Source code for astropy.units.format.base

# Licensed under a 3-clause BSD style license - see LICENSE.rst

from __future__ import (absolute_import, division, print_function,
                        unicode_literals)


from ...utils.misc import InheritDocstrings
from ...extern import six


class _FormatterMeta(InheritDocstrings):
    registry = {}

    def __new__(mcls, name, bases, members):
        if 'name' in members:
            formatter_name = members['name'].lower()
        else:
            formatter_name = members['name'] = name.lower()

        cls = super(mcls, _FormatterMeta).__new__(mcls, name, bases, members)

        mcls.registry[formatter_name] = cls

        return cls


@six.add_metaclass(_FormatterMeta)
class Base(object):
    """
    The abstract base class of all unit formats.
    """

    def parse(self, s):
        """
        Convert a string to a unit object.
        """

        raise NotImplementedError(
            "Can not parse {0}".format(self.__class__.__name__))

    def to_string(self, u):
        """
        Convert a unit object to a string.
        """

        raise NotImplementedError(
            "Can not output in {0} format".format(self.__class__.__name__))