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Re: text nodes of document in XDM

• From: David Carlisle <davidc@nag.co.uk>
• To: xml-dev@lists.xml.org
• Date: Tue, 11 Jan 2011 09:31:29 +0000

On 11/01/2011 03:17, David Lee wrote:

> Q) Why does XDM allow text() children of document nodes, and in fact
> allow multiple element children of document nodes (If I read it right …)
>
> For example in XQuery this is allowed
>
> document { text { "text" } , <elem1/> , text { "text2" } , <elem2/> }
>
> I'm wondering what is the use-case that led to this ?
>
> My best "clue" is a recent question/response on xslt-list which made it
> clear to me that <xsl:variable> produced a document node, but it could
> contain parentless text nodes
>
> I certainly understand the desire for XDM to allow parentless text,
> element, and attribute nodes …
>
> but I don’t understand the use case for document nodes containing text
> and multiple element nodes …
>
> Am I correct in presuming this is to support XSLT 1.0 (and perhaps by
> inference XQuery 1.0 ) which allowed this ?
> Is it a chicken&egg problem ?
>

in both xslt 1 and 2 the common construct
<xsl:variable name="x">
foo
<bar/>
baz
</xsl:variable>
creates a document node with three children, two text nodes and an element.

However XDM supports this not just for xsl:variable, xslt/xquery are 
designed to produce not only xml documents but what the xml rec calls 
external parsed entities, and a document node that can take text or 
multiple element children is exactly what you want for an external 
parsed entity.
> What is the rationale for allowing document nodes to contain children
> which are not parseable from Text XML ?
>
> Is this a critical feature to maintain in a round-trip XDM serialization
> specification ? ( Yes I realize I'm asking for an opinion not an
> objective fact).
>
> Thanks for any advice, opinions, or historical anecdotes.
>
> -David
>
>

David

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