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Re: Regarding the SHOULD for NFC in RDF Literals

From: Sebastian Hellmann <hellmann@informatik.uni-leipzig.de>
Date: Mon, 23 Sep 2013 14:16:29 +0200
Message-ID: <5240311D.1070305@informatik.uni-leipzig.de>
To: Richard Cyganiak <richard@cyganiak.de>
CC: public-rdf-comments@w3.org
Ok, excellent, this already answered my question. If the NFC problem is 
irrelevant in practice, because everybody uses NFC, then there is no 
sense in changing it to MUST.

@Richard: I don't need an official response.  For me your eminence-based 
judgement is enough...

All the best,
Sebastian

Am 23.09.2013 12:32, schrieb Richard Cyganiak:
> (Not an official WG response, but personal opinion)
>
> The short answer is backwards compatibility with legacy content. It said SHOULD in the 2004 version of RDF. If we now change SHOULD to MUST, then some existing RDF 2004 documents would be invalid RDF 1.1 documents. The RDF WG's charter strongly discourages breaking backwards compatibility. I'd say that's sufficient justification for leaving the SHOULD in place.
>
> That being said, as far as I recall, the WG has not seen any evidence that such existing legacy content actually exists, nor has it seen any evidence that changing SHOULD to MUST would in practice increase compatibility. In the absence of evidence pointing in either direction, retaining backwards compatibility seems like a safe and defensible choice.
>
> Best,
> Richard
>
>
> On 22 Sep 2013, at 21:42, Sebastian Hellmann wrote:
>
>> Hello all,
>>
>> I was asking myself another question regarding the "should" in 3.3. http://www.w3.org/TR/rdf11-concepts/#section-Graph-Literal
>>
>>> 	 a lexical form, being a Unicode [UNICODE] string, which SHOULD be in Normal Form C [NFC],
>> http://www.ietf.org/rfc/rfc2119.txt says regarding SHOULD:
>>> 3. SHOULD   This word, or the adjective "RECOMMENDED", mean that there
>>>     may exist valid reasons in particular circumstances to ignore a
>>>     particular item, but the full implications must be understood and
>>>     carefully weighed before choosing a different course.
>>>
>> I am not sure, what reasons could exist not to require NFC . N-Triples doesn't seem to use ASCII any more in its next version. What is the hold up to change this to a MUST and write a validation test case?
>>
>> I am just asking out of curiosity. The topic is complex and the "full implications must be understood and carefully weighed before choosing a different course" justify a SHOULD as well.
>>
>> All the best,
>> Sebastian
>>
>>
>> -- 
>> Dipl. Inf. Sebastian Hellmann
>> Department of Computer Science, University of Leipzig
>> Events:
>> * NLP & DBpedia 2013 (http://nlp-dbpedia2013.blogs.aksw.org, Extended Deadline: *July 18th*)
>> * LSWT 23/24 Sept, 2013 in Leipzig (http://aksw.org/lswt)
>> Venha para a Alemanha como PhD: http://bis.informatik.uni-leipzig.de/csf
>> Projects: http://nlp2rdf.org , http://linguistics.okfn.org , http://dbpedia.org/Wiktionary , http://dbpedia.org
>> Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
>> Research Group: http://aksw.org
>


-- 
Dipl. Inf. Sebastian Hellmann
Department of Computer Science, University of Leipzig
Events:
* NLP & DBpedia 2013 (http://nlp-dbpedia2013.blogs.aksw.org, Extended 
Deadline: *July 18th*)
* LSWT 23/24 Sept, 2013 in Leipzig (http://aksw.org/lswt)
Venha para a Alemanha como PhD: http://bis.informatik.uni-leipzig.de/csf
Projects: http://nlp2rdf.org , http://linguistics.okfn.org , 
http://dbpedia.org/Wiktionary , http://dbpedia.org
Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
Research Group: http://aksw.org
Received on Monday, 23 September 2013 12:16:58 UTC

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