I tested you suggestions and it's works, the last one with little variation: let $number := { 'value': 1, 'inc': fn { map:put(., 'value', .?value + 1) } } return $number=?>inc() I was testing 'cause I need to use values objects. Thanks!!!!! ---------- Forwarded message --------- From: Martin Honnen via BaseX-Talk <basex-talk@mailman.uni-konstanz.de> Date: Wed, Mar 25, 2026 at 6:55 PM Subject: [basex-talk] Re: [XQST0045] Annotation %method is in reserved namespace. To: <basex-talk@mailman.uni-konstanz.de> On 26/03/2026 01:12, Eliúd Santiago Meza y Rivera via BaseX-Talk wrote: Hello, I was testing the feature https://docs.basex.org/main/XQuery_4.0#methods, but the examples raise the error XQST0045 let $vector := { 'x': 5, 'y': 6, 'sum': %method fn() { ?x + ?y } } return $vector =?> sum() In the fiddle the variation let $vector := { 'x': 5, 'y': 6, 'sum': fn { ?x + ?y } } return $vector =?> sum() works let $number := { 'value': 1, 'inc': %method fn() { map:put(., 'value', ?value + 1) } } return $number?inc() as does let $number := { 'value': 1, 'inc': fn { map:put(., 'value', ?value + 1) } } return $number=?>inc() Not sure about the state of the annotation %method -- LSC Eliud Santiago Meza y Rivera