Didier,
What you're doing sounds like a Web Service Orchestration Language.
I've been investigating WSDL[1], XML Pipeline[2], and XLang[3] and looking
at ways to make an XSLT or XForms-like[4] orchestration language does
something like what you're proposed, using XSLT as part of the model. I
believe it is possible to define a processor that uses XSLT for
transformations and uses SOAP to invoke services at defined points, and
re-introduces the SOAP result as a part of the document for further
processing, but the processing model has to define the points where these
steps take place.
Paul Prescod points out that the direct mapping of document('soap://...') to
an invication of a SOAP-based web service may not be the best mechanism for
hooking the SOAP and the XSLT together, since that puts invocations of the
web service under control of the XSLT processing model rather than putting
the results of the SOAP invocation as documents given to XSLT. I believe
what is needed are specific input-output transformation operations that are
orchestration steps producing result documents. These result documents
could then be named and referred to by XSLT "document('result1')"
expression, or perhaps by a simple XPath path expression if the results are
incorporated back into the document itself.
[1] Web Services Description Language (WSDL) 1.1
http://www.w3.org/TR/wsdl
[2] XML Pipeline Definition Language Version 1.0
http://www.w3.org/TR/xml-pipeline/
[3] XLANG: Web Services for Business Process Design
http://www.gotdotnet.com/team/xml_wsspecs/xlang-c
[4] XForms - The Next Generation of Web Forms
http://www.w3.org/MarkUp/Forms
http://www.w3.org/TR/xforms/
