Are there standard namespaces that don't need URIs?

Re: Are there standard namespaces that don't need URIs?

Grant Robertson wrote:The relevant specification is the "Namespaces in XML 1.0" specificaton:
<http://www.w3.org/TR/xml-names/>
You will see that <http://www.w3.org/TR/xml-names/#ns-declreserves a
family of attributes for namespace declaration, namely either 'xmlns' or
a qualified name beginning with 'xmlns:'.
<element xmlns="http://example.com/ns1">
is a default namespace declaration.
So any namespace aware XML parser "knows" the meaning of xmlns and
xmlns:some-prefix attributes as declaring XML namespaces.

--

Martin Honnen
http://JavaScript.FAQTs.com/

Re: Are there standard namespaces that don't need URIs?

On Sat, 3 Feb 2007 08:02:34 -0600, Grant Robertson <bogus@bogus.in valid>
wrote:
xmlns is a namespace prefix, not a namespace; namespaces are identified
by a URI. Anyway, the xmlns prefix is associated with the URI
http://www.w3.org/2000/xmlns/, and the namespace standard forbids any
other prefix from being associated with that URI. You can get all the
details, including a description of other reserved prefixes, from the
standard at http://www.w3.org/TR/2006/REC-xml-names-20060816/.
--
Eric Amick
Columbia, MD

Re: Are there standard namespaces that don't need URIs?


"Grant Robertson" <bogus@bogus.in validwrote in message
news:MPG.202dc3 e4aad002db9896f 8@news.newsguy. com...First of all, any namespace "needs" (has) a namespace-uri. What you are
asking here is not namespaces that don't have uri-s, but *reserved
prefixes*, that must always be associated with specific namespace-uri-s

There are two such reserved prefixes (xml and xmlns) and they are listed in
the Namespaces specification
(http://www.w3.org/TR/xml-names/#sec-namespaces):

"Namespace constraint: Reserved Prefixes and Namespace Names
The prefix xml is by definition bound to the namespace name
http://www.w3.org/XML/1998/namespace. It MAY, but need not, be declared, and
MUST NOT be bound to any other namespace name. Other prefixes MUST NOT be
bound to this namespace name, and it MUST NOT be declared as the default
namespace.

The prefix xmlns is used only to declare namespace bindings and is by
definition bound to the namespace name http://www.w3.org/2000/xmlns/. It
MUST NOT be declared . Other prefixes MUST NOT be bound to this namespace
name, and it MUST NOT be declared as the default namespace. Element names
MUST NOT have the prefix xmlns.

All other prefixes beginning with the three-letter sequence x, m, l, in any
case combination, are reserved. This means that:

a.. users SHOULD NOT use them except as defined by later specifications

b.. processors MUST NOT treat them as fatal errors.

Though they are not themselves reserved, it is inadvisable to use prefixed
names whose LocalPart begins with the letters x, m, l, in any case
combination, as these names would be reserved if used without a prefix. "

So, when using a global attribute like xml:space, one doesn't need to define
the prefix "xml" -- it is known to the parser.



Cheers,

Dimitre Novatchev

Re: Are there standard namespaces that don't need URIs?

In article <MPG.202dc3e4aa d002db9896f8@ne ws.newsguy.com> ,
Grant Robertson <bogus@bogus.in validwrote:
That's the right way to look at it; xmlns is part of the syntax.
There *is* a URI associated with it, which you don't need to declare
(and indeed mustn't) but you can ignore it for most purposes.

The only other prefix that doesn't need to be declared is "xml", as
used in xml:space, xml:lang, xml:base.

-- Richard
--
"Considerat ion shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

Re: Are there standard namespaces that don't need URIs?

Thanks everyone! I always get the best, right to the point, answers in
this newsgroup. It is such a relief from trying to get any straight
answers in any Microsoft newsgroup.

No matter how many times I go over it I keep forgetting that the prefix
is just a local shorthand within the XML document for the actual
namespace which is the URI. I see the prefix with the colon after it and
think I am seeing a namespace name. Hopefully once I learn enough to
start designing my schema and actual work with XML files more than just
looking at examples, then I will get it through my head.

Thanks again.

Re: Are there standard namespaces that don't need URIs?

I always get the best, right to the point, answers inProbably you haven't tried this Microsoft forum:
XML and the .NET Framework


I'll be glad to answer your questions there, too :o)

Cheers,
Dimitre Novatchev



"Grant Robertson" <bogus@bogus.in validwrote in message
news:MPG.202eb6 87de1f891b9896f 9@news.newsguy. com...

Re: Are there standard namespaces that don't need URIs?

On 3 Feb, 21:11, Grant Robertson <b...@bogus.inv alidwrote:Hi Grant,
It looks like you pretty much understand the namespace thing and just
need more practice. However, just in case a alternative way of
looking at it might be helpful, you might find the approach used by
James Clark on the following page useful:



Perhaps more for the benefit of others that happen to drift this way
in future looking for answers, the most concise description of XML
namespaces I've found so far is:



Cheers,

Pete.
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