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From: "Chiusano Joseph" <chiusano_joseph@b...> > <Quote> > <author title="Contracts" title="Professor" title="13">James > Vleek</author> > </Quote> > > The "title" attribute above cannot be repeated. Of course not, but the questioner asked for an example of a name collision that required namespaces for disambiguation. So I posited an author element with a title attribute and two annotations also named "title". IOW: <author title="Contracts" abc:title="Professor" xyz:title="13">James Vleek</author> But I agree a not well-formed example detracts from the point, so here is exactly the same example using elements instead of attributes: <author name="James Vleek"> <title>Contracts</title> <abc:title>Professor</abc:title> <xyz:title>13</xyz:title> </author> Which would be well-formed, but ambiguous, without the namespaces. Such examples arise out of a common use case, e.g., the "foreign elements" allowed by RELAX NG and XML Schema. A schema can be decorated with foreign elements from more than one domain; only the namespaces of the elements prevent collisions. Bob > Kind Regards, > Joe Chiusano > Booz | Allen | Hamilton > > Bob Foster wrote: > > > > From: "Bill de hÓra" <bill@d...> > > > Does anyone have an example of a collision that can only be solved, > > > or even best be solved with XML Namespaces? A neccessary condition > > > is ideal, but examples where namespace represents an optimal design > > > decision will do. I'm asking for two reasons: > > > > > > - in my work with XML I've never run across a collision problem > > > that seemed to require namespaces. I wondering whether they're rare > > > or whether the markup I dela with is unusual. > > > > > > - I'm looking for markup that I can use for test cases and > > > thinking about the matter. > > > > > > I went looking in the Namepsaces spec and found this example and an > > > assertion: > > > > > > [[[ > > > <section><title>Book-Signing Event</title> > > > <signing> > > > <author title="Mr" name="Vikram Seth" /> > > > <book title="A Suitable Boy" price="$22.95" /></signing> > > > <signing> > > > <author title="Dr" name="Oliver Sacks" /> > > > <book title="The Island of the Color-Blind" price="$12.95" > > > /></signing> > > > </section> > > > > > > In this example, there are three occurrences of the name title > > > within markup, and the name alone clearly provides insufficient > > > information to allow correct processing by a software module > > > ]]] > > > > > > It demonstrates no such thing to me. For example, here is the > > > sufficient information: > > > > > > /section/title > > > /section/signing/author@title > > > /section/signing/book@title > > > > > > I suspect this particular assertion about the insufficiency of > > > traditional namespaces in the spec is false. I believe for it to be > > > true, there would need to exist markup for which no keys could be > > > computed to dilineate one element or attribute from another. > > > > You surely don't mean that no homonyms can exist that cannot be resolved by > > XPath? E.g., > > > > <author title="Contracts" title="Professor" title="13">James Vleek</author> > > > > where the first is the title of a paper, the second the title of the author > > and the third Title 13 of the US Code. > > > > Name collisions can easily arise in this way, where attributes are used as > > domain-specific annotations, like "foreign attributes" are used in XML > > Schema and RELAX NG. An annotator in one domain cannot reasonably be > > expected to avoid collisions with all other possible domains, even though > > they are all marking up the same elements. > > > > Bob > > > > When ideas fail, words come in very handy. | http://www.xmlbuddy.com > > - Goethe > > > > ----------------------------------------------------------------- > > The xml-dev list is sponsored by XML.org <http://www.xml.org>, an > > initiative of OASIS <http://www.oasis-open.org> > > > > The list archives are at http://lists.xml.org/archives/xml-dev/ > > > > To subscribe or unsubscribe from this list use the subscription > > manager: <http://lists.xml.org/ob/adm.pl>
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