Hello,

I'm testing some XQuery 3.1 features against a JSON-LD[1] document and had a few questions. In the JSON-LD format, the "@" symbol has special semantics in key names, but seems to cause problems with the 3.1 lookup operator.

For example:

json-doc("http://lae.princeton.edu/catalog/0bp35.jsonld")("@context")

works as expected, but

json-doc("http://lae.princeton.edu/catalog/0bp35.jsonld")?@context

throws an error: [XPST0003] No specifier after lookup operator: '@'.

Also, when using the "=>" operator, should it be possible to perform a lookup on the last expression in a chain, if that expression returns a map?

For example:

json-doc("http://lae.princeton.edu/catalog/0bp35.jsonld")("@context") evaluates to "http://iiif.io/api/presentation/2/context.json"

and

json-doc("http://lae.princeton.edu/catalog/0bp35.jsonld")("@context") => json-doc()

returns another map object. So, how would one achieve this:

json-doc(json-doc("http://lae.princeton.edu/catalog/0bp35.jsonld")("@context"))("@context")

using the arrow operator?

Thanks,
Tim


[1] http://www.w3.org/TR/json-ld/


--
Tim A. Thompson
Metadata Librarian (Spanish/Portuguese Specialty)
Princeton University Library