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Gustaf Liljegren <gustaf.liljegren@x...> wrote: | Ever since XML Schema started to evolve and the talk about datatypes in | XML took off, I've been wondering secretly why XML validation needs the | concept of datatypes at all. It doesn't. | XML is a plain text format, so content validation in XML should be no | different from regular pattern matching. And referential consistency checking (as in IDREF/ENTITY/NOTATION declared values.) Exactly right. | If my application wants an integer, all I'd do would be to check if all | characters are in the range 0-9. Regular expressions would be enough for | that. If possible, I'd have this check written in the schema, or some | special module of patterns attached to the schema. Again, exactly right. Semantics are at the application level, and the universe of semantics is unbounded. Try to shoehorn this into XML - a lexical formalism - invites the Farglebarp Problem [*], in spades. The politics of it so far have determined that a bunch of DB-wonks and type theorists have been allowed to transfer the costs of "standardizing" their particular hobbyhorses onto everyone else. http://groups.google.com/groups?selm=pmfirtkcuscft4s6agsod570jd1oiig8ra@4... (IOW, the fundamental problem with XML Schema is not technical: it's social. But geeks have a habit of shying away from such unmentionables.)
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