I have to say thank you, christian! I think your intent - provide the basis for designers of python's advanced control mechanisms to truly explore, and choose the direction in a well informed way - is ideal, and it's a rare and wonderful opportunity to be able to pursue something like an ideal course. Thanks to your hard work. Whatever comes of this, i think we all have at least refined our understandings of the issues - i know i have. (Thanks also to the ensuing discussion's clarity and incisiveness - i need to thank everyone involved for that...) I may not be able to contribute particularly to the implementation, but i'm glad to be able to grasp the implications as whatever proceeds, proceeds. And i actually expect that the outcome will be much better informed than it would have been without your following through on your own effort to understand. Yay! Ken klm@digicool.com