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Re: [xsl] namespace values


Subject: Re: [xsl] namespace values
From: "Jonathan Borden" <jborden@xxxxxxxxxxxx>
Date: Tue, 13 Mar 2001 14:26:11 -0500

Kevin,

>
> Can namespaces contain  values? Is it possible to store these values in a
> URI?
>
>  I am under the assumption it can not but because the URI doesn't even
> really need to exist but I thought that maybe if it does exist you could
> put values or definitions  inside it.
>

You've hit upon the heart of the issue. The W3C XML Namespace recommendation
left open the possibility that a namespace name, being a URI reference,
might be dereferenced. It did not say what need or ought be returned when
dereferencing a namespace name.

RDDL http://www.rddl.org/ was created explicity as *an* answer to this
question. As you say assuming that "if it does exist you could put values or
definitions inside it". What form ought these values and/or definitions
take?

RDDL says that these definitions should be readable in browsers (hence based
on XHTML Basic) as well as be readable by programs (hence XLinks). That's
it, it really is very simple.

Since this is the XSLT list, I'd like to highlight several which I think are
particularly relevent to XSLT.

Leigh Dodds suggested that RDDL might be used to cobble together transforms.
For example suppose you want to transform format A -> format C, but don't
have a transform to do this. You might find a transform for A -> B (i.e. in
the RDDL document for A) and one for B -> C (in the RDDL document for B) and
then pipe A -> B -> C. Leigh has suggested that the "purpose" of an XSLT
ought be the resulting format (i.e. "nature"). Using this convention such
compilation of transforms is possible.

The EXSLT is another example. James Clark created the precedent in XT for
using a namespace URI to bind to a particular external code format (i.e.
Java classes in XT's case). EXSLT provides a mechanism that enables the
creation and binding of *language neutral* external functions. By inserting
resources referencing implementations in various languages (e.g. python,
java, c#, javascript etc) XSLT implementations can bind to the EXSLT
functions in a language neutral fashion. This enables language neutral XSLT
stylesheets that use external functions to be created.

Jonathan Borden
The Open Healthcare Group
http://www.openhealth.org



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