Tail recursion in Python

Admittedly, not the most "pythonic" code, whatever that means...

#!/usr/bin/python

from inspect import isfunction

recur = 0

def loop(func):
  def inner(a,b):
    global recur
    old_recur = recur
    recur = lambda a,b: lambda:func(a,b)
    ret = func(a,b)
    while isfunction(ret):
      ret = ret()
    recur = old_recur
    return ret
  return inner

Which creates a nice decorator:

@loop
def foo(n, a):
  if n == 0:
    return a
  else:
    return recur(n-1,a*n)

print(foo(6,1))