On Thu, Apr 7, 2016 at 4:44 AM, Random832 <random...@fastmail.com> wrote: > On Wed, Apr 6, 2016, at 14:23, Marko Rauhamaa wrote: >> Chris Angelico <ros...@gmail.com>: >> >> > Plus, anyone could implement a Python interpreter with TCE. >> >> Tricky in practice because None is the default return value. >> >> If the programmer were careful to return the value of the tail call, it >> can be eliminated. > > Well, the interpreter can know that the calling function doesn't return > anything (returns None). Maybe it could pass a secret argument to the > called function telling it not to return its value and to return None > instead.
This is the exact sort of shenanigans that it takes to convert recursion into tail recursion - and in MOST cases, it's very little effort to go from there to explicit while loops. That's why TCE is so infrequently important that it's just not worth the cost - which in this case is damage to tracebacks. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
