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Re: Plain literals in Canonical N-triples

From: David Booth <david@dbooth.org>
Date: Sat, 27 Dec 2014 18:56:25 -0500
Message-ID: <549F4729.7000806@dbooth.org>
To: Peter Ansell <ansell.peter@gmail.com>, Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>
CC: public-rdf-comments <public-rdf-comments@w3.org>
Even aside from OWL this looks like a gap in the N-Triples spec that an 
erratum should address, since the whole intent of Canonical N-Triples is 
to eliminate variability like that.

David Booth

On 12/27/2014 06:13 PM, Peter Ansell wrote:
> Hi Stian,
>
> RDF-1.1 does not have the concept of plain literals [1]. Hence, it is
> difficult to map the OWL-WG-derived rdf:PlainLiteral set to RDF-1.1,
> if that is where you are coming at the issue from [2].
>
> Cheers,
>
> Peter
>
> [1] http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-Graph-Literal
> [2] https://github.com/owlcs/owlapi/issues/172
>
> On 27 December 2014 at 16:37, Stian Soiland-Reyes
> <soiland-reyes@cs.manchester.ac.uk> wrote:
>> In http://www.w3.org/TR/n-triples/#canonical-ntriples I read:
>>
>>> Canonical N-Triples has the following additional constraints on layout:
>>>
>>>      The whitespace following subject, predicate, and object MUST be a single space, (U+0020). All other locations that allow whitespace MUST be empty.
>>>      There MUST be no comments.
>>>      HEX MUST use only uppercase letters ([A-F]).
>>>      Characters MUST NOT be represented by UCHAR.
>>>      Within STRING_LITERAL_QUOTE, only the characters U+0022, U+005C, U+000A, U+000D are encoded using ECHAR. ECHAR MUST NOT be used for characters that are allowed directly in STRING_LITERAL_QUOTE.
>>
>>
>> and in http://www.w3.org/TR/n-triples/#sec-parsing-terms
>>
>>> If neither a language tag nor a datatype IRI is provided, the literal has a datatype of xsd:string.
>>
>>
>> and in http://www.w3.org/TR/n-triples/#sec-literals
>>
>>> If there is no datatype IRI and no language tag it is a simple literal and the datatype is http://www.w3.org/2001/XMLSchema#string.
>>
>>> Example 3
>>>      <http://example.org/show/218> <http://www.w3.org/2000/01/rdf-schema#label> "That Seventies Show"^^<http://www.w3.org/2001/XMLSchema#string> . # literal with XML Schema string datatype
>>>      <http://example.org/show/218> <http://www.w3.org/2000/01/rdf-schema#label> "That Seventies Show" . # same as above
>>
>>
>> So I am not any wiser with regards to how to serialize plain literals
>> in RDF 1.1 Canoical N-Triples..
>>
>>
>> Are both of the two examples allowed in Canonical N-Triples? (it seems
>> so by the spec.. :-( ).
>>
>> Which variant should I generate?
>>
>>
>> --
>> Stian Soiland-Reyes, myGrid team
>> School of Computer Science
>> The University of Manchester
>> http://soiland-reyes.com/stian/work/ http://orcid.org/0000-0001-9842-9718
>>
>
>
>
>
Received on Saturday, 27 December 2014 23:56:54 UTC

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