Re: [xsl] identity transform - include CDATA's, etc

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Abie,

As we often have to point out on this list, XSL engines do not work on a 
file or a sequence of characters, but rather on a data object (an "XPath 
tree") that represents the XML document tolerably well for many purposes, 
and extremely well for the purposes for which it was designed.

Accordingly, an XSLT "identity transform" does not and cannot work to 
create a character-by-character mirror of an input file ... it's the result 
tree that's identical to the source (tree). For better or worse, the 
difference between (say) "& lt;" (pls remove fooler-space) and 
"<![CDATA[<]]>" is not represented in the model, so these cannot be 
distinguished by the processor or represented differently in the output.

Whether it's a "true" identity transform is a matter for metaphysical 
debate. :-> But if you need character-for-character fidelity, XSLT isn't 
the tool for the job.

Cheers,
Wendell

At 03:58 PM 6/26/2003, you wrote:
> I saw an identity transform on msdn online that goes like this:
>
> <?xml version="1.0"?>
> <xsl:stylesheet version="1.0" 
> xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; >
>
>  <xsl:template match="/ | @* | node()">
>    <xsl:copy>
>      <xsl:apply-templates select="@* | node()"/>
>    </xsl:copy>
>  </xsl:template>
>
> </xsl:stylesheet>
>
> however this is not a true identity transform since CDATA sections 
> enclosed in the original xml document in <![CDATA[ ]]> is output as 
> regular characters.  I don't know if there are other elements besides 
> CDATA elements that also don't get translated truthfully.
> can someone suggest a new identity template that will render the output 
> based on the input exactly as if one were to issue a 'copy' command at a 
> dos prompt, or at least get closer to it than the template above?
> eg:
> <?xml version="1.0"?>
> <docroot>
>   <element id="a"/>
>   <![CDATA[ this is cdata ]]>
>   <element id="b"/>
> </docroot>
>
> should become:
> <?xml version="1.0"?>
> <docroot>
>   <element id="a"/>
>   <![CDATA[ this is cdata ]]>
>   <element id="b"/>
> </docroot>


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.                http://www.mulberrytech.com
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Suite 207                                          Phone: 301/315-9631
Rockville, MD  20850                                 Fax: 301/315-8285
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