5Cn579b024ab03.71%3A92%3Abb020%5C%21+4875parse-json%7B%22%286%7D%27%7Econtext7%5C%278%2C+9aa014A%29%22%01A9876540.*_ .
If we are talking about the JSON standard, not xQuery, devs will expect the function which behaves in the same way as it does in many other languages.
Well, I have been around long enough to remember JavaScript/ECMAScript objects as unordered so some features change in the course of time, I also think, Python, for instance only recently switched to some order preservation in its dictionary type.
I don't know what to suggest for the current BaseX release, unfortunately http://www.woerteler.de/xquery/modules/ordered-map.html is not accessible.
-- s0rr0w