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Re: Issue #3306

From: Erik Bruchez <ebruchez@orbeon.com>
Date: Mon, 05 Jun 2006 18:47:25 +0100
Message-ID: <44846E2D.3050602@orbeon.com>
To: public-xml-processing-model-wg@w3.org

Jeni Tennison wrote:

 > I think there are two separate questions here:
 >
 > 1. Can components return as an output the same (unmodified) document
 > that it receives as input, or must it always copy any documents it
 > receives? It might be more efficient for implementations if
 > components like 'filter', 'union' and 'identity' didn't have to
 > create copies.

I think this is an implementation detail.

If not, what is the visible difference between copying and not
copying?

 > 2. Can a document sequence contain the same document twice?

This can only be answered if you answer the following question: what
is "the same document".

Certainly, we won't require that implementations compare the documents
produced by steps. So we can't mean that the documents are identical.

The logic could work if all the documents in a pipeline are identified
uniquely by a URL. But then, how would this work as a step produces
multiple documents dynamically? Does it have to assign a new URL to
each document produced? And what would be the benefit of doing this?

Barring a good model for this part, my answer would be "no, a document
sequence cannot contain the same document twice".

-Erik

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Received on Monday, 5 June 2006 17:47:32 GMT

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