Perhaps more specifically, I want to define a "grouping" (as encapsulated semantically and syntactically in a dict), at the place where the transition from atomic element into a group occurs. Syntactically this will be *denoted* by the curly brackets {}, operationally this will be defined in the CPython code itself. But the semantics in the middle must be "hashed out" for either to occur (pardon the pun). The question is whether it's premature to attempt such a task or not.... mark