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Re: Possible problems with unsupported steps

From: Norman Walsh <ndw@nwalsh.com>
Date: Fri, 31 Oct 2008 09:50:24 -0400
To: public-xml-processing-model-comments@w3.org
Message-ID: <m2mygkho0v.fsf@nwalsh.com>
Toman_Vojtech@emc.com writes:
> So far so good. But the thing about unsupported steps is that the
> processor not only does not support them, but it also does not know
> their declarations - which, among other things, means that it doesn't
> know what the step's input and output ports are (and which of them, if
> any, are primary). This can cause problems when the processor processes
> the pipeline document, establishes the running order of steps and
> detects static errors.

Hmm. I think perhaps the spec is unclear, but I believe the intent is
that a declaration must always be present. If the processor encounters
an element for which it doesn't have a declaration, then I think
that's err:XS0044.

My implementation, for example, implicitly imports a set of
declarations for its extension steps. I wonder if its allowed to do
that, or if the author is required to explicitly import that
library...

In any event, I believe that this pipeline can be rejected statically:

  <p:pipeline xmlns:p="..." xmlns:cx="...">
    <cx:message message="Hi Mom"/>
  </p:pipeline>

while this pipeline can be rejected either statically or dynamically:

  <p:pipeline xmlns:p="..." xmlns:cx="...">

    <p:declare-step type="cx:message">
      <p:input port="source"/>
      <p:output port="result"/>
      <p:option name="message" required="true"/>
    </p:declare-step>

    <cx:message message="Hi Mom"/>
  </p:pipeline>

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | It is so comic to hear oneself called
http://nwalsh.com/            | old, even at ninety I suppose.--Alice
                              | James

Received on Friday, 31 October 2008 13:51:09 UTC

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