Python TCO
Ivan Molina Rebolledo- 1 min read
This is just the Python version of https://ivmoreau.com/rust-tail-cail-functions-i/
It's horrible, and I love it. (I also did a pseudo-match "expression")
class TCO:
pass
class Ret(TCO):
def __init__(self, value):
self.v = value
class Rec(TCO):
def __init__(self, *args):
self.v = args
def tco(f):
def g(*args):
c = f(*args)
while True:
if isinstance(c, Ret):
return c.v
else:
c = f(*(c.v[0]))
return g
def match(x):
def g(*funs):
for (cmp, fun) in funs:
if cmp == x:
return fun()
return g
@tco
def fib(c, i, j):
return match(c)(
(0, lambda: Ret(i)),
(1, lambda: Ret(j)),
(2, lambda: Ret(i + j)),
(c, lambda: Rec((c - 1, j, i + j))),
)
print(fib(1000000, 0, 1))Yes, this somehow works, though I don't understand Python tuple destructuring (the v[0] part) all that well.