[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: A Line in the Declarative Syntax Sand(Was: XML complexity, namespace
From: David Megginson <david@m...> >You're modelling exactly the same information about the picture in >both -- data attributes provide an alternative mechanism for modelling >the information, but they do not allow you to represent anything that >you could not represent without them. Except that the SGML example gives the attributes as belonging to the thing pointed to (the entity) and not the particular invocation. In the XML version, there is nothing to say that the attributes belong to the thing pointed to rather than at the invocation. For example, take the common case of where the entity has a size (natural size) and the element also has size attributes (scaled size). Surely the equivalent XML to the SGML examples given is really: <doc> <photodef id="p1" href="pic1.png" notation="text/png" width="300" height="200" depth="16" type="I point to some object called an NDATA entity" content-model="I must be empty" addressing="don't count me as an element when doing treeloc" /> <photo href="#p1" /> </doc> (and perhaps the photo element should not be simple link) The information modelled does not only include the elements and attributes but also the structure, and the fact that an entity is labelled as an entity, which have different addressing rules. In the absense of XML having conventions for the last three attributes, I dont think one can say that one can model everying that SGML models using XML. 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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