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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: groves dissent (was RE: RFC: Attributes and XML-RPC)
 [Matthew Gertner:] > ... HyTime throws out too many hard-to-understand concepts at > once. The linking model is hard to understand. Groves are hard to > understand. Architectural forms are hard to understand. Throwing > these together in a 1000 page document is not a recipe for > commercial success. It seems to be an unambiguously good thing that > these concepts are now being split into bite-sized chunks in the > process of transfering them into an XML context. I have no choice but to agree with you (and believe me, it has been difficult for me to stomach this particular reality). I *would* rather have it all broken into bite-sized chunks, if that's what it takes. I only hope we can put Humpty Dumpty back together again later. (By "Humpty Dumpty" I mean the meticulous balance with which all the concepts of component addressing, re-use, and semantic assignment fit together seamlessly, consistently, and with minimum implementational redundancy in the HyTime family of information architectures.) Indeed, the problems I have with XML Namespaces all have to do with the fact that there are ways of using XML Namespaces that will create unnecessary -- and maybe even insuperable -- difficulties for those who will have to put Humpty back together again. XML namespaces, as presently defined, are widely (and perhaps unconsciously) regarded as meeting the same requirements that the architectural forms paradigm (inheritable DTDs) already meets. Some Very Influential People at W3C are on public record as believing/expecting XML namespaces to meet the same requirements that are met by the architectural forms paradigm, even though the Namespace Rec correctly makes no claims that Namespace paradigm can meet any of the same requirements that the architectural forms paradigm meets. Architectural forms, which are presently formally representable only via the hoary and suboptimal (but at least standard) DTD syntax, *do* meet those requirements. Architectural forms already work perfectly with XML, as I demonstrated last February at XTech 1999, and as Eliot Kimber and others described at Metastructures 1999 last August in Montreal. In my public speaking lately, I've been urging all my listeners to pray for the XML Schemas committee, which has a very hard job to do, and which is trying to do it under circumstances which are, well, trying. Although I am not privy to the discussions in that committee, I detect stronger and stronger linkage between XML Schemas and XML Namespaces in the information that W3C chooses to publish about that project. If XML Schemas only affect XML Namespaces, or if they are totally dependent on XML Namespaces... well, I don't like to think about it. Many systems and industries will stick with DTDs and architectural forms, because they work. Architectural forms allow the "finger of blame" (for failures of information interchange) to be pointed, even when there is local control of the DTD, and they allow all elements and attributes to have any names at all, while still being automatically recognized as architectural forms. Anyway, I'm still hoping that the XML Schemas committee * will act favorably on its recognition of the importance of being able to validate the use of vocabularies in instances, * will harmonize all the concepts of DTDs, namespaces, and inheritable architectures in XML Schemas, creating a single schema syntax that will accomplish that goal, so we can say good-bye to DTD syntax at last, and start using something much richer, much more convenient, and much more helpful in promoting the reliability of information interchange in a system-vendor-neutral fashion, and in a multi-system-vendor environment. It may not be easy to design that syntax, but I see no technical reason why it's not doable. It's also pretty obvious that the schema language itself should be formally modeled and expressed in its own syntax. (On the way to that goal, some bootstrap problems can be solved by using the old DTD syntax.) I believe that Paul Prescod's "Hedge Automata" presentation at Metastructures 1999 should be well-understood by whoever's trying to design the long-awaited XML Schemas recommendation. There is hope that the formal expressions of architectures (vocabularies) can be validated for conformance to their base architectures (their inherited vocabularies). The ISO architectural forms paradigm only permits *instances* to be validated against their base architectures (inherited vocabularies), not *DTDs*. While this is not a weakness that diminishes the usefulness of architectural forms, it would be very nice to be able to validate the formal expressions (such as DTDs or other schemas) of architectures against the formal expressions of the architectures that they declare themselves to be based on. For example, it would allow people who are trying to design DTDs that declare themselves to inherit from one or more base architectures to have a tool that will detect inconsistencies between the DTD that they are writing, and the base architectures from which they wish to inherit certain architectural forms. > (BTW: I have to make a big plug for Paul Prescod's July99 grove > tutorial. After reading this I *finally* feel like I understand what > the #%@$! a grove is. Great work Paul! If you are trying to > understand groves without reading this, don't torture yourself.) Good advice. Paul's tutorial can be found at http://www.prescod.net/groves/shorttut/. -Steve -- Steven R. Newcomb, President, TechnoTeacher, Inc. srn@t... http://www.techno.com ftp.techno.com voice: +1 972 231 4098 fax +1 972 994 0087 pager (150 characters max): srn-page@t... 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/ 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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