Your argument works for text nodes but not elements and who says that
the contents of a static value that contains nothing is a text node?
That certainly isn't defined in the spec today. In fact we have at least
2 open issues on exactly this kind of problem.
Assaf Arkin wrote:
> In XML empty is still a content. An empty text node contains zero
> characters. Different from nothing or null.
>
> For example, if I have the expression concat($X,$Y) it is valid for Y to
> be empty, and its reasonable for someone to set it to empty and be used.
> $Y needs to have a value in this case and the expression need to evaluate.
>
> Un-initialize will require its own construct, a) to not confuse between
> empty and null, and b) since we currently do not allow null to be selected.
>
> Assaf
>
> Tony Fletcher wrote:
>
>> This issue has been added to the wsbpel issue list with a status of
>> "received". The status will be changed to "open" if the TC accepts it
>> as identifying a bug in the spec or decides it should be accepted
>> specially. Otherwise it will be closed without further consideration
>> (but will be marked as "Revisitable")
>>
>> The issues list is posted as a Technical Committee document to the
>> OASIS WSBPEL TC pages
>> <http://www.oasis-open.org/apps/org/workgroup/wsbpel> on a regular
>> basis. The current edition, as a TC document, is the most recent
>> version of the document entitled in the "Issues" folder of the WSBPEL
>> TC document list
>> <http://www.oasis-open.org/apps/org/workgroup/wsbpel/documents.php> -
>> the next posting as a TC document will include this issue. The list
>> editor's working copy, which will normally include an issue when it is
>> announced, is available at this constant URL
>> <http://www.choreology.com/external/WS_BPEL_issues_list.html>.
>>
>>
>> ------------------------------------------------------------------------
>>
>>
>> Issue 197: Un-initializing BPEL variables
>>
>> *Status:* received
>> *Date added:* 12 Mar 2005
>> *Categories:* Data Handling
>> <http://www.choreology.com/external/WS_BPEL_issues_list.html#category_data_handling>
>>
>> *Date submitted:* 11 March 2004
>> *Submitter:* Yaron Y. Goland <mailto:>
>> *Description:* Is it legal/possible to un-initialize a variable in
>> BPEL? What happens, for example, if one tries to assign a static from
>> value that is empty? Should we allow for from-spec to be empty and
>> have that mean that the target is uninitialized?
>> *Submitter’s proposal:* Being able to un-initialize variables is a
>> generically useful thing. It makes it clear when a variable doesn't
>> contain a 'useful' value. So I think we should provide a way to
>> un-initialize variables.
>> *Changes:* 12 Mar 2005 - new issue
>>
>> ------------------------------------------------------------------------
>> Best Regards,
>>
>> Tony/ /
>>
>> / <http://www.choreology.com/>/
>>
>>
>>
>> Tony Fletcher
>>
>> Technical Advisor
>> Choreology Ltd.
>> 68, Lombard Street, London EC3V 9L J UK
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>
