Re: [wsbpel] Issue 147 - making <forEach> more extensible

Hi all,

I have circulated a proposal of adding XPath-expression
iteratorVariable logic back to the <forEach> construct among a
number of TC members. The iteratorVariable syntax will look like the
following: 

----------------------------------------

<forEach> 
          <iterator name="expensiveItem" type="po:itemType"> 
               
<expression> $po/items[@amt>300] </expression> 
          </iterator>

     <scope>

        <sequence> 

          <invoke
inputVariable="expensiveItem" ...  /> 

          ... 

        </sequence> 

     </scope>
</forEach>

----------------------------------------

[
The main theme of the iterator proposal is based
on macro-expansion. It is similar to how
propertyAlias works today and in BPEL 1.1. The
iteratorVariable provides users convenience and
encapsulation and the higher level encapsulation will ease code
optimization.]

I have received some warm responses to this iterator idea. However, at
the same time, Yaron still have some concern about the iteratorVariable
model. E.g. whether we can wrap up the BPEL 2.0 spec on time.  I had
some offline chat with him. I came up with
a compromised proposal, which Yaron prefers. 

Basically, dropping the iteratorVariable and adding an xsd:any
extension point for us to add iteratorVariable in future (maybe as an
extension first). 

-------------------------

<forEach counterName="ncname" standard-attributes >

     standard-elements

    <iteration>  

        (

           <numericCounter>

                 <startCounterValue expressionLanguage="anyURI"?>

                       ...

                 </startCounterValue>

                 <finalCounterValue expressionLanguage="anyURI"?>

                        ...

                 </finalCounterValue>

           </numericCounter>

           |

           xsd:any namespace="##other"

        )

    </iteration> 

     scope

</forEach>

------------------------

I am OK with the new compromised proprosal mainly because
I want to finish the spec earlier also. :-) 

Please voice your opinion here. (I can send out the full proposal of
iteratorVariable, if the TC members request.)

Thanks!

Regards,

Alex Yiu