keyword alias with `"@prefix"=true` ?

[pchampin]

The following is quite ugly, and in my opinion it should break.

{
  "@context": {
    "@version": 1.1,
    "id": {
        "@id": "@id",
        "@prefix": true
     }
  },
  "id:foo": "#x"
}

The thing is: nothing in the spec explicitly prevents it:

• Step 25 of Create Term Definition does not check that iri mapping is not a keyword.
• Step 5.4 of IRI Expansion does not either, so should happily use the keyword as a prefix.

This is what the Ruby distiller is doing: the JSON-LD above generates a "@idfoo" property... The playground ignores it silently, which in my view is not complying with the spec. But that's not the point. I think the spec should reject the use of keyword aliases as prefix, by updating either of the steps above.

I can provide the PR, if we agree that it's a bug and not a feature.

[azaroth42]

Related to w3c/json-ld-syntax#246

[iherman]

This issue was discussed in a meeting.

• RESOLVED: When encountering a term in the form of a compact IRI for which the prefix would expand to a keyword, do not expand the term
• ACTION: determine if <code>@prefix:</code> false will prevent the term from being used in expanding IRIs, and file an issue if it does (Gregg Kellogg)

View the transcript

Rob Sanderson: time to summarize for the minutes
… we accept that issue 153 is an issue
Gregg Kellogg: a bug
Rob Sanderson: true. a bug
… it should not in fact generate @idfoo
Gregg Kellogg: it should treat id:foo as an IRI
… so the result of expanding should be id:foo
Proposed resolution: When encountering a term in the form of a compact IRI for which the prefix would expand to a keyword, do not expand the term (Rob Sanderson)
Rob Sanderson: so if there was an @vocab it would expand to that value + id:foo?
Rob Sanderson: +1
Pierre-Antoine Champin: +1
Gregg Kellogg: it won’t be expanded as a relative URI because of the colon
Gregg Kellogg: +1
Benjamin Young: +1
Simon Steyskal: +1
Resolution #4: When encountering a term in the form of a compact IRI for which the prefix would expand to a keyword, do not expand the term
Gregg Kellogg: if there is an id term that’s legit, and I see @prefix: false
… it won’t expand that because prefix is false
Action #1: determine if @prefix: false will prevent the term from being used in expanding IRIs, and file an issue if it does (Gregg Kellogg)

[pchampin]

(duplicating my comment on c482f45, to make the discussion easier to follow:

It seems to me that this change was meant precisely to prevent a term from being used in expanding IRIs when @Prefix is false...

From what I see, the Expand IRI algorithm in the Ruby distiller does honnor @prefix, conforming to the letter of the spec since c482f45 (but possibly not conforming to its spirit). The Playground does not honnor @prefix during expansion.

My PR above is based on the current version of Expand IRI. If we were to revert it to not honnor @prefix, it would be moot.

[gkellogg]

WG resolved to close the issue as complete.