I had promised to Dejan I would respond to your earlier comment, but I will try to respond here as the thread has continued in the same vein.
Thanks - this is all very helpful. Pleae let me know if this isn't a good place to continue the discussion ..
There may be other semantics that are undefined or not clearly defined. I am not sure. Do you have any other examples?
I don't have any example immediately, but I haven't looked at it in a lot of detail. I'm sure there would be if I attempted an implementation. My worry is that this is almost certin if you do not write down the intended semantics clearly enough.
2) Languages like system configuration grammars are hard for people to write. People don't think this way. Tooling is typically very important for the successful implementation of any system. Vanish from HP was very helpful in showing the BPEL example. BPEL is a very rich language, but almost impossible to write by hand due to its complexity. However, it is very clear how to create a tool that can write well-formed BPEL, and many vendors and independents have done just that.
The purpose of CDL is to allow many contributors to a system definition. I am not sure that people will directly author CDL. On my side, we are implementing higher level tooling that can use CIM and CMDBs to derive a well-formed description, then parse down to CDL. It works quite nice.
I am very interested in all of this - my major interest is in building system configurations from independent contributions, and there is a lot we could discuss here. In this context though, the main question, is why the CDL contains the template mechanics - if the CDL is being generated by tools, why not have the tools handle templating in any way they want and evaluate down to a simpler common language (CDL with no templates) ?
3) It would be helpful for me to understand what you consider research features. Working Groups don't do research. We write specs based on experience and implementations.
Dejan brought up the question of doing things which were considered "research". I don't think that there is sufficient real-world experience of templating mechnisms in collaborative configuration specification to be sure that this particular approach is going to work well. I would rather have left this out (or as an "optional" layer) because I'm not sure it belongs at this level, and it may turn out that there are better ways of doing this once you have hardwired it into the standard. I'm still planning to look more closely at the CDL spec, and I'll probably have some more detailed questions later. Many thanks for the response Paul