Hierarchical namespaces?

Joe Lapp jlapp at webMethods.com
Fri Dec 31 15:07:50 GMT 1999


Err.  How did that happen?  I only sent this bugger once.
The Y2K cataclysm has begun.

At 08:44 PM 12/29/99 -0500, Joe Lapp wrote:
>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 at webMethods.com           http://www.webMethods.com
>
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--
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 at webMethods.com           http://www.webMethods.com

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