Cart
[Home] [By Thread] [By Date] [Recent Entries]
> Grammars should be an implementation technique, > not the nub of the question. Yes. I wouldn't claim that people should necessarily model their information structures directly in a grammar-based language such as TREX or RELAX. I think it's a fine strategy for people to model in some higher-level language (such as the component-oriented one which you sketched) and then map into a grammar as one possible implementation technique. However, whatever mechanism you use for modelling the conceptual structures, you still need a mechanism to describe the syntax, so that you can interchange the representations of these structures. Grammars are one such mechanism, which have been proven by more than a decade of experience to be useful for this. I certainly wouldn't claim that they are the best possible mechanism in all cases; in some cases, mechanisms like Schematron may be better. One way to look at a type in the context of XML is simply that it is a set of XML documents. In that sense, RELAX, TREX and indeed Schematron all define types. I am afraid I still don't see how RELAX or TREX are interposing a type system between the markup structure and the conceptual model, except in a completely vacuous sense that is equally true of Schematron. I see RELAX or TREX as a mechanism for the describing the syntax that you use to represent a conceptual model in XML. I don't see how that is a hindrance to conceptual modelling. James
|
