tailcall.py

def factorial(n, accumulator=1):
    if n == 1:
        return accumulator
    return factorial(n - 1, accumulator * n)


try:
    factorial(1000)
except RecursionError:
    print("TOO MUCH RECURSION!")


def tailcall(fn, *args):
    fn = fn(*args)
    while callable(fn):
        fn = fn()
    return fn


from functools import partial


def safe_factorial(n, accumulator=1):
    if n == 1:
        return accumulator
    return partial(safe_factorial, n - 1, accumulator * n)


tailcall(safe_factorial, 20000)# WORKS!