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# 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 __new__(cls, *args, **kwargs):
# This __new__ is to make it clear that there is no reason to
# instantiate a Formatter--if you try to you'll just get back the
# class
return cls
@classmethod
def parse(cls, s):
"""
Convert a string to a unit object.
"""
raise NotImplementedError(
"Can not parse {0}".format(cls.__name__))
@classmethod
def to_string(cls, u):
"""
Convert a unit object to a string.
"""
raise NotImplementedError(
"Can not output in {0} format".format(cls.__name__))
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