[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Hierarchical namespaces?
I've been thinking about the utility of naming all elements and most attributes using a namespace-URI/local-name pair. Let's denote such a name as (namespace, local-name). (I say "most" attributes because it won't name anything in the per-element-type partition.) Seems to me that filtering operations would commonly extract names belonging to a particular namespace, so requests for (namespace, *) might be pretty common. Let's look at this more closely... Suppose I'm defining elements that describe electronics parts. I'm going to want to organize them hierarchically. For example: www.parts.com/computer/memory/sram www.parts.com/computer/memory/dram www.parts.com/computer/cpus/intel www.parts.com/computer/cpus/amd www.parts.com/stereo/speaker/surround www.parts.com/stereo/speaker/subwoofer etc. It may make sense for one application to examine all computer parts, another to examine all computer memory parts, and so on. If I want all memory parts I have to know all the pertinent namespace URIs. If I know that the URIs are structured hierarchically, I could do a wildcard search on the URI itself -- assuming I had a tool that let me do so (do any yet?). But because URIs allow this, the next guy organizes his namespaces differently: www.nextguy.com/computer-memory-sram www.nextguy.com/computer-memory-dram www.nextguy.com/computer-cpus-intel www.nextguy.com/computer-cpus-amd www.nextguy.com/stereo-speaker-surround www.nextguy.com/stereo-speaker-subwoofer And the next next guy does so as follows: www.nextnextguy.com/computer?memory=true+type=sram www.nextnextguy.com/computer?memory=true+type=dram www.nextnextguy.com/computer?cputype=intel www.nextnextguy.com/computer?cputype=amd www.nextnextguy.com/stereo/speaker?surround www.nextnextguy.com/stereo/speaker?subwoofer To make namespace filtering work for the general case requires regex-like matching capabilities. And regex matching isn't very easy to optimize for performance (such as via indexing). It also isn't the kind of thing we want the average XML user to have to learn -- seems to me that it would have to bubble up to the user interface, at least on generic XML tools. So I'm thinking that we need a *standard* way to organize namespaces hierarchically, and that we need one before namespace usage is so widespread that we absolutely have to provide regex support. But maybe I'm jumping the gun. I haven't yet heard anyone scream out in pain, though I'm not sure we should be waiting for pain to come. -- Joe Lapp (Looking for some good people to help design Principal Architect and build the Internet's business-to-business webMethods, Inc. XML infrastructure. We are 100% Java.) jlapp@w... http://www.webMethods.com xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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