| from __future__ import absolute_import, unicode_literals |
| |
| import abc |
| from abc import abstractmethod, abstractproperty |
| import collections |
| 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. |
| |
| |
| # 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. |
| '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', |
| |
| # 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 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): |
| return super(TypingMeta, cls).__new__(cls, str(name), bases, namespace) |
| |
| @classmethod |
| def assert_no_subclassing(cls, bases): |
| for base in bases: |
| if isinstance(base, cls): |
| raise TypeError("Cannot subclass %s" % |
| (', '.join(map(_type_repr, bases)) or '()')) |
| |
| 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(object): |
| """Indicator of special typing constructs.""" |
| __metaclass__ = TypingMeta |
| __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(_TypingBase, cls).__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): |
| """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, **kwds): |
| self = super(_FinalTypingBase, cls).__new__(cls, *args, **kwds) |
| if '_root' in kwds and kwds['_root'] is True: |
| return self |
| raise TypeError("Cannot instantiate %r" % cls) |
| |
| def __reduce__(self): |
| return _trim_name(type(self).__name__) |
| |
| |
| class _ForwardRef(_TypingBase): |
| """Wrapper to hold a forward reference.""" |
| |
| __slots__ = ('__forward_arg__', '__forward_code__', |
| '__forward_evaluated__', '__forward_value__', |
| '__forward_frame__') |
| |
| def __init__(self, arg): |
| super(_ForwardRef, self).__init__(arg) |
| if not isinstance(arg, basestring): |
| 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 __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): |
| """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, basestring), 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 __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. |
| |
| 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, basestring): |
| 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 _gorg(arg) 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. |
| |
| 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__ == '__builtin__': |
| return _qualname(obj) |
| return '%s.%s' % (obj.__module__, _qualname(obj)) |
| if obj is Ellipsis: |
| return('...') |
| if isinstance(obj, types.FunctionType): |
| return obj.__name__ |
| return repr(obj) |
| |
| |
| class ClassVarMeta(TypingMeta): |
| """Metaclass for _ClassVar""" |
| |
| def __new__(cls, name, bases, namespace): |
| cls.assert_no_subclassing(bases) |
| self = super(ClassVarMeta, cls).__new__(cls, name, bases, namespace) |
| return self |
| |
| |
| class _ClassVar(_FinalTypingBase): |
| """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 = {} # type: ClassVar[Dict[str, int]] # class variable |
| damage = 10 # type: int # 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(). |
| """ |
| |
| __metaclass__ = ClassVarMeta |
| __slots__ = ('__type__',) |
| |
| def __init__(self, tp=None, _root=False): |
| self.__type__ = tp |
| |
| def __getitem__(self, item): |
| cls = type(self) |
| if self.__type__ is None: |
| return cls(_type_check(item, |
| '{} accepts only types.'.format(cls.__name__[1:])), |
| _root=True) |
| raise TypeError('{} cannot be further subscripted' |
| .format(cls.__name__[1:])) |
| |
| def _eval_type(self, globalns, localns): |
| return type(self)(_eval_type(self.__type__, globalns, localns), |
| _root=True) |
| |
| def __repr__(self): |
| r = super(_ClassVar, self).__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) |
| |
| |
| class AnyMeta(TypingMeta): |
| """Metaclass for Any.""" |
| |
| def __new__(cls, name, bases, namespace): |
| cls.assert_no_subclassing(bases) |
| self = super(AnyMeta, cls).__new__(cls, name, bases, namespace) |
| return self |
| |
| |
| class _Any(_FinalTypingBase): |
| """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. |
| """ |
| __metaclass__ = AnyMeta |
| __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 TypeVarMeta(TypingMeta): |
| def __new__(cls, name, bases, namespace): |
| cls.assert_no_subclassing(bases) |
| return super(TypeVarMeta, cls).__new__(cls, name, bases, namespace) |
| |
| |
| class TypeVar(_TypingBase): |
| """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) |
| """ |
| |
| __metaclass__ = TypeVarMeta |
| __slots__ = ('__name__', '__bound__', '__constraints__', |
| '__covariant__', '__contravariant__') |
| |
| def __init__(self, name, *constraints, **kwargs): |
| super(TypeVar, self).__init__(name, *constraints, **kwargs) |
| bound = kwargs.get('bound', None) |
| covariant = kwargs.get('covariant', False) |
| contravariant = kwargs.get('contravariant', False) |
| 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, unicode) |
| |
| |
| def _replace_arg(arg, tvars, args): |
| """ A helper fuunction: 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'): |
| return arg._subs_tree(tvars, args) |
| if isinstance(arg, TypeVar): |
| for i, tvar in enumerate(tvars): |
| if arg == tvar: |
| return args[i] |
| return arg |
| |
| |
| def _subs_tree(cls, tvars=None, args=None): |
| """ Calculate substitution tree for generic cls after |
| replacing its type parameters with substitutions in tvars -> args (if any). |
| Repeat the same cyclicaly following __origin__'s. |
| """ |
| |
| 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 i, arg in enumerate(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): |
| """ A 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. |
| 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)) |
| |
| |
| def _tp_cache(func): |
| maxsize = 128 |
| cache = {} |
| |
| @functools.wraps(func) |
| def inner(*args): |
| key = args |
| try: |
| return cache[key] |
| except TypeError: |
| # Assume it's an unhashable argument. |
| return func(*args) |
| except KeyError: |
| value = func(*args) |
| if len(cache) >= maxsize: |
| # If the cache grows too much, just start over. |
| cache.clear() |
| cache[key] = value |
| return value |
| |
| return inner |
| |
| |
| class UnionMeta(TypingMeta): |
| """Metaclass for Union.""" |
| |
| def __new__(cls, name, bases, namespace): |
| cls.assert_no_subclassing(bases) |
| return super(UnionMeta, cls).__new__(cls, name, bases, namespace) |
| |
| |
| class _Union(_FinalTypingBase): |
| """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]. |
| """ |
| |
| __metaclass__ = UnionMeta |
| __slots__ = ('__parameters__', '__args__', '__origin__', '__tree_hash__') |
| |
| def __new__(cls, parameters=None, origin=None, *args, **kwds): |
| self = super(_Union, cls).__new__(cls, parameters, origin, *args, **kwds) |
| 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(_Union, self).__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(_Union, self).__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 not isinstance(other, _Union): |
| return self._subs_tree() == other |
| return self.__tree_hash__ == other.__tree_hash__ |
| |
| 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 OptionalMeta(TypingMeta): |
| """Metaclass for Optional.""" |
| |
| def __new__(cls, name, bases, namespace): |
| cls.assert_no_subclassing(bases) |
| return super(OptionalMeta, cls).__new__(cls, name, bases, namespace) |
| |
| |
| class _Optional(_FinalTypingBase): |
| """Optional type. |
| |
| Optional[X] is equivalent to Union[X, None]. |
| """ |
| |
| __metaclass__ = OptionalMeta |
| __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 _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__(cls, subclass): |
| _valid_for_check(cls) |
| res = cls.__extra__.__subclasshook__(subclass) |
| if res is not NotImplemented: |
| return res |
| if cls.__extra__ in getattr(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__(cls, subclass): |
| _valid_for_check(cls) |
| if cls.__extra__ and issubclass(subclass, cls.__extra__): |
| return True |
| return NotImplemented |
| return classmethod(__extrahook__) |
| |
| |
| class GenericMeta(TypingMeta, abc.ABCMeta): |
| """Metaclass for generic types.""" |
| |
| def __new__(cls, name, bases, namespace, |
| tvars=None, args=None, origin=None, extra=None, orig_bases=None): |
| 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 None: |
| extra = namespace.get('__extra__') |
| if extra is not None and type(extra) is abc.ABCMeta and extra not in bases: |
| bases = (extra,) + bases |
| bases = tuple(_gorg(b) 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) |
| self = super(GenericMeta, cls).__new__(cls, name, bases, namespace) |
| |
| self.__parameters__ = tvars |
| # Be prepared that GenericMeta will be subclassed by TupleMeta |
| # and CallableMeta, those two allow ..., (), or [] in __args___. |
| self.__args__ = tuple(Ellipsis if a is _TypingEllipsis else |
| () if a is _TypingEmpty else |
| a for a in args) if args else None |
| self.__origin__ = origin |
| self.__extra__ = extra |
| # 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 # allow overriding |
| or hasattr(self.__subclasshook__, '__name__') and |
| self.__subclasshook__.__name__ == '__extrahook__'): |
| self.__subclasshook__ = _make_subclasshook(self) |
| |
| 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 hash((self.__name__,)) |
| return self |
| |
| def __init__(self, *args, **kwargs): |
| super(GenericMeta, self).__init__(*args, **kwargs) |
| if isinstance(self.__extra__, abc.ABCMeta): |
| self._abc_registry = self.__extra__._abc_registry |
| |
| 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__, |
| dict(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(GenericMeta, self).__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(GenericMeta, self).__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 (_gorg(self),) + 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 not _gorg(self) is 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 |
| return self.__class__(self.__name__, |
| self.__bases__, |
| dict(self.__dict__), |
| tvars=tvars, |
| args=args, |
| origin=self, |
| extra=self.__extra__, |
| orig_bases=self.__orig_bases__) |
| |
| 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. |
| if not isinstance(instance, type): |
| return issubclass(instance.__class__, self) |
| return False |
| |
| def __copy__(self): |
| return self.__class__(self.__name__, self.__bases__, dict(self.__dict__), |
| self.__parameters__, self.__args__, self.__origin__, |
| self.__extra__, self.__orig_bases__) |
| |
| |
| # 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: |
| return base_cls.__new__(cls) |
| else: |
| origin = _gorg(cls) |
| obj = base_cls.__new__(origin) |
| try: |
| obj.__orig_class__ = cls |
| except AttributeError: |
| pass |
| obj.__init__(*args, **kwds) |
| return obj |
| |
| |
| class Generic(object): |
| """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 |
| """ |
| |
| __metaclass__ = GenericMeta |
| __slots__ = () |
| |
| def __new__(cls, *args, **kwds): |
| if _geqv(cls, 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(object): |
| """Placeholder for () or []. Used by TupleMeta and CallableMeta |
| to allow empy list/tuple in specific places, without allowing them |
| to sneak in where prohibited. |
| """ |
| |
| |
| class _TypingEllipsis(object): |
| """Ditto for ...""" |
| |
| |
| class TupleMeta(GenericMeta): |
| """Metaclass for Tuple""" |
| |
| @_tp_cache |
| def __getitem__(self, parameters): |
| if self.__origin__ is not None or not _geqv(self, Tuple): |
| # Normal generic rules apply if this is not the first subscription |
| # or a subscription of a subclass. |
| return super(TupleMeta, self).__getitem__(parameters) |
| if parameters == (): |
| return super(TupleMeta, self).__getitem__((_TypingEmpty,)) |
| if not isinstance(parameters, tuple): |
| parameters = (parameters,) |
| if len(parameters) == 2 and parameters[1] is Ellipsis: |
| msg = "Tuple[t, ...]: t must be a type." |
| p = _type_check(parameters[0], msg) |
| return super(TupleMeta, self).__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(TupleMeta, self).__getitem__(parameters) |
| |
| def __instancecheck__(self, obj): |
| if self.__args__ == None: |
| return isinstance(obj, tuple) |
| raise TypeError("Parameterized Tuple cannot be used " |
| "with isinstance().") |
| |
| def __subclasscheck__(self, cls): |
| if self.__args__ == None: |
| return issubclass(cls, tuple) |
| raise TypeError("Parameterized Tuple cannot be used " |
| "with issubclass().") |
| |
| |
| class Tuple(tuple): |
| """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, ...]. |
| """ |
| |
| __metaclass__ = TupleMeta |
| __extra__ = tuple |
| __slots__ = () |
| |
| def __new__(cls, *args, **kwds): |
| if _geqv(cls, Tuple): |
| raise TypeError("Type Tuple cannot be instantiated; " |
| "use tuple() instead") |
| return _generic_new(tuple, cls, *args, **kwds) |
| |
| |
| class CallableMeta(GenericMeta): |
| """ Metaclass for Callable.""" |
| |
| def __repr__(self): |
| if self.__origin__ is None: |
| return super(CallableMeta, self).__repr__() |
| return self._tree_repr(self._subs_tree()) |
| |
| def _tree_repr(self, tree): |
| if _gorg(self) is not Callable: |
| return super(CallableMeta, self)._tree_repr(tree) |
| # For actual Callable (not its subclass) we override |
| # super(CallableMeta, self)._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 not _geqv(self, Callable): |
| return super(CallableMeta, self).__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(CallableMeta, self).__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(CallableMeta, self).__getitem__(parameters) |
| |
| |
| class Callable(object): |
| """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. |
| """ |
| |
| __metaclass__ = CallableMeta |
| __extra__ = collections_abc.Callable |
| __slots__ = () |
| |
| def __new__(cls, *args, **kwds): |
| if _geqv(cls, Callable): |
| raise TypeError("Type Callable cannot be instantiated; " |
| "use a non-abstract subclass instead") |
| return _generic_new(cls.__next_in_mro__, cls, *args, **kwds) |
| |
| |
| 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 |
| |
| |
| def get_type_hints(obj, globalns=None, localns=None): |
| """In Python 2 this is not supported and always returns None.""" |
| return None |
| |
| |
| 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 != '_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 != '__orig_bases__' and |
| attr != '__extra__' and |
| attr != '__tree_hash__' and |
| attr != '__module__'): |
| attrs.add(attr) |
| |
| return attrs |
| |
| |
| class _Protocol(object): |
| """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). |
| """ |
| |
| __metaclass__ = _ProtocolMeta |
| __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. |
| |
| |
| class Iterable(Generic[T_co]): |
| __slots__ = () |
| __extra__ = collections_abc.Iterable |
| |
| |
| class Iterator(Iterable[T_co]): |
| __slots__ = () |
| __extra__ = collections_abc.Iterator |
| |
| |
| class SupportsInt(_Protocol): |
| __slots__ = () |
| |
| @abstractmethod |
| def __int__(self): |
| pass |
| |
| |
| class SupportsFloat(_Protocol): |
| __slots__ = () |
| |
| @abstractmethod |
| def __float__(self): |
| pass |
| |
| |
| class SupportsComplex(_Protocol): |
| __slots__ = () |
| |
| @abstractmethod |
| def __complex__(self): |
| pass |
| |
| |
| class SupportsAbs(_Protocol[T_co]): |
| __slots__ = () |
| |
| @abstractmethod |
| def __abs__(self): |
| pass |
| |
| |
| if hasattr(collections_abc, 'Reversible'): |
| class Reversible(Iterable[T_co]): |
| __slots__ = () |
| __extra__ = collections_abc.Reversible |
| else: |
| class Reversible(_Protocol[T_co]): |
| __slots__ = () |
| |
| @abstractmethod |
| def __reversed__(self): |
| pass |
| |
| |
| Sized = collections_abc.Sized # Not generic. |
| |
| |
| class Container(Generic[T_co]): |
| __slots__ = () |
| __extra__ = collections_abc.Container |
| |
| |
| # Callable was defined earlier. |
| |
| |
| class AbstractSet(Sized, Iterable[T_co], Container[T_co]): |
| __slots__ = () |
| __extra__ = collections_abc.Set |
| |
| |
| class MutableSet(AbstractSet[T]): |
| __slots__ = () |
| __extra__ = collections_abc.MutableSet |
| |
| |
| # NOTE: It is only covariant in the value type. |
| class Mapping(Sized, Iterable[KT], Container[KT], Generic[KT, VT_co]): |
| __slots__ = () |
| __extra__ = collections_abc.Mapping |
| |
| |
| class MutableMapping(Mapping[KT, VT]): |
| __slots__ = () |
| __extra__ = collections_abc.MutableMapping |
| |
| |
| if hasattr(collections_abc, 'Reversible'): |
| class Sequence(Sized, Reversible[T_co], Container[T_co]): |
| __slots__ = () |
| __extra__ = collections_abc.Sequence |
| else: |
| class Sequence(Sized, Iterable[T_co], Container[T_co]): |
| __slots__ = () |
| __extra__ = collections_abc.Sequence |
| |
| |
| class MutableSequence(Sequence[T]): |
| __slots__ = () |
| __extra__ = collections_abc.MutableSequence |
| |
| |
| class ByteString(Sequence[int]): |
| pass |
| |
| |
| ByteString.register(str) |
| ByteString.register(bytearray) |
| |
| |
| class List(list, MutableSequence[T]): |
| __slots__ = () |
| __extra__ = list |
| |
| def __new__(cls, *args, **kwds): |
| if _geqv(cls, List): |
| raise TypeError("Type List cannot be instantiated; " |
| "use list() instead") |
| return _generic_new(list, cls, *args, **kwds) |
| |
| |
| class Set(set, MutableSet[T]): |
| __slots__ = () |
| __extra__ = set |
| |
| def __new__(cls, *args, **kwds): |
| if _geqv(cls, Set): |
| raise TypeError("Type Set cannot be instantiated; " |
| "use set() instead") |
| return _generic_new(set, cls, *args, **kwds) |
| |
| |
| class FrozenSet(frozenset, AbstractSet[T_co]): |
| __slots__ = () |
| __extra__ = frozenset |
| |
| def __new__(cls, *args, **kwds): |
| if _geqv(cls, FrozenSet): |
| raise TypeError("Type FrozenSet cannot be instantiated; " |
| "use frozenset() instead") |
| return _generic_new(frozenset, cls, *args, **kwds) |
| |
| |
| class MappingView(Sized, Iterable[T_co]): |
| __slots__ = () |
| __extra__ = collections_abc.MappingView |
| |
| |
| class KeysView(MappingView[KT], AbstractSet[KT]): |
| __slots__ = () |
| __extra__ = collections_abc.KeysView |
| |
| |
| class ItemsView(MappingView[Tuple[KT, VT_co]], |
| AbstractSet[Tuple[KT, VT_co]], |
| Generic[KT, VT_co]): |
| __slots__ = () |
| __extra__ = collections_abc.ItemsView |
| |
| |
| class ValuesView(MappingView[VT_co]): |
| __slots__ = () |
| __extra__ = collections_abc.ValuesView |
| |
| |
| class Dict(dict, MutableMapping[KT, VT]): |
| __slots__ = () |
| __extra__ = dict |
| |
| def __new__(cls, *args, **kwds): |
| if _geqv(cls, 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]): |
| __slots__ = () |
| __extra__ = collections.defaultdict |
| |
| def __new__(cls, *args, **kwds): |
| if _geqv(cls, DefaultDict): |
| raise TypeError("Type DefaultDict cannot be instantiated; " |
| "use collections.defaultdict() instead") |
| return _generic_new(collections.defaultdict, 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]): |
| __slots__ = () |
| __extra__ = _G_base |
| |
| def __new__(cls, *args, **kwds): |
| if _geqv(cls, Generator): |
| raise TypeError("Type Generator cannot be instantiated; " |
| "create a subclass instead") |
| return _generic_new(_G_base, 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]): |
| """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__ = () |
| __extra__ = type |
| |
| |
| 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.) |
| """ |
| fields = [(n, t) for n, t in fields] |
| cls = collections.namedtuple(typename, [n for n, t in fields]) |
| cls._field_types = dict(fields) |
| # Set the module to the caller's module (otherwise it'd be 'typing'). |
| try: |
| cls.__module__ = sys._getframe(1).f_globals.get('__name__', '__main__') |
| except (AttributeError, ValueError): |
| pass |
| return cls |
| |
| |
| 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): |
| # type: (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 |
| |
| # Some versions of Python 2 complain because of making all strings unicode |
| new_type.__name__ = str(name) |
| new_type.__supertype__ = tp |
| return new_type |
| |
| |
| # Python-version-specific alias (Python 2: unicode; Python 3: str) |
| Text = unicode |
| |
| |
| # 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): |
| pass |
| |
| @abstractproperty |
| def name(self): |
| pass |
| |
| @abstractmethod |
| def close(self): |
| pass |
| |
| @abstractmethod |
| def closed(self): |
| pass |
| |
| @abstractmethod |
| def fileno(self): |
| pass |
| |
| @abstractmethod |
| def flush(self): |
| pass |
| |
| @abstractmethod |
| def isatty(self): |
| pass |
| |
| @abstractmethod |
| def read(self, n = -1): |
| pass |
| |
| @abstractmethod |
| def readable(self): |
| pass |
| |
| @abstractmethod |
| def readline(self, limit = -1): |
| pass |
| |
| @abstractmethod |
| def readlines(self, hint = -1): |
| pass |
| |
| @abstractmethod |
| def seek(self, offset, whence = 0): |
| pass |
| |
| @abstractmethod |
| def seekable(self): |
| pass |
| |
| @abstractmethod |
| def tell(self): |
| pass |
| |
| @abstractmethod |
| def truncate(self, size = None): |
| pass |
| |
| @abstractmethod |
| def writable(self): |
| pass |
| |
| @abstractmethod |
| def write(self, s): |
| pass |
| |
| @abstractmethod |
| def writelines(self, lines): |
| pass |
| |
| @abstractmethod |
| def __enter__(self): |
| pass |
| |
| @abstractmethod |
| def __exit__(self, type, value, traceback): |
| pass |
| |
| |
| class BinaryIO(IO[bytes]): |
| """Typed version of the return of open() in binary mode.""" |
| |
| __slots__ = () |
| |
| @abstractmethod |
| def write(self, s): |
| pass |
| |
| @abstractmethod |
| def __enter__(self): |
| pass |
| |
| |
| class TextIO(IO[unicode]): |
| """Typed version of the return of open() in text mode.""" |
| |
| __slots__ = () |
| |
| @abstractproperty |
| def buffer(self): |
| pass |
| |
| @abstractproperty |
| def encoding(self): |
| pass |
| |
| @abstractproperty |
| def errors(self): |
| pass |
| |
| @abstractproperty |
| def line_buffering(self): |
| pass |
| |
| @abstractproperty |
| def newlines(self): |
| pass |
| |
| @abstractmethod |
| def __enter__(self): |
| pass |
| |
| |
| class io(object): |
| """Wrapper namespace for IO generic classes.""" |
| |
| __all__ = ['IO', 'TextIO', 'BinaryIO'] |
| IO = IO |
| TextIO = TextIO |
| BinaryIO = BinaryIO |
| |
| io.__name__ = __name__ + b'.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(object): |
| """Wrapper namespace for re type aliases.""" |
| |
| __all__ = ['Pattern', 'Match'] |
| Pattern = Pattern |
| Match = Match |
| |
| re.__name__ = __name__ + b'.re' |
| sys.modules[re.__name__] = re |
