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Re: QName is ambiguous; aren't datatypes unambiguous? union types total?

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 16 Aug 2002 11:13:42 +0100
To: noah_mendelsohn@us.ibm.com
Cc: "Ashok Malhotra" <ashokma@microsoft.com>, "Dan Connolly" <connolly@w3.org>, www-rdf-comments@w3.org, www-xml-schema-comments@w3.org
Message-ID: <f5bsn1fnmax.fsf@cogsci.ed.ac.uk>

noah_mendelsohn@us.ibm.com writes:

Some minor quibbles

<snip/>

> I think we have to admit that the lexical space for QName is context 
> dependent, for better or worse.

I'd say rather that the mapping from lexical to value space is
context-dependent.  We've already agreed that specifying that mapping
for each simple type is a goal for 1.1.

<snip/>

> My preferred resolution would be different than yours, I think.  I think 
> we should workb backwards from the validation rules, make clear that order 
> matters, and that in your example the decimal 10 is NOT in the value space 
> of the union.   So the value space of a union would be the values 
> corresponding to lexical forms that validate per the order sensitive rule. 
>  Thus, neither the value spaces nor the lexical spaces can be a union. 
> Actually, I think it's clear that the lexical spaces can't be a union, 
> since the form "10" would appear twice, which seems wrong to me.

That can't be right, since the following is allowed, given a
definition of my:u as union(xs:string,xs:decimal) and foo declared to
have my:u as its type:

<foo xsi:type="xs:decimal">10</foo>

I agree that this just makes the interpretation of "Each value in the
value space of a datatype is denoted by one or more literals in its
*lexical space*" even more unclear. . .

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2002, part-time member of W3C Team
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	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
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Received on Friday, 16 August 2002 06:13:53 GMT

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