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Re: New issue [distobj@acm.org: Re: What does WSDL describe?]

From: Mark Baker <distobj@acm.org>
Date: Fri, 24 Oct 2003 12:59:31 -0400
To: Jonathan Marsh <jmarsh@microsoft.com>
Cc: www-ws-desc@w3.org
Message-ID: <20031024125931.G9730@www.markbaker.ca>

On Fri, Oct 24, 2003 at 08:14:29AM -0700, Jonathan Marsh wrote:
> I'm with Sanjiva in not grasping this issue.  Is this just a fancy way
> to ask whether message signatures should be unique on the wire (an issue
> which we are already debating)?  I don't see any difference between a
> SOAP body of <state>12345</state> and <add>12345</add> from the WSDL
> processor point of view, though they may imply different application
> semantics.

Consider the question, "What is being asked of the service"?

If you're only sending state, then what is being asked is that the
state be processed.  If you're sending state+operation, what is being
asked?  There are two possibilities;

- that the state+operation be treated as just state and that it be
processed as in the first example, or
- that the operation be executed

To understand the difference between "operation execution" and
"state processing", consider the example of a Web service which
takes any state it receives, and spits it out on a scrolling LED
ticker.  That's state processing.

TimBL also had some comments on this recently, though not in the context
of service description;

"What can a symbol  
require of a person? Nothing. What can receipt of a message which uses  
a symbol require of a person? Nothing. You can't require people to do  
thing by sending them things.

We can define a *protocol* in which people do do things, and we can  
demonstrate
that if people adhere to the protocol interesting results can be  
assured.  Then conformance with the protocol would require that one do  
something."
 -- http://lists.w3.org/Archives/Public/public-sw-meaning/2003Sep/0130.html

Mark.
-- 
Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca
Received on Friday, 24 October 2003 12:58:30 GMT

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