[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Syntax and Semantics
I think the cases of actually processing the infornation in a document and documents from different sources are often overlooked. For example, a document with some MathML, ChemML, and HTML mixed together. A DTD or schema may allow the syntax of the sections to be validated, but it won't render the formula, molecule or text. The rendering is done by an application which understands the semantics of the language involved. There is no current specification for the cooperation of rendering engines for MathML, ChemML and HTML - except perhaps through browser plugins and a delegating XML browser. All namespaces provide is avoidance of ambiguity. All tying a namespace to a schema adds is validity checking. Consider documents of different namespaces that represent the same information. Two companies may each have an product DTD or schema that includes elements of SKU, ProductName, Description, and Price. Each uses their own namespace. But each of these elements have the same meaning. If the companies want to share information they must construct a namespace they both use for the common elements. They also have to modify ALL of their existing documents to use this new namespace. This is like the class problem of languages like C++: Identity is determined by class derivation, not form. Even if 2 instances are identical in form they are not the same unless they are instances of the same class. In the web context this is what drives 'standard' markup languages - create your documents in this syntax so you don't have to modify it later when you try to share it. Unfortunately we can't envision the entire set of markup languages needed and if we could we would be establishing a central language authority. I would keep namespaces as they are - a means of resolving ambuigity. The addition of a DTD or Schema doesn't really convey what an element means. The embodiment of meaning is the application that processes the elements. Marc B. McDonald Principal Software Scientist Design Intelligence Inc (www.design-intelligence.com) *************************************************************************** This is xml-dev, the mailing list for XML developers. To unsubscribe, mailto:majordomo@x...&BODY=unsubscribe%20xml-dev List archives are available at http://xml.org/archives/xml-dev/ ***************************************************************************
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