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Re: p:for-each

From: Norman Walsh <Norman.Walsh@Sun.COM>
Date: Thu, 20 Jul 2006 10:31:54 -0400
To: public-xml-processing-model-wg@w3.org
Message-ID: <8764hs4aat.fsf@nwalsh.com>
/ Alessandro Vernet <avernet@orbeon.com> was heard to say:
| On 7/19/06, Norman Walsh <Norman.Walsh@sun.com> wrote:
|> A for-each looks like:
|>   for-each := ($over, $select?, $label, with-output, {body})
| Norm,
| In your proposed syntax, the 3 attributes related to the input are on
| <p:for-each>, while the attributes related the output are on an inner
| element <p:with-output>.
| I think that having attributes related to the input directly on the
| <p:for-each> but having attributes related to the output on an inner
| element is somewhat inconsistent. So I suggest we use 2 inner
| elements.

That's a good point. Because I had 'select' as an attribute it made
sense to me to have 'over' (or 'from' if you prefer) as an attribute.
But we could do

  for-each := ($select, $label, with-input, with-output, { body })

I suppose we could even say:

  for-each := ($select, input, with-input, with-output, { body })

but that might be more confusing rather than less.

| Also, just as we like to have a <p:with-output> which has a different
| element name than the pipeline <p:output>, I suggest we used different
| element names here: <p:for-each-input> and <p:for-each-output>. This
| makes it clear that a <p:for-each-input> is an input, but not exactly
| like the <p:input> and <p:with-input> (all those elements also accept
| different set of attributes).
| That gives:
| <p:for-each>
|   <p:for-each-input from="documents-to-import"
|           select="/xpath"
|           label="one-document"/>
|   <p:for-each-output label="sequence-of-errors"
|           from="error-for-this-document"/>

I see your point, but I'm not yet convinced. Given that for-each-input
can only occur inside a for-each, it seems entirely reasonable to me
to use the same element name ("input") and allow the context to
influence its definition.

                                        Be seeing you,

Norman Walsh
XML Standards Architect
Sun Microsystems, Inc.

Received on Thursday, 20 July 2006 14:32:06 UTC

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