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Re: Comments on RDFa Core 1.1 Working Draft

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Wed, 11 Jan 2012 16:15:08 +0000
Message-ID: <4F0DB58C.6050409@epimorphics.com>
To: public-rdf-wg@w3.org


On 11/01/12 13:34, David Wood wrote:
> Hi all,
>
> This message records my comments on RDFa Core 1.1 WD dated 15 Dec
> 2011 [1].  This review completes my action from the RDF WG [2].
>
> I was pleased to see the RDFa Core WD refer to IRIs in place of URIs.
> This will ease transition of the RDF documents to using IRIs and not
> require a revisiting of the RDFa Core document.  However, there are
> still several places in the document that refer to URIs (even when
> not in direct relation to CURIEs); those should be revisited for
> consistency.
>
> Most of the RDFa Core WD discusses syntactical issues.  As such, I
> (and hopefully the RDF WG) are agnostic.  I agree with Ivan that we
> should think of RDFa 1.1 as "just" another standard RDF serialization
> syntax.

One nearly-syntactic issue from RDF 1.1 is plain literals/xsd:string and 
rdf:langString.

>
> However, we don't want to encounter any syntax or usage patterns
> within RDFa that results in a conflation of IRIs for both resource
> names and resource contents, as with SPARQL's named graphs.  This is
> especially important to the RDF WG, given our resolutions related to
> this problem in SPARQL:

This should include pointers to what your talking about.

I would suggest

  (SPARQL 1.0)
http://www.w3.org/TR/rdf-sparql-query/#sparqlDataset
http://www.w3.org/TR/rdf-sparql-query/#namedGraphs

but they do not back up using the word "conflate" which comes more from 
common practice.

> - At the RDF WG's first FTF [3], we resolved, "Named Graphs in SPARQL
> associate IRIs and graphs *but* they do not necessarily "name" graphs
> in the strict model-theoretic sense. A SPARQL Dataset does not
> establish graphs as referents of IRIs (relevant to ISSUE-30)".
> ISSUE-30 is at [4].
>
> The RDFa Core WD refers to RDF Concepts in relation to graph
> definition (sec. 3.7) [5].  This is very helpful and will allow us to
> update RDF Concepts as required.  However, there is possibly a
> confusion between a graph's name (a g-snap) and its contents at a
> point in time (a g-text) in RDFa Core, depending on the
> interpretation of the base IRI.

Minor: "its contents"

I read it as "its" refers to the graph, and so its "contents" risk 
mixing the contents of a graph container (g-box) and the graph (g-snap - 
contents are triples as it is a set of triples).

Suggest: "its representation" (AWWW term).

> The RDFa Core WD, section 7.2 [6] specifies the base IRI of a
> document this way: "The base. This will usually be the IRI of the
> document being processed, but it could be some other IRI, set by some
> other mechanism, such as the (X)HTML base element. The important
> thing is that it establishes an IRI against which relative paths can
> be resolved."
>
> That means, to me at least, that the base IRI is often going to be
> the *same as* the document IRI, thus resulting in conflation of
> denotation of the graph and the document.

FWIW: I read the RDFa doc as restating the usual handling of base IRIs.

>
> I don't think that needs to change in the RDFa Core document, but it
> does mean that our named graphs discussion should take note.  The
> following RDF WG issues relate (and possibly more):
>
> - ISSUE-14 "What is a named graph and what should we call it?" [7] -
> ISSUE-15 "What is the relationship between the IRI and the triples in
> a dataset/quad-syntax/etc" [8] - ISSUE-17 "How are RDF datasets to be
> merged?" [9] - ISSUE-29 "Do we support SPARQL's notion of "default
> graph"?" [10] - especially ISSUE-32 "Can we identify both g-boxes and
> g-snaps?" [11] - ISSUE-38 "What new vocabulary should be added to RDF
> to talk about graphs?" [12]
>
> Andy Seaborne has pointed out [13] that, "the doc URI is not the
> graph name in every case -- it is in the web cache pattern."  (By
> "doc URI" he meant "the RDFa document's base IRI")  That is a good
> point and should be considered.

As part of that discussion, didn't conclude that RDFa does not talk 
about named graphs (any sense) at all?  One document -> some triples.

A quick check of the processing model suggests to me that RDFa just 
generates triples, no clumping into any units, so it's a single graph, 
just as if it were a Turtle or N-triples document.  But it is a quick 
check (and needs checking!).

>
> Dan Brickley asked [13], "what about # URIs in RDFa: can they
> identify any resource?"  The RDFa Core WD has a note on this [14]
> which basically says "unfortunately not".
>
> Regards, Dave
>
> [1]  http://www.w3.org/TR/2011/WD-rdfa-core-20111215/ [2]
> http://www.w3.org/2011/rdf-wg/track/actions/128 [3]
> http://www.w3.org/2011/rdf-wg/meeting/2011-04-14 [4]
> http://www.w3.org/2011/rdf-wg/track/issues/30 [5]
> http://www.w3.org/TR/2011/WD-rdfa-core-20111215/#graphs [6]
> http://www.w3.org/TR/2011/WD-rdfa-core-20111215/#evaluation-context
> [7]  http://www.w3.org/2011/rdf-wg/track/issues/14 [8]
> http://www.w3.org/2011/rdf-wg/track/issues/15 [9]
> http://www.w3.org/2011/rdf-wg/track/issues/17 [10]
> http://www.w3.org/2011/rdf-wg/track/issues/29 [11]
> http://www.w3.org/2011/rdf-wg/track/issues/32 [12]
> http://www.w3.org/2011/rdf-wg/track/issues/38 [13]
> http://www.w3.org/2011/rdf-wg/meeting/2012-01-04#RDFa_LC [14]
> http://www.w3.org/TR/2011/WD-rdfa-core-20111215/#s_Syntax_overview
>
>
Received on Wednesday, 11 January 2012 16:15:43 GMT

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