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Message Reference, Message|element encore

From: Bijan Parsia <bparsia@isr.umd.edu>
Date: Wed, 11 Feb 2004 17:44:05 -0500
Message-Id: <CBBAA7BA-5CE3-11D8-BB61-0003939E0B44@isr.umd.edu>
To: www-ws-desc@w3.org

So, mulling over section 2.4  
(http://dev.w3.org/cvsweb/~checkout~/2002/ws/desc/wsdl20/ 
wsdl20.html#MessageReference) yet again:

1) At the F2F, did we agree to change the name of the component  
property {message} to "element", or only the attribute?
2) At the F2F, Roberto (I believe) assuaged my worries by pointing to  
the mapping in 2.4.3:
	"""{message}	 The element declaration resolved to by the value of the  
message attribute information item if present, otherwise a similar  
construct in some type system as referred to by some other attribute  
information item if present, otherwise empty."""

	This suggests that the {message} *component* can refer to types in  
arbitrary type systems. However:
	a) The text in 2.4.1 reads:
	""" {message} A reference to an XML element declaration. This element  
represents the content or "payload" of 	the message"""
	Which pretty much *states* that the value of a {message} component  
property is an element declaration 	*only*. This seems to be a tension  
in the text.
	b) I don't see any way to tell *which* type system the {message}  
component property refers too
3) In section 3.1.3:
  """A named, global xs:element declaration may be referenced from the  
message attribute information item of an input or output element  
information item. The QName is constructed from the targetNamespace of  
the schema and the content of the name attribute information item of  
the xs:element element information item. A message attribute  
information item may not refer to an xs:simpleType or an xs:complexType  
element information item."""

I don't understand why there is a restriction against referencing  
xs:simpleTypes. It seems to me that there are plenty of messages (HTTP  
reponses with text/plain bodies?) that are properly described by  
xs:simpleTypes (maybe UPnP as well?) If at all possible, I'd like to  
see the restriction removed.

All this suggests (to me) that having to add an attribute for each type  
system is, well, annoying :) Why not have a pair of component  
properties, {typeSystem} and {type}. And better, let there be two  
attributes in the XML as well. For XML Schema element declarations, we  
can make that omitting the type system attribute defaulst to XML Schema  
element declarations.

Cheers,
Bijan Parsia.
Received on Wednesday, 11 February 2004 17:44:16 UTC

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