Are @subject and @iri redundant?

[lanthaler]

In the spec, @subject is used to denote the subject of an item, and @iri is used to denote a value which is an IRI. However, from chaining, the distinction seems to go away. For example, consider the following two graphs:

{
  "@subject": "http://greggkellogg.net/foaf#me",
  "foaf:homepage":
  {
    "@iri": "http://greggkellogg.net/"
  }
}

and

{
  "@subject": "http://greggkellogg.net/foaf#me",
  "foaf:homepage":
  {
      "@subject": "http://greggkellogg.net/"
  }
}

From step 2.6.1 in the spec, the first use of "@subject" ("@" in that version) generates a triple in the same way that step 2.2, for "@iri", does.

We could simplify the spec by either removing "@iri", or replacing "@subject" with "@iri". Of course, using the aliasing mechanism we've discussed, the other could continue to exist as semantic sugar in the default context.

So, @subject works the same as @iri when given in an object of a property, so @iri could be considered redundant
(albeit more understandable at least for @Coerce). The question would be if @iri is sugar for objects with only that key (an no other properties), or if it works just like @subject.

[msporny]

Technically, they are redundant. However, I think that just like @type and @datatype, we should keep the two concepts separate to help people understand what is going on in the markup a bit better.

[lanthaler]

This issue was originally raised by Gregg:

http://lists.w3.org/Archives/Public/public-linked-json/2011Jul/0060.html

I think in this case it makes sense to keep both @subject and @iri even though @subject is just syntactic sugar. So for me it would be fine to close this issue.. let's see what Gregg thinks about it - I've CCed him.

P.S.: For me this issue is quite different from the @type/@datatype issue (#31). I wouldn't like to treat them the same way.

-----Original Message-----
From: Manu Sporny [mailto:reply+i-1477642-
[email protected]]
Sent: Tuesday, November 29, 2011 12:42 PM
To: Markus Lanthaler
Subject: Re: [json-ld.org] Are @subject and @iri redundant? (#15)

Technically, they are redundant. However, I think that just like @type
and @datatype, we should keep the two concepts separate to help people
understand what is going on in the markup a bit better.

---

Reply to this email directly or view it on GitHub:
#15 (comment)

[lanthaler]

RESOLVED: Use the same keyword for the concepts of @subject and @iri.

RESOLVED: Use the keyword '@id' for the combined concept of @subject and @iri.

Minutes of the 2011-12-13 telecon

[gkellogg]

Updated specs in 44c7dde.

[msporny]

http://json-ld.org/spec/ED/json-ld-syntax/20120122/#identifying-the-subject