Re: [wsbpel] Issue 103 - draft proposal

[Danny van der Rijn <dannyv@tibco.com>]

i agree that your interpretation is one that is consistent with the
proposal.  the question boils down to this, though:

the $var syntax is proposed to make *addressing* easier.  however, once it
exists, it enables new *functionality*.  where we used to have to write:

exists(getVariableData('foo', 'a')//bar) or exists(getVariableData('foo',
'b')//bar)

we can now write

exists($foo//bar)

this is new functionality in that our shorthand now gives us the ability to
operate on the variable as a whole, rather than multiple parts
independently.

i think we should allow it, as well, but i also think that it should be
allowed explicitly rather than implicitly.

danny

----- Original Message ----- 
From: "Alex Yiu" <alex.yiu@oracle.com>
To: "Danny van der Rijn" <dannyv@tibco.com>
Cc: "wsbpeltc" <wsbpel@lists.oasis-open.org>
Sent: Tuesday, May 04, 2004 4:38 PM
Subject: Re: [wsbpel] Issue 103 - draft proposal


>
> Hi Danny,
>
> Thanks for reviewing the proposal and asking questions. :-)
>
> In your example, $foo//bar will yield a nodeset of two elements.
>
> If that expression is used in <assign> of (executable) BPEL, that will
> trigger bpws:selectionFailure fault in runtime (as described in Section
> 14.3).  A BPEL implementation can detect this problem with static
> analysis also.
>
> People would use $foo/a/bar or $foo/b/bar instead for the assignment.
>
> A similar situation would occur for current specification. E.g.:
> <from variable="foo" part="a" query="/abc//def" />
>
> I hope I have answered your question.
> Thanks!
>
>
> Regards,
> Alex Yiu
>
>
>
> Danny van der Rijn wrote:
>
> >ok, here's a question for this new syntax.  in XPath one can use the
> >"descendent" axis (shorthand //) to find all nodes that are children of a
> >particular node.  assuming we have a WSDL variable 'foo' with 2 parts, a
and
> >b, and each part is an element whose name is 'bar':
> >
> >foo
> >    - a - bar
> >    - b - bar
> >
> >would an expression like exists($foo//bar) be one that we would allow?
> >
> >danny
> >
> >
> >
>
>
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