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Re: Unknown prefix xml?

From: Martin Gudgin <marting@develop.com>
Date: Mon, 29 Jan 2001 11:17:56 -0000
Message-ID: <001801c089e5$2260f6f0$0200a8c0@develop.com>
To: "Eric van der Vlist" <vdv@dyomedea.com>
Cc: "XML Schema Dev" <xmlschema-dev@w3.org>

Hi Eric,

Thanks very-much for you input, comments inline.

Martin Gudgin
DevelopMentor

----- Original Message -----
From: "Eric van der Vlist" <vdv@dyomedea.com>
To: "Martin Gudgin" <marting@develop.com>
Cc: "XML Schema Dev" <xmlschema-dev@w3.org>
Sent: Monday, January 29, 2001 11:06 AM
Subject: Re: Unknown prefix xml?


> Martin Gudgin wrote:
> >
> > Just to be sure... You are saying I have to put
> >
> >     xmlns:xml='http://www.w3.org/XML/1998/namespace'
> >
> > in my schema document?
>
> Yes.
>
> > That seems very weird. The xml namespace prefix is always in scope, why
> > should I have to declare it.
>
> My take on this is that W3C XML Schema is trying to kill 2 birds with a
> single declaration.
>
> When you write xmlns:foo="http://bar" in a schema, you do 2 different
> things:
>
> 1) you declare a namespace prefix per the namespaces in XML 1.0 rec
> that, most of the time, you will not use as a namespace prefix.

[MJG]
Well, I will use it as a namespace prefix. Maybe not in the name of an element or attribute but
elsewhere where QNames are needed ( element and attribute decls for example ).

>
> 2) you declare to the schema processor that you will be using the prefix
> 'foo' inside W3C XML Schema attributes to identify the namespace
> "http://bar".

[MJG]
I don't really see the distinction. Element names and attributes names are QNames. Certain
attributes in the schema language are QNames.

>
> The xml namespace prefix is always in your scope per the namespace rec
> to perform 1), but not ins your scope to perform 2).

[MJG]
Hmmm. This seems counterintuitive to me. I know Henry was keen that he be allowed to map
http://www.w3.org/1998/XML/namespace to an arbitrary prefix but I didn't think it was because the
xml prefix wasn't in-scope for attributes of type QName. But I could be misremembering...

>
> > MSXML sees this as an error, complaing that the prefix xml is invalid.
> > Xerces and Oracle accept it. Either way it doesn't solve my problem. A modified schema with the
> > above declaration still gives the same error[3]
>
> I am confused with your schema. It has no global element definition...
> Is it intended to be included in another one ? Otherwise I don't see
> which instance document can be validated ? Could you provide one ?

[MJG]
The schema is the instance. I'm trying to validate it against the schema-for-schemas. This is a
minimum repro test case from a much larger schema I'm trying to validate. I can provide a schema
with an element decl if you like but it won't make any difference to the problem at hand :-(
Received on Monday, 29 January 2001 06:18:52 GMT

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