[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Inheritance using DTDs
Hi, The more I look into it, I don't see DTD's as an efficient way to support inheritance. The use of internal subsets seems just a workaround. The use of parameter entities and the INCLUDE and IGNORE statements require too much collaboration between the interested parties. I guess you could make every element and attribute an entity, but that does not seem appropriate. Also, as stated, inheritance at more than one level is especially difficult. For instance, how would I implement the following type of an N-deep object for a memo: Let's say a memo is maintained as an industry standard DTD of (header, body, trailer), each of these having their own subelements. Now, an individual firm will use this DTD, but wants to simply extend the header element for internal needs, and reuse the other subelements without having to redefine those. Then, a department within that firm wants to tack on its own attributes to one of the header elements, again, reusing the base definition, and not having to redefine it as part of an entity. This can continue to a group within the dept., and finally to the application in that group which actually uses the memo. This kind of structure would allow the flexibility for changes at the company or department level without the normal dependencies. Without the use of namespaces, simply redefining the elements as is supported now is not appropriate because of the possible name clashing. Is namespaces the answer, or is the "extends" feature from DCD's what I need? Thanks, -Avneet 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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