Hello Dimitre,



I ran your solution:



let $aircraft := {"altitude": {"units" : "Flight_Level"} } return

in the Oxygen XPath bar and it gave me this error message:



Unexpected token "{" at start of expression.



Do you know what is causing that error?

Roger, what Dimitre showed there works in XPath 4.0 where an explicit
"map" constructor keyword is optional but in XPath 3.1 you need e.g.