Re: proposed changes to the rdf:text document for option 5

I really want to come to peace with this, but can't unless I understand
it. I'm sorry if the following repeats what Pat has said.

The current draft has:

"Because RDF plain literals are already a part of RDF and SPARQL
syntaxes, rdf:PlainLiteral literals are written as RDF plain literals
in RDF and SPARQL syntaxes."

Based on your comments I interpret this as follows:

"Because RDF plain literals [in the sense of nodes in RDF graphs]
are already a part of RDF and SPARQL
syntaxes [including RDF/XML and Turtle], rdf:PlainLiteral literals
(graph nodes) are written
(by those who have never heard of this new datatype, as well as by those who
follow the advice given herein) as (serialized / syntactic) RDF plain literals
in RDF and SPARQL syntaxes."

But I got caught up on "rdf:PlainLiteral literals".
I guess that an "rdf:PlainLiteral literal" is
a literal node whose datatype is rdf:PlainLiteral. Is this
what you meant to say? And just to be sure, are such
literal nodes typed, untyped, both, or does it
not matter?

Thanks

Jonathan

On Wed, May 27, 2009 at 8:04 PM, Peter F.Patel-Schneider
<pfps@research.bell-labs.com> wrote:
> From: Jonathan Rees <jar@creativecommons.org>
> Subject: Re: proposed changes to the rdf:text document for option 5
> Date: Wed, 27 May 2009 16:24:05 -0500
>
>> On Wed, May 27, 2009 at 11:26 AM, Peter F.Patel-Schneider
>> <pfps@research.bell-labs.com> wrote:
>>>
>>> [Changes to two last paragraphs of Section 1]
>>>
>>> To address these deficiencies, this specification introduces a datatype
>>> called rdf:text, which uses the rdf: prefix because it refers to parts
>>> of the conceptual model of RDF.  This extension, however, does not
>>> change the conceptual model of RDF, and thus does not affect the
>>> specifications that depend on the conceptual model of RDF such as
>>> SPARQL.  The value space of rdf:text consists of all data values
>>> assigned to RDF plain literals, which allows RDF applications to
>>> explicitly refer to this set (e.g., in rdfs:range assertions).
>>>
>>> Because RDF plain literals are already a part of RDF and SPARQL
>>> syntaxes, rdf:text literals are always written as RDF plain literals in
>>> RDF and SPARQL syntaxes.
>>
>> "literals are written as literals" is a use/mention confusion; a
>> literal can't be written
>> as a different literal, because it is already written. You're really
>> talking about how the
>> values are written.
>
> This is RDF.  Check your assumptions at the door.
>
> Literals in RDF graphs (the data model of RDF) are indeed written as
> literals in RDF surface syntaxes (e.g., RDF/XML and Turtle).  Already in
> RDF some typed literals in RDF graphs are not written as typed literals
> of the surface syntax.  A particularly interesting example is typed
> literals with datatype rdf:XMLLiteral, which are written as XML Literals.
>
>> How about:
>>   Because the syntaxes of RDF and SPARQL already provide a way to
>>   write these values, they are always written using plain literals in
>> RDF and SPARQL,
>>   not as typed literals with type rdf:type_formerly_known_as_rdf_text.
>
> But this is not what I wanted to say at all.  This has the effect that
> you can't use xsd:string in RDF syntaxes.
>
> I could have been more precise, saying something like
>
>  typed literals with datatype URI rdf:type_formerly_known_as_rdf_text
>  in RDF graphs are always written as plain literals in linear and
>  exchange syntaxes for RDF (including but not limited to RDF/XML and
>  Turtle)
>
> Perhaps this is going to be the required wording, but it does have to be
> very carefully crafted to cover no more and no less than needed.
>
> Peter F. Patel-Schneider
> Bell Labs Research
>

Received on Sunday, 31 May 2009 01:12:06 UTC