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Re: it is impossible to compare QNames

From: Steve Ross-Talbot <steve@pi4tech.com>
Date: Mon, 29 May 2006 20:25:44 +0100
Message-Id: <9103fe2b135ee9749d6a6fc43a630e47@pi4tech.com>
Cc: 'WS-Choreography List' <public-ws-chor@w3.org>, Nickolas Kavantzas <nickolas.kavantzas@oracle.com>, Tony Fletcher <tony_fletcher@btopenworld.com>
To: <matthew@stickledown.com>

I'd like to deal with this at the next conf call (Tuesday if possible).
We ought to be able to fix this or provide an sensible answer to 
Matthew.

Cheers

Steve T

On 27 May 2006, at 22:45, Matthew Rawlings wrote:

>
> This is feedback on the WS-CDL Choreography CR of 2005-11-09. I have 
> been
> implementing CDL at a bank and have some questions and feedback on the 
> CR.
>
> The problem I have with the CR is the XML Schema for WS-CDL requires 
> you to
> compare a QName type with an NCName type. This comparison is impossible
> because the QName type does not have equality or ordering defined for 
> it.
>
> Section 4.2 of the CDL specification states that field
> /package/relationshipType/roleType/@typeRef (a QName), must reference 
> the
> field /package/roleType/@name (a NCName). I took this from the text: 'A
> relationshipType element MUST have exactly two roleTypes defined. Each
> roleType is specified by the typeRef attribute within the roleType 
> element.
> The "QName" value of the typeRef attribute of the roleType element MUST
> reference the name of a roleType.'
>
> Please tell me why the datatype QName was used. I have been unable to 
> work
> out why QName was used. QName is normally used to reference elements 
> rather
> than the contents of elements.
>
> I have been assuming the word "reference" is as an equality test as 
> defined
> by XPath 1.0. This should be explicit in the specification.
>
> Looking through the mail-list examples (e.g.
> http://lists.w3.org/Archives/Public/public-ws-chor/2005Sep/0001) it 
> seems
> that QName and NCName are being used in the style of xs:ID and 
> xs:IDREF. Why
> not just use xs:ID and xs:IDREF? This would also have the benefit of 
> making
> the constraint that a typeRef must reference a roleType name explicit. 
> Both
> xs:ID and xs:IDREF are subtypes of xs:NCName.
>
> At the very least typeRef and roleType should be some type of string 
> that is
> comparable, otherwise references cannot be tested.
>
> Matthew Rawlings
> +44 791 539 7824
>
>
>
>
>
>
Received on Monday, 29 May 2006 19:25:56 GMT

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