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"Fuchs, Matthew" wrote: > DTDs provide a mapping from well formed documents into, essentially, a term > algebra for a particular set of structures. So far so good. > I.e., once you've validated a > document, any element structure (but, alas, not attributes - but at least > there's only one level of nesting) with a particular label is of the set of > structures "labeled" by an element definition with the same label. Of > course, as you've pointed out, this is only one piece of the semantics, the > "label->meaning" map, but it's the piece validition provides. <minor_annoyance_and_aside> Mapping elements/attribute to t&*&%s is not validation, since validation includes things above and beyond this mapping, such as checking that IDREF values point to actual IDs and that IDs are unique. In other words, it is not necessary to generate the complete PSVI or to validate a document to do this mapping. Unfortunately, the PSVI is defined in these terms, rather than having separate layers, a mapping layer and a constraint checking layer. And, yes, I finally did understand what Elliotte Rusty Harold was talking about when he said, "W3C XML Schema Language confuses the two separate issues of typing and constraints checking" :) </minor_annoyance_and_aside> -- Ron
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