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Re: #rdf-containers-syntax-ambiguity, #rdf-containers-syntax-vs-schema

From: Jan Grant <Jan.Grant@bristol.ac.uk>
Date: Wed, 13 Jun 2001 16:54:29 +0100 (BST)
To: Brian McBride <bwm@hplb.hpl.hp.com>
cc: rdf core <w3c-rdfcore-wg@w3.org>
Message-ID: <Pine.GSO.4.31.0106131648340.27373-100000@mail.ilrt.bris.ac.uk>
On Wed, 13 Jun 2001, Brian McBride wrote:

>   <rdf:Bag>
>     <rdf:li>1</rdf:li>
>     <foo:ten>10</rdf:li>
>     <rdf:li>11</rdf:li>
>   </rdf:Bag>
>
> What triples does the above example generate.  Either the parser has to process
> subPropertyOf relations, or it will generate a different set of triples from the
> first example.

Excellent example. Parsers should not be required to know anything about
the schema they're parsing, I think; particularly if RDFSchema is
considered to be in a state of flux.

> I think therefore there is a case to be made for simplifying this aspect of
> the proposal so that rdf:li elements within a description are translated to
> rdf:_nnn where nnn starts at 1 and is incremented by one for each rdf:li
> encountered.
>
> This the example given above:
>
>   <rdf:Bag>
>     <rdf:li>1</rdf:li>
>     <rdf:_10>10</rdf:li>
>     <rdf:li>11</rdf:li>
>   </rdf:Bag>
>
> would generate:
>
>   _:genid <rdf:type> <rdf:Bag>.
>   _:genid <rdf:_1>   "1" .
>   _:genid <rdf:_10>  "10" .
>   _:genid <rdf:_11>  "2" .

I think you mean
    _:genid <rdf:_2> "11" .
for that last triple.

In which case, this seems a simple definitive answer.

> This solution also neatly ducks the issue of what do to with:
>
>   <rdf:Bag rdf:_1="1" rdf:_2="2">
>     <rdf:li>?</rdf:li>
>   </rdf:Bag>

It seems to me from a pragmatic point of view that the <rdf:li> forms
are likely to be machine-generated. I'd not be too concerned if your
pathological example here generated

    _:genid <rdf:type> <rdf:Bag> .
    _:genid <rdf:_1> "1" .
    _:genid <rdf:_2> "2" .
    _:genid <rdf:_1> "?" .

- if we decide that this is not a legal set of RDF triples, then your
last example is simply not legal RDF.

> I'd welcome feedback from the WG on which way they would like me to proceed
> as I write up the test cases.

Keep it simple (and implementable).

-- 
jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44(0)117 9287163 Fax +44 (0)117 9287112 RFC822 jan.grant@bris.ac.uk
ioctl(2): probably the coolest Unix system call in the world
Received on Wednesday, 13 June 2001 11:55:50 EDT

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