Re: RE: Abstraction in Science, Mathematics, Software,and Mark
On 12/03/2011 10:34, Costello, Roger L. wrote: > Hi Stephen, > >> Are you suggesting or even hinting that it should be possible >> to define a type whose contents are types rather than elements? > Funny you should ask! Yes! > > A couple weeks ago I pitched that very idea on the xmlschema-dev list: > Well, "complexType" and "simpleType" are the names of two types whose instances are types - the set of complexTypes and the set of simpleTypes respectively. I guess Roger's "cross-product" is another type whose instances are types, though he presented it more as a constructor for new types, akin to construction-by-list and construction-by-union. The IRDS model from the 1980s had four layers: loosely, objects like "John Smith", types like "Person", meta-types like "Complex Type", and meta-meta-types like "Concept". The things in each layer are instances of the types in the layer above. The idea was that the meta-meta-types were fixed (they define the ontological framework), but the meta-types are completely extensible - the idea being that you can always incorporate new "data models" like the relational model, the XML model, etc. I put "data model" in quotes, because one of the problems is that the term is used by some people to mean a set of types like "Person", and by others to mean a set of meta-types like "Complex Type". Michael Kay Saxonica
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index]
PURCHASE STYLUS STUDIO ONLINE TODAY!
Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!
Download The World's Best XML IDE!
Accelerate XML development with our award-winning XML IDE - Download a free trial today!
Subscribe in XML format