regexp.py 文件源码

def _gen_combinator(variants, _merge=True):
    if not hasattr(variants, '__iter__'):
        return [variants] if variants is not None else []

    res = []
    need_product = False
    for var in variants:
        if isinstance(var, list):
            sol = _gen_combinator(var, _merge=False)
            res.append(sol)
            need_product = True
        elif var is not None:
            res.append(var)

    if need_product:
        producted = itertools.product(*res)
        if _merge:
            # TODO(buglloc): ??!
            return list(six.moves.map(_merge_variants, producted))
        return producted
    elif _merge:
        return list(six.moves.map(_merge_variants, [res]))
    return res