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Re: [Bug 7796] New: Misleading statement on change to unions

From: C. M. Sperberg-McQueen <cmsmcq@blackmesatech.com>
Date: Mon, 5 Oct 2009 09:40:16 -0600
Cc: "C. M. Sperberg-McQueen" <cmsmcq@blackmesatech.com>, www-xml-schema-comments@w3.org
Message-Id: <25BF68C0-36F7-4164-B3B4-D12CFA2A3207@blackmesatech.com>
To: Kevin Braun <kbraun@obj-sys.com>

On 5 Oct 2009, at 08:19 , Kevin Braun wrote:

> I understand your point about trying to reference all of the  
> changes.  Very true.
>
> Regarding eliminating the "flattening" of {member type definitions}  
> (so as to now include member unions rather than recursively remove  
> the unions by replacing with their members), my question (of the  
> text) is what is the significance of that change?  Or, where does  
> the specification make use of this change?  I finally came to figure  
> out that, combined with  2.2.4.3 of 3.16.6.3 Type Derivation OK  
> (Simple), this has an implication for type substitution.  I think it  
> would be helpful if the description of the change mentioned that.   
> If there are other significant implications (I gather that is not  
> the case), it would be helpful to mention them.
>
> Perhaps that goes beyond the purpose of listing the changes, but it  
> would be helpful to implementors.  I spent some time trying to  
> figure out how the facets for a union restriction were being  
> correctly enforced even when xsi:type was used to specify a member  
> type, figuring there must be some new complicated rule somewhere  
> that did that.  When I made the above discovery, I realized the  
> truth of the matter.  A pointer to 3.16.6.3 and a slightly better  
> explanation (such as what you suggested) would have been more  
> helpful to me.
>
> I hope that helps.

Thank you; it does.  I will see if I can come up with wording that
is more helpful to the reader.

-- 
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* C. M. Sperberg-McQueen, Black Mesa Technologies LLC
* http://www.blackmesatech.com
* http://cmsmcq.com/mib
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Received on Monday, 5 October 2009 15:40:47 GMT

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