[regrep] Re: [xml-dev] Registered Namespace prefixes

[Chiusano Joseph <chiusano_joseph@bah.com>]

[Cross-posting from XML-DEV to the OASIS/ebXML Registry TC]

Jeff,

Regarding the following:

<Quote>
My opinion is that the answer lies in a prefix registry.  I know that's
controversial, mainly because it creates an authority structure that has
to be consulted prior to assigning prefixes to names.  I think this can
be mitigate, though, by having a provisional namespace prefix mechanism
that is essentially the same as it exists now, minus default
namespaces.  Registered prefixes would then be denoted by special naming
conventions.
</Quote>

I think you are *very very* close to something, but not quite there.
What I mean is this: namespace prefixes in XML schemas/documents are the
proverbial "syntactic sugar" - that is, they are really "local" to the
XML schema/document in which they are declared. However, what really
matters is the actual namespace identifier that the prefix represents
(that is the "something" that you were close to). I believe it would be
very beneficial for one to be able to use a "namespace registry", so
that they could accurately reference namespace identifiers and "include"
them (using term loosely) in XML schemas/documents with whatever prefix
they choose.

This opens up all sorts of possibilities in an XML registry, such as:

  (1)Query on all "XML artifacts" (elements/attributes/datatypes" that
are in a given namespace;

  (2)Reassign XML artifacts from one namespace to another (would
automatically search all registered XML schemas/documents for all
declarations/use of such artifacts in such namespace and change the
namespace identifier in the XML schema/document);  

  (3)Perform an automatic comparison of the "contents" of 2 (or more)
namespaces, for harmonization purposes (perhaps an organization has a
"test" namespace and an equivalent "production" namespace, and they wish
to determine which artifacts need to be promoted from test to production
at the proper time);       

...and countless more.

Thanks so much for bringing this idea up.

Kind Regards,
Joe Chiusano
Booz | Allen | Hamilton
Member, OASIS/ebXML Registry TC

Jeff Lowery wrote:
> 
> Wait a sec while I change into my Nomex suit...
> 
> I'd like to propose a mechanism for minimizing namespace hassles while
> maintaining readability. I expect this will raise hackles immediately, but
> hear me out:
> 
> The mechanism for declaring namespace prefixes seems to be the primary
> failure point for namespaces. The association by scope of a prefix and it's
> declaration gives rise to all sorts of mischief when scope changes during
> document manipulation. Add default namespace declarations and things get way
> too interesting sometimes.
> 
> All-in-all, given the design motivations of the WG, the basic mechanism is
> sound on a syntax level.  Unfortunately, it creates dependencies withing a
> document that then need to be managed both internally and externally. Is
> there a way to manage these dependencies better,  make them more
> idiot-proof?
> 
> My opinion is that the answer lies in a prefix registry.  I know that's
> controversial, mainly because it creates an authority structure that has to
> be consulted prior to assigning prefixes to names.  I think this can be
> mitigate, though, by having a provisional namespace prefix mechanism that is
> essentially the same as it exists now, minus default namespaces.  Registered
> prefixes would then be denoted by special naming conventions.
> 
> The advantage of a registry is that prefixed names become universal names
> when prefixes are registered.  There are no scope issues. The primary
> disadvantage of registration is that there will be a prefix rush.  I don't
> see a dependency on access to the registry at parse time, unless there are
> resources to be associated with the prefix (such as a URI to a RDDL doc)
> that the parser needs.
> 
> And, lastly, default namespace declarations would have to go...
> 
> I'm sure this is not a new proposal, but it's been at least a year since it
> was shot down last time... :-}   Those permathreads need regular wear or
> they grow stiff.
> 
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