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Re: Where's the parallelize step?

From: Norman Walsh <ndw@nwalsh.com>
Date: Tue, 21 Apr 2009 08:38:33 -0400
To: XProc Dev <xproc-dev@w3.org>
Message-ID: <m2ocuqyyeu.fsf@nwalsh.com>
"Costello, Roger L." <costello@mitre.org> writes:
>>> The identity step only allows me to connect its input port to the
>>> output of one of the parallel workflows. I'm dumping the other
>>> workflow's output. This seems rather bad. I can't think of what else
>>> to do. Can you suggest a better way to handle the merging of two
>>> parallel workflows?
>> <p:identity>
>>   <p:input port="source">
>>     <p:pipe step="branch-1" name="result"/>
>>     <p:pipe step="branch-2" name="result"/>
>>   </p:input>
>> </p:identity>
> I tried that, and got this error:
>     Error  : Pipeline failed: err:XD0006: 
>     2 documents appear on the 'source' port.
>     If sequence is not specified, or has the 
>     value false, then it is a dynamic error
>     unless exactly one document appears on 
>     the declared port.

That's bizarre. The source port on p:identity *does* accept a
sequence. Looks like a Calabash bug. Can you reproduce it in 0.9.8
released this morning?

> Even if it did work, what would it mean? Doesn't p:identity mean
> that the input flows unaltered to the output? Since there are two
> inputs, which one flows through to the output?

The output would be a sequence, the result from branch-1 preceding the
result from branch-2. I'm not sure what you *expect* the result of the
join to be...

                                        Be seeing you,

Norman Walsh <ndw@nwalsh.com> | Do not seek to follow in the footsteps
http://nwalsh.com/            | of men of old; seek what they
                              | sought.--Matsuo Basho

Received on Tuesday, 21 April 2009 12:39:16 UTC

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