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Re: Summary of the QName to URI Mapping Problem

From: Devon Smith <devon@taller.pscl.cwru.edu>
Date: Thu, 16 Aug 2001 10:38:11 -0400
To: www-rdf-interest@w3.org
Message-ID: <20010816103811.B17345@taller.pscl.cwru.edu>

i'm confused.
mostly by how people are able to completely dismiss patrick's concerns.

he is completely on target.

maybe he just isn't stating his case in terms y'all can understand.
perhaps a paraphrase will help. (apologies to patrick if i misparaphrase)

QName -> URI mappping is broken because

1) 
	possibility of URI collsion.
	
	person a maintains namespace 'urn:abc' and has a property defined
	in that space called 'xyz'.
	person b maintains namespace 'urn:ab' and has a property defined
	in that space called 'cxyz'.

	so, when each gets serialized to 'XML', they look something like
	this, respectively:
	abc:xyz
	ab:cxyz
	
	and this becomes a problem when the RDF processor does it's concat
	maneuver and gets two identical URIs for two different properties.

	this really looks like a problem to me. 
	if it's not, someone will have to explain why it isn't.

2)
	URI scheme where concat doesn't make sense.
	
	person a maintains namespace urn:abc(foo).
	names within the space are formed like urn:abc(foo(bar)).
	
	now, there are two possibilities for QName construction here.
	either we seperate the name from the namespace and get
	'xmlns:foo=urn:abc(foo)' and 'foo:bar'
	or we just cut off some random suffix and get something like
	'xmlns:foo=urn:abc(foo(' and 'foo:bar))'

	now, the latter allows, theoretically, for correct URI reconstruction,
	but i don't think too many XML parsers i going to like it.

	and the former is accepted by parsers, but doesn't allow for correct
	URI reconstruction, because urn:abc(foo)bar is not the correct URI.

	again, this seems like a problem. 
	sure, the spec implicitly says that properties have to be of the
	kind that allow for the concat maneuver, but a) that kind of
	restriction seems like a bad idea in the long term, and b) should
	be stated explicitly if that's the intention.

again, i apologize if i've misrepresented what patrick has said.
i hope this helps, but doubt it will.

devon smith
smithde@oclc.org
Received on Thursday, 16 August 2001 10:42:56 GMT

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