- From: Jeni Tennison <jeni@jenitennison.com>
- Date: Wed, 04 Oct 2006 17:15:48 +0100
- To: public-xml-processing-model-wg@w3.org
Hi Alex,
OK, I'm persuaded by your argument that if there's no technical reason
for components to be ordered then users should be able to order them in
whatever way makes sense to them. If they choose to use an order that
makes their pipeline hard to maintain or follow, that's up to them.
However, given that we have no other way of indicating out-of-band
dependencies, I do think step order needs to be significant. If a user
writes
<p:step name="C" ...>
<p:input port="doc" step="A" source="result" />
<p:input port="aux" step="B" source="result" />
</p:step>
<p:step name="A" ...>...</p:step>
<p:step name="B" ...>...</p:step>
and (implicitly) step A depends on step B, then the user will want step
A to be performed before step B.
In other words, the explicit dependencies between steps provide a
partial ordering; where the explicit dependencies do not specify an
ordering between two steps, the result must be as if the implementation
performed the steps in the order given in the pipeline specification.
Cheers,
Jeni
--
Jeni Tennison
http://www.jenitennison.com
Received on Wednesday, 4 October 2006 16:16:13 UTC