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Re: Do pipelines have ports?

From: James Garriss <james@garriss.org>
Date: Fri, 19 Sep 2008 08:42:08 -0400
To: XProc Dev <xproc-dev@w3.org>
Message-ID: <C4F91660.86A%james@garriss.org>
In 2:1:  Steps have ³ports² into which inputs and outputs are connected.
In 2:2:  The input ports declared on a step are its declared inputs.
In 2:3:  Each step may have one input port designated as the primary input
port and one output port designated as the primary output port.
In 2:4:  Steps are connected together by their input ports and output ports.
In 5:1:  A p:input identifies an input port for a step.

Itıs pretty clear that steps have ports.  Itıs not so clear (at least to me)
that pipelines have ports (hence my question below).  Now itıs certainly
clear that pipelines have inputs/outputs, but once the WD starts talking
about ports (in the middle of 2:1), it only refers to steps having ports.
Maybe it should be more clear that pipelines also have ports?

The closest thing I have found is this, an indirect reference in section 2:
A pipeline is a set of connected steps, with outputs of one step flowing
into inputs of another.] A pipeline is itself a step.

Thanks for your help, Jeni!

James Garriss
http://garriss.blogspot.com




From: Jeni Tennison <jeni@jenitennison.com>
Date: Thu, 18 Sep 2008 22:02:12 +0100
To: James Garriss <james@garriss.org>
Cc: XProc Dev <xproc-dev@w3.org>
Subject: Re: Do pipelines have ports?

James,

> Is it correct to say that pipelines have ports as well, given an
> example such as this?
>
> <p:declare-step xmlns:p="http://www.w3.org/ns/xproc">
>     <p:input port="source">
>         <p:document href="BookStore.xml"/>
>     </p:input>
>     <p:output port="result"/>
>     <p:identity/>
> </p:declare-step>
>
> If not, what do you call them?


Absolutely. And if you ever give that step a type, then you can invoke
it as a step in another pipeline in exactly the same way you can the
built-in steps.

Jeni
-- 
Jeni Tennison
http://www.jenitennison.com
Received on Friday, 19 September 2008 12:42:52 GMT

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