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Re: Questions + comments on XProc WD 14 December 2007

From: Norman Walsh <ndw@nwalsh.com>
Date: Mon, 28 Jan 2008 15:42:31 -0500
To: public-xml-processing-model-comments@w3.org
Message-ID: <m2sl0hadhk.fsf@nwalsh.com>
/ Toman_Vojtech@emc.com was heard to say:
|> / Toman_Vojtech@emc.com was heard to say:
|> | 3. The spec allows recursive invocations of pipelines. Is the 
|> | following example valid (only name specified, no type 
|> | informationprovided)?
|> |
|> | <p:pipeline name="test"> <test>...</test> </p:pipeline>
|> |
|> | Or do I have to use the "type" attribute here?
|> |
|> | <p:pipeline type="test:mypipeline" 
|> xmlns:test="http://www.test.com">  
|> | <test:mypipeline>...</test:mypipeline> </p:pipeline>
|> |
|> | I think the spec is not very clear on this topic.
|> 
|> I think this has also been overtaken by events.
|
| I am not so sure. Are the following (reursive) pipelines legal?
|
| <p:pipeline type="test:mypipeline" xmlns:test="http://www.test.com">
|   <test:mypipeline>...</test:mypipeline>
| </p:pipeline>
|
| and:
|
| <p:pipeline type="mypipeline">
|   <mypipeline>...</mypipeline>
| </p:pipeline>

As written, I think both of them recurse until the processor runs out
of resources and falls over. Or did you mean to suggest that the inner
call is inside a choose or something?

| My feeling is that the second pipeline should not be legal. The
| specification does demand that the value of "type" must be in a nonempty
| namespace (compare to p:declare-step), but I think that if one wants to
| write recursive pipelines, a non-local type has to be used.

The p:pipeline element is just syntactic sugar at this point for a
particular p:declare-step. I think the type attribute on p:pipeline
inherits the constraints given on p:declare-step (though the spec is
not clear on that point).

Since the type must be in a non-null namespace, and since we interpret
all unqualified QName values as being in the null-namespace, I think
it does follow that the second example above is not valid.

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | The delivering of knowledge in distinct
http://nwalsh.com/            | and disjointed aphorisms doth leave the
                              | wit of man more free to turn and toss,
                              | and to make use of that which is so
                              | delivered to more several purposes and
                              | applications.--Sir Francis Bacon

Received on Monday, 28 January 2008 20:42:41 GMT

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