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That sounds good and thanks, John. Has anyone any prognostication of how this would work in the projected DSDL? In other words, what kind of tools would that provide and what kinds of functionality? If one starts with RNG, will the upgrade to DSDL be smoother? In short, what kinds of legacy problems are we looking at post-RNG and maybe post XSD? len From: John Cowan [mailto:jcowan@r...] "Bullard, Claude L (Len)" scripsit: > 1. More productive. Can one compose faster, is it easier to learn, > does is do what I need to do in the framework? Well, I'm a fairly bright sort of guy, and I could run RNG into my rapidly aging brain with no trouble, but XSD (part 1) is still defeating me. I would say that RNG is far and away the least restrictive schema language of its type (excluding Schematron, Examplotron, Hook, etc.). In essence, if you can write down RNG, and it makes any sense at all (no elements within attributes or consecutive datatypes, e.g.) then it just *works*, period. It has three syntaxes: XML-instance, programming-language, and DTD, for validators, schema authors, and legacy respectively. Its main weakness as against XSD is that it has no key/keyref support other that DTD-compatible ID, IDREF, and IDREFS (which are technically an extension, but supported in the existing validators). These were present in earlier drafts, but were too messy and hard to get right in the general case, and were dropped from RNG 1.0. Identity constraints are really orthogonal to structural ones in any case. This is a job waiting for someone to have a brain-wave. The spirit of RNG is closely related to that of DTDs: there is a smooth mental upgrade path. As a result, the DTD-RNG conversion tool is a masterpiece of structure preservation: it does its very best to make whatever structuring in the way of parameter entities that the DTD has, appear transparently in the RNG as well.
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