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---------- Forwarded message ---------- Date: Thu, 14 Dec 2000 08:52:04 -0700 (MST) From: Uche Ogbuji <uche.ogbuji@l...> To: Nikita Ogievetsky <nogievet@c...> Cc: xml-dev@x..., martind@n... Subject: RDF? TM? (was Re: Didier's lab report) > Lets take this as an example: > > > In the scope of WML aware client use this stylesheet, > > > in the scope IE5 use another stylesheet > > > and in the scope of NC and IE4 and IE3 use yet third stylesheet. > > > I used this approach a couple of months ago and quite successfully!. > > > Same thing applies to the values of XSLT parameters. > > Here is XTM syntax for it (my $.02): > > <topic id="abc"> > <subjectIdentity><resourceRef xlink:href="abc.xml"/></subjectIdentity> > <occurrence> > <instanceOf><topicRef xlink:href="#xslt-stylesheet"/></instanceOf> > <scope><topicRef xlink:href="#wml"/></scope> > <resourceRef xlink:href="wml.xsl"/> > </occurrence> > <occurrence> > <instanceOf><topicRef xlink:href="#xslt-stylesheet"/></instanceOf> > <scope><topicRef xlink:href="#ie5"/></scope> > <resourceRef xlink:href="ie5.xsl"/> > </occurrence> > <occurrence> > <instanceOf><topicRef xlink:href="#xslt-stylesheet"/></instanceOf> > <scope><topicRef xlink:href="#nc"/></scope> > <resourceRef xlink:href="nc.xsl"/> > </occurrence> > </topic> > > The "xslt-stylesheet" topic defined elsewhere specifies that this occurrence > is XSLT stylesheet > The "wml" scoping topic (theme) defined elsewhere specifies that "wml.xsl" > stylesheet should be used in the scope of WML aware browsers; > same goes for "ie5" and "nc" > > Note that this is a very RDF-like case because the subject of the topic is a > resource. Sure. And here's just one of ten vigintillion ways to express this in RDF right in the original XML <MyOriginElement rdf:ID="origin1"> <incstyle:remotestyle> <rdf:Alt> <incstyle:sheet incstyle:case="WML" xlink:href="wml.xslt"/> <incstyle:sheet incstyle:case="IE5" xlink:href="ie.xslt" incstyle:param="version=5"/> <incstyle:sheet incstyle:case="IE4" xlink:href="ie.xslt" incstyle:param="version=4"/> <incstyle:sheet incstyle:case="other" xlink:href="default.xslt"/> </rdf:Alt> </incstyle:remotestyle> </MyOriginElement> Again, I even included a few bonuses, and it's still quite simple. Of course it does illustrate another of RDF's annoyances: that you must have a namespace on all attributes if you wish to them to be considered abbreviated properties. And RDF is flexible enough that you can also express this without a single "rdf" element or attribute besides the envelopes. > (XTM topic can also have a real-world subject, one that can not be addressed > directly. So can RDF with anonymous resources. > In this case "the subject may be indicated through one or more resources > that describe the subject" -- xtm spec.) > > In any case, could you give an equivalent to the above example that uses RDF > triples? Would you like to go for this exercise? Your statement makes me wonder how you understand the role of "triples" in RDF. I get the impression that you might not realize that they are simply a database and list-processing convenient representation of the RDF abstract model, which is a graph, just like TM's. You can work with RDF just fine without worrying about constructing "triples" if you like. You can use the graph or the XML serialization. -- Uche Ogbuji Principal Consultant uche.ogbuji@f... +1 303 583 9900 x 101 Fourthought, Inc. http://Fourthought.com 4735 East Walnut St, Ste. C, Boulder, CO 80301-2537, USA Software-engineering, knowledge-management, XML, CORBA, Linux, Python
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