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Re: Extensibility questions

From: Norman Walsh <ndw@nwalsh.com>
Date: Mon, 12 May 2008 08:49:43 -0400
To: public-xml-processing-model-wg@w3.org
Message-ID: <m2iqxjd6vs.fsf@nwalsh.com>
/ "Innovimax SARL" <innovimax@gmail.com> was heard to say:
|>  | Following is a an example for 1)
|>  |
|>  | 1) for example : p:count, with xmlns:my="http://my.site.com/ns/"
|>  |
|>  | a) Is this valid ?
|>  | <p:count my:option="myvalue"/>
|>  Yes, but my:option is an extension attribute, not an option.
| Am I allowed to change the behaviour of step with that extension attribute ?

Presumably that's the point of adding it. However,

  The presence of an extension attribute must not cause the
  connections between steps to differ from the connections that would
  arise in the absence of the attribute. They must not cause the
  processor to fail to signal an error that would be signalled in the
  absence of the attribute.

So it can't manufacture new connections nor can it allow things that
would otherwise be an error. I'm open to adding more constraints.

|>  | <p:count>
|>  | <p:with-option name="my:option" select="'myvalue'"/>
|>  | </p:count>
|>  Nope.
| Yeah ! I do think the same, but don't see clearly where it is not
| allowed in the spec ...

That use of p:count does not match the signature of p:count.

   [Definition: A step matches its signature if and only if it
   specifies an input for each declared input, it specifies no inputs
   that are not declared, it specifies an option for each option that
   is declared to be required, and it specifies no options that are
   not declared.] In other words, every input and required option must
   be specified and only inputs and options that are declared may be
   specified. Options that aren't required do not have to be

|>  | c) ..or this ?
|>  | <p:count>
|>  | <p:pipeinfo>
|>  | <p:with-option name="my:option" select="'myvalue'"/>
|>  | </p:pipeinfo>
|>  | </p:count>
|>  That's legal. But it doesn't have any defined semantics.
| Same as above, am I allowed to change the behaviour of step with that
| p:pipeinfo ?

I don't think we say at the moment, but we probably should.

                                        Be seeing you,

Norman Walsh <ndw@nwalsh.com> | Even while a thing is in the act of
http://nwalsh.com/            | coming into existence, some part of it
                              | has already ceased to be.--Marcus
                              | Aurelius

Received on Monday, 12 May 2008 12:50:22 UTC

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