specifiers.py 文件源码

def _compare_compatible(self, prospective, spec):
        # Compatible releases have an equivalent combination of >= and ==. That
        # is that ~=2.2 is equivalent to >=2.2,==2.*. This allows us to
        # implement this in terms of the other specifiers instead of
        # implementing it ourselves. The only thing we need to do is construct
        # the other specifiers.

        # We want everything but the last item in the version, but we want to
        # ignore post and dev releases and we want to treat the pre-release as
        # it's own separate segment.
        prefix = ".".join(
            list(
                itertools.takewhile(
                    lambda x: (not x.startswith("post") and not
                               x.startswith("dev")),
                    _version_split(spec),
                )
            )[:-1]
        )

        # Add the prefix notation to the end of our string
        prefix += ".*"

        return (self._get_operator(">=")(prospective, spec) and
                self._get_operator("==")(prospective, prefix))