I think it's a lot easier to ignore uninteresting stack frames than to reconstruct those that have been optimized away. But for experienced programmers, I agre

I think it's a lot easier to ignore uninteresting stack frames than to reconstruct those that have been optimized away. But for experienced programmers, I agree global TCO doesn't quite rise to the level of a major impediment, though I have found it an annoyance at times. It particularly bugs me when the code I'm debugging is not recursive, so I'm not getting any benefit from TCO in this particular case. For novice programmers, however, I think it could be a serious barrier. I think van Rossum was right not to have Python do it by default. But I think he should also have provided a way to define a set of mutually-tail-recursive functions. I have long experience with Franz Allegro CL, which does TCO only on local calls. I think it's the best of both worlds: debugging usually isn't interfered with, and on those occasions where I really want to write a set of mutually-tail-recursive routines, it gives me a way to do that. I have certainly also used CL implementations that do global TCO -- I think that's all of the major open-source ones -- and they're certainly usable, but I prefer the Allegro compromise.