tailrec

Provides a decorator tailrec which executes a tail recursive function iteratively

Installation

pip install tailrec

Examples

from tailrec import tailrec


@tailrec
def factorial(n: int, accum: int = 1) -> int:
    """Calculates n!"""
    if n == 0:
        return accum
    else:
        return factorial(n - 1, accum * n)


@tailrec
def fibonacci(n: int, current: int = 0, next_: int = 1) -> int:
    """Returns the n-th number of the fibonacci sequence"""
    if n == 0:
        return current
    else:
        return fibonacci(n - 1, next_, current + next_)


print(factorial(5))  # 120
print(factorial(1_100))  # 5343708488092637703...

print(fibonacci(5))  # 8
print(fibonacci(2_000))  # 42246963333923...