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From: David Megginson <david@m...> >That same issue might be what keeps DTD syntax alive for simple uses >-- sure, DTDs aren't all that powerful compared to most of the new >proposals out there, but it's compact and easy to parse and it doesn't >require you to process yet another XML document (it's also supported >by lots of existing software and is backed up by approved ISO and W3C >specs). Furthermore, I think there is human factors element involved: when there is a change in domain, (at least some) people expect or need this to be flagged by using a difference syntax. When the data is highly cohesive, it is natural to couple it syntactically to distinguish it from the markup in which it is embedded. I think it is a really important design principle, and too easily dismissed. It helps explain * why are URLs not factored out into attributes? & * why are scripting languages not in instance notation? & * why are the patterns in XSL not in instance notation? & * why don't people like LISP syntax (i.e., does the unified syntax actually cause reading panic in newcomers: it has been widely commented that computer languages with different syntaxes each for assignment, declarations, infix maths, and prefix functions, such as C and ALGOL family languages have been much more successful)? Apart from that, there is an issue of the perceived cost-benefit of metadata (i.e. schemas) compared to data. If I have a 1K Docbook instance and a 600K Docbook Schema in instance syntax, it is a strong dissuader against using that schema. So I don't think that terseness is of minimal importance for schemas: appropraite balance to the size of the instance is, however. There is also clearly some contradictory factors at work too: some people feel saturated with too many little language and love a unified syntax. You can see their personality, in this regard, reflected in the DTDs they write. Rick Jelliffe 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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