semver.py 文件源码

def _nat_cmp(a, b):
    def convert(text):
        return int(text) if re.match('[0-9]+', text) else text

    def split_key(key):
        return [convert(c) for c in key.split('.')]

    def cmp_prerelease_tag(a, b):
        if isinstance(a, int) and isinstance(b, int):
            return cmp(a, b)
        elif isinstance(a, int):
            return -1
        elif isinstance(b, int):
            return 1
        else:
            return cmp(a, b)

    a, b = a or '', b or ''
    a_parts, b_parts = split_key(a), split_key(b)
    for sub_a, sub_b in zip(a_parts, b_parts):
        cmp_result = cmp_prerelease_tag(sub_a, sub_b)
        if cmp_result != 0:
            return cmp_result
    else:
        return cmp(len(a), len(b))