Re: "do not occur"

On Tue, Jun 2, 2009 at 3:41 PM, Axel Polleres <axel.polleres@deri.org> wrote:
> Peter F.Patel-Schneider wrote:
>>
>> From: Sandro Hawke <sandro@w3.org>
>> Subject: "do not occur"
>> Date: Tue, 2 Jun 2009 12:00:54 -0500
>>
>>> [FYI, today, SPARQL and RIF said they're okay with the current drafts;
>>> in RIF's case, this is modulo the name change being made in the
>>> builtins.]
>>>
>>> At the risk of waking sleeping dragons, Axel and I were talking about
>>> this delicate sentence:
>>>
>>>    Therefore, typed literals with rdf:PlainLiteral as the datatype do
>>>    not occur in syntaxes for RDF graphs, nor in syntaxes for SPARQL.
>>>
>>> and how it seems normative, even though it's stated as purely logical.
>>>
>>> The confusion, as I understand it, is that typed literals with the
>>> datatype rdf:PlainLiteral:
>>>
>>>        - DO NOT occur in the syntax, which means they
>>>        - MUST NOT occur in the documents.
>>>
>>> This is a little confusing.
>>>
>>> Option 1:
>>>
>>>    leave it as is
>>>
>>>     (my vote: +0)
>
>> +1
>
> -1
>
> To me this last sentence indicates that if I now go out and publish a graph.
>
>     :s :p "gotcha, haha"^^rdf:PlainLiteral.

Here's my interpretation of the spec: "haha"^^rdf:PlainLiteral is not
a typed rdf:PlainLiteral literal.
It means something, just not what you think. That's because the only
syntax for rdf:PlainLiteral literals is that of plain literals.

-Alan

> I consequently yield the whole spec invalid (by ex falso quod libet)....
>
> There is no guarantee that there is no such graph published out there
> already.  Current RDF APIs swallow that graph without trouble, I can even
> write SPARQL queries against it that filter the datatype rdf:PlainLiteral
> with current implementations) and it is totally compliant with RDF. So, the
> sentence as it stands just doesn't make sense to me.
>
>
>> I put the sentence in to emphasize the previous sentence, which provides
>> the normative force.  That sentence as well does not use a MUST, also by
>> design.  The rationale is that this is the way that things are.
>
> Let us have a look at the previous sentence again:
>
> "To eliminate another source of syntactic redundancy and to retain a large
> degree of interoperability with applications that do not understand the
> rdf:PlainLiteral datatype, the form of rdf:PlainLiteral literals in syntaxes
> for RDF graphs and for SPARQL is the already existing syntax for the
> corresponding plain literal, not the syntax for a typed literal."
>
> Hmm, to my understanding that sentence indicates only that a
> rdf:PlainLiteral typed literal is not a plain literal in the sense of this
> spec not that rdf:PlainLiteral typed literals
> do not exist - which however the other sentence does say. At the very least,
> I find the second sentence more confusing than enlightning in its current
> state.
>
>
>> A MUST
>> would be directives to implementations, and this is not that.
>
>>> Option 2:
>>>
>>>    rephrase as: Therefore, typed literals with rdf:PlainLiteral as the
>>>    datatype are considered by this specification to be not valid in
>>>    syntaxes for RDF graphs or SPARQL.
>>>
>>>    (my vote: -0)
>
>
> +1
>
> This is precise and on the safe side. I have a much better feeling with
> that.
>
>> +0
>>
>>> Option 3:
>>>
>>>    (just drop the sentence; it's doesn't add much itself.)
>>>
>>>    (my vote: +1)
>>
>> +0
>
> +0 I can live with that, although indeed the sense of the sentence before is
> a bit lost with that, i.e. it doesn't say anything about explicitly
> rdf:PlainLiteral typed literals.
>
>>> That's it.  (Dear sleeping dragons: If you're going to breath fire,
>>> please give me time to run away first.)
>>
>> But sleeping dragons don't work that way.  :-)
>
> (I guess after that mail, you are safe Sandro, they'll run after me :-))
>
> Axel
>
>>>       -- Sandro
>>
>> peter
>>
>>
>
>
> --
> Dr. Axel Polleres
> Digital Enterprise Research Institute, National University of Ireland,
> Galway
> email: axel.polleres@deri.org  url: http://www.polleres.net/
>
>
>

Received on Tuesday, 2 June 2009 20:47:37 UTC