Python 是否将docstring添加到_插槽_描述符?
我正在编写一个存储自动化模块,用于提供卷。我没有传递实际在存储控制器上创建卷所需的六个或更多参数,而是使用Python 是否将docstring添加到_插槽_描述符?,python,Python,我正在编写一个存储自动化模块,用于提供卷。我没有传递实际在存储控制器上创建卷所需的六个或更多参数,而是使用\uuuuu slots\uuuu创建了一个参数类,该参数类被传递到create方法中,如下所示: from mock import Mock from six import with_metaclass class VolumeParameterMeta(type): def __new__(mcs, name, bases, dct): # set __slot
\uuuuu slots\uuuu
创建了一个参数类,该参数类被传递到create方法中,如下所示:
from mock import Mock
from six import with_metaclass
class VolumeParameterMeta(type):
def __new__(mcs, name, bases, dct):
# set __slots__ docstrings here?
return super(VolumeParameterMeta, mcs).__new__(mcs, name, bases, dct)
class VolumeParameter(with_metaclass(VolumeParameterMeta, object)):
__slots__ = ('name', 'size', 'junctionPath', 'svmName', 'securityStyle'
'spaceReserve')
def __init__(self, name):
self.name = name
class Volume(object):
def __init__(self, driver, name):
self.driver = driver
self.name = name
@classmethod
def create(cls, driver, param):
# do sanity check on param (volume not too large, etc)
driver.provision(param)
return cls(driver, param.name)
if __name__ == '__main__':
param = VolumeParameter('volume1')
param.svmName = 'vserver1'
param.junctionPath = '/some/path'
param.size = 2 ** 30
param.spaceReserve = param.size * 0.1
param.securityStyle = 'mixed'
volume = Volume.create(driver=Mock(), param=param)
上面的示例非常有效,但有一个小的例外。如何将docstring添加到参数类中的描述符并不明显。看起来元类应该是可以的,但是元类实例化时没有定义描述符
我清楚地意识到,有些人可能不同意我使用\uuuuu slots\uuuuu
的副作用,但我喜欢它有助于消除打字错误。尝试设置一个不存在的参数,并弹出AttributeError
。都没有任何样板代码。可以说,让它在卷创建时失败更像python,但结果将是使用默认值而不是拼写错误的参数。这实际上是一次无声的失败
我意识到可以简单地扩展参数类docstring,但是pydoc
和其他文档构建脚本的结果是类的大型自由格式docstring和每个描述符的空docstring
肯定有办法为
创建的描述符定义docstring吗?也许除了吃角子老虎还有别的办法?一个可变的名称双倍
或类似的?
否,没有选项将docstring添加到为\uuuuu slots\uuu
中定义的名称生成的描述符对象中。在这方面,它们类似于常规的非描述符属性
在没有插槽的常规对象上,最多可以添加注释并设置默认值:
class VolumeParameter(object):
# the name of the volume (str)
name = ''
# volume size in bytes (int)
size = 0
# ...
即使您将所有这些属性声明为\uuuuu插槽\uuuu
,也同样适用
您可以将每个插槽以属性
对象的形式“包装”到另一个描述符中:
class VolumeParameterMeta(type):
@staticmethod
def _property_for_name(name, docstring):
newname = '_' + name
def getter(self):
return getattr(self, newname)
def setter(self, value):
setattr(self, newname, value)
def deleter(self):
delattr(self, newname)
return newname, property(getter, setter, deleter, docstring)
def __new__(mcs, name, bases, dct):
newslots = []
clsslots = dct.pop('__slots__', ())
slotdocs = dct.pop('__slot_docs__', {})
if isinstance(clsslots, str):
clsslots = clsslots.split()
for name in clsslots:
newname, prop = mcs._property_for_name(name, slotdocs.get(name))
newslots.append(newname)
dct[name] = prop
if newslots:
dct['__slots__'] = tuple(newslots)
return super(VolumeParameterMeta, mcs).__new__(mcs, name, bases, dct)
class VolumeParameter(with_metaclass(VolumeParameterMeta, object)):
__slots__ = ('name', 'size', 'junctionPath', 'svmName', 'securityStyle'
'spaceReserve')
__slot_docs__ = {
'name': 'the name of the volume (str)',
# ...
}
请注意,这几乎使类上的描述符数量增加了一倍:
>>> pprint(VolumeParameter.__dict__)
mappingproxy({'__doc__': None,
'__module__': '__main__',
'__slots__': ('_name',
'_size',
'_junctionPath',
'_svmName',
'_securityStylespaceReserve'),
'_junctionPath': <member '_junctionPath' of 'securityStylespaceReserve' objects>,
'_name': <member '_name' of 'securityStylespaceReserve' objects>,
'_securityStylespaceReserve': <member '_securityStylespaceReserve' of 'securityStylespaceReserve' objects>,
'_size': <member '_size' of 'securityStylespaceReserve' objects>,
'_svmName': <member '_svmName' of 'securityStylespaceReserve' objects>,
'junctionPath': <property object at 0x105edbe08>,
'name': <property object at 0x105edbd68>,
'securityStylespaceReserve': <property object at 0x105edb098>,
'size': <property object at 0x105edbdb8>,
'svmName': <property object at 0x105edb048>})
感谢您的解答和解释!
>>> VolumeParameter.name.__doc__
'the name of the volume (str)'