- From: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr>
- Date: 08 Jun 2001 14:48:14 +0200
- To: www-rdf-interest@w3.org
I'm wondering if we are not deeply misleading with the Namespace URI debate... According to [XMLNS], the *namespace name* has to be unique and persistent, period. Then (and ONLY then) they suggest the use of URNs, or possibly any URI. As a matter of fact, URIs are a (supposedly) efficient and easy way to guarantee uniqueness and persistence. Uniqueness and persistance allow the namespace name to *identify* the namespace. But that does not mean that it has to be the URI of the namespace. Indeed, it does not have to be a URI *at all* ! Still, though the *namespace name* identifies the namespace in this respect, it does so only because it is unique and persistent *as a namespace name*, NOT because it is a URI. Let's explain that subtilty with an example. Suppose I want to publish an XML namespace. I happen to own the unique and peristent domain 'champin.y2001' (see [1]), and the URL http://champin.y2001/ happens to identify my homepage. I could very well decide to use that same URL as a namespace name for my XML namepspace. I am quite sure I won't publish another namespace during the year 2001, so the URL is as simple as can be. Does this mean that the URL does not identify my homepage anymore ? no. Does this mean I'm a naughty boy, using the same URI for 2 distinct things ? no, I argue: - I use it as a URI identifying my homepage - I use it as a unique and persistent string to identify my namespace I could even have used the string "champin.y2001" for the namespace ! So, what *is* the URI of the namespace ?? AFAIK, there is none defined for the moment. An immediate solution would be xmlns:http://champin.y2001/ xmlns:champin.y2001 where 'xmlns:' is a URI scheme, even URN I think. Let's be clear: the xmlns attributes do not have to contain the "xmlns:" prefix ! Why should they, by the way... they clearly define a context where the *string* has to be interpreted as a 'xmlns:' URI. I am sure we could solve the concatenation issue, quite the same way, either by creating a 'qname:' URI scheme or by extending the 'xmlns:' scheme in order to include an optionnal element name. I am also sure I'm not the first one to make that kind of proposition. However I could not remember who else, nor what reason were objected so that the whole world is not using it now :) Please refresh my memory if so. Pierre-Antoine [XMLNS] http://www.w3.org/TR/1999/REC-xml-names-19990114/ [1] http://www.w3.org/DesignIssues/PersistentDomains
Received on Friday, 8 June 2001 08:47:00 UTC