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Re: Semantics of a list datatype derived from another list

From: Simon Cox <Simon.Cox@dem.csiro.au>
Date: Tue, 13 Mar 2001 15:53:17 +0800
Message-ID: <3AADD1ED.F9487443@dem.csiro.au>
To: Walt Yao <Walt.Yao@cl.cam.ac.uk>
CC: xmlschema-dev@w3.org
You can use a Union to derive a list of lists.  
But listOfFloat is no longer an atomic datatype so cannot be the value of itemType.

Walt Yao wrote:
> 
> Hi,
> 
> I am new to the list.  I've been looking through the archive but didn't find
> anything on this topic.  Please accept my apology if this has been discussed
> before.
> 
> I am implementing a Schema parser w.r.t the 24/10/2000 version, and I run
> into a problem with the definition of a list datatype.  As specified in 5.1.2,
> "a list
> datatype must be derived from an atomic or a list datatype, know as the
> itemType
> of the list...".  Does this means that the value for the attribute "itemType"
> can be
> a list type?  If so, what is the semantics of the derived list?  For example,
> consider
> the following definitions,
> 
>     <simpleType name='listOfFloat'>
>         <list itemType='float'/>
>     </simpleType>
> 
>     <simpleType name='listOfListOfFloat'>
>        <list itemType='listOfFloat'/>
>     </simpleType>
> 
> Does this imply the 'real' itemType of listOfListOfFloat is in fact 'float',
> i.e. it's just
> identical to listOfFloat?  Or is the datatype listOfListOfFloat is simply not
> a valid type?
> 
> Please help clarify.  Any suggestions are greatly appreciated.
> 
> Walt

-- 
Simon.Cox@dem.csiro.au    CSIRO Exploration & Mining
T:08 9284 8443 F:08 9389 1906 C:0403 302 672 (Intl +61)
http://www.ned.dem.csiro.au/research/visualisation/
Received on Tuesday, 13 March 2001 02:53:25 GMT

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