Simplifying namespace declarations

09-18-2007

Hi.

I would like to simplify the namespaces declarations, something like that:

<html xmlns="http://www.w3.org/1999/xhtml">
<html:em xmlns:html="http://www.w3.org/1999/xhtml">foo</html:em>
</html>

must become:

<html xmlns="http://www.w3.org/1999/xhtml">
<em>foo</em>
</html>

That is: the em element is already in the XHTML namespace, there is no need
to re-declare the namespace nor to declare the element.

Can someone suggest how to do it efficiently/easily, preferably with
libxml2?

Thanks.

09-19-2007

Nicolas George wrote:

> I would like to simplify the namespaces declarations, something like that:
>
> <html xmlns="http://www.w3.org/1999/xhtml">
> <html:em xmlns:html="http://www.w3.org/1999/xhtml">foo</html:em>
> </html>
>
> must become:
>
> <html xmlns="http://www.w3.org/1999/xhtml">
> <em>foo</em>
> </html>

An XSLT stylesheet as the following could help:

<xsl:stylesheet
xmlns

sl="http://www.w3.org/1999/XSL/Transform"
version="1.0">

<xsl:template match="*">
<xsl:element name="{local-name()}" namespace="{namespace-uri()}">
<xsl:apply-templates select="@* | node()"/>
</xsl:element>
</xsl:template>

<xsl:template match="/ | @* | text() | comment() |
processing-instruction()">
<xsl:copy>
<xsl:apply-templates select="@* | node()"/>
</xsl:copy>
</xsl:template>

</xsl:stylesheet>

--

Martin Honnen
http://JavaScript.FAQTs.com/

09-19-2007

Martin Honnen wrote in message
<46f111a5$0$4534$>:
> An XSLT stylesheet as the following could help:

Thanks. I was hoping for something more straightforward and integrated, but
it seems that it does not exist; that's a shame. I will use either this XSLT
stylesheet or a similar mechanism directly in my program.

09-19-2007

Nicolas George wrote:
> Thanks. I was hoping for something more straightforward and integrated

I think the straightforward solution would involve hand-coded SAX
processing, maintaining a stack of which namespaces are in scope.

BUT: Beware. Remember that in some XML languages, prefixes may appear in
the document's text context as well -- XSLT is an example of that, of
course -- so determining which namespace declarations are "redundant"
can be a MAJOR undertaking, requiring deep understanding of the
document's semantics. Reducing _use_ of prefixes may be doable -- but
you'd better plan on retaining all their declarations unless your
application knows *exactly* what kind of data it's processing and where
the hazards may be.

--
Joe Kesselman / Beware the fury of a patient man. -- John Dryden

09-19-2007

Joseph Kesselman wrote in message <46f195ac$1@kcnews01>:
> I think the straightforward solution would involve hand-coded SAX
> processing, maintaining a stack of which namespaces are in scope.

I already have a full DOM tree. As I have mentioned, I am working with
libxml2.

> BUT: Beware. Remember that in some XML languages, prefixes may appear in
> the document's text context as well -- XSLT is an example of that, of
> course -- so determining which namespace declarations are "redundant"
> can be a MAJOR undertaking, requiring deep understanding of the
> document's semantics.

I was made aware of the problem. Fortunately, the document I am trying to
simplify is no more than XHTML.

09-20-2007

Nicolas George wrote:
> Joseph Kesselman wrote in message <46f195ac$1@kcnews01>:
>> I think the straightforward solution would involve hand-coded SAX
>> processing, maintaining a stack of which namespaces are in scope.
>
> I already have a full DOM tree. As I have mentioned, I am working with
> libxml2.

OK, then an the straightforward solution would be a DOM tree-walk, again
maintaining a stack of which namespace bindings are in scope and
modifying the tree as you go. Or rework the DOM serializer to do this,
if you're only concerned with the generated XML syntax.

--
() ASCII Ribbon Campaign | Joe Kesselman
/\ Stamp out HTML e-mail! | System architexture and kinetic poetry

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