architecture vs. XSL+DTD
Oliver Meyer
I'm wondering about the different uses of SGML (/XML?) architectures and
the use of XSL and an additional DTD.
As far as I understand it an architecture is a DTD (=DT declaration +
semantics) that is used by associating it with an XML document. Some
well defined (but I assume compared to XSL rather simple) mapping maps
elements in the XML documents to elements in the architectural instance.
The result is another XML document. Its validity can be tested against
the architecture.
It seems to me, that I can do the same (and more) with XSL. Transform
XML document to architectural instance (I have to specify the mapping
anyway) via XSL-document and validate the result against the
architecture DTD.
-- Architectures are more specific in there uses than XSL and therefore
might be supported by more processors (Validators, Editors?).
-- The default mappings may help to specify the mapping in an easier an
shorter way than by using XSL.
-- There is no defined way to specify this use of XSL+DTD, but
architectures are will defined.
I'd like to hear some more opinions on this subject.
Bye, Oliver
Charles F. Goldfarb
You make a lot of good points in your posting. Here are a few more ideas to
consider:
-- From the standpoint of data modeling (as opposed to processing) architectures
introduce inheritance to DTDs. The mapping from the XML instance elements to the
architectural element types is a derivation. This brings OOPS-like modeling to
XML schema design. Your "department address" element can be derived from a more
general "address" element type.
-- The client (derived) documents can be processed by systems that know nothing
of architectures.
Chapter 9.3 of David Megginson's "Structuring XML Documents" describes some
practical benefits of architectures that you may find interesting.
Charles Goldfarb
--
Charles F. Goldfarb * Information Management Consulting * +1(408)867-5553
13075 Paramount Court * Saratoga CA 95070 * USA
International Standards Editor * ISO 8879 SGML * ISO/IEC 10744 HyTime
Prentice-Hall Series Editor * Definitive XML * Open Information Management
--
Oliver Meyer
> Oliver,
>
> You make a lot of good points in your posting. Here are a few more ideas to
> consider:
Thanks. I'm honoured.
> -- From the standpoint of data modeling (as opposed to processing) architectures
> introduce inheritance to DTDs. The mapping from the XML instance elements to the
> architectural element types is a derivation. This brings OOPS-like modeling to
> XML schema design. Your "department address" element can be derived from a more
> general "address" element type.
Can't I do the same with XSL?
> -- The client (derived) documents can be processed by systems that know nothing
> of architectures.
As is the case with the result tree of an XSL-Processing, if the result is again in
XML.
Didier PH Martin
The problem is that XSL is XML and actually XML has no architectural forms
provisions. However, we can say that because XML is SGML derived then we can
also support architectural forms. But XSL processors do not support
architectural forms here is why:
a) to fully support architectural forms could be mapped to your own markups
and then you have your own tags with the behavior of the architectural form.
But you need a processor that can recognize the the markup named XXXX is of
form YYYYY so that a style engine can then match this element to YYYYY
element instead of XXXXX. Actually most XSL processor which are not
architectural form aware would instead match to XXXX, which is the markup in
your document but not the architectural form markup.
So, a architectural form aware parser and style engine can go further and
know that a certain tag is in fact the same as a markup from a particular
architecture. This is how, Hytime and Topic maps *(which also uses Hytime)
architectural form could be processed.
Actually only dsssl style processors are architectural form aware but not
XSL. Not until W3C includes Architectural forms which at that time we'll end
up with SGML having a new name :-) (XML)
Most actual XML parsers are not architectural form aware except SP which is.
Regards
Didier PH Martin
mailto:mar...@netfolder.com
http://www.netfolder.com
Oliver Meyer wrote:
> Hi!
>
> I'm wondering about the different uses of SGML (/XML?) architectures and
> the use of XSL and an additional DTD.
>
> As far as I understand it an architecture is a DTD (=DT declaration +
> semantics) that is used by associating it with an XML document. Some
> well defined (but I assume compared to XSL rather simple) mapping maps
> elements in the XML documents to elements in the architectural instance.
> The result is another XML document. Its validity can be tested against
> the architecture.
>
> It seems to me, that I can do the same (and more) with XSL. Transform
> XML document to architectural instance (I have to specify the mapping
> anyway) via XSL-document and validate the result against the
> architecture DTD.
>
> -- Architectures are more specific in there uses than XSL and therefore
> might be supported by more processors (Validators, Editors?).
>
> -- The default mappings may help to specify the mapping in an easier an
> shorter way than by using XSL.
>
> -- There is no defined way to specify this use of XSL+DTD, but
> architectures are will defined.
>
> I'd like to hear some more opinions on this subject.
>
> Bye, Oliver