Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Tip revision: 7e16af499b92def6fc4ab1bbcecd2c055a38de29 authored by Ned Deily on 10 October 2016, 20:09:08 UTC
Version bump for 3.6.0b2
Version bump for 3.6.0b2
Tip revision: 7e16af4
typing.py
import abc
from abc import abstractmethod, abstractproperty
import collections
import contextlib
import functools
import re as stdlib_re # Avoid confusion with the re we export.
import sys
import types
try:
import collections.abc as collections_abc
except ImportError:
import collections as collections_abc # Fallback for PY3.2.
if sys.version_info[:2] >= (3, 3):
from collections import ChainMap
# Please keep __all__ alphabetized within each category.
__all__ = [
# Super-special typing primitives.
'Any',
'Callable',
'ClassVar',
'Generic',
'Optional',
'Tuple',
'Type',
'TypeVar',
'Union',
# ABCs (from collections.abc).
'AbstractSet', # collections.abc.Set.
'Awaitable',
'AsyncIterator',
'AsyncIterable',
'ByteString',
'Container',
'Hashable',
'ItemsView',
'Iterable',
'Iterator',
'KeysView',
'Mapping',
'MappingView',
'MutableMapping',
'MutableSequence',
'MutableSet',
'Sequence',
'Sized',
'ValuesView',
# Structural checks, a.k.a. protocols.
'Reversible',
'SupportsAbs',
'SupportsFloat',
'SupportsInt',
'SupportsRound',
# Concrete collection types.
'Dict',
'DefaultDict',
'List',
'Set',
'FrozenSet',
'NamedTuple', # Not really a type.
'Generator',
# One-off things.
'AnyStr',
'cast',
'get_type_hints',
'NewType',
'no_type_check',
'no_type_check_decorator',
'overload',
'Text',
'TYPE_CHECKING',
]
# The pseudo-submodules 're' and 'io' are part of the public
# namespace, but excluded from __all__ because they might stomp on
# legitimate imports of those modules.
def _qualname(x):
if sys.version_info[:2] >= (3, 3):
return x.__qualname__
else:
# Fall back to just name.
return x.__name__
def _trim_name(nm):
if nm.startswith('_') and nm not in ('_TypeAlias',
'_ForwardRef', '_TypingBase', '_FinalTypingBase'):
nm = nm[1:]
return nm
class TypingMeta(type):
"""Metaclass for every type defined below.
This overrides __new__() to require an extra keyword parameter
'_root', which serves as a guard against naive subclassing of the
typing classes. Any legitimate class defined using a metaclass
derived from TypingMeta (including internal subclasses created by
e.g. Union[X, Y]) must pass _root=True.
This also defines a dummy constructor (all the work is done in
__new__) and a nicer repr().
"""
_is_protocol = False
def __new__(cls, name, bases, namespace, *, _root=False):
if not _root:
raise TypeError("Cannot subclass %s" %
(', '.join(map(_type_repr, bases)) or '()'))
return super().__new__(cls, name, bases, namespace)
def __init__(self, *args, **kwds):
pass
def _eval_type(self, globalns, localns):
"""Override this in subclasses to interpret forward references.
For example, Union['C'] is internally stored as
Union[_ForwardRef('C')], which should evaluate to _Union[C],
where C is an object found in globalns or localns (searching
localns first, of course).
"""
return self
def _get_type_vars(self, tvars):
pass
def __repr__(self):
qname = _trim_name(_qualname(self))
return '%s.%s' % (self.__module__, qname)
class _TypingBase(metaclass=TypingMeta, _root=True):
"""Indicator of special typing constructs."""
__slots__ = ()
def __init__(self, *args, **kwds):
pass
def __new__(cls, *args, **kwds):
"""Constructor.
This only exists to give a better error message in case
someone tries to subclass a special typing object (not a good idea).
"""
if (len(args) == 3 and
isinstance(args[0], str) and
isinstance(args[1], tuple)):
# Close enough.
raise TypeError("Cannot subclass %r" % cls)
return super().__new__(cls)
# Things that are not classes also need these.
def _eval_type(self, globalns, localns):
return self
def _get_type_vars(self, tvars):
pass
def __repr__(self):
cls = type(self)
qname = _trim_name(_qualname(cls))
return '%s.%s' % (cls.__module__, qname)
def __call__(self, *args, **kwds):
raise TypeError("Cannot instantiate %r" % type(self))
class _FinalTypingBase(_TypingBase, _root=True):
"""Mix-in class to prevent instantiation.
Prevents instantiation unless _root=True is given in class call.
It is used to create pseudo-singleton instances Any, Union, Tuple, etc.
"""
__slots__ = ()
def __new__(cls, *args, _root=False, **kwds):
self = super().__new__(cls, *args, **kwds)
if _root is True:
return self
raise TypeError("Cannot instantiate %r" % cls)
class _ForwardRef(_TypingBase, _root=True):
"""Wrapper to hold a forward reference."""
__slots__ = ('__forward_arg__', '__forward_code__',
'__forward_evaluated__', '__forward_value__',
'__forward_frame__')
def __init__(self, arg):
super().__init__(arg)
if not isinstance(arg, str):
raise TypeError('ForwardRef must be a string -- got %r' % (arg,))
try:
code = compile(arg, '<string>', 'eval')
except SyntaxError:
raise SyntaxError('ForwardRef must be an expression -- got %r' %
(arg,))
self.__forward_arg__ = arg
self.__forward_code__ = code
self.__forward_evaluated__ = False
self.__forward_value__ = None
typing_globals = globals()
frame = sys._getframe(1)
while frame is not None and frame.f_globals is typing_globals:
frame = frame.f_back
assert frame is not None
self.__forward_frame__ = frame
def _eval_type(self, globalns, localns):
if not self.__forward_evaluated__:
if globalns is None and localns is None:
globalns = localns = {}
elif globalns is None:
globalns = localns
elif localns is None:
localns = globalns
self.__forward_value__ = _type_check(
eval(self.__forward_code__, globalns, localns),
"Forward references must evaluate to types.")
self.__forward_evaluated__ = True
return self.__forward_value__
def __eq__(self, other):
if not isinstance(other, _ForwardRef):
return NotImplemented
return (self.__forward_arg__ == other.__forward_arg__ and
self.__forward_frame__ == other.__forward_frame__)
def __hash__(self):
return hash((self.__forward_arg__, self.__forward_frame__))
def __instancecheck__(self, obj):
raise TypeError("Forward references cannot be used with isinstance().")
def __subclasscheck__(self, cls):
raise TypeError("Forward references cannot be used with issubclass().")
def __repr__(self):
return '_ForwardRef(%r)' % (self.__forward_arg__,)
class _TypeAlias(_TypingBase, _root=True):
"""Internal helper class for defining generic variants of concrete types.
Note that this is not a type; let's call it a pseudo-type. It cannot
be used in instance and subclass checks in parameterized form, i.e.
``isinstance(42, Match[str])`` raises ``TypeError`` instead of returning
``False``.
"""
__slots__ = ('name', 'type_var', 'impl_type', 'type_checker')
def __init__(self, name, type_var, impl_type, type_checker):
"""Initializer.
Args:
name: The name, e.g. 'Pattern'.
type_var: The type parameter, e.g. AnyStr, or the
specific type, e.g. str.
impl_type: The implementation type.
type_checker: Function that takes an impl_type instance.
and returns a value that should be a type_var instance.
"""
assert isinstance(name, str), repr(name)
assert isinstance(impl_type, type), repr(impl_type)
assert not isinstance(impl_type, TypingMeta), repr(impl_type)
assert isinstance(type_var, (type, _TypingBase)), repr(type_var)
self.name = name
self.type_var = type_var
self.impl_type = impl_type
self.type_checker = type_checker
def __repr__(self):
return "%s[%s]" % (self.name, _type_repr(self.type_var))
def __getitem__(self, parameter):
if not isinstance(self.type_var, TypeVar):
raise TypeError("%s cannot be further parameterized." % self)
if self.type_var.__constraints__ and isinstance(parameter, type):
if not issubclass(parameter, self.type_var.__constraints__):
raise TypeError("%s is not a valid substitution for %s." %
(parameter, self.type_var))
if isinstance(parameter, TypeVar):
raise TypeError("%s cannot be re-parameterized." % self.type_var)
return self.__class__(self.name, parameter,
self.impl_type, self.type_checker)
def __eq__(self, other):
if not isinstance(other, _TypeAlias):
return NotImplemented
return self.name == other.name and self.type_var == other.type_var
def __hash__(self):
return hash((self.name, self.type_var))
def __instancecheck__(self, obj):
if not isinstance(self.type_var, TypeVar):
raise TypeError("Parameterized type aliases cannot be used "
"with isinstance().")
return isinstance(obj, self.impl_type)
def __subclasscheck__(self, cls):
if not isinstance(self.type_var, TypeVar):
raise TypeError("Parameterized type aliases cannot be used "
"with issubclass().")
return issubclass(cls, self.impl_type)
def _get_type_vars(types, tvars):
for t in types:
if isinstance(t, TypingMeta) or isinstance(t, _TypingBase):
t._get_type_vars(tvars)
def _type_vars(types):
tvars = []
_get_type_vars(types, tvars)
return tuple(tvars)
def _eval_type(t, globalns, localns):
if isinstance(t, TypingMeta) or isinstance(t, _TypingBase):
return t._eval_type(globalns, localns)
else:
return t
def _type_check(arg, msg):
"""Check that the argument is a type, and return it.
As a special case, accept None and return type(None) instead.
Also, _TypeAlias instances (e.g. Match, Pattern) are acceptable.
The msg argument is a human-readable error message, e.g.
"Union[arg, ...]: arg should be a type."
We append the repr() of the actual value (truncated to 100 chars).
"""
if arg is None:
return type(None)
if isinstance(arg, str):
arg = _ForwardRef(arg)
if not isinstance(arg, (type, _TypingBase)) and not callable(arg):
raise TypeError(msg + " Got %.100r." % (arg,))
return arg
def _type_repr(obj):
"""Return the repr() of an object, special-casing types.
If obj is a type, we return a shorter version than the default
type.__repr__, based on the module and qualified name, which is
typically enough to uniquely identify a type. For everything
else, we fall back on repr(obj).
"""
if isinstance(obj, type) and not isinstance(obj, TypingMeta):
if obj.__module__ == 'builtins':
return _qualname(obj)
else:
return '%s.%s' % (obj.__module__, _qualname(obj))
else:
return repr(obj)
class _Any(_FinalTypingBase, _root=True):
"""Special type indicating an unconstrained type.
- Any is compatible with every type.
- Any assumed to have all methods.
- All values assumed to be instances of Any.
Note that all the above statements are true from the point of view of
static type checkers. At runtime, Any should not be used with instance
or class checks.
"""
__slots__ = ()
def __instancecheck__(self, obj):
raise TypeError("Any cannot be used with isinstance().")
def __subclasscheck__(self, cls):
raise TypeError("Any cannot be used with issubclass().")
Any = _Any(_root=True)
class TypeVar(_TypingBase, _root=True):
"""Type variable.
Usage::
T = TypeVar('T') # Can be anything
A = TypeVar('A', str, bytes) # Must be str or bytes
Type variables exist primarily for the benefit of static type
checkers. They serve as the parameters for generic types as well
as for generic function definitions. See class Generic for more
information on generic types. Generic functions work as follows:
def repeat(x: T, n: int) -> Sequence[T]:
'''Return a list containing n references to x.'''
return [x]*n
def longest(x: A, y: A) -> A:
'''Return the longest of two strings.'''
return x if len(x) >= len(y) else y
The latter example's signature is essentially the overloading
of (str, str) -> str and (bytes, bytes) -> bytes. Also note
that if the arguments are instances of some subclass of str,
the return type is still plain str.
At runtime, isinstance(x, T) will raise TypeError. However,
issubclass(C, T) is true for any class C, and issubclass(str, A)
and issubclass(bytes, A) are true, and issubclass(int, A) is
false. (TODO: Why is this needed? This may change. See #136.)
Type variables defined with covariant=True or contravariant=True
can be used do declare covariant or contravariant generic types.
See PEP 484 for more details. By default generic types are invariant
in all type variables.
Type variables can be introspected. e.g.:
T.__name__ == 'T'
T.__constraints__ == ()
T.__covariant__ == False
T.__contravariant__ = False
A.__constraints__ == (str, bytes)
"""
__slots__ = ('__name__', '__bound__', '__constraints__',
'__covariant__', '__contravariant__')
def __init__(self, name, *constraints, bound=None,
covariant=False, contravariant=False):
super().__init__(name, *constraints, bound=bound,
covariant=covariant, contravariant=contravariant)
self.__name__ = name
if covariant and contravariant:
raise ValueError("Bivariant types are not supported.")
self.__covariant__ = bool(covariant)
self.__contravariant__ = bool(contravariant)
if constraints and bound is not None:
raise TypeError("Constraints cannot be combined with bound=...")
if constraints and len(constraints) == 1:
raise TypeError("A single constraint is not allowed")
msg = "TypeVar(name, constraint, ...): constraints must be types."
self.__constraints__ = tuple(_type_check(t, msg) for t in constraints)
if bound:
self.__bound__ = _type_check(bound, "Bound must be a type.")
else:
self.__bound__ = None
def _get_type_vars(self, tvars):
if self not in tvars:
tvars.append(self)
def __repr__(self):
if self.__covariant__:
prefix = '+'
elif self.__contravariant__:
prefix = '-'
else:
prefix = '~'
return prefix + self.__name__
def __instancecheck__(self, instance):
raise TypeError("Type variables cannot be used with isinstance().")
def __subclasscheck__(self, cls):
raise TypeError("Type variables cannot be used with issubclass().")
# Some unconstrained type variables. These are used by the container types.
# (These are not for export.)
T = TypeVar('T') # Any type.
KT = TypeVar('KT') # Key type.
VT = TypeVar('VT') # Value type.
T_co = TypeVar('T_co', covariant=True) # Any type covariant containers.
V_co = TypeVar('V_co', covariant=True) # Any type covariant containers.
VT_co = TypeVar('VT_co', covariant=True) # Value type covariant containers.
T_contra = TypeVar('T_contra', contravariant=True) # Ditto contravariant.
# A useful type variable with constraints. This represents string types.
# (This one *is* for export!)
AnyStr = TypeVar('AnyStr', bytes, str)
def _tp_cache(func):
cached = functools.lru_cache()(func)
@functools.wraps(func)
def inner(*args, **kwds):
try:
return cached(*args, **kwds)
except TypeError:
pass # All real errors (not unhashable args) are raised below.
return func(*args, **kwds)
return inner
class _Union(_FinalTypingBase, _root=True):
"""Union type; Union[X, Y] means either X or Y.
To define a union, use e.g. Union[int, str]. Details:
- The arguments must be types and there must be at least one.
- None as an argument is a special case and is replaced by
type(None).
- Unions of unions are flattened, e.g.::
Union[Union[int, str], float] == Union[int, str, float]
- Unions of a single argument vanish, e.g.::
Union[int] == int # The constructor actually returns int
- Redundant arguments are skipped, e.g.::
Union[int, str, int] == Union[int, str]
- When comparing unions, the argument order is ignored, e.g.::
Union[int, str] == Union[str, int]
- When two arguments have a subclass relationship, the least
derived argument is kept, e.g.::
class Employee: pass
class Manager(Employee): pass
Union[int, Employee, Manager] == Union[int, Employee]
Union[Manager, int, Employee] == Union[int, Employee]
Union[Employee, Manager] == Employee
- Similar for object::
Union[int, object] == object
- You cannot subclass or instantiate a union.
- You cannot write Union[X][Y] (what would it mean?).
- You can use Optional[X] as a shorthand for Union[X, None].
"""
__slots__ = ('__union_params__', '__union_set_params__')
def __new__(cls, parameters=None, *args, _root=False):
self = super().__new__(cls, parameters, *args, _root=_root)
if parameters is None:
self.__union_params__ = None
self.__union_set_params__ = None
return self
if not isinstance(parameters, tuple):
raise TypeError("Expected parameters=<tuple>")
# Flatten out Union[Union[...], ...] and type-check non-Union args.
params = []
msg = "Union[arg, ...]: each arg must be a type."
for p in parameters:
if isinstance(p, _Union):
params.extend(p.__union_params__)
else:
params.append(_type_check(p, msg))
# Weed out strict duplicates, preserving the first of each occurrence.
all_params = set(params)
if len(all_params) < len(params):
new_params = []
for t in params:
if t in all_params:
new_params.append(t)
all_params.remove(t)
params = new_params
assert not all_params, all_params
# Weed out subclasses.
# E.g. Union[int, Employee, Manager] == Union[int, Employee].
# If object is present it will be sole survivor among proper classes.
# Never discard type variables.
# (In particular, Union[str, AnyStr] != AnyStr.)
all_params = set(params)
for t1 in params:
if not isinstance(t1, type):
continue
if any(isinstance(t2, type) and issubclass(t1, t2)
for t2 in all_params - {t1}
if not (isinstance(t2, GenericMeta) and
t2.__origin__ is not None)):
all_params.remove(t1)
# It's not a union if there's only one type left.
if len(all_params) == 1:
return all_params.pop()
self.__union_params__ = tuple(t for t in params if t in all_params)
self.__union_set_params__ = frozenset(self.__union_params__)
return self
def _eval_type(self, globalns, localns):
p = tuple(_eval_type(t, globalns, localns)
for t in self.__union_params__)
if p == self.__union_params__:
return self
else:
return self.__class__(p, _root=True)
def _get_type_vars(self, tvars):
if self.__union_params__:
_get_type_vars(self.__union_params__, tvars)
def __repr__(self):
r = super().__repr__()
if self.__union_params__:
r += '[%s]' % (', '.join(_type_repr(t)
for t in self.__union_params__))
return r
@_tp_cache
def __getitem__(self, parameters):
if self.__union_params__ is not None:
raise TypeError(
"Cannot subscript an existing Union. Use Union[u, t] instead.")
if parameters == ():
raise TypeError("Cannot take a Union of no types.")
if not isinstance(parameters, tuple):
parameters = (parameters,)
return self.__class__(parameters, _root=True)
def __eq__(self, other):
if not isinstance(other, _Union):
return NotImplemented
return self.__union_set_params__ == other.__union_set_params__
def __hash__(self):
return hash(self.__union_set_params__)
def __instancecheck__(self, obj):
raise TypeError("Unions cannot be used with isinstance().")
def __subclasscheck__(self, cls):
raise TypeError("Unions cannot be used with issubclass().")
Union = _Union(_root=True)
class _Optional(_FinalTypingBase, _root=True):
"""Optional type.
Optional[X] is equivalent to Union[X, None].
"""
__slots__ = ()
@_tp_cache
def __getitem__(self, arg):
arg = _type_check(arg, "Optional[t] requires a single type.")
return Union[arg, type(None)]
Optional = _Optional(_root=True)
class _Tuple(_FinalTypingBase, _root=True):
"""Tuple type; Tuple[X, Y] is the cross-product type of X and Y.
Example: Tuple[T1, T2] is a tuple of two elements corresponding
to type variables T1 and T2. Tuple[int, float, str] is a tuple
of an int, a float and a string.
To specify a variable-length tuple of homogeneous type, use Tuple[T, ...].
"""
__slots__ = ('__tuple_params__', '__tuple_use_ellipsis__')
def __init__(self, parameters=None,
use_ellipsis=False, _root=False):
self.__tuple_params__ = parameters
self.__tuple_use_ellipsis__ = use_ellipsis
def _get_type_vars(self, tvars):
if self.__tuple_params__:
_get_type_vars(self.__tuple_params__, tvars)
def _eval_type(self, globalns, localns):
tp = self.__tuple_params__
if tp is None:
return self
p = tuple(_eval_type(t, globalns, localns) for t in tp)
if p == self.__tuple_params__:
return self
else:
return self.__class__(p, _root=True)
def __repr__(self):
r = super().__repr__()
if self.__tuple_params__ is not None:
params = [_type_repr(p) for p in self.__tuple_params__]
if self.__tuple_use_ellipsis__:
params.append('...')
if not params:
params.append('()')
r += '[%s]' % (
', '.join(params))
return r
@_tp_cache
def __getitem__(self, parameters):
if self.__tuple_params__ is not None:
raise TypeError("Cannot re-parameterize %r" % (self,))
if not isinstance(parameters, tuple):
parameters = (parameters,)
if len(parameters) == 2 and parameters[1] == Ellipsis:
parameters = parameters[:1]
use_ellipsis = True
msg = "Tuple[t, ...]: t must be a type."
else:
use_ellipsis = False
msg = "Tuple[t0, t1, ...]: each t must be a type."
parameters = tuple(_type_check(p, msg) for p in parameters)
return self.__class__(parameters,
use_ellipsis=use_ellipsis, _root=True)
def __eq__(self, other):
if not isinstance(other, _Tuple):
return NotImplemented
return (self.__tuple_params__ == other.__tuple_params__ and
self.__tuple_use_ellipsis__ == other.__tuple_use_ellipsis__)
def __hash__(self):
return hash((self.__tuple_params__, self.__tuple_use_ellipsis__))
def __instancecheck__(self, obj):
if self.__tuple_params__ == None:
return isinstance(obj, tuple)
raise TypeError("Parameterized Tuple cannot be used "
"with isinstance().")
def __subclasscheck__(self, cls):
if self.__tuple_params__ == None:
return issubclass(cls, tuple)
raise TypeError("Parameterized Tuple cannot be used "
"with issubclass().")
Tuple = _Tuple(_root=True)
class _Callable(_FinalTypingBase, _root=True):
"""Callable type; Callable[[int], str] is a function of (int) -> str.
The subscription syntax must always be used with exactly two
values: the argument list and the return type. The argument list
must be a list of types; the return type must be a single type.
There is no syntax to indicate optional or keyword arguments,
such function types are rarely used as callback types.
"""
__slots__ = ('__args__', '__result__')
def __init__(self, args=None, result=None, _root=False):
if args is None and result is None:
pass
else:
if args is not Ellipsis:
if not isinstance(args, list):
raise TypeError("Callable[args, result]: "
"args must be a list."
" Got %.100r." % (args,))
msg = "Callable[[arg, ...], result]: each arg must be a type."
args = tuple(_type_check(arg, msg) for arg in args)
msg = "Callable[args, result]: result must be a type."
result = _type_check(result, msg)
self.__args__ = args
self.__result__ = result
def _get_type_vars(self, tvars):
if self.__args__ and self.__args__ is not Ellipsis:
_get_type_vars(self.__args__, tvars)
def _eval_type(self, globalns, localns):
if self.__args__ is None and self.__result__ is None:
return self
if self.__args__ is Ellipsis:
args = self.__args__
else:
args = [_eval_type(t, globalns, localns) for t in self.__args__]
result = _eval_type(self.__result__, globalns, localns)
if args == self.__args__ and result == self.__result__:
return self
else:
return self.__class__(args, result, _root=True)
def __repr__(self):
r = super().__repr__()
if self.__args__ is not None or self.__result__ is not None:
if self.__args__ is Ellipsis:
args_r = '...'
else:
args_r = '[%s]' % ', '.join(_type_repr(t)
for t in self.__args__)
r += '[%s, %s]' % (args_r, _type_repr(self.__result__))
return r
def __getitem__(self, parameters):
if self.__args__ is not None or self.__result__ is not None:
raise TypeError("This Callable type is already parameterized.")
if not isinstance(parameters, tuple) or len(parameters) != 2:
raise TypeError(
"Callable must be used as Callable[[arg, ...], result].")
args, result = parameters
return self.__class__(args, result, _root=True)
def __eq__(self, other):
if not isinstance(other, _Callable):
return NotImplemented
return (self.__args__ == other.__args__ and
self.__result__ == other.__result__)
def __hash__(self):
return hash(self.__args__) ^ hash(self.__result__)
def __instancecheck__(self, obj):
# For unparametrized Callable we allow this, because
# typing.Callable should be equivalent to
# collections.abc.Callable.
if self.__args__ is None and self.__result__ is None:
return isinstance(obj, collections_abc.Callable)
else:
raise TypeError("Parameterized Callable cannot be used "
"with isinstance().")
def __subclasscheck__(self, cls):
if self.__args__ is None and self.__result__ is None:
return issubclass(cls, collections_abc.Callable)
else:
raise TypeError("Parameterized Callable cannot be used "
"with issubclass().")
Callable = _Callable(_root=True)
def _gorg(a):
"""Return the farthest origin of a generic class."""
assert isinstance(a, GenericMeta)
while a.__origin__ is not None:
a = a.__origin__
return a
def _geqv(a, b):
"""Return whether two generic classes are equivalent.
The intention is to consider generic class X and any of its
parameterized forms (X[T], X[int], etc.) as equivalent.
However, X is not equivalent to a subclass of X.
The relation is reflexive, symmetric and transitive.
"""
assert isinstance(a, GenericMeta) and isinstance(b, GenericMeta)
# Reduce each to its origin.
return _gorg(a) is _gorg(b)
def _next_in_mro(cls):
"""Helper for Generic.__new__.
Returns the class after the last occurrence of Generic or
Generic[...] in cls.__mro__.
"""
next_in_mro = object
# Look for the last occurrence of Generic or Generic[...].
for i, c in enumerate(cls.__mro__[:-1]):
if isinstance(c, GenericMeta) and _gorg(c) is Generic:
next_in_mro = cls.__mro__[i+1]
return next_in_mro
def _valid_for_check(cls):
if cls is Generic:
raise TypeError("Class %r cannot be used with class "
"or instance checks" % cls)
if (cls.__origin__ is not None and
sys._getframe(3).f_globals['__name__'] not in ['abc', 'functools']):
raise TypeError("Parameterized generics cannot be used with class "
"or instance checks")
def _make_subclasshook(cls):
"""Construct a __subclasshook__ callable that incorporates
the associated __extra__ class in subclass checks performed
against cls.
"""
if isinstance(cls.__extra__, abc.ABCMeta):
# The logic mirrors that of ABCMeta.__subclasscheck__.
# Registered classes need not be checked here because
# cls and its extra share the same _abc_registry.
def __extrahook__(subclass):
_valid_for_check(cls)
res = cls.__extra__.__subclasshook__(subclass)
if res is not NotImplemented:
return res
if cls.__extra__ in subclass.__mro__:
return True
for scls in cls.__extra__.__subclasses__():
if isinstance(scls, GenericMeta):
continue
if issubclass(subclass, scls):
return True
return NotImplemented
else:
# For non-ABC extras we'll just call issubclass().
def __extrahook__(subclass):
_valid_for_check(cls)
if cls.__extra__ and issubclass(subclass, cls.__extra__):
return True
return NotImplemented
return __extrahook__
class GenericMeta(TypingMeta, abc.ABCMeta):
"""Metaclass for generic types."""
def __new__(cls, name, bases, namespace,
tvars=None, args=None, origin=None, extra=None):
if extra is not None and type(extra) is abc.ABCMeta and extra not in bases:
bases = (extra,) + bases
self = super().__new__(cls, name, bases, namespace, _root=True)
if tvars is not None:
# Called from __getitem__() below.
assert origin is not None
assert all(isinstance(t, TypeVar) for t in tvars), tvars
else:
# Called from class statement.
assert tvars is None, tvars
assert args is None, args
assert origin is None, origin
# Get the full set of tvars from the bases.
tvars = _type_vars(bases)
# Look for Generic[T1, ..., Tn].
# If found, tvars must be a subset of it.
# If not found, tvars is it.
# Also check for and reject plain Generic,
# and reject multiple Generic[...].
gvars = None
for base in bases:
if base is Generic:
raise TypeError("Cannot inherit from plain Generic")
if (isinstance(base, GenericMeta) and
base.__origin__ is Generic):
if gvars is not None:
raise TypeError(
"Cannot inherit from Generic[...] multiple types.")
gvars = base.__parameters__
if gvars is None:
gvars = tvars
else:
tvarset = set(tvars)
gvarset = set(gvars)
if not tvarset <= gvarset:
raise TypeError(
"Some type variables (%s) "
"are not listed in Generic[%s]" %
(", ".join(str(t) for t in tvars if t not in gvarset),
", ".join(str(g) for g in gvars)))
tvars = gvars
self.__parameters__ = tvars
self.__args__ = args
self.__origin__ = origin
self.__extra__ = extra
# Speed hack (https://github.com/python/typing/issues/196).
self.__next_in_mro__ = _next_in_mro(self)
# This allows unparameterized generic collections to be used
# with issubclass() and isinstance() in the same way as their
# collections.abc counterparts (e.g., isinstance([], Iterable)).
if ('__subclasshook__' not in namespace and extra # allow overriding
or hasattr(self.__subclasshook__, '__name__') and
self.__subclasshook__.__name__ == '__extrahook__'):
self.__subclasshook__ = _make_subclasshook(self)
if isinstance(extra, abc.ABCMeta):
self._abc_registry = extra._abc_registry
return self
def _get_type_vars(self, tvars):
if self.__origin__ and self.__parameters__:
_get_type_vars(self.__parameters__, tvars)
def __repr__(self):
if self.__origin__ is not None:
r = repr(self.__origin__)
else:
r = super().__repr__()
if self.__args__:
r += '[%s]' % (
', '.join(_type_repr(p) for p in self.__args__))
if self.__parameters__:
r += '<%s>' % (
', '.join(_type_repr(p) for p in self.__parameters__))
return r
def __eq__(self, other):
if not isinstance(other, GenericMeta):
return NotImplemented
if self.__origin__ is not None:
return (self.__origin__ is other.__origin__ and
self.__args__ == other.__args__ and
self.__parameters__ == other.__parameters__)
else:
return self is other
def __hash__(self):
return hash((self.__name__, self.__parameters__))
@_tp_cache
def __getitem__(self, params):
if not isinstance(params, tuple):
params = (params,)
if not params:
raise TypeError(
"Parameter list to %s[...] cannot be empty" % _qualname(self))
msg = "Parameters to generic types must be types."
params = tuple(_type_check(p, msg) for p in params)
if self is Generic:
# Generic can only be subscripted with unique type variables.
if not all(isinstance(p, TypeVar) for p in params):
raise TypeError(
"Parameters to Generic[...] must all be type variables")
if len(set(params)) != len(params):
raise TypeError(
"Parameters to Generic[...] must all be unique")
tvars = params
args = None
elif self is _Protocol:
# _Protocol is internal, don't check anything.
tvars = params
args = None
elif self.__origin__ in (Generic, _Protocol):
# Can't subscript Generic[...] or _Protocol[...].
raise TypeError("Cannot subscript already-subscripted %s" %
repr(self))
else:
# Subscripting a regular Generic subclass.
if not self.__parameters__:
raise TypeError("%s is not a generic class" % repr(self))
alen = len(params)
elen = len(self.__parameters__)
if alen != elen:
raise TypeError(
"Too %s parameters for %s; actual %s, expected %s" %
("many" if alen > elen else "few", repr(self), alen, elen))
tvars = _type_vars(params)
args = params
return self.__class__(self.__name__,
(self,) + self.__bases__,
dict(self.__dict__),
tvars=tvars,
args=args,
origin=self,
extra=self.__extra__)
def __instancecheck__(self, instance):
# Since we extend ABC.__subclasscheck__ and
# ABC.__instancecheck__ inlines the cache checking done by the
# latter, we must extend __instancecheck__ too. For simplicity
# we just skip the cache check -- instance checks for generic
# classes are supposed to be rare anyways.
return issubclass(instance.__class__, self)
# Prevent checks for Generic to crash when defining Generic.
Generic = None
class Generic(metaclass=GenericMeta):
"""Abstract base class for generic types.
A generic type is typically declared by inheriting from an
instantiation of this class with one or more type variables.
For example, a generic mapping type might be defined as::
class Mapping(Generic[KT, VT]):
def __getitem__(self, key: KT) -> VT:
...
# Etc.
This class can then be used as follows::
def lookup_name(mapping: Mapping[KT, VT], key: KT, default: VT) -> VT:
try:
return mapping[key]
except KeyError:
return default
"""
__slots__ = ()
def __new__(cls, *args, **kwds):
if cls.__origin__ is None:
return cls.__next_in_mro__.__new__(cls)
else:
origin = _gorg(cls)
obj = cls.__next_in_mro__.__new__(origin)
obj.__init__(*args, **kwds)
return obj
class _ClassVar(_FinalTypingBase, _root=True):
"""Special type construct to mark class variables.
An annotation wrapped in ClassVar indicates that a given
attribute is intended to be used as a class variable and
should not be set on instances of that class. Usage::
class Starship:
stats: ClassVar[Dict[str, int]] = {} # class variable
damage: int = 10 # instance variable
ClassVar accepts only types and cannot be further subscribed.
Note that ClassVar is not a class itself, and should not
be used with isinstance() or issubclass().
"""
__slots__ = ('__type__',)
def __init__(self, tp=None, **kwds):
self.__type__ = tp
def __getitem__(self, item):
cls = type(self)
if self.__type__ is None:
return cls(_type_check(item,
'{} accepts only single type.'.format(cls.__name__[1:])),
_root=True)
raise TypeError('{} cannot be further subscripted'
.format(cls.__name__[1:]))
def _eval_type(self, globalns, localns):
new_tp = _eval_type(self.__type__, globalns, localns)
if new_tp == self.__type__:
return self
return type(self)(new_tp, _root=True)
def _get_type_vars(self, tvars):
if self.__type__:
_get_type_vars(self.__type__, tvars)
def __repr__(self):
r = super().__repr__()
if self.__type__ is not None:
r += '[{}]'.format(_type_repr(self.__type__))
return r
def __hash__(self):
return hash((type(self).__name__, self.__type__))
def __eq__(self, other):
if not isinstance(other, _ClassVar):
return NotImplemented
if self.__type__ is not None:
return self.__type__ == other.__type__
return self is other
ClassVar = _ClassVar(_root=True)
def cast(typ, val):
"""Cast a value to a type.
This returns the value unchanged. To the type checker this
signals that the return value has the designated type, but at
runtime we intentionally don't check anything (we want this
to be as fast as possible).
"""
return val
def _get_defaults(func):
"""Internal helper to extract the default arguments, by name."""
code = func.__code__
pos_count = code.co_argcount
arg_names = code.co_varnames
arg_names = arg_names[:pos_count]
defaults = func.__defaults__ or ()
kwdefaults = func.__kwdefaults__
res = dict(kwdefaults) if kwdefaults else {}
pos_offset = pos_count - len(defaults)
for name, value in zip(arg_names[pos_offset:], defaults):
assert name not in res
res[name] = value
return res
if sys.version_info[:2] >= (3, 3):
def get_type_hints(obj, globalns=None, localns=None):
"""Return type hints for an object.
This is often the same as obj.__annotations__, but it handles
forward references encoded as string literals, and if necessary
adds Optional[t] if a default value equal to None is set.
The argument may be a module, class, method, or function. The annotations
are returned as a dictionary, or in the case of a class, a ChainMap of
dictionaries.
TypeError is raised if the argument is not of a type that can contain
annotations, and an empty dictionary is returned if no annotations are
present.
BEWARE -- the behavior of globalns and localns is counterintuitive
(unless you are familiar with how eval() and exec() work). The
search order is locals first, then globals.
- If no dict arguments are passed, an attempt is made to use the
globals from obj, and these are also used as the locals. If the
object does not appear to have globals, an exception is raised.
- If one dict argument is passed, it is used for both globals and
locals.
- If two dict arguments are passed, they specify globals and
locals, respectively.
"""
if getattr(obj, '__no_type_check__', None):
return {}
if globalns is None:
globalns = getattr(obj, '__globals__', {})
if localns is None:
localns = globalns
elif localns is None:
localns = globalns
if (isinstance(obj, types.FunctionType) or
isinstance(obj, types.BuiltinFunctionType) or
isinstance(obj, types.MethodType)):
defaults = _get_defaults(obj)
hints = obj.__annotations__
for name, value in hints.items():
if value is None:
value = type(None)
if isinstance(value, str):
value = _ForwardRef(value)
value = _eval_type(value, globalns, localns)
if name in defaults and defaults[name] is None:
value = Optional[value]
hints[name] = value
return hints
if isinstance(obj, types.ModuleType):
try:
hints = obj.__annotations__
except AttributeError:
return {}
# we keep only those annotations that can be accessed on module
members = obj.__dict__
hints = {name: value for name, value in hints.items()
if name in members}
for name, value in hints.items():
if value is None:
value = type(None)
if isinstance(value, str):
value = _ForwardRef(value)
value = _eval_type(value, globalns, localns)
hints[name] = value
return hints
if isinstance(object, type):
cmap = None
for base in reversed(obj.__mro__):
new_map = collections.ChainMap if cmap is None else cmap.new_child
try:
hints = base.__dict__['__annotations__']
except KeyError:
cmap = new_map()
else:
for name, value in hints.items():
if value is None:
value = type(None)
if isinstance(value, str):
value = _ForwardRef(value)
value = _eval_type(value, globalns, localns)
hints[name] = value
cmap = new_map(hints)
return cmap
raise TypeError('{!r} is not a module, class, method, '
'or function.'.format(obj))
else:
def get_type_hints(obj, globalns=None, localns=None):
"""Return type hints for a function or method object.
This is often the same as obj.__annotations__, but it handles
forward references encoded as string literals, and if necessary
adds Optional[t] if a default value equal to None is set.
BEWARE -- the behavior of globalns and localns is counterintuitive
(unless you are familiar with how eval() and exec() work). The
search order is locals first, then globals.
- If no dict arguments are passed, an attempt is made to use the
globals from obj, and these are also used as the locals. If the
object does not appear to have globals, an exception is raised.
- If one dict argument is passed, it is used for both globals and
locals.
- If two dict arguments are passed, they specify globals and
locals, respectively.
"""
if getattr(obj, '__no_type_check__', None):
return {}
if globalns is None:
globalns = getattr(obj, '__globals__', {})
if localns is None:
localns = globalns
elif localns is None:
localns = globalns
defaults = _get_defaults(obj)
hints = dict(obj.__annotations__)
for name, value in hints.items():
if isinstance(value, str):
value = _ForwardRef(value)
value = _eval_type(value, globalns, localns)
if name in defaults and defaults[name] is None:
value = Optional[value]
hints[name] = value
return hints
def no_type_check(arg):
"""Decorator to indicate that annotations are not type hints.
The argument must be a class or function; if it is a class, it
applies recursively to all methods and classes defined in that class
(but not to methods defined in its superclasses or subclasses).
This mutates the function(s) or class(es) in place.
"""
if isinstance(arg, type):
arg_attrs = arg.__dict__.copy()
for attr, val in arg.__dict__.items():
if val in arg.__bases__:
arg_attrs.pop(attr)
for obj in arg_attrs.values():
if isinstance(obj, types.FunctionType):
obj.__no_type_check__ = True
if isinstance(obj, type):
no_type_check(obj)
try:
arg.__no_type_check__ = True
except TypeError: # built-in classes
pass
return arg
def no_type_check_decorator(decorator):
"""Decorator to give another decorator the @no_type_check effect.
This wraps the decorator with something that wraps the decorated
function in @no_type_check.
"""
@functools.wraps(decorator)
def wrapped_decorator(*args, **kwds):
func = decorator(*args, **kwds)
func = no_type_check(func)
return func
return wrapped_decorator
def _overload_dummy(*args, **kwds):
"""Helper for @overload to raise when called."""
raise NotImplementedError(
"You should not call an overloaded function. "
"A series of @overload-decorated functions "
"outside a stub module should always be followed "
"by an implementation that is not @overload-ed.")
def overload(func):
"""Decorator for overloaded functions/methods.
In a stub file, place two or more stub definitions for the same
function in a row, each decorated with @overload. For example:
@overload
def utf8(value: None) -> None: ...
@overload
def utf8(value: bytes) -> bytes: ...
@overload
def utf8(value: str) -> bytes: ...
In a non-stub file (i.e. a regular .py file), do the same but
follow it with an implementation. The implementation should *not*
be decorated with @overload. For example:
@overload
def utf8(value: None) -> None: ...
@overload
def utf8(value: bytes) -> bytes: ...
@overload
def utf8(value: str) -> bytes: ...
def utf8(value):
# implementation goes here
"""
return _overload_dummy
class _ProtocolMeta(GenericMeta):
"""Internal metaclass for _Protocol.
This exists so _Protocol classes can be generic without deriving
from Generic.
"""
def __instancecheck__(self, obj):
raise TypeError("Protocols cannot be used with isinstance().")
def __subclasscheck__(self, cls):
if not self._is_protocol:
# No structural checks since this isn't a protocol.
return NotImplemented
if self is _Protocol:
# Every class is a subclass of the empty protocol.
return True
# Find all attributes defined in the protocol.
attrs = self._get_protocol_attrs()
for attr in attrs:
if not any(attr in d.__dict__ for d in cls.__mro__):
return False
return True
def _get_protocol_attrs(self):
# Get all Protocol base classes.
protocol_bases = []
for c in self.__mro__:
if getattr(c, '_is_protocol', False) and c.__name__ != '_Protocol':
protocol_bases.append(c)
# Get attributes included in protocol.
attrs = set()
for base in protocol_bases:
for attr in base.__dict__.keys():
# Include attributes not defined in any non-protocol bases.
for c in self.__mro__:
if (c is not base and attr in c.__dict__ and
not getattr(c, '_is_protocol', False)):
break
else:
if (not attr.startswith('_abc_') and
attr != '__abstractmethods__' and
attr != '__annotations__' and
attr != '__weakref__' and
attr != '_is_protocol' and
attr != '__dict__' and
attr != '__args__' and
attr != '__slots__' and
attr != '_get_protocol_attrs' and
attr != '__next_in_mro__' and
attr != '__parameters__' and
attr != '__origin__' and
attr != '__extra__' and
attr != '__module__'):
attrs.add(attr)
return attrs
class _Protocol(metaclass=_ProtocolMeta):
"""Internal base class for protocol classes.
This implements a simple-minded structural isinstance check
(similar but more general than the one-offs in collections.abc
such as Hashable).
"""
__slots__ = ()
_is_protocol = True
# Various ABCs mimicking those in collections.abc.
# A few are simply re-exported for completeness.
Hashable = collections_abc.Hashable # Not generic.
if hasattr(collections_abc, 'Awaitable'):
class Awaitable(Generic[T_co], extra=collections_abc.Awaitable):
__slots__ = ()
else:
Awaitable = None
if hasattr(collections_abc, 'AsyncIterable'):
class AsyncIterable(Generic[T_co], extra=collections_abc.AsyncIterable):
__slots__ = ()
class AsyncIterator(AsyncIterable[T_co],
extra=collections_abc.AsyncIterator):
__slots__ = ()
else:
AsyncIterable = None
AsyncIterator = None
class Iterable(Generic[T_co], extra=collections_abc.Iterable):
__slots__ = ()
class Iterator(Iterable[T_co], extra=collections_abc.Iterator):
__slots__ = ()
class SupportsInt(_Protocol):
__slots__ = ()
@abstractmethod
def __int__(self) -> int:
pass
class SupportsFloat(_Protocol):
__slots__ = ()
@abstractmethod
def __float__(self) -> float:
pass
class SupportsComplex(_Protocol):
__slots__ = ()
@abstractmethod
def __complex__(self) -> complex:
pass
class SupportsBytes(_Protocol):
__slots__ = ()
@abstractmethod
def __bytes__(self) -> bytes:
pass
class SupportsAbs(_Protocol[T_co]):
__slots__ = ()
@abstractmethod
def __abs__(self) -> T_co:
pass
class SupportsRound(_Protocol[T_co]):
__slots__ = ()
@abstractmethod
def __round__(self, ndigits: int = 0) -> T_co:
pass
if hasattr(collections_abc, 'Reversible'):
class Reversible(Iterable[T_co], extra=collections_abc.Reversible):
__slots__ = ()
else:
class Reversible(_Protocol[T_co]):
__slots__ = ()
@abstractmethod
def __reversed__(self) -> 'Iterator[T_co]':
pass
Sized = collections_abc.Sized # Not generic.
class Container(Generic[T_co], extra=collections_abc.Container):
__slots__ = ()
if hasattr(collections_abc, 'Collection'):
class Collection(Sized, Iterable[T_co], Container[T_co],
extra=collections_abc.Collection):
__slots__ = ()
__all__.append('Collection')
# Callable was defined earlier.
if hasattr(collections_abc, 'Collection'):
class AbstractSet(Collection[T_co],
extra=collections_abc.Set):
__slots__ = ()
else:
class AbstractSet(Sized, Iterable[T_co], Container[T_co],
extra=collections_abc.Set):
__slots__ = ()
class MutableSet(AbstractSet[T], extra=collections_abc.MutableSet):
__slots__ = ()
# NOTE: It is only covariant in the value type.
if hasattr(collections_abc, 'Collection'):
class Mapping(Collection[KT], Generic[KT, VT_co],
extra=collections_abc.Mapping):
__slots__ = ()
else:
class Mapping(Sized, Iterable[KT], Container[KT], Generic[KT, VT_co],
extra=collections_abc.Mapping):
__slots__ = ()
class MutableMapping(Mapping[KT, VT], extra=collections_abc.MutableMapping):
__slots__ = ()
if hasattr(collections_abc, 'Reversible'):
if hasattr(collections_abc, 'Collection'):
class Sequence(Reversible[T_co], Collection[T_co],
extra=collections_abc.Sequence):
__slots__ = ()
else:
class Sequence(Sized, Reversible[T_co], Container[T_co],
extra=collections_abc.Sequence):
__slots__ = ()
else:
class Sequence(Sized, Iterable[T_co], Container[T_co],
extra=collections_abc.Sequence):
__slots__ = ()
class MutableSequence(Sequence[T], extra=collections_abc.MutableSequence):
__slots__ = ()
class ByteString(Sequence[int], extra=collections_abc.ByteString):
__slots__ = ()
class List(list, MutableSequence[T], extra=list):
__slots__ = ()
def __new__(cls, *args, **kwds):
if _geqv(cls, List):
raise TypeError("Type List cannot be instantiated; "
"use list() instead")
return list.__new__(cls, *args, **kwds)
class Set(set, MutableSet[T], extra=set):
__slots__ = ()
def __new__(cls, *args, **kwds):
if _geqv(cls, Set):
raise TypeError("Type Set cannot be instantiated; "
"use set() instead")
return set.__new__(cls, *args, **kwds)
class FrozenSet(frozenset, AbstractSet[T_co], extra=frozenset):
__slots__ = ()
def __new__(cls, *args, **kwds):
if _geqv(cls, FrozenSet):
raise TypeError("Type FrozenSet cannot be instantiated; "
"use frozenset() instead")
return frozenset.__new__(cls, *args, **kwds)
class MappingView(Sized, Iterable[T_co], extra=collections_abc.MappingView):
__slots__ = ()
class KeysView(MappingView[KT], AbstractSet[KT],
extra=collections_abc.KeysView):
__slots__ = ()
class ItemsView(MappingView[Tuple[KT, VT_co]],
AbstractSet[Tuple[KT, VT_co]],
Generic[KT, VT_co],
extra=collections_abc.ItemsView):
__slots__ = ()
class ValuesView(MappingView[VT_co], extra=collections_abc.ValuesView):
__slots__ = ()
if hasattr(contextlib, 'AbstractContextManager'):
class ContextManager(Generic[T_co], extra=contextlib.AbstractContextManager):
__slots__ = ()
__all__.append('ContextManager')
class Dict(dict, MutableMapping[KT, VT], extra=dict):
__slots__ = ()
def __new__(cls, *args, **kwds):
if _geqv(cls, Dict):
raise TypeError("Type Dict cannot be instantiated; "
"use dict() instead")
return dict.__new__(cls, *args, **kwds)
class DefaultDict(collections.defaultdict, MutableMapping[KT, VT],
extra=collections.defaultdict):
__slots__ = ()
def __new__(cls, *args, **kwds):
if _geqv(cls, DefaultDict):
raise TypeError("Type DefaultDict cannot be instantiated; "
"use collections.defaultdict() instead")
return collections.defaultdict.__new__(cls, *args, **kwds)
# Determine what base class to use for Generator.
if hasattr(collections_abc, 'Generator'):
# Sufficiently recent versions of 3.5 have a Generator ABC.
_G_base = collections_abc.Generator
else:
# Fall back on the exact type.
_G_base = types.GeneratorType
class Generator(Iterator[T_co], Generic[T_co, T_contra, V_co],
extra=_G_base):
__slots__ = ()
def __new__(cls, *args, **kwds):
if _geqv(cls, Generator):
raise TypeError("Type Generator cannot be instantiated; "
"create a subclass instead")
return super().__new__(cls, *args, **kwds)
# Internal type variable used for Type[].
CT_co = TypeVar('CT_co', covariant=True, bound=type)
# This is not a real generic class. Don't use outside annotations.
class Type(Generic[CT_co], extra=type):
"""A special construct usable to annotate class objects.
For example, suppose we have the following classes::
class User: ... # Abstract base for User classes
class BasicUser(User): ...
class ProUser(User): ...
class TeamUser(User): ...
And a function that takes a class argument that's a subclass of
User and returns an instance of the corresponding class::
U = TypeVar('U', bound=User)
def new_user(user_class: Type[U]) -> U:
user = user_class()
# (Here we could write the user object to a database)
return user
joe = new_user(BasicUser)
At this point the type checker knows that joe has type BasicUser.
"""
__slots__ = ()
def _make_nmtuple(name, types):
nm_tpl = collections.namedtuple(name, [n for n, t in types])
nm_tpl._field_types = dict(types)
try:
nm_tpl.__module__ = sys._getframe(2).f_globals.get('__name__', '__main__')
except (AttributeError, ValueError):
pass
return nm_tpl
if sys.version_info[:2] >= (3, 6):
class NamedTupleMeta(type):
def __new__(cls, typename, bases, ns, *, _root=False):
if _root:
return super().__new__(cls, typename, bases, ns)
types = ns.get('__annotations__', {})
return _make_nmtuple(typename, types.items())
class NamedTuple(metaclass=NamedTupleMeta, _root=True):
"""Typed version of namedtuple.
Usage::
class Employee(NamedTuple):
name: str
id: int
This is equivalent to::
Employee = collections.namedtuple('Employee', ['name', 'id'])
The resulting class has one extra attribute: _field_types,
giving a dict mapping field names to types. (The field names
are in the _fields attribute, which is part of the namedtuple
API.) Backward-compatible usage::
Employee = NamedTuple('Employee', [('name', str), ('id', int)])
"""
def __new__(self, typename, fields):
return _make_nmtuple(typename, fields)
else:
def NamedTuple(typename, fields):
"""Typed version of namedtuple.
Usage::
Employee = typing.NamedTuple('Employee', [('name', str), 'id', int)])
This is equivalent to::
Employee = collections.namedtuple('Employee', ['name', 'id'])
The resulting class has one extra attribute: _field_types,
giving a dict mapping field names to types. (The field names
are in the _fields attribute, which is part of the namedtuple
API.)
"""
return _make_nmtuple(typename, fields)
def NewType(name, tp):
"""NewType creates simple unique types with almost zero
runtime overhead. NewType(name, tp) is considered a subtype of tp
by static type checkers. At runtime, NewType(name, tp) returns
a dummy function that simply returns its argument. Usage::
UserId = NewType('UserId', int)
def name_by_id(user_id: UserId) -> str:
...
UserId('user') # Fails type check
name_by_id(42) # Fails type check
name_by_id(UserId(42)) # OK
num = UserId(5) + 1 # type: int
"""
def new_type(x):
return x
new_type.__name__ = name
new_type.__supertype__ = tp
return new_type
# Python-version-specific alias (Python 2: unicode; Python 3: str)
Text = str
# Constant that's True when type checking, but False here.
TYPE_CHECKING = False
class IO(Generic[AnyStr]):
"""Generic base class for TextIO and BinaryIO.
This is an abstract, generic version of the return of open().
NOTE: This does not distinguish between the different possible
classes (text vs. binary, read vs. write vs. read/write,
append-only, unbuffered). The TextIO and BinaryIO subclasses
below capture the distinctions between text vs. binary, which is
pervasive in the interface; however we currently do not offer a
way to track the other distinctions in the type system.
"""
__slots__ = ()
@abstractproperty
def mode(self) -> str:
pass
@abstractproperty
def name(self) -> str:
pass
@abstractmethod
def close(self) -> None:
pass
@abstractmethod
def closed(self) -> bool:
pass
@abstractmethod
def fileno(self) -> int:
pass
@abstractmethod
def flush(self) -> None:
pass
@abstractmethod
def isatty(self) -> bool:
pass
@abstractmethod
def read(self, n: int = -1) -> AnyStr:
pass
@abstractmethod
def readable(self) -> bool:
pass
@abstractmethod
def readline(self, limit: int = -1) -> AnyStr:
pass
@abstractmethod
def readlines(self, hint: int = -1) -> List[AnyStr]:
pass
@abstractmethod
def seek(self, offset: int, whence: int = 0) -> int:
pass
@abstractmethod
def seekable(self) -> bool:
pass
@abstractmethod
def tell(self) -> int:
pass
@abstractmethod
def truncate(self, size: int = None) -> int:
pass
@abstractmethod
def writable(self) -> bool:
pass
@abstractmethod
def write(self, s: AnyStr) -> int:
pass
@abstractmethod
def writelines(self, lines: List[AnyStr]) -> None:
pass
@abstractmethod
def __enter__(self) -> 'IO[AnyStr]':
pass
@abstractmethod
def __exit__(self, type, value, traceback) -> None:
pass
class BinaryIO(IO[bytes]):
"""Typed version of the return of open() in binary mode."""
__slots__ = ()
@abstractmethod
def write(self, s: Union[bytes, bytearray]) -> int:
pass
@abstractmethod
def __enter__(self) -> 'BinaryIO':
pass
class TextIO(IO[str]):
"""Typed version of the return of open() in text mode."""
__slots__ = ()
@abstractproperty
def buffer(self) -> BinaryIO:
pass
@abstractproperty
def encoding(self) -> str:
pass
@abstractproperty
def errors(self) -> str:
pass
@abstractproperty
def line_buffering(self) -> bool:
pass
@abstractproperty
def newlines(self) -> Any:
pass
@abstractmethod
def __enter__(self) -> 'TextIO':
pass
class io:
"""Wrapper namespace for IO generic classes."""
__all__ = ['IO', 'TextIO', 'BinaryIO']
IO = IO
TextIO = TextIO
BinaryIO = BinaryIO
io.__name__ = __name__ + '.io'
sys.modules[io.__name__] = io
Pattern = _TypeAlias('Pattern', AnyStr, type(stdlib_re.compile('')),
lambda p: p.pattern)
Match = _TypeAlias('Match', AnyStr, type(stdlib_re.match('', '')),
lambda m: m.re.pattern)
class re:
"""Wrapper namespace for re type aliases."""
__all__ = ['Pattern', 'Match']
Pattern = Pattern
Match = Match
re.__name__ = __name__ + '.re'
sys.modules[re.__name__] = re
