Re: Extensibility questions

On Mon, May 12, 2008 at 2:49 PM, Norman Walsh <ndw@nwalsh.com> wrote:
> / "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.

I think we will need to take a look at...

>
>
>  |>  | <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
>    specified.

Thanks for the pointer !
Does it mean that there is no constraint on parameters or outputs ?

>
>
>  |>  | 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.

Probably

Mohamed
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Received on Monday, 12 May 2008 13:34:39 UTC