[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Sequence <was> Access Languages ...
On Sun, 23 Nov 1997, Rick Jelliffe wrote: > > From: Mark L. Fussell <fussellm@a...> > > I am not saying sequence is unimportant, but I think SGML is overly > > focused on it (from an IM perspective) because it comes from a > > paper/linear background. Information is rarely linear: it is only time > > that is, which has caused some media [and the humans who use them] to be > > (mostly) linear also. It can be difficult to break that linear > > assumption when it doesn't apply if your tools keep reinforcing it. > > But do you think HTML would have become a popular markup language if its DTD > was like this? > > <!ELEMENT html > ( h1*, h2*, h3*, p*, I*, table*, tr*, td*, th*)> > > > This is reductio ad absurdum of what you are saying. A DTD where all > sequence information is made explicit. I certainly wasn't trying to say that sequencing should be removed but just that it can be difficult to see when it doesn't apply. Sometimes information is (at least dominantly) organized as a sequence: Ordered Sections contain Ordered Paragraphs. Sometimes information does not inherently need to be sequenced but the application would like it to be so it does not need to worry about ordering it at presentation (I am thinking of a list of citations where there is a natural ordering [by one of the columns/attributes of a citation]). And a variation of this case is: sometimes it is just easier for people to take direct control than to do informational markup. I think HTML and Word Processors represent this end of the spectrum. > If people just want a database dump format for nice relational tables, > comma-delimiter formats are available and attractive. But when they have > text which they don't want to have desequenced, SGML/XML can be useful. Well, I guess I have larger visions of what SGML/XML can do, and I think it is within (or at most a mild extension) of the original vision. Requoting [Goldfarb 90, A.2.40]: --- Generalized markup is based on two novel postulates: a) Markup should describe a document's structure and other attributes rather than specify processing to be performed on it, as descriptive markup need be done only once and will suffice for all future processing. b) Markup should be rigorous so that the techniques available for processing rigorously-defined objects like programs and databases can be used for processing documents as well. --- SGML is designed to describe information, and although the original vision may have been focused on describing documents I believe that was just because it was the particular task at hand. > ... Just folks can write > HTML, at a pinch. If you go too much to a database mentality, you move > to requiring custom-tools for data entry, rather than simple text-editors. No argument that HTML is easier for novices to directly write than more structured information, but that also applies to any of the more sophisticated DTDs. The benefit of a human-readable and human-understandable encoding like SGML/XML is that people can progress from simple DTDs like HTML to more complex ones and still understand what is going on. I have done this with web-site development where content writers now use a "real" DTD that allows generation of different HTML views (and more sophisticated linking... etc.) And I do agree that accurately modeled information (e.g. normalizing in a RDB context) can make it too hard (for the desired writes) to enter data directly. It is likely that some SGML/XML DTDs will be designed to contain all the necessary information with explicitly desired redundancy and artificial sequencing but with the assumption that the processing will later remove them on the way to the information model. This is almost exactly what UI Forms and relational views are doing. So I don't want to get rid of sequence, I just believe people should think twice about it and assertain whether it is really part of the information and is the best way to represent that information. --Mark mark.fussell@c... i ChiMu Corporation Architectures for Information h M info@c... Object-Oriented Information Systems C u www.chimu.com Architecture, Frameworks, and Mentoring 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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