Re: Again wit da AND and Repetitions / Singletons in a DTD
At 11:50 AM 5/17/99, roddey@u... wrote: >>>But I guess the & syntax from SGML is deceptively simple. I don't >>>completely follow that other thread, but I gather it's hard to implement >>>which is probably why they left it out of XML. >> >>No, it is not particularly hard to implement support for the AND connector >>in a validating parser. However, the AND connector is redundant, as one can >>express the same using the other connectors (although not very elegant). >> >>For example, take the content model (A & B & C) expressing that we require >>the three elements in any order. Here is the XML equivalent content model: > > [snip] > >>However, there are better ways of implementing support for AND connectors >>than to convert AND content model into such tree structures. Simply make >>the parser keep track of which elements in the AND list have not yet been >>parsed. For each element encountered, remove its item from the list. Signal >>an error if the parser encounter an element not in the list of remainders, >>unless all of the remainding elements in the list are optional. Repeat >>until the list is empty or a parsed element is not in the list and all >>remainders are optional. > >But that ignores the issue of what happens when an AND connector is embedded >deeply with some very complex content model that is otherwise totally a >straight >XML type DFA! Do you then give up on doing a DFA for the entire content model >when that happens? If not, then how do you do it? If you do, then its not >terribly simple to do and its definitely not terribly quick. This gets back to >my original question of how to deal with AND. Please provide an example of such a complex content model that includes use of AND, simplified as much as possible while still demonstrating your point. -- Terje <Terje@i...> | Media Design in*Progress Software for Mac Web Professionals at <http://www.in-progress.com> Take advantage of XML with Emile, the first XML editor for Mac. 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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