- From: David Booth <david@dbooth.org>
- Date: Mon, 29 Dec 2014 13:36:53 -0500
- To: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>
- CC: "public-rdf-comments@w3.org" <public-rdf-comments@w3.org>
FWIW, it certainly seems to me like this detail was omitted unintentionally and would be helpful to include in the errata. David Booth On 12/29/2014 12:50 PM, Stian Soiland-Reyes wrote: > OK, thank you all for recollecting! So I'll settle for the "naked" > literal in output of an xsd:string. > > Should this go into an errata or is it too much of a change? > > On 29 Dec 2014 07:41, "Andy Seaborne" <andy@apache.org > <mailto:andy@apache.org>> wrote: > > On 29/12/14 06:31, Pat Hayes wrote: > > > On Dec 28, 2014, at 6:10 PM, Gregg Kellogg > <gregg@greggkellogg.com <mailto:gregg@greggkellogg.com>> wrote: > > On Dec 28, 2014, at 3:32 PM, Pat Hayes <phayes@ihmc.us > <mailto:phayes@ihmc.us>> wrote: > > > > On Dec 28, 2014, at 5:40 AM, Andy Seaborne > <andy@apache.org <mailto:andy@apache.org>> wrote: > > On 28/12/14 05:04, Pat Hayes wrote: > > On Dec 27, 2014, at 9:24 PM, Stian > Soiland-Reyes > <soiland-reyes@cs.manchester.__ac.uk > <mailto:soiland-reyes@cs.manchester.ac.uk>> > wrote: > > No, for once I am not coming from OWL :) > > I'm just writing a simple n-triples > serializer, and I am not sure if I should > simply always include the type if there is > no @lang (e.g. ^^xsd:string) > > > It was certainly the intention of the RDF 1.1 WG > that every literal should have a type. We even > provided a special 'type' for the @lang case, to > preserve this intention. It seems to me that one > should not ever go wrong by including the > ^^xsd:string, which was semantically correct > even in original RDF, whereas really plain plain > literals now have the shadow of deprecation > hanging over them, at the very least. > > Hope this helps. > > Pat Hayes > > > And for serialization, the WG intention IIRC was > that all ^^xsd:strings should be written without the > ^^xsd:string in all formats where possible. > > > Really? I have no recollection of that, but I may have > missed some discussions. Can you find this in the > minutes or emails anywhere? > > > I share Andy's recollection > > > OK, two is enough :-) I bow to your superior recollection, and > withdraw my implicit advice to use explicit xsd:string typing. > Apologies to all concerned. > > > I went looking (OK, a bit of looking) the first time but couldn't > find spec text except the MAY. This discussion was over an extended > period. > > The examples for Turtle are without xsd:string (except to show they > are the same). > > >From memory, the line of argument was that simple literals were > more common than explicit ^^xsd:string though the community of use > is going to be a major factor. > > Like Gregg, Jena outputs without explicit datatype as the best > choice overall. > > Andy > > > Pat > > , and that is how my serializer behaves. > Shame that the spec-text doesn't cspture that. > > Gregg > > It look nicer. > > > Maybe, but it also can produce uncertainty, as for example: > > "Before rdf 1.1 the norm tended to be to NOT express > xsd:string unless it really was a character-by-character > string (e.g. a genome identifier), and not when it was > human text (but in unknown or mixed language)." > > Even in RDF 1.0, plain literals were specified to be > semantically identical to xsd:string-typed literals, but > this was buried in the semantics dociument which nobody > read, and because the syntactic distinction was > available, people assumed it meant something. As long as > a syntax offers both choices, this misreading process > will continue to operate, even now RDF 1.1 has said > explicitly that plain literals are only syntactic sugar > for the typed version. > > http://www.w3.org/TR/rdf11-__concepts/#section-Graph-__Literal > <http://www.w3.org/TR/rdf11-concepts/#section-Graph-Literal> > only says "MAY" -- that is mainly so as not to > suggest much RDF 1.0 data output by pre-existing > software is suddenly invalidated, which it isn't. > > > Certainly, plain literal surface syntax is not > *invalidated* by RDF 1.1. Sorry if I gave that impression. > > Pat > > > > Andy > > > > ..Or if I should have a special case to > output anything with type xsd:string as a > classic "plain literal", e.g. no @ or ^^. > > Surely just one of these should be in the > canonical version ? My guts says to always > include the type for non-lang, but the spec > is ambigous on this - if xsd:string is > implied, should I then prefer to generate > this implied version? > > Before rdf 1.1 the norm tended to be to NOT > express xsd:string unless it really was a > character-by-character string (e.g. a genome > identifier), and not when it was human text > (but in unknown or mixed language). > > As we SHOULD be generating the Canonical > N-Triples, then it would be good to know if > there already is a silent de facto agreement > that is just not expressed in the spec. > > You might know the code base - > https://github.com/stain/__commons-rdf/blob/tests/src/__test/java/com/github/__commonsrdf/dummyimpl/__LiteralImpl.java#L99 > <https://github.com/stain/commons-rdf/blob/tests/src/test/java/com/github/commonsrdf/dummyimpl/LiteralImpl.java#L99> > > On 27 Dec 2014 17:14, "Peter Ansell" > <ansell.peter@gmail.com > <mailto:ansell.peter@gmail.com>> 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 > <http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-Graph-Literal> > [2] > https://github.com/owlcs/__owlapi/issues/172 > <https://github.com/owlcs/owlapi/issues/172> > > On 27 December 2014 at 16:37, Stian > Soiland-Reyes > <soiland-reyes@cs.manchester.__ac.uk > <mailto:soiland-reyes@cs.manchester.ac.uk>> > wrote: > > In > http://www.w3.org/TR/n-__triples/#canonical-ntriples > <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 > <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 > <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 > <http://www.w3.org/2001/XMLSchema#string>. > > > Example 3 > <http://example.org/show/218> > <http://www.w3.org/2000/01/__rdf-schema#label > <http://www.w3.org/2000/01/rdf-schema#label>> > "That Seventies > Show"^^<http://www.w3.org/__2001/XMLSchema#string > <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 > <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://soiland-reyes.com/stian/work/> > http://orcid.org/0000-0001-__9842-9718 > <http://orcid.org/0000-0001-9842-9718> > > > ------------------------------__------------------------------ > IHMC > (850)434 8903 home > 40 South Alcaniz St. (850)202 4416 > office > Pensacola (850)202 > 4440 fax > FL 32502 (850)291 > 0667 mobile (preferred) > phayes@ihmc.us <mailto:phayes@ihmc.us> > http://www.ihmc.us/users/__phayes > <http://www.ihmc.us/users/phayes> > > > ------------------------------__------------------------------ > IHMC (850)434 8903 home > 40 South Alcaniz St. (850)202 4416 office > Pensacola (850)202 4440 fax > FL 32502 (850)291 0667 > mobile (preferred) > phayes@ihmc.us <mailto:phayes@ihmc.us> > http://www.ihmc.us/users/__phayes > <http://www.ihmc.us/users/phayes> > > > ------------------------------__------------------------------ > IHMC (850)434 8903 home > 40 South Alcaniz St. (850)202 4416 office > Pensacola (850)202 4440 fax > FL 32502 (850)291 0667 mobile > (preferred) > phayes@ihmc.us <mailto:phayes@ihmc.us> > http://www.ihmc.us/users/__phayes <http://www.ihmc.us/users/phayes> > > > > > > > >
Received on Monday, 29 December 2014 18:37:24 UTC