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David Megginson wrote: > > Sean Mc Grath writes: > > > This is an interesting thread. Many non-tag-minimization > > reliables can be put forth as things that SGML "can do" that > > XML cannot. Things like data attributes, exclusion exceptions, > > internal SDATA entities and so on. > > I think that I agree with what Sean is saying here and later in the > message -- think of *what* you can represent rather than *how* you > represent it. That representation alone isn't good enough -- standardization is also important. Here's what I heard Sean saying: * SGML favours globally standardized declarations over locally maintained custom code. * XML restricts the number of globally standardized declarations in favor of locally maintained custom code. In other words: SGML favours standarization and XML favours one-off system-specific ad-hocery. If I really believed that then I would drop XML and advise my customers not to use it. XML removed certain specific declarative features of SGML that were either not used enough or could be added in at another level. But little by little XML is becoming more and ore declarative through other layers like XLink, XSL, RDF and XML Schemas. The move towards declarativeness and away from ad hoc code is precisely XML's gift to the Web. Standardized declarativeness is the real XML revolution. XML just happens to be the syntax. Let me demonstrate that XML is also standard declaration-focused by turning around the "notations" example. The SGML way was to declare a notation and have a second level validate that the data adhered to the notation. Unfortunately, we never really standardized a decent declarative syntax for the second level. In other words, SGML was not declarative *enough*. XML, on the other hand, will likely have a mechanism where notations can be declared in the schema (under the title of "user-defined data types"). So the XML family will have a more powerful, standardized, declarative mechanism which will reduce the need for maintaining custom code. The declarativeness baton has been passed from SGML to XML. Custom code is the enemy. We will always need it but we must continue to relegate it to more and more complex or esoteric problems. -- Paul Prescod - ISOGEN Consulting Engineer speaking for only himself http://itrc.uwaterloo.ca/~papresco "Perpetually obsolescing and thus losing all data and programs every 10 years (the current pattern) is no way to run an information economy or a civilization." - Stewart Brand, founder of the Whole Earth Catalog http://www.wired.com/news/news/culture/story/10124.html xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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