'namespace delete ::' works. It seems, in fact, it prevents you from
doing anything else after that, with it's on logic. But beside, that I
found that a bit inconsisten (becaus the interp forgets everything,
not only the commands in the global space) I can't see for what this
is god for. On the other side it could be a matter of harm. Hm. Nifty
details.

rolf