[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Inheritance
Paul, No argument with your posting (I decided not to post a similar statement after rereading yours), but could you change your terms slightly? Although the OO terms themselves were definitely conflated during the eighties they have by now settled down to: Type: The declaration of the interface of any set of [objects] that conforms to this common protocol. Any set of objects or values with similar behavior... [Firesmith+E 95] Class: A class is the realization of a type. [UML] The idea of class is closely linked...with the description of implementation details of software objects [Cook+D 94]. Type vs. Class: Types classify objects according to a common interface; classes classify objects according to a common implementation. [Firesmith+E 95] Subtyping: The incremental definition of a new type in terms of one or more existing types, whereby the subtype conforms to all of its supertypes [an is-kind-of relationship] [Firesmith+E 95] And subclassing implies implementation-inheritance (i.e. code reuse), exactly what you were trying to avoid implying. So I would suggest rewriting your example to: > > Anyhow, you can emulate OTHER using subtyping without an explicit > > OTHER construct. > > > > <!ELEMENT CITATION (name, author, date, OTHER-CIT* )> > > <!ELEMTYPE OTHER-CIT> <!-- no constraints on subtypes --> > > <!ELEMTYPE ANOTHER-TYPE ISA ANY> <!-- Be explicit about the automatic root --> > > > > <!ELEMENT URL (#PCDATA) ISA (OTHER-CIT & ANOTHER-TYPE)> Which makes it use the standard terminology. So, ELEMENTs would be the leaves of a tree/digraph of Types with ANY as the root. Note that ISA should formally be IS-A-KIND-OF but that is an annoyingly long keyword. (My dog is-a Dog which is-a-kind-of Mammal vs: My dog is-a Dog which is-a Mammal). --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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