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Re: Data Model WD - Issue-0054: Complex types with simple content

From: Nagy, Marton <MARTON.NAGY@saic.com>
Date: Tue, 22 Jan 2002 16:00:16 -0500
Message-Id: <E727291BF590D41187C800508BF9B35608107950@mcl-its-exs02.mail.saic.com>
To: jeni@jenitennison.com
Cc: www-xml-query-comments@w3.org, jmarsh@microsoft.com

Hi Jeni,

Thank you for your remarks on "Complex types with simple content".
Given the approval of the working groups, we will remove the special
handling (i.e. enforcing that it is the empty sequence) of elements
with complex types and then indeed any element that has a non-absent
[schema normalized  value] in the PSVI will have a typed-value.
But the mention of the special significance of xsi:nil or other
magic attributes for that matter may still be desired for clarification.

We will fix the typo in the signature of the simple-typed-value constructor
by stating that it returns a sequence of simple typed values. 
Also, as you suggest, we will consider putting in a forward references to
this function in Sections 4.2 and 4.3 to clarify how the typed-value
is computed.

Finally, we will add a new issue to reflect your comment regarding
"Whitespace normalization of the string-value of elements with simple
content"

Best regards,
Marton Nagy


> 
> Date: Sun, 13 Jan 2002 14:20:54 +0000
> From: Jeni Tennison <jeni@jenitennison.com>
> Message-ID: <93539003455.20020113142054@jenitennison.com>
> To: www-xml-query-comments@w3.org
> Subject: Data Model WD - Issue-0054: Complex types with simple content
> 
> Hi,
> 
> Re: Issue-0054: Complex types with simple content.
> 
> I strongly agree with this comment - complex types with simple content
> should also have typed values. Otherwise it makes it very difficult to
> get useful information from constructs such as the common <price
> currency="GBP">12.99</price>.
> 
> I think that any element that has a non-absent [schema normalized
> value] in the PSVI should have a typed-value; this includes elements
> with complex types with simple content and elements with default/fixed
> value constraints (which would be worth noting). It also means you
> don't have to mention the special significance of xsi:nil, since it's
> already covered in the definition of the [schema normalized value] in
> the XML Schema Rec.
> 
> On the topic of the typed-value of an element, it's worth noting that
> the [schema normalized value] PSVI property is described as a string
> in the XML Schema Rec. Obviously you need to convert this string into
> a sequence of typed values. I think that you could do this by stating
> in Sections 4.2 and 4.3 that the [schema normalized value] is
> converted into a sequence of simple types via the
> simple-typed-value-from-string constructor in Section 5, although I
> think that the signature of the constructor should be:
> 
>   simple-typed-value-from-string : (xs:string, SchemaComponent)
>                                  -> Sequence<SimpleTypedValue>
> 
> if you're going to handle generating sequences of simple typed values
> from strings like "1 2 3".
> 
> Note also that when getting the simple typed value for an element with
> a complex type, the second input to the simple-typed-value-from-string
> should be the element's [type definition]'s [content type] (which will
> be a simple type definition in all applicable cases), rather than
> simply the [type definition] (which you can use directly if the
> element's type definition is a simple type definition).
> 
> I know that I commented before on getting access to the member type
> definition (the title of Issue-0064 although the text of that issue is
> actually about something completely different, about which more later
> ;). However, since the typed value of an element or attribute will
> have that (member) type (rather than the union type), I don't think
> it's a problem - just might be worth making a note that the type of an
> element is not necessarily the same as the type of the simple typed
> value(s) retrieved by the typed-value accessor.
> 
> Also on this topic, I notice that the string value of an attribute
> node is normalized (according to the whitespace facet of its type); on
> the other hand, the string value of an element node is not normalized.
> I think that the string value of elements with simple content should
> be normalized in the same way as the string value of attributes.
> 
> Cheers,
> 
> Jeni
> ---
> Jeni Tennison
> http://www.jenitennison.com/
> 
Received on Tuesday, 22 January 2002 16:00:50 GMT

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