3rd homework

solution.py

__author__ = 'kpace'


def fibonacci():
    yield 1
    prev = 0
    after = 1
    while True:
        result = prev + after
        prev = after
        after = result
        yield result


def primes():
    yield 2
    yield 3
    pl = [2, 3]
    pp = 3
    while True:
        pp += 2
        for i in pl: # SQRT
            if pp % i == 0:
                break
        else:
            pl.append(pp)
            yield pp


alphabets = {
    'lat': 'abcdefghijklmnopqrstuvwxyz',
    'bg': 'абвгдежзийклмнопрстуфхцчшщъьюя'
}


def alphabet(*, code='bg', letters=''):
    seq = ''

    if len(letters) > 0:
        seq = letters
    else:
        seq = alphabets[code]

    for el in seq:
        yield el


no_argument_generators = {
    'fibonacci': fibonacci(),
    'primes': primes(),
}


def intertwined_sequences(specs, *, generator_definitions):
    alph_gen = None

    for spec in specs:
        gen = None
        if spec['sequence'] == 'alphabet':
            if alph_gen is None:
                code = spec.get('code', 'bg')
                letters = spec.get('letters', '')
                alph_gen = alphabet(code=code, letters=letters)
            gen = alph_gen
        else:
            gen = no_argument_generators[spec['sequence']]

        for _ in range(spec['length']):
            yield next(gen)