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Re: removing/adding xmlns:xxx attributes

From: Geert Bormans <geert@gbormans.telenet.be>
Date: Wed, 05 May 2010 09:28:13 +0200
To: James Sulak <jsulak@gmail.com>,Romain Deltour <rdeltour@gmail.com>
Cc: xproc-dev@w3.org
Message-ID: <E1O9Z2J-0005Yb-EW@lisa.w3.org>
having to deal with DTD validation and XProc a lot myself,
I got used to the following approach:
I add a namespace-normalisation step prior to DTD 
validation (which is a simple XSLT)
this normalisation step is tied explicitely to the DTD
and it makes sure that
- I have a template explicit adding the namespace 
node (with correct prefix) for those elements 
that have the (pseudo)attribute xmlns declared in the DTD
- I have an identity copy template that 
implicitly removes all namespace nodes (by not copying them)
If it is OK for Saxon (read: if the XSLT sets 
them right), Calabash doesn't add or remove any 
nodes in serialisation, so DTD validation will go smoothly

The code for this is really straightforward, and 
I only have it available with customer namespaces in it,
but if you can't do the above proposed XSLT 
yourself, I am happy to make a mockup from what I have

To be entirely correct about how we deal with it, I only do this on delivery.
If we need to deliver XML that is valid according 
a DTD, this normalizer is the last step in the process.
Inside the pipeline we use RelaxNG or w3C schema 
variants of the DTD for internal validation
(as suggested earlier). In that case the 
namespace nodes will no cause any problems

cheers

Geert



At 20:52 4/05/2010, James Sulak wrote:
>Well, as I predicted, I stand corrected. :)  I thought the whole
>implied namespace binding would give just enough wiggle room to make
>xproc treat them as actual attributes (like the DTD wants to), but
>apparently not.
>
>
>
>On Tue, May 4, 2010 at 1:15 PM, Romain Deltour <rdeltour@gmail.com> wrote:
> >> That said, it seems like it should be valid to specifically add (with
> >> p:add-attribute) or match/delete (with p:delete) namespace declaration
> >> attributes.
> >
> > I don't think namespace declarations should be considered as attributes. By
> > the way the p:add-attribute step cannot be used to add namespace
> > declarations (see [err:XC0059]), the same for the p:delete (see
> > [err:XC0062]).
> >
> > [err:XC0059] http://www.w3.org/TR/xproc/#err.C0059
> > [err:XC0062] http://www.w3.org/TR/xproc/#err.C0062
> >
> > I assume the issue must be either dealt-with at serialization time or you
> > have to explicitly undeclare the "law" namespace on the 'chunk' element,
> > although I couldn't tell how to implement these approaches...
> >
> > Romain.
> >
> > Le 4 mai 10 à 18:54, James Sulak a écrit :
> >
> >> Hi Tom,
> >>
> >> Namespace cleanup is hard, especially when DTDs are involved.
> >>
> >> My technical understanding of namespaces isn't the best, but I think
> >> the root of the problem is that DTDs don't support namespaces
> >> properly.  (For way too much detail, see [1].)  In an ideal world, DTD
> >> validation wouldn't treat xmlns attributes as "real" attributes, and
> >> you wouldn't have a problem.
> >>
> >> That said, it seems like it should be valid to specifically add (with
> >> p:add-attribute) or match/delete (with p:delete) namespace declaration
> >> attributes.  From the namespace spec [2]:
> >>
> >> "The prefix xmlns is used only to declare namespace bindings and is by
> >> definition bound to the namespace name http://www.w3.org/2000/xmlns/.
> >> It MUST NOT be declared . Other prefixes MUST NOT be bound to this
> >> namespace name, and it MUST NOT be declared as the default namespace.
> >> Element names MUST NOT have the prefix xmlns."
> >>
> >> So if xmlns is implicitly bound to http://www.w3.org/2000/xmlns/, I
> >> would think that you could use the xmlns prefix to match the
> >> attributes.  In that case, it would be a bug in the processor that you
> >> can't.  But I'll leave it to more knowledgeable folks to tell me that
> >> I'm wrong :)
> >>
> >> [1] http://www.rpbourret.com/xml/NamespacesFAQ.htm#dtd_6
> >> [2] http://www.w3.org/TR/REC-xml-names/
> >>
> >> -James
> >>
> >>
> >>
> >> On Tue, May 4, 2010 at 11:09 AM, HILLMAN, Tomos <tomos.hillman@oup.com>
> >> wrote:
> >>>
> >>> Hi List,
> >>>
> >>> I'm wondering if anyone has a solution to the following problem:
> >>>
> >>> I'm writing a chunking script that takes one large document and filters
> >>> out particular 'chunks' - say //div1.  The document needs to be valid
> >>> against a declared DTD.
> >>>
> >>> The root element of the original document has an xmlns:law attribute
> >>> declaration for <law:extract> elements; 
> these may also occur multiple times
> >>> within each 'chunk'.
> >>>
> >>> Unfortunately, although the xmlns:law attribute is allowed both on the
> >>> original root element and the law:extract 
> element, it is not allowed on the
> >>> filtered elements by the DTD: however, this is where my xproc processor
> >>> (calabash under oxygen) adds them.
> >>>
> >>> How should I go about removing these attributes from the div1 elements
> >>> and add them to the law:extract 
> elements?  Trying to treat the elements as
> >>> simple attributes gives errors like 'xmlns namespace not declared'...
> >>>
> >>> Help!
> >>> Tom
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Received on Wednesday, 5 May 2010 07:28:57 GMT

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