[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Another look at namespaces
-----Original Message----- From: David Megginson <david@m...> >Tim Berners-Lee writes: > > > What happens when a version one program meets a version 2 document? > >As Tim points out, this is (or at least, should be) >application-specific. I have omitted his summary, but I agree with >its broad outlines. I'm not sure what you mean by "application -specific". If you mean that one is entitled to do feed a document into any app program and depending on what the program does anything can happen, and be taken as a valid interpretation of the document, then no! My point was that the combination of the document and the definition of the language it is written in have a certain meaning and that nothing must be allowed to produce a different (contradictory or superset) meaning ostensibly from the original document. >Unfortunately, I think that Tim B-L and Paul Prescod are wasting a >little of their typing preaching to the converted; Good. Then my message can be consided a summary I guess. > we all (or at >least, most of us) agree and always have agreed that the following are >basic requirements for dealing with Namespaces: > >1. An application must be able to determine the general language used > by (part of) a document. >2. An application must be able to determine the specific dialect used > by (part of) a document. >3. An application must be able to locate schemas, stylesheets, and > other materials related to a language (or dialect). Here you introduce a distinction between a "general language" and a "dialect". I am not convinced that this is a well-defined concept. I feel that language subsets are completely well defined, by the change of namsespace preserving validity. What is the definition of a "dialect"? To me, nesting a level of naming of "version" inside a "general" language suggets that nothing at all is really known about the general langauge. >What is contentious is not whether these three requirements are real, I'm not currently accepting the concepts on which they are based. [...] If as I fear, the "general language" refers to some approximate similarity then I would not want one single ecommerce application or data-in-xml application to use the concept. A langauge is a language IMHO. I think that you can in fact crystalize the concept of "general language" by specifying a set of languages which are all subsets of a given language L. So for example if you define xHTML-all as a language whose document content model accepts any strict or transitional or frameset document, then you can use that namespace for refering any xHTML document. You now have a clean definition of validity, and well-defined compatability rules. >b. the applications concerned only with #1 will tend to be the > lightest-weight ones. I do not believe that lightweight applications will just be fuzzy. You can imagine them for simplicity just advertizing a few superset languages as things they accept. I would not be in favor of anything which made the precise definition of the language in which a document was written anything other than a URI. You can introduce more metadata about a namespace and enrich the world, but let's keep a namepsace a namepsace as identified by the namespace URI. >We mustn't make easy tasks difficult for the sake of theoretical >purity -- I know, because we tried to do that over and over again in >the SGML world, and, well, we're not debating SGML any more, are we? I hope not. But in general simplicity tends to make easy tasks easier. If it didn't happen in the SGML design I who was not there cannot comment. You can in general optimze things which are well defined cleanly. Tim BL 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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