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Re: Question on equality of lists

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 18 Nov 2002 19:01:13 +0000
To: Stefan Wachter <Stefan.Wachter@gmx.de>
Cc: xmlschema-dev@w3.org, www-xml-schema-comments@w3.org
Message-ID: <f5b1y5in1mu.fsf@erasmus.inf.ed.ac.uk>

Stefan Wachter <Stefan.Wachter@gmx.de> writes:

> When a list valued element or attribute is used as a key then the equality
> of the values is important. In the following example there are 3 lists with
> item types "Name", "double", "nameOrDouble":
> 
> <simpleType name="l1">
>   <list itemType="Name"/>
> </simpleType>
> 
> <simpleType name="l2">
>   <list itemType="double"/>
> </simpleType>
> 
> <simpleType name="l3">
>   <list itemType="tns:nameOrDouble"/>
> </simpleType>
> 
> <simpleType name="nameOrDouble">
>   <union memberTypes="Name double"/>
> </simpleType>
> 
> Are these lists equal?
> 
> 1. Items types of lists are different but item types of items are equal:
> <element xsi:type="l1">1.0 2.0</element> = <element xsi:type="l3">1.0
> 2.0</element>

I think not, but this is certainly an area we should look at and
possibly clean up and/or change for 1.1.

> 2. Item types of lists are different but there are no items.
> <element xsi:type="l1"/> = <element xsi:type="l2"/>

Again, not.

> What are the exact rules for comparing lists? Thanks for your attention,

Not sure :-(.  The reason for my 'no' answers above is the general
rule-of-thumb that for schema-validation purposes two values must have
the same or related-by-derivation types to be _able_ to compare as
equal.

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2002, part-time member of W3C Team
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    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 Monday, 18 November 2002 14:01:16 GMT

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