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- From: Andrew Layman <firstname.lastname@example.org>
- To: "'G. Ken Holman'" <gkholman@CraneSoftwrights.com>, email@example.com
- Date: Wed, 27 Dec 2000 17:26:23 -0800
Yes. Thanks for posting this answer.
The URI for a namespace needs only to be a unique name. Per the namespaces
specification, it does not need to actually reference a retrievable
resource, though it may, the spec allows either. (There is a long thread
debating whether or not this is a good design, which I will not rehash here.
I only report what the design is.)
By choosing a URI based on a URL scheme, first and second-tier domain names,
the authority to create and define a specific URI is as strong and durable
as the rights that go with the domain names.
From: G. Ken Holman [mailto:gkholman@CraneSoftwrights.com]
Sent: Friday, February 09, 2001 4:54 PM
Subject: Re: simple question on namespaces.
At 00/12/27 16:16 -0800, Paul Tchistopolskii wrote:
>Why namespace looks exactly like URL when it is in fact not ?
A URL is expressed using a URI and a URI is used to ensure namespaces are
unique. The URI used in a namespace isn't required to represent a URL.
>Just to confuse people, right ?
That question does not deserve comment.
>I think that
>Is better design than
> > Why something which is not a URL and was not
> > supposed to be a URL ( right? ) looks like URL ?
Because the protocol indication at the beginning of the URL governs the
format of the rest of the string. If it wasn't there, then there wouldn't
be any formal rules for the format of the string.
By saying the string is a URI, the rules governing URI strings direct the
creation of unambiguous URI string values between users of namespaces. If
it were a free-for-all on the string then two people could end up with the
same string values and introduce ambiguity. If it were assumed to be a web
address (as you are proposing) then that prevents people who don't own
domains to write valid strings that are theirs. There are other protocols
encompassed by URI strings allowing people who may have ownership of other
unique values to validly use other protocol indicators to govern the syntax
of the strings they are using to be unique.
One could even validly use mailto:firstname.lastname@example.org as a unique URI
string, thus not requiring them to have their own web site or ISBN
publisher's prefix or whatever ... this URI is sufficient.
Why invent a new way in the Internet world for ensuring unique values in as
many possible domains in a coherent scheme? There is already one to use,
it is best to use it than have something either ambiguous or competing that
has the same benefits.
I hope this helps.
G. Ken Holman mailto:gkholman@CraneSoftwrights.com
Crane Softwrights Ltd. http://www.CraneSoftwrights.com/x/
Box 266, Kars, Ontario CANADA K0A-2E0 +1(613)489-0999 (Fax:-0995)
Web site: XSL/XML/DSSSL/SGML services, training, libraries, products.
Book: Practical Transformation Using XSLT and XPath ISBN1-894049-05-5
Article: What is XSLT? http://www.xml.com/pub/2000/08/holman
Next public instructor-led training: 2001-01-27,2001-02-21,