[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] The *hard* problem (was: external dtd subsets ...)
Tim Bray scripsit: > I have not suggested a solution for > how to solve the *hard* problem, namely how to go about making a > compound DTD, and would like to hear input on that. -Tim As far as I can see, such a thing is not possible even in principle, except through the promiscuous use of ANY content models. Given that you want to combine two separate DTDs, {A} and {B}, with or without prefixes, initially only {A} elements will be permissible content for other {A} elements, and likewise for {B} elements. So whatever the root element of a document may be will dictate what elements are to be used within it. In order to make this otherwise, someone must decide exactly which elements from {A} can have {B} content and vice versa. That is inherently beyond the ability of an algorithmic process unless it has detailed semantic information on the elements, *far* beyond what any DTD provides. IBTWSH uses a trick, a parameter entity that a containing DTD may define in order to specify elements from the containing DTD that can appear within IBTWSH elements. But average DTDs don't have such a mechanism, and it may not even be possible. (Nonetheless, this trick suggests how DCD/XML-Data elements with "open" content might be translated back into DTD element declarations. -- 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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