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Re: Implications of XML 1.1 for WSDL 2.0

From: Mark Nottingham <mark.nottingham@bea.com>
Date: Wed, 12 May 2004 10:58:38 -0700
Message-Id: <FEBE6229-A43D-11D8-BAE7-000A95BD86C0@bea.com>
Cc: www-ws-desc@w3.org
To: Arthur Ryman <ryman@ca.ibm.com>

Note that the XMLP WG is just finalising its decision for this issue as 
it impacts SOAP 1.2; it would be good if the approaches were 
co-ordinated (apologies if this was already well-known).


On May 12, 2004, at 10:41 AM, Arthur Ryman wrote:

>
> This note completes my action item of 2004-04-29.
>
> The WSDL 2.0 spec is written in terms of the XML Infoset. The Infoset 
> spec was recently revised [1] to cover XML 1.1. There are at least two 
> changes in XML 1.1 that affect the Infoset:
>
> 1. The set of legal values for character data has increased. However, 
> on closer reading of the Infoset spec, it defines a character code as 
> any number in the ISO 10646 range of 0 to #x10FFFF, even though not 
> all of these are legal XML codes. So in this case there is no problem 
> since the Infoset spec is general enough to describe even documents 
> that are not well-formed XML 1.1, i.e. that contain illegal character 
> codes.
>
> 2. The set of legal values for characters that may appear in element 
> names, attributes names, enumerated attribute values, targets of 
> processing instructions, etc., has increased. The Infoset spec doesn't 
> define these, instead saying that it takes whatever an XML parser 
> hands it.
>
> There are also changes to Namespaces that are reflected in the new 
> Infoset spec.
>
> My conclusion is that the Infoset spec is loose in the sense that it 
> doesn't nail down every aspect of an Infoset. That is fine for the 
> Infoset spec, but I do NOT think it is fine for WSDL 2.0, since in 
> practice systems will be interchanging concrete documents using XML 
> 1.0 or XML 1.1. If we are not clear on this, then we will probably hit 
> interoperability problems when XML 1.1 gets adopted.
>
> I think there are two extreme approaches and probably some 
> intermediate cases.
>
> Case 1. We state that WSDL 2.0 MUST use  XML 1.0 only. This means WSDL 
> 2.0 documents MUST use XML 1.0 and that any imported or included 
> document MUST also use XML 1.0.
>
> Case 2. We state that WSDL 2.0 MAY use either XML 1.0 or XML 1.1 and 
> that conformant processors MUST support both, and any combination of 
> versions for all imported or included documents.
>
> Case 1 has the advantage of simplicity and ease of implementation. 
> However, it denies the benefits of XML 1.1 which may be significant to 
> some users. For example, ease of authoring on IBM-compatible 
> mainframes (NEL), and the flexibility to use more international 
> characters in names.
>
> Case 2 has the disadvantage that it is harder to implement since there 
> are not a lot of XML 1.1 parsers in production yet. It has the benefit 
> of making the features of XML 1.1 available.
>
> I suspect that even if we adopt Case 2 that WS-I will issue a Profile 
> that specifies Case 1.
>
> [1]  http://www.w3.org/TR/xml-infoset/
>
>  Arthur Ryman,
>  Rational Desktop Tools Development
>
>  phone: +1-905-413-3077, TL 969-3077
>  assistant: +1-905-413-2411, TL 969-2411
>  fax: +1-905-413-4920, TL 969-4920
>  mobile: +1-416-939-5063
>  intranet: http://w3.torolab.ibm.com/DRY6/

--
Mark Nottingham   Principal Technologist
Office of the CTO   BEA Systems
Received on Wednesday, 12 May 2004 13:59:07 GMT

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