[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Object Hierarchie with XML
[Cécile Baille-Pierre (cecile.baille-pierre@b...):] > > But how simply implement a class hierarchy, i.e "element E is > > derived from super-Element S and inherit attributes and properties"? [Andrew Layman (andrewl@m...):] > A type hierarchy would use a vocabulary (schema) designed for that > purpose. Such vocabularies are not presently part of XML per se, > though you can find type-hierarchy concepts discussed in several > papers, such as those at the W3C RDF site and in a paper that I > co-authored, > http://www.w3.org/TR/1998/NOTE-XML-data-0105/Overview.html. In fact, this capability is already available to XML users, by virtue of the fact that the derivation of object types from one another is provided by ISO/IEC 10744:1997 for SGML in general, and this standard has been amended specifically to allow XML's use of these concepts by means of an XML-legal PI-based declaration syntax. There is literally nothing to prevent the adoption and use of this facility by anyone, regardless of whether W3C chooses to acknowledge that this internationally standardized facility exists. The idea of object type inheritance is far too useful for XML users to ignore it forever. As the ISO 10744 "enabling architectures" facility demonstrates, it is not necessary to create a special DTD syntax or a special kind of schema to support hierarchies of element type inheritance. What is needed is a way to inherit the semantics and structure of any element types of any DTDs (schemas), regardless of whether they were intended to be inherited. That kind of functionality (among others) is supported by this facility. There is a pointer to the relevant standard at http://www.hytime.org. When you get there, look in the table of contents for Annex A. A.3 ("Architectural Form Definition Requirements [AFDR]") is where the "enabling architectures" facility is described. -Steve -- Steven R. Newcomb, President, TechnoTeacher, Inc. srn@t... http://www.techno.com ftp.techno.com voice: +1 972 231 4098 (at ISOGEN: +1 214 953 0004 x137) fax +1 972 994 0087 (at ISOGEN: +1 214 953 3152) 3615 Tanner Lane Richardson, Texas 75082-2618 USA 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/ 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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