- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Sun, 21 Aug 2011 15:06:04 +0100
- To: Ivan Herman <ivan@w3.org>
- Cc: RDF Working Group WG <public-rdf-wg@w3.org>
On 20 Aug 2011, at 05:39, Ivan Herman wrote: > Do we know of any place whatsoever where #x0 was used? I remember a D2RQ support question where a database contained #x0 and that caused an error when serializing it to RDF/XML. So yes, it happens. > I would propose we flag this explicitly as an issue in the document asking for feedback, with the expectation that we will have this restriction in 1.1 Works for me. Richard > > > Ivan > > On Aug 19, 2011, at 20:44 , RDF Working Group Issue Tracker wrote: > >> >> RDF-ISSUE-75 (#x0): Valid plain literals containing #x0 are no longer valid in RDF 1.1 >> >> http://www.w3.org/2011/rdf-wg/track/issues/75 >> >> Raised by: Richard Cyganiak >> On product: >> >> The lexical space of xsd:string doesn't cover all Unicode strings. >> >> I assume we will end up referring to XSD 1.1 for the definition of xsd:string [1]. That document leaves it up to implementations whether they support the XML 1.0 or XML 1.1; accordingly, the definition of allowed characters in an xsd:string is [2] or [3]. >> >> The more permissive one from XML 1.1: >> >> Char ::= [#x1-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF] >> >> This excludes #x0, Unicode codepoint U+0000. XML 1.0 also excludes a number of other control codes in the #x0-#x1F range. >> >> The definition of “lexical form” in RDF 2004 [4] says “Unicode string”, which according to [5] includes *all* codepoints including the control codes. >> >> So, any string that includes #x0 was a valid untagged plain literal in RDF 2004. In RDF 1.1, it will be typed as an xsd:string, and thus will be an ill-typed literal. >> >> (On the other hand, such strings could never be serialized in RDF/XML or XHTML+RDFa; they were serializable only in N-Triples and Turtle.) >> >> Is this a problem? Can we go ahead with the new literal design despite this restriction? Should we acknowledge it in the RDF Concepts spec? >> >> [1] http://www.w3.org/TR/2005/WD-xmlschema11-2-20050224/datatypes.html#string >> [2] http://www.w3.org/TR/REC-xml/#dt-character >> [3] http://www.w3.org/TR/xml11/#NT-Char >> [4] http://www.w3.org/TR/rdf-concepts/#dfn-lexical-form >> [5] http://www.unicode.org/versions/Unicode6.0.0/UnicodeStandard-6.0.pdf >> >> >> > > > ---- > Ivan Herman, W3C Semantic Web Activity Lead > Home: http://www.w3.org/People/Ivan/ > mobile: +31-641044153 > PGP Key: http://www.ivan-herman.net/pgpkey.html > FOAF: http://www.ivan-herman.net/foaf.rdf > > > > > >
Received on Sunday, 21 August 2011 14:06:34 UTC