--- /dev/null
+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, 6):
+ import _collections_abc # Needed for private function _check_methods # noqa
+try:
+ from types import WrapperDescriptorType, MethodWrapperType, MethodDescriptorType
+except ImportError:
+ WrapperDescriptorType = type(object.__init__)
+ MethodWrapperType = type(object().__str__)
+ MethodDescriptorType = type(str.join)
+
+
+# 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.
+ 'GenericMeta', # subclass of abc.ABCMeta and a metaclass
+ # for 'Generic' and ABCs below.
+ 'ByteString',
+ 'Container',
+ 'ContextManager',
+ 'Hashable',
+ 'ItemsView',
+ 'Iterable',
+ 'Iterator',
+ 'KeysView',
+ 'Mapping',
+ 'MappingView',
+ 'MutableMapping',
+ 'MutableSequence',
+ 'MutableSet',
+ 'Sequence',
+ 'Sized',
+ 'ValuesView',
+ # The following are added depending on presence
+ # of their non-generic counterparts in stdlib:
+ # Awaitable,
+ # AsyncIterator,
+ # AsyncIterable,
+ # Coroutine,
+ # Collection,
+ # AsyncGenerator,
+ # AsyncContextManager
+
+ # Structural checks, a.k.a. protocols.
+ 'Reversible',
+ 'SupportsAbs',
+ 'SupportsBytes',
+ 'SupportsComplex',
+ 'SupportsFloat',
+ 'SupportsIndex',
+ 'SupportsInt',
+ 'SupportsRound',
+
+ # Concrete collection types.
+ 'Counter',
+ 'Deque',
+ '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',
+ 'NoReturn',
+ '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):
+ whitelist = ('_TypeAlias', '_ForwardRef', '_TypingBase', '_FinalTypingBase')
+ if nm.startswith('_') and nm not in whitelist:
+ nm = nm[1:]
+ return nm
+
+
+class TypingMeta(type):
+ """Metaclass for most types defined in typing module
+ (not a part of public API).
+
+ 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 must pass _root=True.
+
+ This also defines a dummy constructor (all the work for most typing
+ constructs 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, List['C'] is internally stored as
+ List[_ForwardRef('C')], which should evaluate to List[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):
+ """Internal indicator of special typing constructs."""
+
+ __slots__ = ('__weakref__',)
+
+ 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):
+ """Internal 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, Optional, 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)
+
+ def __reduce__(self):
+ return _trim_name(type(self).__name__)
+
+
+class _ForwardRef(_TypingBase, _root=True):
+ """Internal wrapper to hold a forward reference."""
+
+ __slots__ = ('__forward_arg__', '__forward_code__',
+ '__forward_evaluated__', '__forward_value__')
+
+ def __init__(self, arg):
+ super().__init__(arg)
+ if not isinstance(arg, str):
+ raise TypeError('Forward reference must be a string -- got %r' % (arg,))
+ try:
+ code = compile(arg, '<string>', 'eval')
+ except SyntaxError:
+ raise SyntaxError('Forward reference must be an expression -- got %r' %
+ (arg,))
+ self.__forward_arg__ = arg
+ self.__forward_code__ = code
+ self.__forward_evaluated__ = False
+ self.__forward_value__ = None
+
+ def _eval_type(self, globalns, localns):
+ if not self.__forward_evaluated__ or localns is not globalns:
+ 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
+ if self.__forward_evaluated__ and other.__forward_evaluated__:
+ return (self.__forward_arg__ == other.__forward_arg__ and
+ self.__forward_value__ == other.__forward_value__)
+ return self.__forward_arg__ == other.__forward_arg__
+
+ def __hash__(self):
+ return hash(self.__forward_arg__)
+
+ 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) and parameter is not self.type_var:
+ raise TypeError("%s cannot be re-parameterized." % self)
+ 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)
+ return t
+
+
+def _type_check(arg, msg):
+ """Check that the argument is a type, and return it (internal helper).
+
+ 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 (
+ isinstance(arg, _TypingBase) and type(arg).__name__ == '_ClassVar' or
+ not isinstance(arg, (type, _TypingBase)) and not callable(arg)
+ ):
+ raise TypeError(msg + " Got %.100r." % (arg,))
+ # Bare Union etc. are not valid as type arguments
+ if (
+ type(arg).__name__ in ('_Union', '_Optional') and
+ not getattr(arg, '__origin__', None) or
+ isinstance(arg, TypingMeta) and arg._gorg in (Generic, _Protocol)
+ ):
+ raise TypeError("Plain %s is not valid as type argument" % arg)
+ return arg
+
+
+def _type_repr(obj):
+ """Return the repr() of an object, special-casing types (internal helper).
+
+ 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)
+ return '%s.%s' % (obj.__module__, _qualname(obj))
+ if obj is ...:
+ return('...')
+ if isinstance(obj, types.FunctionType):
+ return obj.__name__
+ 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 _NoReturn(_FinalTypingBase, _root=True):
+ """Special type indicating functions that never return.
+ Example::
+
+ from typing import NoReturn
+
+ def stop() -> NoReturn:
+ raise Exception('no way')
+
+ This type is invalid in other positions, e.g., ``List[NoReturn]``
+ will fail in static type checkers.
+ """
+
+ __slots__ = ()
+
+ def __instancecheck__(self, obj):
+ raise TypeError("NoReturn cannot be used with isinstance().")
+
+ def __subclasscheck__(self, cls):
+ raise TypeError("NoReturn cannot be used with issubclass().")
+
+
+NoReturn = _NoReturn(_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) -> List[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) and issubclass(C, T) will raise TypeError.
+
+ 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 _replace_arg(arg, tvars, args):
+ """An internal helper function: replace arg if it is a type variable
+ found in tvars with corresponding substitution from args or
+ with corresponding substitution sub-tree if arg is a generic type.
+ """
+
+ if tvars is None:
+ tvars = []
+ if hasattr(arg, '_subs_tree') and isinstance(arg, (GenericMeta, _TypingBase)):
+ return arg._subs_tree(tvars, args)
+ if isinstance(arg, TypeVar):
+ for i, tvar in enumerate(tvars):
+ if arg == tvar:
+ return args[i]
+ return arg
+
+
+# Special typing constructs Union, Optional, Generic, Callable and Tuple
+# use three special attributes for internal bookkeeping of generic types:
+# * __parameters__ is a tuple of unique free type parameters of a generic
+# type, for example, Dict[T, T].__parameters__ == (T,);
+# * __origin__ keeps a reference to a type that was subscripted,
+# e.g., Union[T, int].__origin__ == Union;
+# * __args__ is a tuple of all arguments used in subscripting,
+# e.g., Dict[T, int].__args__ == (T, int).
+
+
+def _subs_tree(cls, tvars=None, args=None):
+ """An internal helper function: calculate substitution tree
+ for generic cls after replacing its type parameters with
+ substitutions in tvars -> args (if any).
+ Repeat the same following __origin__'s.
+
+ Return a list of arguments with all possible substitutions
+ performed. Arguments that are generic classes themselves are represented
+ as tuples (so that no new classes are created by this function).
+ For example: _subs_tree(List[Tuple[int, T]][str]) == [(Tuple, int, str)]
+ """
+
+ if cls.__origin__ is None:
+ return cls
+ # Make of chain of origins (i.e. cls -> cls.__origin__)
+ current = cls.__origin__
+ orig_chain = []
+ while current.__origin__ is not None:
+ orig_chain.append(current)
+ current = current.__origin__
+ # Replace type variables in __args__ if asked ...
+ tree_args = []
+ for arg in cls.__args__:
+ tree_args.append(_replace_arg(arg, tvars, args))
+ # ... then continue replacing down the origin chain.
+ for ocls in orig_chain:
+ new_tree_args = []
+ for arg in ocls.__args__:
+ new_tree_args.append(_replace_arg(arg, ocls.__parameters__, tree_args))
+ tree_args = new_tree_args
+ return tree_args
+
+
+def _remove_dups_flatten(parameters):
+ """An internal helper for Union creation and substitution: flatten Union's
+ among parameters, then remove duplicates and strict subclasses.
+ """
+
+ # Flatten out Union[Union[...], ...].
+ params = []
+ for p in parameters:
+ if isinstance(p, _Union) and p.__origin__ is Union:
+ params.extend(p.__args__)
+ elif isinstance(p, tuple) and len(p) > 0 and p[0] is Union:
+ params.extend(p[1:])
+ else:
+ params.append(p)
+ # 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)
+ return tuple(t for t in params if t in all_params)
+
+
+def _check_generic(cls, parameters):
+ # Check correct count for parameters of a generic cls (internal helper).
+ if not cls.__parameters__:
+ raise TypeError("%s is not a generic class" % repr(cls))
+ alen = len(parameters)
+ elen = len(cls.__parameters__)
+ if alen != elen:
+ raise TypeError("Too %s parameters for %s; actual %s, expected %s" %
+ ("many" if alen > elen else "few", repr(cls), alen, elen))
+
+
+_cleanups = []
+
+
+def _tp_cache(func):
+ """Internal wrapper caching __getitem__ of generic types with a fallback to
+ original function for non-hashable arguments.
+ """
+
+ cached = functools.lru_cache()(func)
+ _cleanups.append(cached.cache_clear)
+
+ @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 can use Optional[X] as a shorthand for Union[X, None].
+ """
+
+ __slots__ = ('__parameters__', '__args__', '__origin__', '__tree_hash__')
+
+ def __new__(cls, parameters=None, origin=None, *args, _root=False):
+ self = super().__new__(cls, parameters, origin, *args, _root=_root)
+ if origin is None:
+ self.__parameters__ = None
+ self.__args__ = None
+ self.__origin__ = None
+ self.__tree_hash__ = hash(frozenset(('Union',)))
+ return self
+ if not isinstance(parameters, tuple):
+ raise TypeError("Expected parameters=<tuple>")
+ if origin is Union:
+ parameters = _remove_dups_flatten(parameters)
+ # It's not a union if there's only one type left.
+ if len(parameters) == 1:
+ return parameters[0]
+ self.__parameters__ = _type_vars(parameters)
+ self.__args__ = parameters
+ self.__origin__ = origin
+ # Pre-calculate the __hash__ on instantiation.
+ # This improves speed for complex substitutions.
+ subs_tree = self._subs_tree()
+ if isinstance(subs_tree, tuple):
+ self.__tree_hash__ = hash(frozenset(subs_tree))
+ else:
+ self.__tree_hash__ = hash(subs_tree)
+ return self
+
+ def _eval_type(self, globalns, localns):
+ if self.__args__ is None:
+ return self
+ ev_args = tuple(_eval_type(t, globalns, localns) for t in self.__args__)
+ ev_origin = _eval_type(self.__origin__, globalns, localns)
+ if ev_args == self.__args__ and ev_origin == self.__origin__:
+ # Everything is already evaluated.
+ return self
+ return self.__class__(ev_args, ev_origin, _root=True)
+
+ 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 None:
+ return super().__repr__()
+ tree = self._subs_tree()
+ if not isinstance(tree, tuple):
+ return repr(tree)
+ return tree[0]._tree_repr(tree)
+
+ def _tree_repr(self, tree):
+ arg_list = []
+ for arg in tree[1:]:
+ if not isinstance(arg, tuple):
+ arg_list.append(_type_repr(arg))
+ else:
+ arg_list.append(arg[0]._tree_repr(arg))
+ return super().__repr__() + '[%s]' % ', '.join(arg_list)
+
+ @_tp_cache
+ def __getitem__(self, parameters):
+ if parameters == ():
+ raise TypeError("Cannot take a Union of no types.")
+ if not isinstance(parameters, tuple):
+ parameters = (parameters,)
+ if self.__origin__ is None:
+ msg = "Union[arg, ...]: each arg must be a type."
+ else:
+ msg = "Parameters to generic types must be types."
+ parameters = tuple(_type_check(p, msg) for p in parameters)
+ if self is not Union:
+ _check_generic(self, parameters)
+ return self.__class__(parameters, origin=self, _root=True)
+
+ def _subs_tree(self, tvars=None, args=None):
+ if self is Union:
+ return Union # Nothing to substitute
+ tree_args = _subs_tree(self, tvars, args)
+ tree_args = _remove_dups_flatten(tree_args)
+ if len(tree_args) == 1:
+ return tree_args[0] # Union of a single type is that type
+ return (Union,) + tree_args
+
+ def __eq__(self, other):
+ if isinstance(other, _Union):
+ return self.__tree_hash__ == other.__tree_hash__
+ elif self is not Union:
+ return self._subs_tree() == other
+ else:
+ return self is other
+
+ def __hash__(self):
+ return self.__tree_hash__
+
+ 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)
+
+
+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 c._gorg is Generic:
+ next_in_mro = cls.__mro__[i + 1]
+ return next_in_mro
+
+
+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):
+ 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):
+ if cls.__extra__ and issubclass(subclass, cls.__extra__):
+ return True
+ return NotImplemented
+ return __extrahook__
+
+
+def _no_slots_copy(dct):
+ """Internal helper: copy class __dict__ and clean slots class variables.
+ (They will be re-created if necessary by normal class machinery.)
+ """
+ dict_copy = dict(dct)
+ if '__slots__' in dict_copy:
+ for slot in dict_copy['__slots__']:
+ dict_copy.pop(slot, None)
+ return dict_copy
+
+
+class GenericMeta(TypingMeta, abc.ABCMeta):
+ """Metaclass for generic types.
+
+ This is a metaclass for typing.Generic and generic ABCs defined in
+ typing module. User defined subclasses of GenericMeta can override
+ __new__ and invoke super().__new__. Note that GenericMeta.__new__
+ has strict rules on what is allowed in its bases argument:
+ * plain Generic is disallowed in bases;
+ * Generic[...] should appear in bases at most once;
+ * if Generic[...] is present, then it should list all type variables
+ that appear in other bases.
+ In addition, type of all generic bases is erased, e.g., C[int] is
+ stripped to plain C.
+ """
+
+ def __new__(cls, name, bases, namespace,
+ tvars=None, args=None, origin=None, extra=None, orig_bases=None):
+ """Create a new generic class. GenericMeta.__new__ accepts
+ keyword arguments that are used for internal bookkeeping, therefore
+ an override should pass unused keyword arguments to super().
+ """
+ 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
+
+ initial_bases = bases
+ if extra is not None and type(extra) is abc.ABCMeta and extra not in bases:
+ bases = (extra,) + bases
+ bases = tuple(b._gorg if isinstance(b, GenericMeta) else b for b in bases)
+
+ # remove bare Generic from bases if there are other generic bases
+ if any(isinstance(b, GenericMeta) and b is not Generic for b in bases):
+ bases = tuple(b for b in bases if b is not Generic)
+ namespace.update({'__origin__': origin, '__extra__': extra,
+ '_gorg': None if not origin else origin._gorg})
+ self = super().__new__(cls, name, bases, namespace, _root=True)
+ super(GenericMeta, self).__setattr__('_gorg',
+ self if not origin else origin._gorg)
+ self.__parameters__ = tvars
+ # Be prepared that GenericMeta will be subclassed by TupleMeta
+ # and CallableMeta, those two allow ..., (), or [] in __args___.
+ self.__args__ = tuple(... if a is _TypingEllipsis else
+ () if a is _TypingEmpty else
+ a for a in args) if args else None
+ # Speed hack (https://github.com/python/typing/issues/196).
+ self.__next_in_mro__ = _next_in_mro(self)
+ # Preserve base classes on subclassing (__bases__ are type erased now).
+ if orig_bases is None:
+ self.__orig_bases__ = initial_bases
+
+ # 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 or
+ # allow overriding
+ getattr(self.__subclasshook__, '__name__', '') == '__extrahook__'
+ ):
+ self.__subclasshook__ = _make_subclasshook(self)
+ if isinstance(extra, abc.ABCMeta):
+ self._abc_registry = extra._abc_registry
+ self._abc_cache = extra._abc_cache
+ elif origin is not None:
+ self._abc_registry = origin._abc_registry
+ self._abc_cache = origin._abc_cache
+
+ if origin and hasattr(origin, '__qualname__'): # Fix for Python 3.2.
+ self.__qualname__ = origin.__qualname__
+ self.__tree_hash__ = (hash(self._subs_tree()) if origin else
+ super(GenericMeta, self).__hash__())
+ return self
+
+ # _abc_negative_cache and _abc_negative_cache_version
+ # realised as descriptors, since GenClass[t1, t2, ...] always
+ # share subclass info with GenClass.
+ # This is an important memory optimization.
+ @property
+ def _abc_negative_cache(self):
+ if isinstance(self.__extra__, abc.ABCMeta):
+ return self.__extra__._abc_negative_cache
+ return self._gorg._abc_generic_negative_cache
+
+ @_abc_negative_cache.setter
+ def _abc_negative_cache(self, value):
+ if self.__origin__ is None:
+ if isinstance(self.__extra__, abc.ABCMeta):
+ self.__extra__._abc_negative_cache = value
+ else:
+ self._abc_generic_negative_cache = value
+
+ @property
+ def _abc_negative_cache_version(self):
+ if isinstance(self.__extra__, abc.ABCMeta):
+ return self.__extra__._abc_negative_cache_version
+ return self._gorg._abc_generic_negative_cache_version
+
+ @_abc_negative_cache_version.setter
+ def _abc_negative_cache_version(self, value):
+ if self.__origin__ is None:
+ if isinstance(self.__extra__, abc.ABCMeta):
+ self.__extra__._abc_negative_cache_version = value
+ else:
+ self._abc_generic_negative_cache_version = value
+
+ def _get_type_vars(self, tvars):
+ if self.__origin__ and self.__parameters__:
+ _get_type_vars(self.__parameters__, tvars)
+
+ def _eval_type(self, globalns, localns):
+ ev_origin = (self.__origin__._eval_type(globalns, localns)
+ if self.__origin__ else None)
+ ev_args = tuple(_eval_type(a, globalns, localns) for a
+ in self.__args__) if self.__args__ else None
+ if ev_origin == self.__origin__ and ev_args == self.__args__:
+ return self
+ return self.__class__(self.__name__,
+ self.__bases__,
+ _no_slots_copy(self.__dict__),
+ tvars=_type_vars(ev_args) if ev_args else None,
+ args=ev_args,
+ origin=ev_origin,
+ extra=self.__extra__,
+ orig_bases=self.__orig_bases__)
+
+ def __repr__(self):
+ if self.__origin__ is None:
+ return super().__repr__()
+ return self._tree_repr(self._subs_tree())
+
+ def _tree_repr(self, tree):
+ arg_list = []
+ for arg in tree[1:]:
+ if arg == ():
+ arg_list.append('()')
+ elif not isinstance(arg, tuple):
+ arg_list.append(_type_repr(arg))
+ else:
+ arg_list.append(arg[0]._tree_repr(arg))
+ return super().__repr__() + '[%s]' % ', '.join(arg_list)
+
+ def _subs_tree(self, tvars=None, args=None):
+ if self.__origin__ is None:
+ return self
+ tree_args = _subs_tree(self, tvars, args)
+ return (self._gorg,) + tuple(tree_args)
+
+ def __eq__(self, other):
+ if not isinstance(other, GenericMeta):
+ return NotImplemented
+ if self.__origin__ is None or other.__origin__ is None:
+ return self is other
+ return self.__tree_hash__ == other.__tree_hash__
+
+ def __hash__(self):
+ return self.__tree_hash__
+
+ @_tp_cache
+ def __getitem__(self, params):
+ if not isinstance(params, tuple):
+ params = (params,)
+ if not params and self._gorg is not Tuple:
+ 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 = params
+ elif self in (Tuple, Callable):
+ tvars = _type_vars(params)
+ args = params
+ elif self is _Protocol:
+ # _Protocol is internal, don't check anything.
+ tvars = params
+ args = params
+ 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.
+ _check_generic(self, params)
+ tvars = _type_vars(params)
+ args = params
+
+ prepend = (self,) if self.__origin__ is None else ()
+ return self.__class__(self.__name__,
+ prepend + self.__bases__,
+ _no_slots_copy(self.__dict__),
+ tvars=tvars,
+ args=args,
+ origin=self,
+ extra=self.__extra__,
+ orig_bases=self.__orig_bases__)
+
+ def __subclasscheck__(self, cls):
+ if self.__origin__ is not None:
+ if sys._getframe(1).f_globals['__name__'] not in ['abc', 'functools']:
+ raise TypeError("Parameterized generics cannot be used with class "
+ "or instance checks")
+ return False
+ if self is Generic:
+ raise TypeError("Class %r cannot be used with class "
+ "or instance checks" % self)
+ return super().__subclasscheck__(cls)
+
+ 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)
+
+ def __setattr__(self, attr, value):
+ # We consider all the subscripted generics as proxies for original class
+ if (
+ attr.startswith('__') and attr.endswith('__') or
+ attr.startswith('_abc_') or
+ self._gorg is None # The class is not fully created, see #typing/506
+ ):
+ super(GenericMeta, self).__setattr__(attr, value)
+ else:
+ super(GenericMeta, self._gorg).__setattr__(attr, value)
+
+
+# Prevent checks for Generic to crash when defining Generic.
+Generic = None
+
+
+def _generic_new(base_cls, cls, *args, **kwds):
+ # Assure type is erased on instantiation,
+ # but attempt to store it in __orig_class__
+ if cls.__origin__ is None:
+ if (base_cls.__new__ is object.__new__ and
+ cls.__init__ is not object.__init__):
+ return base_cls.__new__(cls)
+ else:
+ return base_cls.__new__(cls, *args, **kwds)
+ else:
+ origin = cls._gorg
+ if (base_cls.__new__ is object.__new__ and
+ cls.__init__ is not object.__init__):
+ obj = base_cls.__new__(origin)
+ else:
+ obj = base_cls.__new__(origin, *args, **kwds)
+ try:
+ obj.__orig_class__ = cls
+ except AttributeError:
+ pass
+ obj.__init__(*args, **kwds)
+ return obj
+
+
+class Generic(metaclass=GenericMeta):
+ """Abstract base class for generic types.
+
+ A generic type is typically declared by inheriting from
+ this class parameterized 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._gorg is Generic:
+ raise TypeError("Type Generic cannot be instantiated; "
+ "it can be used only as a base class")
+ return _generic_new(cls.__next_in_mro__, cls, *args, **kwds)
+
+
+class _TypingEmpty:
+ """Internal placeholder for () or []. Used by TupleMeta and CallableMeta
+ to allow empty list/tuple in specific places, without allowing them
+ to sneak in where prohibited.
+ """
+
+
+class _TypingEllipsis:
+ """Internal placeholder for ... (ellipsis)."""
+
+
+class TupleMeta(GenericMeta):
+ """Metaclass for Tuple (internal)."""
+
+ @_tp_cache
+ def __getitem__(self, parameters):
+ if self.__origin__ is not None or self._gorg is not Tuple:
+ # Normal generic rules apply if this is not the first subscription
+ # or a subscription of a subclass.
+ return super().__getitem__(parameters)
+ if parameters == ():
+ return super().__getitem__((_TypingEmpty,))
+ if not isinstance(parameters, tuple):
+ parameters = (parameters,)
+ if len(parameters) == 2 and parameters[1] is ...:
+ msg = "Tuple[t, ...]: t must be a type."
+ p = _type_check(parameters[0], msg)
+ return super().__getitem__((p, _TypingEllipsis))
+ msg = "Tuple[t0, t1, ...]: each t must be a type."
+ parameters = tuple(_type_check(p, msg) for p in parameters)
+ return super().__getitem__(parameters)
+
+ def __instancecheck__(self, obj):
+ if self.__args__ is None:
+ return isinstance(obj, tuple)
+ raise TypeError("Parameterized Tuple cannot be used "
+ "with isinstance().")
+
+ def __subclasscheck__(self, cls):
+ if self.__args__ is None:
+ return issubclass(cls, tuple)
+ raise TypeError("Parameterized Tuple cannot be used "
+ "with issubclass().")
+
+
+class Tuple(tuple, extra=tuple, metaclass=TupleMeta):
+ """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__ = ()
+
+ def __new__(cls, *args, **kwds):
+ if cls._gorg is Tuple:
+ raise TypeError("Type Tuple cannot be instantiated; "
+ "use tuple() instead")
+ return _generic_new(tuple, cls, *args, **kwds)
+
+
+class CallableMeta(GenericMeta):
+ """Metaclass for Callable (internal)."""
+
+ def __repr__(self):
+ if self.__origin__ is None:
+ return super().__repr__()
+ return self._tree_repr(self._subs_tree())
+
+ def _tree_repr(self, tree):
+ if self._gorg is not Callable:
+ return super()._tree_repr(tree)
+ # For actual Callable (not its subclass) we override
+ # super()._tree_repr() for nice formatting.
+ arg_list = []
+ for arg in tree[1:]:
+ if not isinstance(arg, tuple):
+ arg_list.append(_type_repr(arg))
+ else:
+ arg_list.append(arg[0]._tree_repr(arg))
+ if arg_list[0] == '...':
+ return repr(tree[0]) + '[..., %s]' % arg_list[1]
+ return (repr(tree[0]) +
+ '[[%s], %s]' % (', '.join(arg_list[:-1]), arg_list[-1]))
+
+ def __getitem__(self, parameters):
+ """A thin wrapper around __getitem_inner__ to provide the latter
+ with hashable arguments to improve speed.
+ """
+
+ if self.__origin__ is not None or self._gorg is not Callable:
+ return super().__getitem__(parameters)
+ if not isinstance(parameters, tuple) or len(parameters) != 2:
+ raise TypeError("Callable must be used as "
+ "Callable[[arg, ...], result].")
+ args, result = parameters
+ if args is Ellipsis:
+ parameters = (Ellipsis, result)
+ else:
+ if not isinstance(args, list):
+ raise TypeError("Callable[args, result]: args must be a list."
+ " Got %.100r." % (args,))
+ parameters = (tuple(args), result)
+ return self.__getitem_inner__(parameters)
+
+ @_tp_cache
+ def __getitem_inner__(self, parameters):
+ args, result = parameters
+ msg = "Callable[args, result]: result must be a type."
+ result = _type_check(result, msg)
+ if args is Ellipsis:
+ return super().__getitem__((_TypingEllipsis, result))
+ msg = "Callable[[arg, ...], result]: each arg must be a type."
+ args = tuple(_type_check(arg, msg) for arg in args)
+ parameters = args + (result,)
+ return super().__getitem__(parameters)
+
+
+class Callable(extra=collections_abc.Callable, metaclass=CallableMeta):
+ """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 or ellipsis; 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__ = ()
+
+ def __new__(cls, *args, **kwds):
+ if cls._gorg is Callable:
+ raise TypeError("Type Callable cannot be instantiated; "
+ "use a non-abstract subclass instead")
+ return _generic_new(cls.__next_in_mro__, cls, *args, **kwds)
+
+
+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 __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."""
+ try:
+ code = func.__code__
+ except AttributeError:
+ # Some built-in functions don't have __code__, __defaults__, etc.
+ return {}
+ 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
+
+
+_allowed_types = (types.FunctionType, types.BuiltinFunctionType,
+ types.MethodType, types.ModuleType,
+ WrapperDescriptorType, MethodWrapperType, MethodDescriptorType)
+
+
+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. For classes, annotations include also
+ inherited members.
+
+ 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 (or the respective module's globals for classes),
+ and these are also used as the locals. If the object does not appear
+ to have globals, an empty dictionary is used.
+
+ - 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 {}
+ # Classes require a special treatment.
+ if isinstance(obj, type):
+ hints = {}
+ for base in reversed(obj.__mro__):
+ if globalns is None:
+ base_globals = sys.modules[base.__module__].__dict__
+ else:
+ base_globals = globalns
+ ann = base.__dict__.get('__annotations__', {})
+ for name, value in ann.items():
+ if value is None:
+ value = type(None)
+ if isinstance(value, str):
+ value = _ForwardRef(value)
+ value = _eval_type(value, base_globals, localns)
+ hints[name] = value
+ return hints
+
+ if globalns is None:
+ if isinstance(obj, types.ModuleType):
+ globalns = obj.__dict__
+ else:
+ globalns = getattr(obj, '__globals__', {})
+ if localns is None:
+ localns = globalns
+ elif localns is None:
+ localns = globalns
+ hints = getattr(obj, '__annotations__', None)
+ if hints is None:
+ # Return empty annotations for something that _could_ have them.
+ if isinstance(obj, _allowed_types):
+ return {}
+ else:
+ raise TypeError('{!r} is not a module, class, method, '
+ 'or function.'.format(obj))
+ defaults = _get_defaults(obj)
+ hints = dict(hints)
+ 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
+
+
+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,):
+ 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):
+ if _Protocol not in self.__bases__:
+ return super().__instancecheck__(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 != '_gorg' 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 != '__orig_bases__' and
+ attr != '__extra__' and
+ attr != '__tree_hash__' and
+ attr != '__module__'):
+ attrs.add(attr)
+
+ return attrs
+
+
+class _Protocol(metaclass=_ProtocolMeta):
+ """Internal base class for protocol classes.
+
+ This implements a simple-minded structural issubclass 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__ = ()
+
+ __all__.append('Awaitable')
+
+
+if hasattr(collections_abc, 'Coroutine'):
+ class Coroutine(Awaitable[V_co], Generic[T_co, T_contra, V_co],
+ extra=collections_abc.Coroutine):
+ __slots__ = ()
+
+ __all__.append('Coroutine')
+
+
+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__ = ()
+
+ __all__.append('AsyncIterable')
+ __all__.append('AsyncIterator')
+
+
+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 SupportsIndex(_Protocol):
+ __slots__ = ()
+
+ @abstractmethod
+ def __index__(self) -> int:
+ 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 cls._gorg is List:
+ raise TypeError("Type List cannot be instantiated; "
+ "use list() instead")
+ return _generic_new(list, cls, *args, **kwds)
+
+
+class Deque(collections.deque, MutableSequence[T], extra=collections.deque):
+
+ __slots__ = ()
+
+ def __new__(cls, *args, **kwds):
+ if cls._gorg is Deque:
+ return collections.deque(*args, **kwds)
+ return _generic_new(collections.deque, cls, *args, **kwds)
+
+
+class Set(set, MutableSet[T], extra=set):
+
+ __slots__ = ()
+
+ def __new__(cls, *args, **kwds):
+ if cls._gorg is Set:
+ raise TypeError("Type Set cannot be instantiated; "
+ "use set() instead")
+ return _generic_new(set, cls, *args, **kwds)
+
+
+class FrozenSet(frozenset, AbstractSet[T_co], extra=frozenset):
+ __slots__ = ()
+
+ def __new__(cls, *args, **kwds):
+ if cls._gorg is FrozenSet:
+ raise TypeError("Type FrozenSet cannot be instantiated; "
+ "use frozenset() instead")
+ return _generic_new(frozenset, 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__ = ()
+else:
+ class ContextManager(Generic[T_co]):
+ __slots__ = ()
+
+ def __enter__(self):
+ return self
+
+ @abc.abstractmethod
+ def __exit__(self, exc_type, exc_value, traceback):
+ return None
+
+ @classmethod
+ def __subclasshook__(cls, C):
+ if cls is ContextManager:
+ # In Python 3.6+, it is possible to set a method to None to
+ # explicitly indicate that the class does not implement an ABC
+ # (https://bugs.python.org/issue25958), but we do not support
+ # that pattern here because this fallback class is only used
+ # in Python 3.5 and earlier.
+ if (any("__enter__" in B.__dict__ for B in C.__mro__) and
+ any("__exit__" in B.__dict__ for B in C.__mro__)):
+ return True
+ return NotImplemented
+
+
+if hasattr(contextlib, 'AbstractAsyncContextManager'):
+ class AsyncContextManager(Generic[T_co],
+ extra=contextlib.AbstractAsyncContextManager):
+ __slots__ = ()
+
+ __all__.append('AsyncContextManager')
+elif sys.version_info[:2] >= (3, 5):
+ exec("""
+class AsyncContextManager(Generic[T_co]):
+ __slots__ = ()
+
+ async def __aenter__(self):
+ return self
+
+ @abc.abstractmethod
+ async def __aexit__(self, exc_type, exc_value, traceback):
+ return None
+
+ @classmethod
+ def __subclasshook__(cls, C):
+ if cls is AsyncContextManager:
+ if sys.version_info[:2] >= (3, 6):
+ return _collections_abc._check_methods(C, "__aenter__", "__aexit__")
+ if (any("__aenter__" in B.__dict__ for B in C.__mro__) and
+ any("__aexit__" in B.__dict__ for B in C.__mro__)):
+ return True
+ return NotImplemented
+
+__all__.append('AsyncContextManager')
+""")
+
+
+class Dict(dict, MutableMapping[KT, VT], extra=dict):
+
+ __slots__ = ()
+
+ def __new__(cls, *args, **kwds):
+ if cls._gorg is Dict:
+ raise TypeError("Type Dict cannot be instantiated; "
+ "use dict() instead")
+ return _generic_new(dict, cls, *args, **kwds)
+
+
+class DefaultDict(collections.defaultdict, MutableMapping[KT, VT],
+ extra=collections.defaultdict):
+
+ __slots__ = ()
+
+ def __new__(cls, *args, **kwds):
+ if cls._gorg is DefaultDict:
+ return collections.defaultdict(*args, **kwds)
+ return _generic_new(collections.defaultdict, cls, *args, **kwds)
+
+
+class Counter(collections.Counter, Dict[T, int], extra=collections.Counter):
+
+ __slots__ = ()
+
+ def __new__(cls, *args, **kwds):
+ if cls._gorg is Counter:
+ return collections.Counter(*args, **kwds)
+ return _generic_new(collections.Counter, cls, *args, **kwds)
+
+
+if hasattr(collections, 'ChainMap'):
+ # ChainMap only exists in 3.3+
+ __all__.append('ChainMap')
+
+ class ChainMap(collections.ChainMap, MutableMapping[KT, VT],
+ extra=collections.ChainMap):
+
+ __slots__ = ()
+
+ def __new__(cls, *args, **kwds):
+ if cls._gorg is ChainMap:
+ return collections.ChainMap(*args, **kwds)
+ return _generic_new(collections.ChainMap, 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 cls._gorg is Generator:
+ raise TypeError("Type Generator cannot be instantiated; "
+ "create a subclass instead")
+ return _generic_new(_G_base, cls, *args, **kwds)
+
+
+if hasattr(collections_abc, 'AsyncGenerator'):
+ class AsyncGenerator(AsyncIterator[T_co], Generic[T_co, T_contra],
+ extra=collections_abc.AsyncGenerator):
+ __slots__ = ()
+
+ __all__.append('AsyncGenerator')
+
+
+# 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):
+ msg = "NamedTuple('Name', [(f0, t0), (f1, t1), ...]); each t must be a type"
+ types = [(n, _type_check(t, msg)) for n, t in types]
+ nm_tpl = collections.namedtuple(name, [n for n, t in types])
+ # Prior to PEP 526, only _field_types attribute was assigned.
+ # Now, both __annotations__ and _field_types are used to maintain compatibility.
+ nm_tpl.__annotations__ = nm_tpl._field_types = collections.OrderedDict(types)
+ try:
+ nm_tpl.__module__ = sys._getframe(2).f_globals.get('__name__', '__main__')
+ except (AttributeError, ValueError):
+ pass
+ return nm_tpl
+
+
+_PY36 = sys.version_info[:2] >= (3, 6)
+
+# attributes prohibited to set in NamedTuple class syntax
+_prohibited = ('__new__', '__init__', '__slots__', '__getnewargs__',
+ '_fields', '_field_defaults', '_field_types',
+ '_make', '_replace', '_asdict', '_source')
+
+_special = ('__module__', '__name__', '__qualname__', '__annotations__')
+
+
+class NamedTupleMeta(type):
+
+ def __new__(cls, typename, bases, ns):
+ if ns.get('_root', False):
+ return super().__new__(cls, typename, bases, ns)
+ if not _PY36:
+ raise TypeError("Class syntax for NamedTuple is only supported"
+ " in Python 3.6+")
+ types = ns.get('__annotations__', {})
+ nm_tpl = _make_nmtuple(typename, types.items())
+ defaults = []
+ defaults_dict = {}
+ for field_name in types:
+ if field_name in ns:
+ default_value = ns[field_name]
+ defaults.append(default_value)
+ defaults_dict[field_name] = default_value
+ elif defaults:
+ raise TypeError("Non-default namedtuple field {field_name} cannot "
+ "follow default field(s) {default_names}"
+ .format(field_name=field_name,
+ default_names=', '.join(defaults_dict.keys())))
+ nm_tpl.__new__.__annotations__ = collections.OrderedDict(types)
+ nm_tpl.__new__.__defaults__ = tuple(defaults)
+ nm_tpl._field_defaults = defaults_dict
+ # update from user namespace without overriding special namedtuple attributes
+ for key in ns:
+ if key in _prohibited:
+ raise AttributeError("Cannot overwrite NamedTuple attribute " + key)
+ elif key not in _special and key not in nm_tpl._fields:
+ setattr(nm_tpl, key, ns[key])
+ return nm_tpl
+
+
+class NamedTuple(metaclass=NamedTupleMeta):
+ """Typed version of namedtuple.
+
+ Usage in Python versions >= 3.6::
+
+ class Employee(NamedTuple):
+ name: str
+ id: int
+
+ This is equivalent to::
+
+ Employee = collections.namedtuple('Employee', ['name', 'id'])
+
+ The resulting class has extra __annotations__ and _field_types
+ attributes, giving an ordered dict mapping field names to types.
+ __annotations__ should be preferred, while _field_types
+ is kept to maintain pre PEP 526 compatibility. (The field names
+ are in the _fields attribute, which is part of the namedtuple
+ API.) Alternative equivalent keyword syntax is also accepted::
+
+ Employee = NamedTuple('Employee', name=str, id=int)
+
+ In Python versions <= 3.5 use::
+
+ Employee = NamedTuple('Employee', [('name', str), ('id', int)])
+ """
+ _root = True
+
+ def __new__(*args, **kwargs):
+ if kwargs and not _PY36:
+ raise TypeError("Keyword syntax for NamedTuple is only supported"
+ " in Python 3.6+")
+ if not args:
+ raise TypeError('NamedTuple.__new__(): not enough arguments')
+ _, args = args[0], args[1:] # allow the "cls" keyword be passed
+ if args:
+ typename, args = args[0], args[1:] # allow the "typename" keyword be passed
+ elif 'typename' in kwargs:
+ typename = kwargs.pop('typename')
+ import warnings
+ warnings.warn("Passing 'typename' as keyword argument is deprecated",
+ DeprecationWarning, stacklevel=2)
+ else:
+ raise TypeError("NamedTuple.__new__() missing 1 required positional "
+ "argument: 'typename'")
+ if args:
+ try:
+ fields, = args # allow the "fields" keyword be passed
+ except ValueError:
+ raise TypeError('NamedTuple.__new__() takes from 2 to 3 '
+ 'positional arguments but {} '
+ 'were given'.format(len(args) + 2))
+ elif 'fields' in kwargs and len(kwargs) == 1:
+ fields = kwargs.pop('fields')
+ import warnings
+ warnings.warn("Passing 'fields' as keyword argument is deprecated",
+ DeprecationWarning, stacklevel=2)
+ else:
+ fields = None
+
+ if fields is None:
+ fields = kwargs.items()
+ elif kwargs:
+ raise TypeError("Either list of fields or keywords"
+ " can be provided to NamedTuple, not both")
+ return _make_nmtuple(typename, fields)
+
+ __new__.__text_signature__ = '($cls, typename, fields=None, /, **kwargs)'
+
+
+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
+
+ @abstractproperty
+ 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) -> Optional[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
projects / babeltrace.git / commitdiff
