[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: Object-oriented serialization (Was Re: Some questions)
Sorry I'm a bit late with this... > -----Original Message----- > From: James Tauber [mailto:jtauber@j...] > Sent: Sunday, December 05, 1999 7:25 PM > To: xml-dev@i... > > > The semantic constraints I am > > talking about are one step away from these "ultimate" > semantics; they > > tell you that an integer contained in a given element > cannot be greater > > than 100, but they don't tell you why. These are still > semantics to me > > Ah. This is why I have have some difficulty understanding > some of what you > are saying. To me, the constraint that an integer cannot be > greater than 100 > is not semantics. It's syntax. > > MyInteger ::= ( '100' | digit{1,2} | '-' digit+ ) > > or in some more perspicuous grammar: > > MyInteger = Integer x : x <= 100 > But this won't work outside of Europe. You have to have a clean distinction between syntax and semantics, and an explicit, rigorous mapping from one to the other. The symbols used in your example have no intrinsic meaning, just as numbers have no intrinsic form available to our perception, so the syntax can only constraint the formal properties of expressions using those symbols. Sure, we have conventional meanings for constant symbols like '1' and '0'; but they're still symbols pointing to something else, and as soon as you start writing expressions with a different symbol set - in Sanskrit, say, or Ethiopic, or you name it - then you're out of luck without a formal semantics. On the other hand, the cultural interpretation of the denotatum is beyond the scope of language definition. Doesn't matter what the user intends to model using integers; be it widgets, fingers, or planets, the best the language designer can do is provide a consistent language that accurately models the integers. -gregg 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/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe 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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