RE: [xml-dev] s-expressions and XML was Re: [xml-dev] terra incog nita

> Regarding objects vs. data (which is where we started), the prime
> distinction is between opacity and translucency. When objects are well
> described, and their state can be described by the getter 
> setter properties
> in their interfaces, as data objects they can be translucent. 

What of:
- cardinality?
- max/min values?
- co-constraints?

These are not translucent in the interface, and point up the limitations of
expressing a data model as a set of object interfaces. While the line
between processing/data model is gray, there's a lot to be gained by
expressing certain constraints declaratively (in a schema, not IDL).