- From: Frank Manola <fmanola@mitre.org>
- Date: Fri, 25 Jul 2003 08:05:43 -0400
- To: Graham Klyne <gk@ninebynine.org>
- CC: rdf core <w3c-rdfcore-wg@w3.org>
Graham Klyne wrote: > > This looks good to me. One tiny nit and one small comment: > > Nit: The use of "third" in "using a third value of the rdf:parseType > attribute" seemed a little odd to me. Maybe just: 'using the attribute > rdf:parseType="literal"'? This may look odd because you don't have the context. Four paragraphs before, in the prior section (on rdf:value), I describe "the second use" of rdf:parseType, rdf:parseType="Resource". Two sections before that, the section on Collections introduces rdf:parseType (and notes that it has multiple values), in the process of introducing the first use, rdf:parseType="Collection". Mentioning the third use was just to gently point out that this was something the reader had seen variants of before. > > Comment: it might help to underscore somehow that using > rdf:parseType="literal" doesn't require that the data contain markup. > This is implicit and clear to one who has followed this discussion, but > I'm not sure how clear that would be to someone coming fresh to this text. > > For example, may the sentence: > [[ > The value of the property is a typed literal, whose datatype, > rdf:XMLLiteral, is defined in [RDF-CONCEPTS] specifically to represent > fragments of XML. > ]] > > might be: > > [[ > The value of the property is a typed literal, whose datatype, > rdf:XMLLiteral, is defined in [RDF-CONCEPTS] specifically to represent > fragments of XML, including character sequences that may or may not > include XML markup. > ]] > I agree; this is a useful clarification. On another issue, since we're clarifying things: in the text below, in discussing exclusive canonicalization, the text says: "This causes declarations of used namspaces to be added to the fragment..." I wonder if this wouldn't be clearer if it said: "This causes declarations of *namespaces used in the fragment* to be added to the fragment..." to distinguish namespaces used in the RDF/XML in general from those explicitly used in the fragment. --Frank > -- > > At 15:05 24/07/03 -0400, Frank Manola wrote: > >> Based on Brian's last "take", I propose to put the following text in >> the Primer for parseType="Literal". The typed literal given for the >> value of <dc:title> in the triple is that produced by the RDF >> Validation Service, but someone may want to check this further anyway. >> >> 4.5 XML Literals >> >> Sometimes the value of a property needs to be a fragment of XML, or >> text that might contain XML markup. For example, a publisher might >> maintain RDF metadata that includes the titles of books and articles. >> While such titles are often just simple strings of characters, this is >> not always the case. For instance, the titles of books on mathematics >> may contain mathematical formulas that could be represented using >> MathML [MATHML]. Titles might also include markup for other reasons, >> such as for Ruby annotations [RUBY], or for bidirectional rendering or >> special glyph variants (see, e.g., [CHARMOD]). >> >> RDF/XML provides a special notation to make it easy to write literals >> of this kind. This is done using a third value of the rdf:parseType >> attribute. Giving an element the attribute rdf:parseType="Literal" >> indicates that the contents of the element are to be interpreted as an >> XML fragment. Example 22 illustrates the use of rdf:parseType="Literal": >> >> <?xml version="1.0"?> >> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" >> xmlns:dc="http://purl.org/dc/elements/1.1/" >> xml:base="http://www.example.com/books"> >> >> <rdf:Description rdf:ID="book12345"> >> <dc:title rdf:parseType="Literal"> >> <span xml:lang="en"> >> The <em><br /></em> Element Considered Harmful. >> </span> >> </dc:title> >> </rdf:Description> >> >> </rdf:RDF> >> >> The RDF/XML in Example 22 describes a graph containing one triple: >> >> ex:book12345 <dc:title> "<span xml:lang="en"> The >> <em><br /></em> Element Considered Harmful. >> </span>"^^rdf:XMLLiteral . >> >> The rdf:parseType="Literal" attribute in the RDF/XML indicates that >> all the XML within the <dc:title> element is an XML fragment that is >> the value of the dc:title property. >> >> The value of the property is a typed literal, whose datatype, >> rdf:XMLLiteral, is defined in [RDF-CONCEPTS] specifically to represent >> fragments of XML. The XML fragment is canonicalized according to the >> XML Exclusive Canonicalization recommendation [XML-XC14N]. This >> causes declarations of used namespaces to be added to the fragment, >> the escaping of reserved characters such as '<', '>' and '&', and >> possibly, the re-ordering of attributes. Contextual attributes, such >> as xml:lang and xml:base are not inherited from the RDF/XML document, >> and, if required, must, as shown in the example, be explicitly >> specified in the XML fragment. >> >> This example illustrates that care must be taken designing RDF data. >> It might appear at first glance that titles are simple strings best >> represented as plain literals, and only later might it be discovered >> that some titles contain markup. In cases where the value of a >> property may >> sometimes contain markup and sometimes not, either >> rdf:parseType="Literal" should be used throughout, or software must >> handle both plain literals and rdf:XMLLiterals as values of this >> property. >> >> @@Informational References to be added: >> >> [RUBY] Ruby Annotations, Sawicki, M., Suignard, M., Ishikawa, M., >> Durst, M., Texin, T., World Wide Web Consortium, 31 May 2001. This >> version is http://www.w3.org/TR/2001/REC-ruby-20010531/. The latest >> version is http://www.w3.org/TR/ruby/. >> >> [XML-XC14N] @@use citation in Syntax >> >> [CHARMOD] @@use citation in Syntax >> >> [MATHML] Mathematical Markup Language (MathML) Version 2.0, Carlisle, >> D., Ion, P., Miner, R., Poppelier, N. (Editors); Ausbrooks, R., >> Buswell, S., Dalmas, S., Devitt, S., Diaz, A., Hunter, R., Smith, B., >> Soiffer, N., Sutor, R., Watt, S. (Principal Authors), World Wide Web >> Consortium, 21 February 2001. This version is >> http://www.w3.org/TR/2001/REC-MathML2-20010221. The latest version is >> http://www.w3.org/TR/MathML2. >> >> >> >> >> -- >> Frank Manola The MITRE Corporation >> 202 Burlington Road, MS A345 Bedford, MA 01730-1420 >> mailto:fmanola@mitre.org voice: 781-271-8147 FAX: 781-271-875 > > > ------------------- > Graham Klyne > <GK@NineByNine.org> > PGP: 0FAA 69FF C083 000B A2E9 A131 01B9 1C7A DBCA CB5E > -- Frank Manola The MITRE Corporation 202 Burlington Road, MS A345 Bedford, MA 01730-1420 mailto:fmanola@mitre.org voice: 781-271-8147 FAX: 781-271-875
Received on Friday, 25 July 2003 07:41:34 UTC