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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 16:48:34 +0000
Message-ID: <4F0DBD62.1050103@epimorphics.com>
To: Ivan Herman <ivan@w3.org>
CC: public-rdf-wg@w3.org


On 11/01/12 16:28, Ivan Herman wrote:
>
> On Jan 11, 2012, at 17:15 , Andy Seaborne wrote:
>
>>
>>
>> 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.
>
> This was actually discussed in the RDFa WG. But the problem is that this is not yet a standard, only part of an editor's draft in RDF. It would not be appropriate for the RDFa WG to use something that would be a draft only...

Great - as long as it's on the radar. We've mentioned it before and I 
think if they use our proposed compatibility story is OK.

	Andy

>
>
> Ivan
>
>
>>
>>>
>>> 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
>>>
>>>
>>
>
>
> ----
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> FOAF: http://www.ivan-herman.net/foaf.rdf
>
>
>
>
>
Received on Wednesday, 11 January 2012 16:54:02 GMT

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