Re: Sub-pipelines

Alessandro Vernet wrote:
> Norm/Rui,
> 
> Backtracking a little bit: I agree that we need sub-pipelines, that
> is, the ability to call a pipeline from a pipeline. However, do we
> really need to be able to define those sub-pipelines in the same XML
> file? If we don't, we may not need a special syntax to call
> sub-pipeline (like the <p:call-pipeline> considered in this thread).
> 
> In fact, we could consider that we have a pre-defined component called
> "pipeline" that just runs pipeline, just like "xslt" runs a
> stylesheet:
> 
>     <p:step name="pipeline">
>         <p:input name="pipeline" href="expandandvalidate.xpl"/>
>         <p:input name="schemas" href="a.xsd"/>
>         <p:input name="document" href="mydoc.xml"/>
>         <p:output label="ok1"/>
>     </p:step>
> 
> Alex


Personally, I can live just with externally defined pipelines, but I 
understand if there is a need to define other pipelines internally 
(somewhat like a function). In the latter case, I guess that the 
<p:call-pipeline /> element shouldn't be replaced by a pipeline 
execution component step, as we would end up with two different 
semantics for sub-pipelines specification and execution: 
<p:define-pipeline /> (explicit) and <p:step /> (implicit).

Opting for the <p:call-pipeline /> solution, it may have some impact in 
the pipeline language: if the step flow is defined by document order, we 
may end up with an awkward syntax; otherwise, if the flow is explicitly 
defined by connecting inputs and outputs, then i guess it's ok.


Rui