Re: Semantics (was Re: Inheritance in XML [^*])
>If XML had no semantics, then XSL, XLL and the DOM would have to >explicitly describe the mapping from syntactic features to the abstract >nodes that they work on. But they do not, because XML has semantic >concepts like "element, "element type", "notation" and "attribute" that >are *described by* the syntax. If those are semantic concepts, then what are the syntactic concepts? The syntax of a language defines which sequences of symbols constitute legitimate sentences in that language. The semantics of the language define how to interpret the sentences of the language as statements about objects in some external world. So if you take my GedML as an example, the syntax of GedML is defined partly by the XML specification and partly by the GedML DTD. The semantics of GedML are the rules that say an <INDI> element asserts the existence of a person and a <FAM> element asserts the existence of a married or unmarried couple, etc. Of course some of the semantic constraints (a person can only have one father) can be expressed as syntactic constraints, while others (a person must be born after their father) cannot, because the syntactic metalanguage used for XML is insufficiently powerful. Tim is surely right: there are no semantics implied by the XML spec. XSL, XLL, etc don't change this. They define syntactic (or symbolic) manipulations of XML constructs which are probably most useful if you used XML the way its designers expected you to, but they do not make any assumptions about the semantics of your XML content. This would become obvious if the XSL spec were rewritten (as it could be) in a purely formal way to define a transformation from one sequence of symbols into another. Mike Kay, ICL 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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