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Illegal Characters in Namespace URIs

• To: xml-dev@l...
• Subject: Illegal Characters in Namespace URIs
• From: Elliotte Rusty Harold <elharo@m...>
• Date: Sun, 16 Jun 2002 16:09:17 -0400
• In-reply-to: <20020616180701.15423.qmail@w...>
• References: <20020616180701.15423.qmail@w...>

Consider the following document:

<root xmlns="[^^^^||||]">
...
</root>

All of the characters used as values of the xmlns attribute are 
illegal in namespace URIs according to RFC 2396 and legal in XML 
attribute values.

Is this document namespace well-formed?

I've been hunting through the Namespaces spec and I can find no BNF 
grammar production or namespace constraint that indicates the value 
of an xmlns or xmlns:prefix attribute actually has to be a legal URI 
reference. They key seems to be section 6, which leaves out any 
restriction on namespace names as part of the definition of 
conformance.

What have I missed? Where does the spec normatively require that the 
value of an xmlns attribute actually be a URI reference? If it does 
not so require, then I still wouldn't recommend that people use 
non-URIs as namespace names, but I might have to allow for that 
possibility in my software.

There is one possible reason not to require the namespace names to be 
URI references: if any characters are allowed, then IRIs become 
possible as well. URIs only allow ASCII.
-- 

+-----------------------+------------------------+-------------------+
| Elliotte Rusty Harold | elharo@m... | Writer/Programmer |
+-----------------------+------------------------+-------------------+
|          The XML Bible, 2nd Edition (Hungry Minds, 2001)           |
|             http://www.cafeconleche.org/books/bible2/              |
|   http://www.amazon.com/exec/obidos/ISBN=0764547607/cafeaulaitA/   |
+----------------------------------+---------------------------------+
|  Read Cafe au Lait for Java News:  http://www.cafeaulait.org/      |
|  Read Cafe con Leche for XML News: http://www.cafeconleche.org/    |
+----------------------------------+---------------------------------+

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    • From: "Thomas B. Passin" <tpassin@c...>
  • Re: Illegal Characters in Namespace URIs
    • From: Tim Bray <tbray@t...>

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