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Subject: RE: [wsbpel] Issue - 63 - For Each?
Yaron, I agree with you in that adding a for-each construct, like the one you have detailed, would both be a good way to solve issue 63 and would also simplify writing BPEL since iterating over a node list is a very common scenario. I am just curious why you have added the query as a separate element and not an attribute, like the <from> construct for example, and why not use the query language that can be specified on the <process> element? Regards, Kristofer -----Original Message----- From: Yaron Y. Goland [mailto:ygoland@bea.com] Sent: Thursday, March 25, 2004 4:17 PM To: wsbpeltc Subject: [wsbpel] Issue - 63 - For Each? The following are thoughts I've had on how we could address issue 63. Although these thoughts are still fairly rough I wanted to release them now because 63 is on the agenda for the F2F. Since these are early thoughts I reserve the right to disavow them at any time. I thought an easy way to provide the feature asked for in 63 is to provide a macro that has proven its utility in numerous structured languages - For Each. I was thinking of a syntax like: <foreach sourceVariable="ncname" part="ncname"? \ iteratorVariableName="ncname" iteratorVariableType="qname" standard-attributes> standard-elements <query language="anyURI">...</query> activity </foreach> The idea is that the query element would be an expression that generates zero or more nodes. Each generated node would be assigned to a local variable whose name is given in iteratorVariableName and whose type is iteratorVariableType. The foreach would then walk through each node one by one in document order. If no nodes are returned then the activity would do nothing. For example: foreach sourceVariable="orderManifest" part="somePart"\ iteratorVariableName="anOrder" iteratorVariableType="b:ar" query language="http://www.w3.org/TR/1999/REC-xpath-19991116" ordermanifest/orders ... Would be a Macro for: scope variables variable name="anOrder" type="b:ar" variable name="currentInstanceNum" type="xs:int" sequence assign copy from "1" to variable="currentInstanceNum" while condition="$currentInstanceNum <=\ count($orderList/somePart/ordermanifest/orders)" assign copy from variable="orderList" part="somePart" query "(/ordermanifest/orders)[$currentInstanceNum]" to variable="anOrder" assign copy from expression "$currentInstanceNum+1" to variable="currentInstanceNum" ... To unsubscribe from this mailing list (and be removed from the roster of the OASIS TC), go to http://www.oasis-open.org/apps/org/workgroup/wsbpel/members/leave_workgroup. php.
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