[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: [permathread:semantics] What Markup Is For
Jonathan Borden scripsit: > > This view of typing is common enough, but IMHO goes beyond necessity. > > Goes beyond necessity for what? What is necessary for the use of datatypes in validation contexts. > > The RNG view of a datatype is that it is simply a pair of boolean > > functions on strings: isFoo(string) is true iff string is a syntactically > > sound representation of the type Foo, and sameFoo(string1, string2) is > > true iff string1 and string2 are interchangeable representations of Foo. > > No notion of "objects of type Foo" is or need be introduced. > > I am not sure what you are getting at. One can use the phrase "objects of > type Foo" as a synonym for "the class of x for which isFoo(x) is true". One can, but it's unusual. We typically say that the objects of type Integer are e.g. 1, 5, -256, not "1", "005", "-256". The isInteger and sameInteger predicates are defined on strings, however, and no notion of integers as such is required. > I assume you are saying that XSD can do -without- types, and to the extent > that XSD is used as a language to express -syntactic constraints- on unicode > strings, this is certainly true. Indeed. > The point of semantics is that now that we > have a piece of XML that let's say corresponds to some RNG pattern or XSD > type _now what_. How can we specify how different programs i.e. processes > might use this piece of XML in an interoperable fashion. Walter's point is that outside a master-slave context, we can't in general. > For example suppose > I write: > > Penicillin 500mg p.o. q.i.d. x 3 weeks. Depending on the recipient, this can be instantiated in various ways. The drug dispensing device will interpret it as: drug: penicillin dosage: 500 mg quantity: 84 The label printer will interpret it as: drug: penicillin 500 mg instructions: take one pill four times a day quantity: 84 But the insurance company (or part thereof) may interpret it as: generic drug: true And the state may interpret it as: controlled substance: false > I want to be very precise about what happens when this message is sent to > the pharmacy -- at least as precise as the current situation when I write > this down on a slip of paper and transmit the message via sneakernet. This is indeed a master-slave situation: the pharmacist is your agent. However, Walter's techniques are applicable when the parties to a transaction are not in the master-slave relationship, and indeed may not even know of one another's existence. -- John Cowan <jcowan@r...> http://www.reutershealth.com http://www.ccil.org/~cowan Yakka foob mog. Grug pubbawup zink wattoom gazork. Chumble spuzz. -- Calvin, giving Newton's First Law "in his own words"
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