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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: RDDL (was RE: Negotiate Out The Noise)
 At 7:30 PM -0800 1/17/02, Paul T wrote: >PS. It appears that people, who write articles about RDDL, >are already providing the general public with misleading >information about RDDL (exactly, like it was with >XML Namespaces. As we should remember, each >and every XML book or article was explicitly saying that >Namespaces URLs "point to nothing" and that's the >idea of them. Which is no longer true.) > Really? You've really read "each and every" one? Looking at my own books I see in XML in a Nutshell, 1st edition: Namespace URIs do not necessarily point to any actual document or page. In fact, they don't have to use the http scheme. They might even use some other protocol like mailto in which URIs don't even point to documents. However, if you're defining your own namespace using an http URI, it would not be a bad idea to place some documentation for the specification at the namespace URI. The W3C got tired of receiving broken link reports for the namespace URIs in their specifications so they added some simple pages at their namespace URIs. You are by no means required to do this, though. Many namespace URIs lead to 404-Not Found errors when you actually plug them into a web browser. Namespace URIs are purely formal identifiers. They are not the addresses of a page, and they are not meant to be followed as links. The XML Bible is a little less clear that you can place something at the end of a namespace URI, but still doesn't come close to saying that you can't and that that's the whole idea of them. From the 1st edition: The URI that defines a namespace is purely formal. Its only purpose is to group and disambiguate element and attribute names in the document. It does not necessarily point to anything. In particular, there is no guarantee that the document at the URI describes the syntax used in the document; or, for that matter, that any document exists at the URI. Having said that, if there is a canonical URI for a particular XML application, then that URI is a good choice for the namespace definition. These were all written pre-RDDL but seem pretty accurate to me. -- +-----------------------+------------------------+-------------------+ | Elliotte Rusty Harold | elharo@m... | Writer/Programmer | +-----------------------+------------------------+-------------------+ | The XML Bible, 2nd Edition (Hungry Minds, 2001) | | http://www.ibiblio.org/xml/books/bible2/ | | http://www.amazon.com/exec/obidos/ISBN=0764547607/cafeaulaitA/ | +----------------------------------+---------------------------------+ | Read Cafe au Lait for Java News: http://www.cafeaulait.org/ | | Read Cafe con Leche for XML News: http://www.ibiblio.org/xml/ | +----------------------------------+---------------------------------+ 
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