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from __future__ import absolute_import, division, print_function
import copy
from ._compat import iteritems
from ._make import NOTHING, _obj_setattr, fields
from .exceptions import AttrsAttributeNotFoundError
def asdict(inst, recurse=True, filter=None, dict_factory=dict,
retain_collection_types=False):
"""
Return the ``attrs`` attribute values of *inst* as a dict.
Optionally recurse into other ``attrs``-decorated classes.
:param inst: Instance of an ``attrs``-decorated class.
:param bool recurse: Recurse into classes that are also
``attrs``-decorated.
:param callable filter: A callable whose return code determines whether an
attribute or element is included (``True``) or dropped (``False``). Is
called with the :class:`attr.Attribute` as the first argument and the
value as the second argument.
:param callable dict_factory: A callable to produce dictionaries from. For
example, to produce ordered dictionaries instead of normal Python
dictionaries, pass in ``collections.OrderedDict``.
:param bool retain_collection_types: Do not convert to ``list`` when
encountering an attribute whose type is ``tuple`` or ``set``. Only
meaningful if ``recurse`` is ``True``.
:rtype: return type of *dict_factory*
:raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs``
class.
.. versionadded:: 16.0.0 *dict_factory*
.. versionadded:: 16.1.0 *retain_collection_types*
"""
attrs = fields(inst.__class__)
rv = dict_factory()
for a in attrs:
v = getattr(inst, a.name)
if filter is not None and not filter(a, v):
continue
if recurse is True:
if has(v.__class__):
rv[a.name] = asdict(v, recurse=True, filter=filter,
dict_factory=dict_factory)
elif isinstance(v, (tuple, list, set)):
cf = v.__class__ if retain_collection_types is True else list
rv[a.name] = cf([
asdict(i, recurse=True, filter=filter,
dict_factory=dict_factory)
if has(i.__class__) else i
for i in v
])
elif isinstance(v, dict):
df = dict_factory
rv[a.name] = df((
asdict(kk, dict_factory=df) if has(kk.__class__) else kk,
asdict(vv, dict_factory=df) if has(vv.__class__) else vv)
for kk, vv in iteritems(v))
else:
rv[a.name] = v
else:
rv[a.name] = v
return rv
def astuple(inst, recurse=True, filter=None, tuple_factory=tuple,
retain_collection_types=False):
"""
Return the ``attrs`` attribute values of *inst* as a tuple.
Optionally recurse into other ``attrs``-decorated classes.
:param inst: Instance of an ``attrs``-decorated class.
:param bool recurse: Recurse into classes that are also
``attrs``-decorated.
:param callable filter: A callable whose return code determines whether an
attribute or element is included (``True``) or dropped (``False``). Is
called with the :class:`attr.Attribute` as the first argument and the
value as the second argument.
:param callable tuple_factory: A callable to produce tuples from. For
example, to produce lists instead of tuples.
:param bool retain_collection_types: Do not convert to ``list``
or ``dict`` when encountering an attribute which type is
``tuple``, ``dict`` or ``set``. Only meaningful if ``recurse`` is
``True``.
:rtype: return type of *tuple_factory*
:raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs``
class.
.. versionadded:: 16.2.0
"""
attrs = fields(inst.__class__)
rv = []
retain = retain_collection_types # Very long. :/
for a in attrs:
v = getattr(inst, a.name)
if filter is not None and not filter(a, v):
continue
if recurse is True:
if has(v.__class__):
rv.append(astuple(v, recurse=True, filter=filter,
tuple_factory=tuple_factory,
retain_collection_types=retain))
elif isinstance(v, (tuple, list, set)):
cf = v.__class__ if retain is True else list
rv.append(cf([
astuple(j, recurse=True, filter=filter,
tuple_factory=tuple_factory,
retain_collection_types=retain)
if has(j.__class__) else j
for j in v
]))
elif isinstance(v, dict):
df = v.__class__ if retain is True else dict
rv.append(df(
(
astuple(
kk,
tuple_factory=tuple_factory,
retain_collection_types=retain
) if has(kk.__class__) else kk,
astuple(
vv,
tuple_factory=tuple_factory,
retain_collection_types=retain
) if has(vv.__class__) else vv
)
for kk, vv in iteritems(v)))
else:
rv.append(v)
else:
rv.append(v)
return rv if tuple_factory is list else tuple_factory(rv)
def has(cls):
"""
Check whether *cls* is a class with ``attrs`` attributes.
:param type cls: Class to introspect.
:raise TypeError: If *cls* is not a class.
:rtype: :class:`bool`
"""
return getattr(cls, "__attrs_attrs__", None) is not None
def assoc(inst, **changes):
"""
Copy *inst* and apply *changes*.
:param inst: Instance of a class with ``attrs`` attributes.
:param changes: Keyword changes in the new copy.
:return: A copy of inst with *changes* incorporated.
:raise attr.exceptions.AttrsAttributeNotFoundError: If *attr_name* couldn't
be found on *cls*.
:raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs``
class.
.. deprecated:: 17.1.0
Use :func:`evolve` instead.
"""
import warnings
warnings.warn("assoc is deprecated and will be removed after 2018/01.",
DeprecationWarning, stacklevel=2)
new = copy.copy(inst)
attrs = fields(inst.__class__)
for k, v in iteritems(changes):
a = getattr(attrs, k, NOTHING)
if a is NOTHING:
raise AttrsAttributeNotFoundError(
"{k} is not an attrs attribute on {cl}."
.format(k=k, cl=new.__class__)
)
_obj_setattr(new, k, v)
return new
def evolve(inst, **changes):
"""
Create a new instance, based on *inst* with *changes* applied.
:param inst: Instance of a class with ``attrs`` attributes.
:param changes: Keyword changes in the new copy.
:return: A copy of inst with *changes* incorporated.
:raise TypeError: If *attr_name* couldn't be found in the class
``__init__``.
:raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs``
class.
.. versionadded:: 17.1.0
"""
cls = inst.__class__
attrs = fields(cls)
for a in attrs:
if not a.init:
continue
attr_name = a.name # To deal with private attributes.
init_name = attr_name if attr_name[0] != "_" else attr_name[1:]
if init_name not in changes:
changes[init_name] = getattr(inst, attr_name)
return cls(**changes)
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