Monster fibonacci with generators

fibonacci_generators.py

from __future__ import annotations


class GeneratorWithHistory:
    def __init__(self, generator) -> None:
        self.generator = generator
        self.memory = []
        self.index = 0

    def next(self, needed_index: int):
        while self.index <= needed_index:
            self.memory.append(self.generator.__next__())
            self.index += 1

        return self.memory[needed_index]


class IndexedGeneratorCaller:
    def __init__(self, generator_with_history: GeneratorWithHistory, index: int = 0):
        self.generator_with_history = generator_with_history
        self.index = index

    def next(self):
        value = self.generator_with_history.next(self.index)
        self.index += 1

        return value


class GeneratorRegister:
    __instance = None

    def instance() -> GeneratorRegister:
        if not GeneratorRegister.__instance:
            GeneratorRegister.__instance = GeneratorRegister()

        return GeneratorRegister.__instance

    def __init__(self):
        self.registry = {}

    def register(self, fn):
        self.registry[fn] = GeneratorWithHistory(fn())

    def get(self, fn) -> GeneratorWithHistory:
        return self.registry[fn]


def fib():
    yield 0
    yield 1

    lhs = IndexedGeneratorCaller(GeneratorRegister.instance().get(fib))
    rhs = IndexedGeneratorCaller(GeneratorRegister.instance().get(fib), 1)

    while True:
        yield (lhs.next() + rhs.next())


GeneratorRegister.instance().register(fib)

fib_gen = IndexedGeneratorCaller(GeneratorRegister.instance().get(fib))

for _ in range(0, 10):
    print(fib_gen.next())