W3C home > Mailing lists > Public > public-xml-processing-model-wg@w3.org > October 2006

Re: The Scope of Step Names

From: Jeni Tennison <jeni@jenitennison.com>
Date: Wed, 04 Oct 2006 17:15:48 +0100
Message-ID: <4523DE34.30202@jenitennison.com>
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 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 8 January 2008 14:21:49 GMT