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>Ray Waldin wrote: >> Of all the answers I've received, the ones referring me to SGML publications were the >> most intimidating Marcus Carr replied: >The question was related to a philosophical issue that has been hashed out by SGML >people for ten years now, and that applies directly to XML as well. I think Marcus is wrong. The domain of application of SGML is different from the domain of application of XML, and the distinction between attributes and content which made sense in the SGML world is extremely perplexing to those with a background in data modelling and data structure design in other domains, who are legitimate members of the XML community. Philosophically - at least in terms of any ontological system I am aware of - it is a nonsense, and can be justified only in terms of pragmatic assumptions about information in the form of paper documents. We have a very non-orthogonal design where (as someone pointed out) you need content for some things, you need attributes for others, in some cases you can use either, and in some cases neither does the job very well (e.g. storing a date). I will resign myself to accepting XML as it is, but to suggest that its deficiencies are there because SGML gurus decided ten years ago that they were a good thing is unhelpful and not particularly flattering to the SGML gurus, who designed it that way for a different purpose. In the DTD I've been designing, for what it's worth, I'm currently using content for nearly everything, with very little use of attributes. The main reason is for future extensibility; elements can always acquire a richer internal structure, while attributes can't. The drawbacks (e.g. inability to specify any constraints on values, default values, etc) don't actually lose me much, because the constraints available for attributes are very limited anyway. Mike Kay, ICL M.H.Kay@e... 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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