Jim has published a great article about WSDL – well, modulo the “protocol independence” bit, of course 8-).

But I wonder, how many Web services proponents would agree with him? His views have, as I recall, have been rather controversial.

Ordinarily this wouldn’t be such a big deal, but from a Web services perspective this is basic interop that’s at stake; if a smart guy like Jim can interpret one thing from a WSDL document, and that interpretation is different than the publisher intends, or others read, then Web services interoperability simply will not happen.

The WSDL 2.0 spec doesn’t help much here, and seems to go out of its way to be ambiguous. It describes an operation like so;

An operation is an interaction with the service consisting of a set (ordinary and fault) messages exchanged between the service and the other roles involved in the interaction, in particular the service requester.

Wha? Somebody answer me, please; is it an operation ala an IDL operation? If not, what is it, and how does that differ from Jim’s interpretation? Where’s the contract?