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