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Re: I'm _still_ confused about 3.8 Extension elements

From: Norman Walsh <ndw@nwalsh.com>
Date: Tue, 08 Jan 2008 16:02:59 -0500
To: public-xml-processing-model-comments@w3.org
Message-ID: <m263y4hvy4.fsf@nwalsh.com>
/ ht@inf.ed.ac.uk (Henry S. Thompson) was heard to say:
| Further to the whole question of versioning. . .
|
| 3.8 [1] appears to me to contradict itself:
|
|  "An element is only an extension element if it is an ignorable
|   element that occurs as a direct child of a p:pipeline or
|   p:pipeline-library."
|
|  "[E]lements in a subpipeline are interpreted as follows. . .
|    2. Is in ignorable namespace?
|     a. Is a known extension? Process as appropriate."
|
| How can an element in a sub-pipeline be a direct child of p:pipeline?

Well, all of the elements in the subpipeline are direct children of
p:pipeline, no?

<p:pipeline xmlns:p="..." xmlns:ex="..."
            ignore-prefixes="ex">

  <ex:configure>
     ...
  </ex:configure>

  <p:xslt>
    ...
  </p:xslt>

</p:pipeline>

| I know I originally proposed the interpretation bullets, but I'm still
| confused. . .
|
| Looking at the RNG schema, and other parts of the spec., I _think_ the
| editor's intent was to allow extensions only in subpipelines, as a way

Well, in fact, only in the subpipeline of a p:pipeline. That needs to
be expanded to include p:declare-step now too.

| of allowing for . . . extensions.  But that is completely at odds with
| the following from the beginning of 3.8:
|
|  "The presence of an extension element must not cause the connections
|   between steps to differ from the connections that any other
|   conformant XProc processor would produce."
|
| Such a constraint would render any extension useless, as far as I can
| tell.

That's not the intent. The intent was to provide a modicum of
interoperability if the processor doesn't recognize the extension.

Extensions shouldn't interfer with the static analysis, IMHO.

| Maybe this all is moot, as this aspect of the spec. has to be
| revisited in light of our proposal wrt language evolution at the
| f2f [2], discussion wrt Comment 15.  [Actually, I've excerpted
| that discussion and replied to the Comment 15 thread with it,
| and then sent _this_ message in the resulting thread . . .]

I don't think the language evolution stuff bears on elements that
are in ignored namespaces.

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | Everything should be made as simple as
http://nwalsh.com/            | possible, but no simpler.

Received on Tuesday, 8 January 2008 20:59:25 GMT

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