enum.py 文件源码

def _convert(cls, name, module, filter, source=None):
        """
        Create a new Enum subclass that replaces a collection of global constants
        """
        # convert all constants from source (or module) that pass filter() to
        # a new Enum called name, and export the enum and its members back to
        # module;
        # also, replace the __reduce_ex__ method so unpickling works in
        # previous Python versions
        module_globals = vars(sys.modules[module])
        if source:
            source = vars(source)
        else:
            source = module_globals
        # We use an OrderedDict of sorted source keys so that the
        # _value2member_map is populated in the same order every time
        # for a consistent reverse mapping of number to name when there
        # are multiple names for the same number rather than varying
        # between runs due to hash randomization of the module dictionary.
        members = [
                (name, source[name])
                for name in source.keys()
                if filter(name)]
        try:
            # sort by value
            members.sort(key=lambda t: (t[1], t[0]))
        except TypeError:
            # unless some values aren't comparable, in which case sort by name
            members.sort(key=lambda t: t[0])
        cls = cls(name, members, module=module)
        cls.__reduce_ex__ = _reduce_ex_by_name
        module_globals.update(cls.__members__)
        module_globals[name] = cls
        return cls