Re: [wsbpel] Issue - 63 - For Each?

["Yaron Y. Goland" <ygoland@bea.com>]

Personally I'm o.k. with not introducing a break and instead raising a 
fault but I'm pretty open minded on the issue.

Kristofer Agren wrote:

> 
> 
> Yaron,
> 
> Thank you for the clarification. When applying the "for-each" construct in
> the various structured languages where it is supported, it is also fairly
> common to use the "break" construct to discontinue the iteration for some
> reason. Without a break action, you would be forced to raise a fault to 
> stop
> the iteration.
> 
> Thanks,
> 
> Kristofer
> 
> -----Original Message-----
> From: Yaron Y. Goland [mailto:ygoland@bea.com]
> Sent: Friday, April 09, 2004 5:36 PM
> To: Kristofer Agren
> Cc: wsbpeltc
> Subject: Re: [wsbpel] Issue - 63 - For Each?
> 
> The syntax I proposed is directly adapted from Issue 13. That is where
> we introduced an explicit query element and a local override for the
> query language specified on the process element.
> 
>         Thanks,
>                 Yaron
> 
> Kristofer Agren wrote:
> 
>  >
>  >
>  > 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"
>  >           ...
>  >
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>  > the
>  > OASIS TC), go to
>  >
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> 
> 
>  >
>  > php.
>  >
>