Antoine Pitrou [mailto:solipsis@pitrou.net]:

This example is mixing up the notion of interpreter state and thread state.

Sorry about that, I was making a more general point and not paying so much attention to the specific names. The general point is this: A thread-local variable can work as an implied parameter without creating synchronisation problems. You do not have to worry about painting yourself into an architectural corner by using thread-local variables, because anything you can do with an explicit parameter, you could also have done with an implied one in thread-local memory. Correctness is not at stake. Either approach will work. regards, Anders