Enforcing an array on @type/type

Hello,

for having homogeneous data to query and reuse we decided to always have 
an array with "@type" (aliased to "type") in our JSON-LD. (Mostly, there 
is only one "type" in our data but we also systematically use more than 
one in some places, see e.g. the example [record].)

Currently, we still generate the JSON-LD from N-Triples using a custom 
tool but we want to switch to using the JSON-LD [Java] library. However, 
it does not seem possible to enforce an array on "@type".

1.) You can not use an object on "@type" directly in the context like this:

{
   "@type": {
     "@container": "@set"
   }
}

See also [example1] in the JSON-LD playground. looking at the spec, it 
obviously rules out using the @type keyword as a key in the context:

"A context definition must be a JSON object whose keys must either be 
terms, compact IRIs, absolute IRIs, or the keywords @language, @base, 
and @vocab."

2.) This leaves the option to use "@container": "@set" on the term that 
is aliased to "@type":

{
   "type": {
     "@id": "@type",
     "@container": "@set"
   }
}

But this also currently does not work, see [example2]. I can not 
directly see from the spec why this should not be possible but it seems 
like aliasing is only defined as a direct mapping of a term onto a 
keyword and does not allow an expanded term definition.

We would be happy if at least the second option would work. Maybe it 
could be taken into account for JSON-LD 1.1?

All the best
Adrian

P.S.: My colleague Pascal has already opened a [question] on Stack 
Overflow for this.

[record] http://lobid.org/resources/HT019826954.json
[Java] https://github.com/jsonld-java/jsonld-java
[example1] http://tinyurl.com/ybc7d835
[example2] http://tinyurl.com/y8e7wlmj
[question] 
https://stackoverflow.com/questions/52877462/how-to-enforce-an-array-on-type-in-jsonld

Received on Monday, 22 October 2018 10:43:37 UTC