[cddlm] CDL specification

[Paul Anderson]

>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