Re: A modest attempt to re-open ISSUE-20

On 14 Mar 2013, at 08:26, Reto Bachmann-Gmür <reto@apache.org> wrote:

> 
> 
> On Wed, Mar 13, 2013 at 11:54 AM, Henry Story <henry.story@bblfish.net> wrote:
> 
> On 13 Mar 2013, at 10:40, Andy Seaborne <andy.seaborne@epimorphics.com> wrote:
> 
> >
> >
> > On 13/03/13 07:10, Pierre-Antoine Champin wrote:
> >> Henry,
> >>
> >> On Wed, Mar 13, 2013 at 2:15 AM, Henry Story <henry.story@bblfish.net
> >> <mailto:henry.story@bblfish.net>> wrote:
> >
> >
> >>
> >>    The abstract syntax  specificiation allows for relative URLs:
> >>    http://www.w3.org/TR/rdf11-concepts/#rdf-documents
> >>
> >>
> >> This section is about serialization; it explicitly says "concrete syntaxes".
> >> On the other hand, the definition of IRI for the graph model
> >>
> >> http://www.w3.org/TR/rdf11-concepts/#dfn-iri
> >>
> >> explicitly says "IRIs in the RDF abstract syntax MUST be absolute".
> >
> > Yes.
> >
> > A syntax may allow a relative URI but that's in a document and a document has a base URI.  The relative URI is relative to some base URI.  Relative URI have a role in syntax
> >
> > RFC 3986 makes it clear:
> >
> > [[
> > 5.1.  Establishing a Base URI
> >
> >   The term "relative" implies that a "base URI" exists against which
> >   the relative reference is applied.  Aside from fragment-only
> >   references (Section 4.4), relative references are only usable when a
> >   base URI is known.
> > ]]
> 
> And indeed they are: when you POST content the server will know what
> URIs the relative ones are referring to, once he has created the resource.
> 
> IIUC, the server will know but the producer of the RDF serialization does not. So what is effectively serialized is not actually RDF but a pseudo RDF supporting relative URIs that can only be serialized in those RDF serializations implicitly supporting this. 

What you are serialising is a concrete syntax, not an abstract syntax. Concrete syntaxes can have 
relative URLs. 

When the Jena or Sesame APIs allow you to create such serialisations are those libraries lying because they don't know where the serialisation is going to end up on your hard drive or on your server? When an artist produced HTML with relative URLs and sends a tar of it to the company that made the request, is the html sent  to them flawed because the artist does not know the exact path for where the html is going to end up at? ( Put some RDFa in the html if you feel like saying the example is irrelevant )

> I think not letting the client deal with the RDF on the abstract syntax level is quite a severe limitation.


That is why we are using the concrete syntax Turtle to pass information to and fro, not the abstract one.

Henry

> 
> Cheers,
> Reto
>  

Social Web Architect
http://bblfish.net/