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RE: Derivation by restriction in XML Schema

From: Arnold, Curt <Curt.Arnold@hyprotech.com>
Date: Mon, 6 Mar 2000 17:17:28 -0700
Message-ID: <00E567D938B9D311ACEC00A0C9B468730C760D@THOR>
To: "'xml-dev@xml.org'" <xml-dev@xml.org>, "'www-xml-schema-comments@w3.org'" <www-xml-schema-comments@w3.org>
Henry Thompson wrote:

>1) Renaming is not supported -- communication failure between
>the editors, my apologies.

No problem.  It seemed to be a whole rats nest of problems
and potential for errors as described in the primer.


> 2) The WG considered an XPath-based solution
> very similar to what you propose and rejected it
> as too complex.

Even if you use a content repetition approach, using
special restriction forms of <element> and <attribute>
within a <restrict> clause would minimize the amount of
nasty scenarios like using a different type for
an attribute in the restriction vs its definition and
would not force you to use two separate derivations
when you had a derivation that was both an extension
and a restriction of a base type.

>3) The relevant sections of Chapters 4 and 6 are 
>_way_ short of complete -- I'm very sorry this was
> not better indicated.  I'll post a summary of the new
> material going in there tomorrow, I hope.

Would be appreciated.

>4) You can't restrict material from another namespace, 
>whether it's attribute or element, unless you own, or 
>bogusly claim to own, rights to define elements, 
>attributes, types in that namespace, which, in the 
>case of the XML namespace, you don't.

I don't think I buy that.  If I include the xlink:show
attribute in an element by referencing its attribute
group from the xlink schema, it would seem appropriate
for me to say that the default is "replace" or that "embed"
is prohibited in this context.
Received on Monday, 6 March 2000 19:20:13 GMT

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