[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: John replies to Ron: Differences
Ron Bourret wrote: > Content models of PCDATA and EMPTY represent the terminals in DTDs. True, but not all data models have finite expansion. HTML does not, e.g. > That is, bold, italic, etc. have a PCDATA content model. Not typically. More likely, each would have a mixed model so that we can handle italic within bold and vice versa. 7A separate BI element could do that job otherwise, but that leads to a combinatorial explosion when there are six or seven appearance tags. > Furthermore, in more data (as > opposed to document) applications of XML, PCDATA-only content seems to be > relatively common. Perhaps true. But maybe that's a historical artifact due to there being no standard way to express rich text within databases. > For the moment, I have left PCData in and required Mixed to > take at least one ElementRef, per your earlier suggestion. Okay. BTW, it occurred to me today that SEQ and CHOICE (using my terminology) should be compelled to have at least two children, with content models <!ELEMENT SEQ ((CHOICE | REF), (CHOICE | REF)+)> <!ELEMENT CHOICE ((SEQ | REF), (SEQ | REF)+)> Otherwise, we have <CHOICE><REF name="foo"/></CHOICE> <SEQ><REF name="foo"/></SEQ> <REF name="foo"/> all with the same meaning. -- John Cowan http://www.ccil.org/~cowan cowan@c... You tollerday donsk? N. You tolkatiff scowegian? Nn. You spigotty anglease? Nnn. You phonio saxo? Nnnn. Clear all so! 'Tis a Jute.... (Finnegans Wake 16.5) 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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