structured_data.adt._values_non_empty() - Code Metrics - Inspection of "Break things down further" - mwchase/python-structured-data - Measure and Improve Code Quality continuously with Scrutinizer

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Push — master ( c9efce...20fd99 )

by Max

created 2019-09-02 15:26 UTC

structured_data.adt._values_non_empty() A

↳ Parent: structured_data.adt

Complexity

Conditions

Size

Total Lines	6
Code Lines	6

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	3
eloc	6
nop	2
dl	0
loc	6
rs	10
c	0
b	0
f	0

"""Base classes for defining abstract data types.

This module provides three public members, which are used together.

Given a structure, possibly a choice of different structures, that you'd like
to associate with a type:

- First, create a class, that subclasses the Sum class.
- Then, for each possible structure, add an attribute annotation to the class
  with the desired name of the constructor, and a type of ``Ctor``, with the
  types within the constructor as arguments.

To look inside an ADT instance, use the functions from the
:mod:`structured_data.match` module.

Putting it together:

>>> from structured_data import match
>>> class Example(Sum):
...     FirstConstructor: Ctor[int, str]
...     SecondConstructor: Ctor[bytes]
...     ThirdConstructor: Ctor
...     def __iter__(self):
...         matchable = match.Matchable(self)
...         if matchable(Example.FirstConstructor(match.pat.count, match.pat.string)):
...             count, string = matchable[match.pat.count, match.pat.string]
...             for _ in range(count):
...                 yield string
...         elif matchable(Example.SecondConstructor(match.pat.bytes)):
...             bytes_ = matchable[match.pat.bytes]
...             for byte in bytes_:
...                 yield chr(byte)
...         elif matchable(Example.ThirdConstructor()):
...             yield "Third"
...             yield "Constructor"
>>> list(Example.FirstConstructor(5, "abc"))
['abc', 'abc', 'abc', 'abc', 'abc']
>>> list(Example.SecondConstructor(b"abc"))
['a', 'b', 'c']
>>> list(Example.ThirdConstructor())
['Third', 'Constructor']
"""

import inspect
import sys
import typing

from . import _adt_constructor
from . import _ctor
from . import _prewritten_methods

_T = typing.TypeVar("_T")


if typing.TYPE_CHECKING:  # pragma: nocover

    class Ctor:
        """Dummy class for type-checking purposes."""

    class ConcreteCtor(typing.Generic[_T]):
        """Wrapper class for type-checking purposes.

        The type parameter should be a Tuple type of fixed size.
        Classes containing this annotation (meaning they haven't been
        processed by the ``adt`` decorator) should not be instantiated.
        """


else:
    from ._ctor import Ctor


# This is fine.
def _name(cls: typing.Type[_T], function) -> str:
    """Return the name of a function accessed through a descriptor."""
    return function.__get__(None, cls).__name__


# This is mostly fine, though the list of classes is somewhat ad-hoc, to say
# the least.
def _cant_set_new_functions(cls: typing.Type[_T], *functions) -> typing.Optional[str]:
    for function in functions:
        name = _name(cls, function)
        existing = getattr(cls, name, None)
        if existing not in (
            getattr(object, name, None),
            getattr(Product, name, None),
            None,
            function,
        ):
            return name
    return None


def _set_new_functions(cls: typing.Type[_T], *functions) -> typing.Optional[str]:
    """Attempt to set the attributes corresponding to the functions on cls.

    If any attributes are already defined, fail *before* setting any, and
    return the already-defined name.
    """
    cant_set = _cant_set_new_functions(cls, *functions)
    if cant_set:
        return cant_set
    for function in functions:
        setattr(cls, _name(cls, function), function)
    return None


_K = typing.TypeVar("_K")
_V = typing.TypeVar("_V")


def _nillable_write(dct: typing.Dict[_K, _V], key: _K, value: typing.Optional[_V]):
    if value is None:
        dct.pop(key, typing.cast(_V, None))
    else:
        dct[key] = value


def _sum_new(_cls: typing.Type[_T], subclasses):
    def base(cls, args):
        return super(_cls, cls).__new__(cls, args)

    new = _cls.__dict__.get("__new__", staticmethod(base))

    def __new__(cls, args):
        if cls not in subclasses:
            raise TypeError
        return new.__get__(None, cls)(cls, args)

    _cls.__new__ = staticmethod(__new__)  # type: ignore


def _product_new(
    _cls: typing.Type[_T],
    annotations: typing.Dict[str, typing.Any],
    defaults: typing.Dict[str, typing.Any],
):
    def __new__(*args, **kwargs):
        cls, *args = args
        return super(_cls, cls).__new__(cls, *args, **kwargs)

    __new__.__signature__ = inspect.signature(__new__).replace(
        parameters=[inspect.Parameter("cls", inspect.Parameter.POSITIONAL_ONLY)]
        + [
            inspect.Parameter(
                field,
                inspect.Parameter.POSITIONAL_OR_KEYWORD,
                annotation=annotation,
                default=defaults.get(field, inspect.Parameter.empty),
            )
            for (field, annotation) in annotations.items()
        ]
    )
    _cls.__new__ = __new__


def _all_annotations(
    cls: typing.Type[_T]
) -> typing.Iterator[typing.Tuple[typing.Type[_T], str, typing.Any]]:
    for superclass in reversed(cls.__mro__):
        for key, value in vars(superclass).get("__annotations__", {}).items():
            yield (superclass, key, value)


def _sum_args_from_annotations(cls: typing.Type[_T]) -> typing.Dict[str, typing.Tuple]:
    args: typing.Dict[str, typing.Tuple] = {}
    for superclass, key, value in _all_annotations(cls):
        _nillable_write(
            args, key, _ctor.get_args(value, vars(sys.modules[superclass.__module__]))
        )
    return args


def _product_args_from_annotations(
    cls: typing.Type[_T]
) -> typing.Dict[str, typing.Any]:
    args: typing.Dict[str, typing.Any] = {}
    for _, key, value in _all_annotations(cls):
        if value == "None" or _ctor.annotation_is_classvar(
            value, vars(sys.modules[cls.__module__])
        ):
            value = None
        _nillable_write(args, key, value)
    return args


def _ordering_options_are_valid(*, eq, order):
    if order and not eq:
        raise ValueError("eq must be true if order is true")


def _set_ordering(*, can_set, setter, cls, source):
    if not can_set:
        raise ValueError("Can't add ordering methods if equality methods are provided.")
    collision = setter(cls, source.__lt__, source.__le__, source.__gt__, source.__ge__)
    if collision:
        raise TypeError(
            "Cannot overwrite attribute {collision} in class "
            "{name}. Consider using functools.total_ordering".format(
                collision=collision, name=cls.__name__
            )
        )


def _values_non_empty(cls, field_names):
    for field in field_names:
        default = getattr(cls, field, inspect.Parameter.empty)
        if default is inspect.Parameter.empty:
            return
        yield (field, default)


def _values_until_non_empty(cls, field_names):
    for field in field_names:
        default = getattr(cls, field, inspect.Parameter.empty)
        if default is not inspect.Parameter.empty:
            yield


def _extract_defaults(*, cls, annotations):
    field_names = iter(reversed(tuple(annotations)))
    defaults = {
        field: default for (field, default) in _values_non_empty(cls, field_names)
    }
    for _ in _values_until_non_empty(cls, field_names):
        raise TypeError
    return defaults


def _unpack_args(*, args, kwargs, fields, values):
    fields_iter = iter(fields)
    values.update({field: arg for (arg, field) in zip(args, fields_iter)})
    for field in fields_iter:
        if field in values and field not in kwargs:
            continue
        values[field] = kwargs.pop(field)
    if kwargs:
        raise TypeError(kwargs)


class Sum:
    """Base class of classes with disjoint constructors.

    Examines PEP 526 __annotations__ to determine subclasses.

    If repr is true, a __repr__() method is added to the class.
    If order is true, rich comparison dunder methods are added.

    The Sum class examines the class to find Ctor annotations.
    A Ctor annotation is the adt.Ctor class itself, or the result of indexing
    the class, either with a single type hint, or a tuple of type hints.
    All other annotations are ignored.

    The subclass is not subclassable, but has subclasses at each of the
    names that had Ctor annotations. Each subclass takes a fixed number of
    arguments, corresponding to the type hints given to its annotation, if any.
    """

    __slots__ = ()

    def __new__(*args, **kwargs):  # pylint: disable=no-method-argument
        cls, *args = args
        if not issubclass(cls, _adt_constructor.ADTConstructor):
            raise TypeError
        return super(Sum, cls).__new__(cls, *args, **kwargs)

    # Both of these are for consistency with modules defined in the stdlib.
    # BOOM!
    def __init_subclass__(
        cls,
        *,
        repr=True,  # pylint: disable=redefined-builtin
        eq=True,  # pylint: disable=invalid-name
        order=False,
        **kwargs
    ):
        super().__init_subclass__(**kwargs)
        if issubclass(cls, _adt_constructor.ADTConstructor):
            return
        _ordering_options_are_valid(eq=eq, order=order)

        subclass_order: typing.List[typing.Type[_T]] = []

        for name, args in _sum_args_from_annotations(cls).items():
            _adt_constructor.make_constructor(cls, name, args, subclass_order)

        _prewritten_methods.SUBCLASS_ORDER[cls] = tuple(subclass_order)

        cls.__init_subclass__ = (
            _prewritten_methods.PrewrittenSumMethods.__init_subclass__
        )  # type: ignore

        _sum_new(cls, frozenset(subclass_order))

        _set_new_functions(
            cls,
            _prewritten_methods.PrewrittenSumMethods.__setattr__,
            _prewritten_methods.PrewrittenSumMethods.__delattr__,
        )
        _set_new_functions(cls, _prewritten_methods.PrewrittenSumMethods.__bool__)

        if repr:
            _set_new_functions(cls, _prewritten_methods.PrewrittenSumMethods.__repr__)

        equality_methods_were_set = False
        if eq:
            equality_methods_were_set = not _set_new_functions(
                cls,
                _prewritten_methods.PrewrittenSumMethods.__eq__,
                _prewritten_methods.PrewrittenSumMethods.__ne__,
            )

        if equality_methods_were_set:
            cls.__hash__ = _prewritten_methods.PrewrittenSumMethods.__hash__

        if order:
            _set_ordering(
                can_set=equality_methods_were_set,
                setter=_set_new_functions,
                cls=cls,
                source=_prewritten_methods.PrewrittenSumMethods,
            )


class Product(_adt_constructor.ADTConstructor, tuple):
    """Base class of classes with typed fields.

    Examines PEP 526 __annotations__ to determine fields.

    If repr is true, a __repr__() method is added to the class.
    If order is true, rich comparison dunder methods are added.

    The Product class examines the class to find annotations.
    Annotations with a value of "None" are discarded.
    Fields may have default values, and can be set to inspect.empty to
    indicate "no default".

    The subclass is subclassable. The implementation was designed with a focus
    on flexibility over ideals of purity, and therefore provides various
    optional facilities that conflict with, for example, Liskov
    substitutability. For the purposes of matching, each class is considered
    distinct.
    """

    __slots__ = ()

    def __new__(*args, **kwargs):  # pylint: disable=no-method-argument
        cls, *args = args
        if cls is Product:
            raise TypeError
        # Probably a result of not having positional-only args.
        values = cls.__defaults.copy()  # pylint: disable=protected-access
        _unpack_args(
            args=args,
            kwargs=kwargs,
            fields=cls.__fields,  # pylint: disable=protected-access
            values=values,
        )
        return super(Product, cls).__new__(
            cls,
            [
                values[field]
                for field in cls.__fields  # pylint: disable=protected-access
            ],
        )

    __repr = True
    __eq = True
    __order = False
    __eq_succeeded = None

    # Both of these are for consistency with modules defined in the stdlib.
    # BOOM!
    def __init_subclass__(
        cls,
        *,
        repr=None,  # pylint: disable=redefined-builtin
        eq=None,  # pylint: disable=invalid-name
        order=None,
        **kwargs
    ):
        super().__init_subclass__(**kwargs)

        if repr is not None:
            cls.__repr = repr
        if eq is not None:
            cls.__eq = eq
        if order is not None:
            cls.__order = order

        _ordering_options_are_valid(eq=cls.__eq, order=cls.__order)

        cls.__annotations = _product_args_from_annotations(cls)
        cls.__fields = {field: index for (index, field) in enumerate(cls.__annotations)}

        cls.__defaults = _extract_defaults(cls=cls, annotations=cls.__annotations)

        _product_new(cls, cls.__annotations, cls.__defaults)

        cls.__eq_succeeded = False
        if cls.__eq:
            cls.__eq_succeeded = not _cant_set_new_functions(
                cls,
                _prewritten_methods.PrewrittenProductMethods.__eq__,
                _prewritten_methods.PrewrittenProductMethods.__ne__,
            )

        if cls.__order:
            _set_ordering(
                can_set=cls.__eq_succeeded,
                setter=_cant_set_new_functions,
                cls=cls,
                source=_prewritten_methods.PrewrittenProductMethods,
            )

    def __dir__(self):
        return super().__dir__() + list(self.__fields)

    def __getattribute__(self, name):
        try:
            return super().__getattribute__(name)
        except AttributeError:
            index = self.__fields.get(name)
            if index is None:
                raise
            return tuple.__getitem__(self, index)

    __setattr__ = _prewritten_methods.PrewrittenProductMethods.__setattr__
    __delattr__ = _prewritten_methods.PrewrittenProductMethods.__delattr__
    __bool__ = _prewritten_methods.PrewrittenProductMethods.__bool__

    @property
    def __repr__(self):
        if self.__repr:
            return _prewritten_methods.PrewrittenProductMethods.__repr__.__get__(
                self, type(self)
            )
        return super().__repr__

    @property
    def __hash__(self):
        if self.__eq_succeeded:
            return _prewritten_methods.PrewrittenProductMethods.__hash__.__get__(
                self, type(self)
            )
        return super().__hash__

    @property
    def __eq__(self):  # pylint: disable=unexpected-special-method-signature
        if self.__eq_succeeded:
            # I think this is a Pylint bug, but I'm not sure how to reduce it.
            # pylint: disable=no-value-for-parameter
            return _prewritten_methods.PrewrittenProductMethods.__eq__.__get__(
                self, type(self)
            )
        return super().__eq__

    @property
    def __ne__(self):  # pylint: disable=unexpected-special-method-signature
        if self.__eq_succeeded:
            # I think this is a Pylint bug, but I'm not sure how to reduce it.
            # pylint: disable=no-value-for-parameter
            return _prewritten_methods.PrewrittenProductMethods.__ne__.__get__(
                self, type(self)
            )
        return super().__ne__

    @property
    def __lt__(self):  # pylint: disable=unexpected-special-method-signature
        if self.__order:
            # I think this is a Pylint bug, but I'm not sure how to reduce it.
            # pylint: disable=no-value-for-parameter
            return _prewritten_methods.PrewrittenProductMethods.__lt__.__get__(
                self, type(self)
            )
        return super().__lt__

    @property
    def __le__(self):  # pylint: disable=unexpected-special-method-signature
        if self.__order:
            # I think this is a Pylint bug, but I'm not sure how to reduce it.
            # pylint: disable=no-value-for-parameter
            return _prewritten_methods.PrewrittenProductMethods.__le__.__get__(
                self, type(self)
            )
        return super().__le__

    @property
    def __gt__(self):  # pylint: disable=unexpected-special-method-signature
        if self.__order:
            # I think this is a Pylint bug, but I'm not sure how to reduce it.
            # pylint: disable=no-value-for-parameter
            return _prewritten_methods.PrewrittenProductMethods.__gt__.__get__(
                self, type(self)
            )
        return super().__gt__

    @property
    def __ge__(self):  # pylint: disable=unexpected-special-method-signature
        if self.__order:
            # I think this is a Pylint bug, but I'm not sure how to reduce it.
            # pylint: disable=no-value-for-parameter
            return _prewritten_methods.PrewrittenProductMethods.__ge__.__get__(
                self, type(self)
            )
        return super().__ge__


__all__ = ["Ctor", "Product", "Sum"]


1			"""Base classes for defining abstract data types.
2
3			This module provides three public members, which are used together.
4
5			Given a structure, possibly a choice of different structures, that you'd like
6			to associate with a type:
7
8			- First, create a class, that subclasses the Sum class.
9			- Then, for each possible structure, add an attribute annotation to the class
10			with the desired name of the constructor, and a type of ``Ctor``, with the
11			types within the constructor as arguments.
12
13			To look inside an ADT instance, use the functions from the
14			:mod:`structured_data.match` module.
15
16			Putting it together:
17
18			>>> from structured_data import match
19			>>> class Example(Sum):
20			... FirstConstructor: Ctor[int, str]
21			... SecondConstructor: Ctor[bytes]
22			... ThirdConstructor: Ctor
23			... def __iter__(self):
24			... matchable = match.Matchable(self)
25			... if matchable(Example.FirstConstructor(match.pat.count, match.pat.string)):
26			... count, string = matchable[match.pat.count, match.pat.string]
27			... for _ in range(count):
28			... yield string
29			... elif matchable(Example.SecondConstructor(match.pat.bytes)):
30			... bytes_ = matchable[match.pat.bytes]
31			... for byte in bytes_:
32			... yield chr(byte)
33			... elif matchable(Example.ThirdConstructor()):
34			... yield "Third"
35			... yield "Constructor"
36			>>> list(Example.FirstConstructor(5, "abc"))
37			['abc', 'abc', 'abc', 'abc', 'abc']
38			>>> list(Example.SecondConstructor(b"abc"))
39			['a', 'b', 'c']
40			>>> list(Example.ThirdConstructor())
41			['Third', 'Constructor']
42			"""
43
44			import inspect
45			import sys
46			import typing
47
48			from . import _adt_constructor
49			from . import _ctor
50			from . import _prewritten_methods
51
52			_T = typing.TypeVar("_T")
53
54
55			if typing.TYPE_CHECKING: # pragma: nocover
56
57			class Ctor:
58			"""Dummy class for type-checking purposes."""
59
60			class ConcreteCtor(typing.Generic[_T]):
61			"""Wrapper class for type-checking purposes.
62
63			The type parameter should be a Tuple type of fixed size.
64			Classes containing this annotation (meaning they haven't been
65			processed by the ``adt`` decorator) should not be instantiated.
66			"""
67
68
69			else:
70			from ._ctor import Ctor
71
72
73			# This is fine.
74			def _name(cls: typing.Type[_T], function) -> str:
75			"""Return the name of a function accessed through a descriptor."""
76			return function.__get__(None, cls).__name__
77
78
79			# This is mostly fine, though the list of classes is somewhat ad-hoc, to say
80			# the least.
81			def _cant_set_new_functions(cls: typing.Type[_T], *functions) -> typing.Optional[str]:
82			for function in functions:
83			name = _name(cls, function)
84			existing = getattr(cls, name, None)
85			if existing not in (
86			getattr(object, name, None),
87			getattr(Product, name, None),
88			None,
89			function,
90			):
91			return name
92			return None
93
94
95			def _set_new_functions(cls: typing.Type[_T], *functions) -> typing.Optional[str]:
96			"""Attempt to set the attributes corresponding to the functions on cls.
97
98			If any attributes are already defined, fail before setting any, and
99			return the already-defined name.
100			"""
101			cant_set = _cant_set_new_functions(cls, *functions)
102			if cant_set:
103			return cant_set
104			for function in functions:
105			setattr(cls, _name(cls, function), function)
106			return None
107
108
109			_K = typing.TypeVar("_K")
110			_V = typing.TypeVar("_V")
111
112
113			def _nillable_write(dct: typing.Dict[_K, _V], key: _K, value: typing.Optional[_V]):
114			if value is None:
115			dct.pop(key, typing.cast(_V, None))
116			else:
117			dct[key] = value
118
119
120			def _sum_new(_cls: typing.Type[_T], subclasses):
121			def base(cls, args):
122			return super(_cls, cls).__new__(cls, args)
123
124			new = _cls.__dict__.get("__new__", staticmethod(base))
125
126			def __new__(cls, args):
127			if cls not in subclasses:
128			raise TypeError
129			return new.__get__(None, cls)(cls, args)
130
131			_cls.__new__ = staticmethod(__new__) # type: ignore
132
133
134			def _product_new(
135			_cls: typing.Type[_T],
136			annotations: typing.Dict[str, typing.Any],
137			defaults: typing.Dict[str, typing.Any],
138			):
139			def __new__(args, *kwargs):
140			cls, *args = args
141			return super(_cls, cls).__new__(cls, args, *kwargs)
142
143			__new__.__signature__ = inspect.signature(__new__).replace(
144			parameters=[inspect.Parameter("cls", inspect.Parameter.POSITIONAL_ONLY)]
145			+ [
146			inspect.Parameter(
147			field,
148			inspect.Parameter.POSITIONAL_OR_KEYWORD,
149			annotation=annotation,
150			default=defaults.get(field, inspect.Parameter.empty),
151			)
152			for (field, annotation) in annotations.items()
153			]
154			)
155			_cls.__new__ = __new__
156
157
158			def _all_annotations(
159			cls: typing.Type[_T]
160			) -> typing.Iterator[typing.Tuple[typing.Type[_T], str, typing.Any]]:
161			for superclass in reversed(cls.__mro__):
162			for key, value in vars(superclass).get("__annotations__", {}).items():
163			yield (superclass, key, value)
164
165
166			def _sum_args_from_annotations(cls: typing.Type[_T]) -> typing.Dict[str, typing.Tuple]:
167			args: typing.Dict[str, typing.Tuple] = {}
168			for superclass, key, value in _all_annotations(cls):
169			_nillable_write(
170			args, key, _ctor.get_args(value, vars(sys.modules[superclass.__module__]))
171			)
172			return args
173
174
175			def _product_args_from_annotations(
176			cls: typing.Type[_T]
177			) -> typing.Dict[str, typing.Any]:
178			args: typing.Dict[str, typing.Any] = {}
179			for _, key, value in _all_annotations(cls):
180			if value == "None" or _ctor.annotation_is_classvar(
181			value, vars(sys.modules[cls.__module__])
182			):
183			value = None
184			_nillable_write(args, key, value)
185			return args
186
187
188			def _ordering_options_are_valid(*, eq, order):
189			if order and not eq:
190			raise ValueError("eq must be true if order is true")
191
192
193			def _set_ordering(*, can_set, setter, cls, source):
194			if not can_set:
195			raise ValueError("Can't add ordering methods if equality methods are provided.")
196			collision = setter(cls, source.__lt__, source.__le__, source.__gt__, source.__ge__)
197			if collision:
198			raise TypeError(
199			"Cannot overwrite attribute {collision} in class "
200			"{name}. Consider using functools.total_ordering".format(
201			collision=collision, name=cls.__name__
202			)
203			)
204
205
206			def _values_non_empty(cls, field_names):
207			for field in field_names:
208			default = getattr(cls, field, inspect.Parameter.empty)
209			if default is inspect.Parameter.empty:
210			return
211			yield (field, default)
212
213
214			def _values_until_non_empty(cls, field_names):
215			for field in field_names:
216			default = getattr(cls, field, inspect.Parameter.empty)
217			if default is not inspect.Parameter.empty:
218			yield
219
220
221			def _extract_defaults(*, cls, annotations):
222			field_names = iter(reversed(tuple(annotations)))
223			defaults = {
224			field: default for (field, default) in _values_non_empty(cls, field_names)
225			}
226			for _ in _values_until_non_empty(cls, field_names):
227			raise TypeError
228			return defaults
229
230
231			def _unpack_args(*, args, kwargs, fields, values):
232			fields_iter = iter(fields)
233			values.update({field: arg for (arg, field) in zip(args, fields_iter)})
234			for field in fields_iter:
235			if field in values and field not in kwargs:
236			continue
237			values[field] = kwargs.pop(field)
238			if kwargs:
239			raise TypeError(kwargs)
240
241
242			class Sum:
243			"""Base class of classes with disjoint constructors.
244
245			Examines PEP 526 __annotations__ to determine subclasses.
246
247			If repr is true, a __repr__() method is added to the class.
248			If order is true, rich comparison dunder methods are added.
249
250			The Sum class examines the class to find Ctor annotations.
251			A Ctor annotation is the adt.Ctor class itself, or the result of indexing
252			the class, either with a single type hint, or a tuple of type hints.
253			All other annotations are ignored.
254
255			The subclass is not subclassable, but has subclasses at each of the
256			names that had Ctor annotations. Each subclass takes a fixed number of
257			arguments, corresponding to the type hints given to its annotation, if any.
258			"""
259
260			__slots__ = ()
261
262			def __new__(args, *kwargs): # pylint: disable=no-method-argument
263			cls, *args = args
264			if not issubclass(cls, _adt_constructor.ADTConstructor):
265			raise TypeError
266			return super(Sum, cls).__new__(cls, args, *kwargs)
267
268			# Both of these are for consistency with modules defined in the stdlib.
269			# BOOM!
270			def __init_subclass__(
271			cls,
272			*,
273			repr=True, # pylint: disable=redefined-builtin
274			eq=True, # pylint: disable=invalid-name
275			order=False,
276			**kwargs
277			):
278			super().__init_subclass__(**kwargs)
279			if issubclass(cls, _adt_constructor.ADTConstructor):
280			return
281			_ordering_options_are_valid(eq=eq, order=order)
282
283			subclass_order: typing.List[typing.Type[_T]] = []
284
285			for name, args in _sum_args_from_annotations(cls).items():
286			_adt_constructor.make_constructor(cls, name, args, subclass_order)
287
288			_prewritten_methods.SUBCLASS_ORDER[cls] = tuple(subclass_order)
289
290			cls.__init_subclass__ = (
291			_prewritten_methods.PrewrittenSumMethods.__init_subclass__
292			) # type: ignore
293
294			_sum_new(cls, frozenset(subclass_order))
295
296			_set_new_functions(
297			cls,
298			_prewritten_methods.PrewrittenSumMethods.__setattr__,
299			_prewritten_methods.PrewrittenSumMethods.__delattr__,
300			)
301			_set_new_functions(cls, _prewritten_methods.PrewrittenSumMethods.__bool__)
302
303			if repr:
304			_set_new_functions(cls, _prewritten_methods.PrewrittenSumMethods.__repr__)
305
306			equality_methods_were_set = False
307			if eq:
308			equality_methods_were_set = not _set_new_functions(
309			cls,
310			_prewritten_methods.PrewrittenSumMethods.__eq__,
311			_prewritten_methods.PrewrittenSumMethods.__ne__,
312			)
313
314			if equality_methods_were_set:
315			cls.__hash__ = _prewritten_methods.PrewrittenSumMethods.__hash__
316
317			if order:
318			_set_ordering(
319			can_set=equality_methods_were_set,
320			setter=_set_new_functions,
321			cls=cls,
322			source=_prewritten_methods.PrewrittenSumMethods,
323			)
324
325
326			class Product(_adt_constructor.ADTConstructor, tuple):
327			"""Base class of classes with typed fields.
328
329			Examines PEP 526 __annotations__ to determine fields.
330
331			If repr is true, a __repr__() method is added to the class.
332			If order is true, rich comparison dunder methods are added.
333
334			The Product class examines the class to find annotations.
335			Annotations with a value of "None" are discarded.
336			Fields may have default values, and can be set to inspect.empty to
337			indicate "no default".
338
339			The subclass is subclassable. The implementation was designed with a focus
340			on flexibility over ideals of purity, and therefore provides various
341			optional facilities that conflict with, for example, Liskov
342			substitutability. For the purposes of matching, each class is considered
343			distinct.
344			"""
345
346			__slots__ = ()
347
348			def __new__(args, *kwargs): # pylint: disable=no-method-argument
349			cls, *args = args
350			if cls is Product:
351			raise TypeError
352			# Probably a result of not having positional-only args.
353			values = cls.__defaults.copy() # pylint: disable=protected-access
354			_unpack_args(
355			args=args,
356			kwargs=kwargs,
357			fields=cls.__fields, # pylint: disable=protected-access
358			values=values,
359			)
360			return super(Product, cls).__new__(
361			cls,
362			[
363			values[field]
364			for field in cls.__fields # pylint: disable=protected-access
365			],
366			)
367
368			__repr = True
369			__eq = True
370			__order = False
371			__eq_succeeded = None
372
373			# Both of these are for consistency with modules defined in the stdlib.
374			# BOOM!
375			def __init_subclass__(
376			cls,
377			*,
378			repr=None, # pylint: disable=redefined-builtin
379			eq=None, # pylint: disable=invalid-name
380			order=None,
381			**kwargs
382			):
383			super().__init_subclass__(**kwargs)
384
385			if repr is not None:
386			cls.__repr = repr
387			if eq is not None:
388			cls.__eq = eq
389			if order is not None:
390			cls.__order = order
391
392			_ordering_options_are_valid(eq=cls.__eq, order=cls.__order)
393
394			cls.__annotations = _product_args_from_annotations(cls)
395			cls.__fields = {field: index for (index, field) in enumerate(cls.__annotations)}
396
397			cls.__defaults = _extract_defaults(cls=cls, annotations=cls.__annotations)
398
399			_product_new(cls, cls.__annotations, cls.__defaults)
400
401			cls.__eq_succeeded = False
402			if cls.__eq:
403			cls.__eq_succeeded = not _cant_set_new_functions(
404			cls,
405			_prewritten_methods.PrewrittenProductMethods.__eq__,
406			_prewritten_methods.PrewrittenProductMethods.__ne__,
407			)
408
409			if cls.__order:
410			_set_ordering(
411			can_set=cls.__eq_succeeded,
412			setter=_cant_set_new_functions,
413			cls=cls,
414			source=_prewritten_methods.PrewrittenProductMethods,
415			)
416
417			def __dir__(self):
418			return super().__dir__() + list(self.__fields)
419
420			def __getattribute__(self, name):
421			try:
422			return super().__getattribute__(name)
423			except AttributeError:
424			index = self.__fields.get(name)
425			if index is None:
426			raise
427			return tuple.__getitem__(self, index)
428
429			__setattr__ = _prewritten_methods.PrewrittenProductMethods.__setattr__
430			__delattr__ = _prewritten_methods.PrewrittenProductMethods.__delattr__
431			__bool__ = _prewritten_methods.PrewrittenProductMethods.__bool__
432
433			@property
434			def __repr__(self):
435			if self.__repr:
436			return _prewritten_methods.PrewrittenProductMethods.__repr__.__get__(
437			self, type(self)
438			)
439			return super().__repr__
440
441			@property
442			def __hash__(self):
443			if self.__eq_succeeded:
444			return _prewritten_methods.PrewrittenProductMethods.__hash__.__get__(
445			self, type(self)
446			)
447			return super().__hash__
448
449			@property
450			def __eq__(self): # pylint: disable=unexpected-special-method-signature
451			if self.__eq_succeeded:
452			# I think this is a Pylint bug, but I'm not sure how to reduce it.
453			# pylint: disable=no-value-for-parameter
454			return _prewritten_methods.PrewrittenProductMethods.__eq__.__get__(
455			self, type(self)
456			)
457			return super().__eq__
458
459			@property
460			def __ne__(self): # pylint: disable=unexpected-special-method-signature
461			if self.__eq_succeeded:
462			# I think this is a Pylint bug, but I'm not sure how to reduce it.
463			# pylint: disable=no-value-for-parameter
464			return _prewritten_methods.PrewrittenProductMethods.__ne__.__get__(
465			self, type(self)
466			)
467			return super().__ne__
468
469			@property
470			def __lt__(self): # pylint: disable=unexpected-special-method-signature
471			if self.__order:
472			# I think this is a Pylint bug, but I'm not sure how to reduce it.
473			# pylint: disable=no-value-for-parameter
474			return _prewritten_methods.PrewrittenProductMethods.__lt__.__get__(
475			self, type(self)
476			)
477			return super().__lt__
478
479			@property
480			def __le__(self): # pylint: disable=unexpected-special-method-signature
481			if self.__order:
482			# I think this is a Pylint bug, but I'm not sure how to reduce it.
483			# pylint: disable=no-value-for-parameter
484			return _prewritten_methods.PrewrittenProductMethods.__le__.__get__(
485			self, type(self)
486			)
487			return super().__le__
488
489			@property
490			def __gt__(self): # pylint: disable=unexpected-special-method-signature
491			if self.__order:
492			# I think this is a Pylint bug, but I'm not sure how to reduce it.
493			# pylint: disable=no-value-for-parameter
494			return _prewritten_methods.PrewrittenProductMethods.__gt__.__get__(
495			self, type(self)
496			)
497			return super().__gt__
498
499			@property
500			def __ge__(self): # pylint: disable=unexpected-special-method-signature
501			if self.__order:
502			# I think this is a Pylint bug, but I'm not sure how to reduce it.
503			# pylint: disable=no-value-for-parameter
504			return _prewritten_methods.PrewrittenProductMethods.__ge__.__get__(
505			self, type(self)
506			)
507			return super().__ge__
508
509
510			__all__ = ["Ctor", "Product", "Sum"]
511

mwchase / python-structured-data

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structured_data.adt._values_non_empty() A

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