| # TODO: |
| # - Tuple[..., t] |
| # - @no_type_check as class decorator |
| # - Look for TODO below |
| # - FrozenSet |
| |
| # TODO nits: |
| # Get rid of asserts that are the caller's fault. |
| # Docstrings (e.g. ABCs). |
| |
| import abc |
| from abc import abstractmethod, abstractproperty |
| import collections |
| import functools |
| import inspect |
| 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', |
| 'Generic', |
| 'Optional', |
| 'TypeVar', |
| 'Union', |
| 'Tuple', |
| |
| # 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', |
| 'SupportsRound', |
| |
| # Concrete collection types. |
| 'Dict', |
| 'List', |
| 'Set', |
| 'NamedTuple', # Not really a type. |
| |
| # Compile-time constants. |
| 'POSIX', |
| 'PY2', |
| 'PY3', |
| 'WINDOWS', |
| |
| # One-off things. |
| 'AnyStr', |
| 'Undefined', |
| 'cast', |
| 'get_type_hints', |
| 'no_type_check', |
| 'no_type_check_decorator', |
| 'overload', |
| |
| # Submodules. |
| 'io', |
| 're', |
| ] |
| |
| |
| # Simple constants defined in the PEP. |
| PY2 = sys.version_info[0] == 2 |
| PY3 = sys.version_info[0] >= 3 |
| WINDOWS = sys.platform == 'win32' |
| POSIX = not WINDOWS |
| |
| |
| def _qualname(x): |
| if sys.version_info[:2] >= (3, 3): |
| return x.__qualname__ |
| else: |
| # Fall back to just name. |
| return x.__name__ |
| |
| |
| class TypingMeta(type): |
| """Metaclass for every type defined below. |
| |
| This overrides __new__() to require an extra keyword parameter |
| '_root', which serves as a guard against naive subclassing of the |
| typing classes. Any legitimate class defined using a metaclass |
| derived from TypingMeta (including internal subclasses created by |
| e.g. Union[X, Y]) must pass _root=True. |
| |
| This also defines a dummy constructor (all the work is done in |
| __new__) and a nicer repr(). |
| """ |
| |
| _is_protocol = False |
| |
| def __new__(cls, name, bases, namespace, *, _root=False): |
| if not _root: |
| raise TypeError("Cannot subclass %s" % |
| (', '.join(map(_type_repr, bases)) or '()')) |
| return super().__new__(cls, name, bases, namespace) |
| |
| def __init__(self, *args, **kwds): |
| pass |
| |
| def _eval_type(self, globalns, localns): |
| """Override this in subclasses to interpret forward references. |
| |
| For example, Union['C'] is internally stored as |
| Union[_ForwardRef('C')], which should evaluate to _Union[C], |
| where C is an object found in globalns or localns (searching |
| localns first, of course). |
| """ |
| return self |
| |
| def _has_type_var(self): |
| return False |
| |
| def __repr__(self): |
| return '%s.%s' % (self.__module__, _qualname(self)) |
| |
| |
| class Final: |
| """Mix-in class to prevent instantiation.""" |
| |
| def __new__(self, *args, **kwds): |
| raise TypeError("Cannot instantiate %r" % self.__class__) |
| |
| |
| class _ForwardRef(TypingMeta): |
| """Wrapper to hold a forward reference.""" |
| |
| def __new__(cls, arg): |
| if not isinstance(arg, str): |
| raise TypeError('ForwardRef must be a string -- got %r' % (arg,)) |
| try: |
| code = compile(arg, '<string>', 'eval') |
| except SyntaxError: |
| raise SyntaxError('ForwardRef must be an expression -- got %r' % |
| (arg,)) |
| self = super().__new__(cls, arg, (), {}, _root=True) |
| self.__forward_arg__ = arg |
| self.__forward_code__ = code |
| self.__forward_evaluated__ = False |
| self.__forward_value__ = None |
| return self |
| |
| def _eval_type(self, globalns, localns): |
| if not isinstance(localns, dict): |
| raise TypeError('ForwardRef localns must be a dict -- got %r' % |
| (localns,)) |
| if not isinstance(globalns, dict): |
| raise TypeError('ForwardRef globalns must be a dict -- got %r' % |
| (globalns,)) |
| if not self.__forward_evaluated__: |
| self.__forward_value__ = eval(self.__forward_code__, |
| globalns, localns) |
| self.__forward_evaluated__ = True |
| return self.__forward_value__ |
| |
| def __repr__(self): |
| return '_ForwardRef(%r)' % (self.__forward_arg__,) |
| |
| |
| class _TypeAlias: |
| """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 can |
| be used in instance and subclass checks, e.g. isinstance(m, Match) |
| or issubclass(type(m), Match). However, it cannot be itself the |
| target of an issubclass() call; e.g. issubclass(Match, C) (for |
| some arbitrary class C) raises TypeError rather than returning |
| False. |
| """ |
| |
| def __new__(cls, *args, **kwds): |
| """Constructor. |
| |
| This only exists to give a better error message in case |
| someone tries to subclass a type alias (not a good idea). |
| """ |
| if (len(args) == 3 and |
| isinstance(args[0], str) and |
| isinstance(args[1], tuple)): |
| # Close enough. |
| raise TypeError("A type alias cannot be subclassed") |
| return object.__new__(cls) |
| |
| 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(type_var, type), repr(type_var) |
| assert isinstance(impl_type, type), repr(impl_type) |
| assert not isinstance(impl_type, TypingMeta), repr(impl_type) |
| 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): |
| assert isinstance(parameter, type), repr(parameter) |
| if not isinstance(self.type_var, TypeVar): |
| raise TypeError("%s cannot be further parameterized." % self) |
| if not issubclass(parameter, self.type_var): |
| raise TypeError("%s is not a valid substitution for %s." % |
| (parameter, self.type_var)) |
| return self.__class__(self.name, parameter, |
| self.impl_type, self.type_checker) |
| |
| def __instancecheck__(self, obj): |
| return (isinstance(obj, self.impl_type) and |
| isinstance(self.type_checker(obj), self.type_var)) |
| |
| def __subclasscheck__(self, cls): |
| if cls is Any: |
| return True |
| if isinstance(cls, _TypeAlias): |
| # Covariance. For now, we compare by name. |
| return (cls.name == self.name and |
| issubclass(cls.type_var, self.type_var)) |
| else: |
| # Note that this is too lenient, because the |
| # implementation type doesn't carry information about |
| # whether it is about bytes or str (for example). |
| return issubclass(cls, self.impl_type) |
| |
| |
| def _has_type_var(t): |
| return t is not None and isinstance(t, TypingMeta) and t._has_type_var() |
| |
| |
| def _eval_type(t, globalns, localns): |
| if isinstance(t, TypingMeta): |
| return t._eval_type(globalns, localns) |
| else: |
| return t |
| |
| |
| def _type_check(arg, msg): |
| """Check that the argument is a type, and return it. |
| |
| As a special case, accept None and return type(None) instead. |
| Also, _TypeAlias instances (e.g. Match, Pattern) are acceptable. |
| |
| The msg argument is a human-readable error message, e.g. |
| |
| "Union[arg, ...]: arg should be a type." |
| |
| We append the repr() of the actual value (truncated to 100 chars). |
| """ |
| if arg is None: |
| return type(None) |
| if isinstance(arg, str): |
| arg = _ForwardRef(arg) |
| if not isinstance(arg, (type, _TypeAlias)): |
| raise TypeError(msg + " Got %.100r." % (arg,)) |
| return arg |
| |
| |
| def _type_repr(obj): |
| """Return the repr() of an object, special-casing types. |
| |
| If obj is a type, we return a shorter version than the default |
| type.__repr__, based on the module and qualified name, which is |
| typically enough to uniquely identify a type. For everything |
| else, we fall back on repr(obj). |
| """ |
| if isinstance(obj, type) and not isinstance(obj, TypingMeta): |
| if obj.__module__ == 'builtins': |
| return _qualname(obj) |
| else: |
| return '%s.%s' % (obj.__module__, _qualname(obj)) |
| else: |
| return repr(obj) |
| |
| |
| class AnyMeta(TypingMeta): |
| """Metaclass for Any.""" |
| |
| def __new__(cls, name, bases, namespace, _root=False): |
| self = super().__new__(cls, name, bases, namespace, _root=_root) |
| return self |
| |
| def __instancecheck__(self, instance): |
| return True |
| |
| def __subclasscheck__(self, cls): |
| if not isinstance(cls, type): |
| return super().__subclasscheck__(cls) # To TypeError. |
| return True |
| |
| |
| class Any(Final, metaclass=AnyMeta, _root=True): |
| """Special type indicating an unconstrained type. |
| |
| - Any object is an instance of Any. |
| - Any class is a subclass of Any. |
| - As a special case, Any and object are subclasses of each other. |
| """ |
| |
| |
| class TypeVar(TypingMeta, metaclass=TypingMeta, _root=True): |
| """Type variable. |
| |
| Usage:: |
| |
| T1 = TypeVar('T1') # Unconstrained |
| T2 = TypeVar('T2', t1, t2, ...) # Constrained to any of (t1, t2, ...) |
| |
| For an unconstrained type variable T, isinstance(x, T) is false |
| for all x, and similar for issubclass(cls, T). Example:: |
| |
| T = TypeVar('T') |
| assert not isinstance(42, T) |
| assert not issubclass(int, T) |
| |
| For a constrained type variable T, isinstance(x, T) is true for |
| any x that is an instance of at least one of T's constraints, |
| and similar for issubclass(cls, T). Example:: |
| |
| AnyStr = TypeVar('AnyStr', str, bytes) |
| # AnyStr behaves similar to Union[str, bytes] (but not exactly!) |
| assert not isinstance(42, AnyStr) |
| assert isinstance('', AnyStr) |
| assert isinstance(b'', AnyStr) |
| assert not issubclass(int, AnyStr) |
| assert issubclass(str, AnyStr) |
| assert issubclass(bytes, AnyStr) |
| |
| Type variables that are distinct objects are never equal (even if |
| created with the same parameters). |
| |
| You can temporarily *bind* a type variable to a specific type by |
| calling its bind() method and using the result as a context |
| manager (i.e., in a with-statement). Example:: |
| |
| with T.bind(int): |
| # In this block, T is nearly an alias for int. |
| assert isinstance(42, T) |
| assert issubclass(int, T) |
| |
| There is still a difference between T and int; issubclass(T, int) |
| is False. However, issubclass(int, T) is true. |
| |
| Binding a constrained type variable will replace the binding type |
| with the most derived of its constraints that matches. Example:: |
| |
| class MyStr(str): |
| pass |
| |
| with AnyStr.bind(MyStr): |
| # In this block, AnyStr is an alias for str, not for MyStr. |
| assert isinstance('', AnyStr) |
| assert issubclass(str, AnyStr) |
| assert not isinstance(b'', AnyStr) |
| assert not issubclass(bytes, AnyStr) |
| |
| """ |
| |
| def __new__(cls, name, *constraints): |
| self = super().__new__(cls, name, (Final,), {}, _root=True) |
| msg = "TypeVar(name, constraint, ...): constraints must be types." |
| self.__constraints__ = tuple(_type_check(t, msg) for t in constraints) |
| self.__binding__ = None |
| return self |
| |
| def _has_type_var(self): |
| return True |
| |
| def __repr__(self): |
| return '~' + self.__name__ |
| |
| def __instancecheck__(self, instance): |
| if self.__binding__ is not None: |
| return isinstance(instance, self.__binding__) |
| elif not self.__constraints__: |
| return False |
| else: |
| return isinstance(instance, Union[self.__constraints__]) |
| |
| def __subclasscheck__(self, cls): |
| if cls is Any: |
| return True |
| if cls is self: |
| return True |
| elif self.__binding__ is not None: |
| return issubclass(cls, self.__binding__) |
| elif not self.__constraints__: |
| return False |
| else: |
| return issubclass(cls, Union[self.__constraints__]) |
| |
| def bind(self, binding): |
| binding = _type_check(binding, "TypeVar.bind(t): t must be a type.") |
| if self.__constraints__: |
| best = None |
| for t in self.__constraints__: |
| if (issubclass(binding, t) and |
| (best is None or issubclass(t, best))): |
| best = t |
| if best is None: |
| raise TypeError( |
| "TypeVar.bind(t): t must match one of the constraints.") |
| binding = best |
| return VarBinding(self, binding) |
| |
| def _bind(self, binding): |
| old_binding = self.__binding__ |
| self.__binding__ = binding |
| return old_binding |
| |
| def _unbind(self, binding, old_binding): |
| assert self.__binding__ is binding, (self.__binding__, |
| binding, old_binding) |
| self.__binding__ = old_binding |
| |
| |
| # Compatibility for for mypy's typevar(). |
| def typevar(name, values=()): |
| return TypeVar(name, *values) |
| |
| |
| class VarBinding: |
| """TypeVariable binding returned by TypeVar.bind().""" |
| |
| # TODO: This is not thread-safe. We could solve this in one of |
| # two ways: by using a lock or by using thread-local state. But |
| # either of these feels overly heavy, and still doesn't work |
| # e.g. in an asyncio Task. |
| |
| def __init__(self, var, binding): |
| assert isinstance(var, TypeVar), (var, binding) |
| assert isinstance(binding, type), (var, binding) |
| self._var = var |
| self._binding = binding |
| self._old_binding = None |
| self._entered = False |
| |
| def __enter__(self): |
| if self._entered: |
| # This checks for the following scenario: |
| # bv = T.bind(<some_type>) |
| # with bv: |
| # with bv: # Will raise here. |
| # ... |
| # However, the following scenario is OK (if somewhat odd): |
| # bv = T.bind(<some_type>) |
| # with bv: |
| # ... |
| # with bv: |
| # ... |
| # The following scenario is also fine: |
| # with T.bind(<some_type>): |
| # with T.bind(<some_other_type>): |
| # ... |
| raise TypeError("Cannot reuse variable binding recursively.") |
| self._old_binding = self._var._bind(self._binding) |
| self._entered = True |
| |
| def __exit__(self, *args): |
| try: |
| self._var._unbind(self._binding, self._old_binding) |
| finally: |
| self._entered = False |
| self._old_binding = None |
| |
| |
| # Some unconstrained type variables. These are used by the container types. |
| T = TypeVar('T') # Any type. |
| KT = TypeVar('KT') # Key type. |
| VT = TypeVar('VT') # Value type. |
| |
| # A useful type variable with constraints. This represents string types. |
| # TODO: What about bytearray, memoryview? |
| AnyStr = TypeVar('AnyStr', bytes, str) |
| |
| |
| class UnionMeta(TypingMeta): |
| """Metaclass for Union.""" |
| |
| def __new__(cls, name, bases, namespace, parameters=None, _root=False): |
| if parameters is None: |
| return super().__new__(cls, name, bases, namespace, _root=_root) |
| if not isinstance(parameters, tuple): |
| raise TypeError("Expected parameters=<tuple>") |
| # Flatten out Union[Union[...], ...] and type-check non-Union args. |
| params = [] |
| msg = "Union[arg, ...]: each arg must be a type." |
| for p in parameters: |
| if isinstance(p, UnionMeta): |
| params.extend(p.__union_params__) |
| else: |
| params.append(_type_check(p, msg)) |
| # Weed out strict duplicates, preserving the first of each occurrence. |
| all_params = set(params) |
| if len(all_params) < len(params): |
| new_params = [] |
| for t in params: |
| if t in all_params: |
| new_params.append(t) |
| all_params.remove(t) |
| params = new_params |
| assert not all_params, all_params |
| # Weed out subclasses. |
| # E.g. Union[int, Employee, Manager] == Union[int, Employee]. |
| # If Any or object is present it will be the sole survivor. |
| # If both Any and object are present, Any wins. |
| all_params = set(params) |
| for t1 in params: |
| if t1 is Any: |
| return Any |
| if any(issubclass(t1, t2) for t2 in all_params - {t1}): |
| all_params.remove(t1) |
| # It's not a union if there's only one type left. |
| if len(all_params) == 1: |
| return all_params.pop() |
| # Create a new class with these params. |
| self = super().__new__(cls, name, bases, {}, _root=True) |
| self.__union_params__ = tuple(t for t in params if t in all_params) |
| self.__union_set_params__ = frozenset(self.__union_params__) |
| return self |
| |
| def _eval_type(self, globalns, localns): |
| p = tuple(_eval_type(t, globalns, localns) |
| for t in self.__union_params__) |
| if p == self.__union_params__: |
| return self |
| else: |
| return self.__class__(self.__name__, self.__bases__, {}, |
| p, _root=True) |
| |
| def _has_type_var(self): |
| if self.__union_params__: |
| for t in self.__union_params__: |
| if _has_type_var(t): |
| return True |
| return False |
| |
| def __repr__(self): |
| r = super().__repr__() |
| if self.__union_params__: |
| r += '[%s]' % (', '.join(_type_repr(t) |
| for t in self.__union_params__)) |
| return r |
| |
| def __getitem__(self, parameters): |
| if self.__union_params__ is not None: |
| raise TypeError( |
| "Cannot subscript an existing Union. Use Union[u, t] instead.") |
| if parameters == (): |
| raise TypeError("Cannot take a Union of no types.") |
| if not isinstance(parameters, tuple): |
| parameters = (parameters,) |
| return self.__class__(self.__name__, self.__bases__, |
| dict(self.__dict__), parameters, _root=True) |
| |
| def __eq__(self, other): |
| if not isinstance(other, UnionMeta): |
| return NotImplemented |
| return self.__union_set_params__ == other.__union_set_params__ |
| |
| def __hash__(self): |
| return hash(self.__union_set_params__) |
| |
| def __instancecheck__(self, instance): |
| return (self.__union_set_params__ is not None and |
| any(isinstance(instance, t) for t in self.__union_params__)) |
| |
| def __subclasscheck__(self, cls): |
| if cls is Any: |
| return True |
| if self.__union_params__ is None: |
| return isinstance(cls, UnionMeta) |
| elif isinstance(cls, UnionMeta): |
| if cls.__union_params__ is None: |
| return False |
| return all(issubclass(c, self) for c in (cls.__union_params__)) |
| elif isinstance(cls, TypeVar): |
| if cls in self.__union_params__: |
| return True |
| if cls.__constraints__: |
| return issubclass(Union[cls.__constraints__], self) |
| return False |
| else: |
| return any(issubclass(cls, t) for t in self.__union_params__) |
| |
| |
| class Union(Final, metaclass=UnionMeta, _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 |
| |
| - Corollary: if Any is present it is the sole survivor, e.g.:: |
| |
| Union[int, Any] == Any |
| |
| - Similar for object:: |
| |
| Union[int, object] == object |
| |
| - To cut a tie: Union[object, Any] == Union[Any, object] == Any. |
| |
| - You cannot subclass or instantiate a union. |
| |
| - You cannot write Union[X][Y] (what would it mean?). |
| |
| - You can use Optional[X] as a shorthand for Union[X, None]. |
| """ |
| |
| # Unsubscripted Union type has params set to None. |
| __union_params__ = None |
| __union_set_params__ = None |
| |
| |
| class OptionalMeta(TypingMeta): |
| """Metaclass for Optional.""" |
| |
| def __new__(cls, name, bases, namespace, _root=False): |
| return super().__new__(cls, name, bases, namespace, _root=_root) |
| |
| def __getitem__(self, arg): |
| arg = _type_check(arg, "Optional[t] requires a single type.") |
| return Union[arg, type(None)] |
| |
| |
| class Optional(Final, metaclass=OptionalMeta, _root=True): |
| """Optional type. |
| |
| Optional[X] is equivalent to Union[X, type(None)]. |
| """ |
| |
| |
| class TupleMeta(TypingMeta): |
| """Metaclass for Tuple.""" |
| |
| def __new__(cls, name, bases, namespace, parameters=None, _root=False): |
| self = super().__new__(cls, name, bases, namespace, _root=_root) |
| self.__tuple_params__ = parameters |
| return self |
| |
| def _has_type_var(self): |
| if self.__tuple_params__: |
| for t in self.__tuple_params__: |
| if _has_type_var(t): |
| return True |
| return False |
| |
| def _eval_type(self, globalns, localns): |
| tp = self.__tuple_params__ |
| if tp is None: |
| return self |
| p = tuple(_eval_type(t, globalns, localns) for t in tp) |
| if p == self.__tuple_params__: |
| return self |
| else: |
| return self.__class__(self.__name__, self.__bases__, {}, |
| p, _root=True) |
| |
| def __repr__(self): |
| r = super().__repr__() |
| if self.__tuple_params__ is not None: |
| r += '[%s]' % ( |
| ', '.join(_type_repr(p) for p in self.__tuple_params__)) |
| return r |
| |
| def __getitem__(self, parameters): |
| if self.__tuple_params__ is not None: |
| raise TypeError("Cannot re-parameterize %r" % (self,)) |
| if not isinstance(parameters, tuple): |
| parameters = (parameters,) |
| msg = "Class[arg, ...]: each arg must be a type." |
| parameters = tuple(_type_check(p, msg) for p in parameters) |
| return self.__class__(self.__name__, self.__bases__, |
| dict(self.__dict__), parameters, _root=True) |
| |
| def __eq__(self, other): |
| if not isinstance(other, TupleMeta): |
| return NotImplemented |
| return self.__tuple_params__ == other.__tuple_params__ |
| |
| def __hash__(self): |
| return hash(self.__tuple_params__) |
| |
| def __instancecheck__(self, t): |
| if not isinstance(t, tuple): |
| return False |
| if self.__tuple_params__ is None: |
| return True |
| return (len(t) == len(self.__tuple_params__) and |
| all(isinstance(x, p) |
| for x, p in zip(t, self.__tuple_params__))) |
| |
| def __subclasscheck__(self, cls): |
| if cls is Any: |
| return True |
| if not isinstance(cls, type): |
| return super().__subclasscheck__(cls) # To TypeError. |
| if issubclass(cls, tuple): |
| return True # Special case. |
| if not isinstance(cls, TupleMeta): |
| return super().__subclasscheck__(cls) # False. |
| if self.__tuple_params__ is None: |
| return True |
| if cls.__tuple_params__ is None: |
| return False # ??? |
| # Covariance. |
| return (len(self.__tuple_params__) == len(cls.__tuple_params__) and |
| all(issubclass(x, p) |
| for x, p in zip(cls.__tuple_params__, |
| self.__tuple_params__))) |
| |
| |
| class Tuple(Final, metaclass=TupleMeta, _root=True): |
| """Tuple type; Tuple[X, Y] is the cross-product type of X and Y. |
| |
| Example: Tuple[T1, T2] is a tuple of two elements corresponding |
| to type variables T1 and T2. Tuple[int, float, str] is a tuple |
| of an int, a float and a string. |
| |
| To specify a variable-length tuple of homogeneous type, use Sequence[T]. |
| """ |
| |
| |
| class CallableMeta(TypingMeta): |
| """Metaclass for Callable.""" |
| |
| def __new__(cls, name, bases, namespace, _root=False, |
| args=None, result=None): |
| if args is None and result is None: |
| pass # Must be 'class Callable'. |
| else: |
| if args is not Ellipsis: |
| if not isinstance(args, list): |
| raise TypeError("Callable[args, result]: " |
| "args must be a list." |
| " Got %.100r." % (args,)) |
| msg = "Callable[[arg, ...], result]: each arg must be a type." |
| args = tuple(_type_check(arg, msg) for arg in args) |
| msg = "Callable[args, result]: result must be a type." |
| result = _type_check(result, msg) |
| self = super().__new__(cls, name, bases, namespace, _root=_root) |
| self.__args__ = args |
| self.__result__ = result |
| return self |
| |
| def _has_type_var(self): |
| if self.__args__: |
| for t in self.__args__: |
| if _has_type_var(t): |
| return True |
| return _has_type_var(self.__result__) |
| |
| def _eval_type(self, globalns, localns): |
| if self.__args__ is None and self.__result__ is None: |
| return self |
| args = [_eval_type(t, globalns, localns) for t in self.__args__] |
| result = _eval_type(self.__result__, globalns, localns) |
| if args == self.__args__ and result == self.__result__: |
| return self |
| else: |
| return self.__class__(self.__name__, self.__bases__, {}, |
| args=args, result=result, _root=True) |
| |
| def __repr__(self): |
| r = super().__repr__() |
| if self.__args__ is not None or self.__result__ is not None: |
| r += '%s[[%s], %s]' % (_qualname(self), |
| ', '.join(_type_repr(t) |
| for t in self.__args__), |
| _type_repr(self.__result__)) |
| return r |
| |
| def __getitem__(self, parameters): |
| if self.__args__ is not None or self.__result__ is not None: |
| raise TypeError("This Callable type is already parameterized.") |
| if not isinstance(parameters, tuple) or len(parameters) != 2: |
| raise TypeError( |
| "Callable must be used as Callable[[arg, ...], result].") |
| args, result = parameters |
| return self.__class__(self.__name__, self.__bases__, |
| dict(self.__dict__), _root=True, |
| args=args, result=result) |
| |
| def __eq__(self, other): |
| if not isinstance(other, CallableMeta): |
| return NotImplemented |
| return (self.__args__ == other.__args__ and |
| self.__result__ == other.__result__) |
| |
| def __hash__(self): |
| return hash(self.__args__) ^ hash(self.__result__) |
| |
| def __instancecheck__(self, instance): |
| if not callable(instance): |
| return False |
| if self.__args__ is None and self.__result__ is None: |
| return True |
| assert self.__args__ is not None |
| assert self.__result__ is not None |
| my_args, my_result = self.__args__, self.__result__ |
| # Would it be better to use Signature objects? |
| try: |
| (args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, |
| annotations) = inspect.getfullargspec(instance) |
| except TypeError: |
| return False # We can't find the signature. Give up. |
| msg = ("When testing isinstance(<callable>, Callable[...], " |
| "<calleble>'s annotations must be types.") |
| if my_args is not Ellipsis: |
| if kwonlyargs and (not kwonlydefaults or |
| len(kwonlydefaults) < len(kwonlyargs)): |
| return False |
| if isinstance(instance, types.MethodType): |
| # For methods, getfullargspec() includes self/cls, |
| # but it's not part of the call signature, so drop it. |
| del args[0] |
| min_call_args = len(args) |
| if defaults: |
| min_call_args -= len(defaults) |
| if varargs: |
| max_call_args = 999999999 |
| if len(args) < len(my_args): |
| args += [varargs] * (len(my_args) - len(args)) |
| else: |
| max_call_args = len(args) |
| if not min_call_args <= len(my_args) <= max_call_args: |
| return False |
| for my_arg_type, name in zip(my_args, args): |
| if name in annotations: |
| annot_type = _type_check(annotations[name], msg) |
| else: |
| annot_type = Any |
| if not issubclass(my_arg_type, annot_type): |
| return False |
| # TODO: If mutable type, check invariance? |
| if 'return' in annotations: |
| annot_return_type = _type_check(annotations['return'], msg) |
| # Note contravariance here! |
| if not issubclass(annot_return_type, my_result): |
| return False |
| # Can't find anything wrong... |
| return True |
| |
| def __subclasscheck__(self, cls): |
| if cls is Any: |
| return True |
| if not isinstance(cls, CallableMeta): |
| return super().__subclasscheck__(cls) |
| if self.__args__ is None and self.__result__ is None: |
| return True |
| # We're not doing covariance or contravariance -- this is *invariance*. |
| return self == cls |
| |
| |
| class Callable(Final, metaclass=CallableMeta, _root=True): |
| """Callable type; Callable[[int], str] is a function of (int) -> str. |
| |
| The subscription syntax must always be used with exactly two |
| values: the argument list and the return type. The argument list |
| must be a list of types; the return type must be a single type. |
| |
| There is no syntax to indicate optional or keyword arguments, |
| such function types are rarely used as callback types. |
| """ |
| |
| |
| class GenericMeta(TypingMeta, abc.ABCMeta): |
| """Metaclass for generic types.""" |
| |
| # TODO: Constrain more how Generic is used; only a few |
| # standard patterns should be allowed. |
| |
| __extra__ = None |
| |
| def __new__(cls, name, bases, namespace, parameters=None, extra=None): |
| if parameters is None: |
| # Extract parameters from direct base classes. Only |
| # direct bases are considered and only those that are |
| # themselves generic, and parameterized with type |
| # variables. Don't use bases like Any, Union, Tuple, |
| # Callable or type variables. |
| params = None |
| for base in bases: |
| if isinstance(base, TypingMeta): |
| if not isinstance(base, GenericMeta): |
| raise TypeError( |
| "You cannot inherit from magic class %s" % |
| repr(base)) |
| if base.__parameters__ is None: |
| continue # The base is unparameterized. |
| for bp in base.__parameters__: |
| if _has_type_var(bp) and not isinstance(bp, TypeVar): |
| raise TypeError( |
| "Cannot inherit from a generic class " |
| "parameterized with " |
| "non-type-variable %s" % bp) |
| if params is None: |
| params = [] |
| if bp not in params: |
| params.append(bp) |
| if params is not None: |
| parameters = tuple(params) |
| self = super().__new__(cls, name, bases, namespace, _root=True) |
| self.__parameters__ = parameters |
| if extra is not None: |
| self.__extra__ = extra |
| # Else __extra__ is inherited, eventually from the |
| # (meta-)class default above. |
| return self |
| |
| def _has_type_var(self): |
| if self.__parameters__: |
| for t in self.__parameters__: |
| if _has_type_var(t): |
| return True |
| return False |
| |
| def __repr__(self): |
| r = super().__repr__() |
| if self.__parameters__ is not None: |
| r += '[%s]' % ( |
| ', '.join(_type_repr(p) for p in self.__parameters__)) |
| return r |
| |
| def __eq__(self, other): |
| if not isinstance(other, GenericMeta): |
| return NotImplemented |
| return (self.__name__ == other.__name__ and |
| self.__parameters__ == other.__parameters__) |
| |
| def __hash__(self): |
| return hash((self.__name__, self.__parameters__)) |
| |
| def __getitem__(self, params): |
| if not isinstance(params, tuple): |
| params = (params,) |
| if not params: |
| raise TypeError("Cannot have empty parameter list") |
| msg = "Parameters to generic types must be types." |
| params = tuple(_type_check(p, msg) for p in params) |
| if self.__parameters__ is None: |
| for p in params: |
| if not isinstance(p, TypeVar): |
| raise TypeError("Initial parameters must be " |
| "type variables; got %s" % p) |
| else: |
| if len(params) != len(self.__parameters__): |
| raise TypeError("Cannot change parameter count from %d to %d" % |
| (len(self.__parameters__), len(params))) |
| for new, old in zip(params, self.__parameters__): |
| if isinstance(old, TypeVar) and not old.__constraints__: |
| # Substituting for an unconstrained TypeVar is always OK. |
| continue |
| if not issubclass(new, old): |
| raise TypeError( |
| "Cannot substitute %s for %s in %s" % |
| (_type_repr(new), _type_repr(old), self)) |
| |
| return self.__class__(self.__name__, self.__bases__, |
| dict(self.__dict__), |
| parameters=params, extra=self.__extra__) |
| |
| def __subclasscheck__(self, cls): |
| if cls is Any: |
| return True |
| if super().__subclasscheck__(cls): |
| return True |
| if self.__extra__ is None: |
| return False |
| return issubclass(cls, self.__extra__) |
| |
| def __instancecheck__(self, obj): |
| if super().__instancecheck__(obj): |
| return True |
| if self.__extra__ is None: |
| return False |
| return isinstance(obj, self.__extra__) |
| |
| |
| class Generic(metaclass=GenericMeta): |
| """Abstract base class for generic types. |
| |
| A generic type is typically declared by inheriting from an |
| instantiation of this class with one or more type variables. |
| For example, a generic mapping type might be defined as:: |
| |
| class Mapping(Generic[KT, VT]): |
| def __getitem__(self, key: KT) -> VT: |
| ... |
| # Etc. |
| |
| This class can then be used as follows:: |
| |
| def lookup_name(mapping: Mapping, key: KT, default: VT) -> VT: |
| try: |
| return mapping[key] |
| except KeyError: |
| return default |
| |
| For clarity the type variables may be redefined, e.g.:: |
| |
| X = TypeVar('X') |
| Y = TypeVar('Y') |
| def lookup_name(mapping: Mapping[X, Y], key: X, default: Y) -> Y: |
| # Same body as above. |
| """ |
| |
| |
| class Undefined: |
| """An undefined value. |
| |
| Example:: |
| |
| x = Undefined(typ) |
| |
| This tells the type checker that x has the given type but its |
| value should be considered undefined. At runtime x is an instance |
| of Undefined. The actual type can be introspected by looking at |
| x.__type__ and its str() and repr() are defined, but any other |
| operations or attributes will raise an exception. |
| |
| An alternative syntax is also supported: |
| |
| x = Undefined # type: typ |
| |
| This has the same meaning to the static type checker but uses less |
| overhead at run-time, at the cost of not being introspectible. |
| |
| NOTE: Do not under any circumstances check for Undefined. We |
| don't want this to become something developers rely upon, like |
| JavaScript's undefined. Code that returns or uses an Undefined |
| value in any way should be considered broken. Static type |
| checkers should warn about using potentially Undefined values. |
| """ |
| |
| __slots__ = ['__type__'] |
| |
| def __new__(cls, typ): |
| typ = _type_check(typ, "Undefined(t): t must be a type.") |
| self = super().__new__(cls) |
| self.__type__ = typ |
| return self |
| |
| __hash__ = None |
| |
| def __repr__(self): |
| return '%s(%s)' % (_type_repr(self.__class__), |
| _type_repr(self.__type__)) |
| |
| |
| 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 |
| kw_count = code.co_kwonlyargcount |
| arg_names = code.co_varnames |
| kwarg_names = arg_names[pos_count:pos_count+kw_count] |
| 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): |
| """Return type hints for a function or method object. |
| |
| This is often the same as obj.__annotations__, but it handles |
| forward references encoded as string literals, and if necessary |
| adds Optional[t] if a default value equal to None is set. |
| |
| BEWARE -- the behavior of globalns and localns is counterintuitive |
| (unless you are familiar with how eval() and exec() work). The |
| search order is locals first, then globals. |
| |
| - If no dict arguments are passed, the defaults are taken from the |
| globals and locals of the caller, respectively. |
| |
| - If one dict argument is passed, it is used for both globals and |
| locals. |
| |
| - If two dict arguments are passed, they specify globals and |
| locals, respectively. |
| """ |
| if getattr(obj, '__no_type_check__', None): |
| return {} |
| if globalns is None: |
| globalns = sys._getframe(1).f_globals |
| if localns is None: |
| localns = sys._getframe(1).f_locals |
| elif localns is None: |
| localns = globalns |
| defaults = _get_defaults(obj) |
| hints = dict(obj.__annotations__) |
| for name, value in hints.items(): |
| if isinstance(value, str): |
| value = _ForwardRef(value) |
| value = _eval_type(value, globalns, localns) |
| if name in defaults and defaults[name] is None: |
| value = Optional[value] |
| hints[name] = value |
| return hints |
| |
| |
| # TODO: Also support this as a class decorator. |
| def no_type_check(func): |
| """Decorator to indicate that annotations are not type hints. |
| |
| This mutates the function in place. |
| """ |
| func.__no_type_check__ = True |
| return func |
| |
| |
| 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(func): |
| raise RuntimeError("Overloading is only supported in library stubs") |
| |
| |
| class _Protocol(Generic): |
| """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). |
| """ |
| |
| _is_protocol = True |
| |
| @classmethod |
| def __subclasshook__(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 NotImplemented |
| return True |
| |
| @classmethod |
| 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 != '_get_protocol_attrs' and |
| attr != '__module__'): |
| attrs.add(attr) |
| |
| return attrs |
| |
| |
| # 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], extra=collections_abc.Iterable): |
| pass |
| |
| |
| class Iterator(Iterable, extra=collections_abc.Iterator): |
| pass |
| |
| |
| class SupportsInt(_Protocol): |
| |
| @abstractmethod |
| def __int__(self) -> int: |
| pass |
| |
| |
| class SupportsFloat(_Protocol): |
| |
| @abstractmethod |
| def __float__(self) -> float: |
| pass |
| |
| |
| class SupportsAbs(_Protocol[T]): |
| |
| @abstractmethod |
| def __abs__(self) -> T: |
| pass |
| |
| |
| class SupportsRound(_Protocol[T]): |
| |
| @abstractmethod |
| def __round__(self, ndigits: int = 0) -> T: |
| pass |
| |
| |
| class Reversible(_Protocol[T]): |
| |
| @abstractmethod |
| def __reversed__(self) -> 'Iterator[T]': |
| pass |
| |
| |
| Sized = collections_abc.Sized # Not generic. |
| |
| |
| class Container(Generic[T], extra=collections_abc.Container): |
| pass |
| |
| |
| # Callable was defined earlier. |
| |
| |
| class AbstractSet(Sized, Iterable, Container, extra=collections_abc.Set): |
| pass |
| |
| |
| class MutableSet(AbstractSet, extra=collections_abc.MutableSet): |
| pass |
| |
| |
| class Mapping(Sized, Iterable[KT], Container[KT], Generic[KT, VT], |
| extra=collections_abc.Mapping): |
| pass |
| |
| |
| class MutableMapping(Mapping, extra=collections_abc.MutableMapping): |
| pass |
| |
| |
| class Sequence(Sized, Iterable, Container, extra=collections_abc.Sequence): |
| pass |
| |
| |
| class MutableSequence(Sequence, extra=collections_abc.MutableSequence): |
| pass |
| |
| |
| class ByteString(Sequence[int], extra=collections_abc.ByteString): |
| pass |
| |
| |
| ByteString.register(type(memoryview(b''))) |
| |
| |
| class _ListMeta(GenericMeta): |
| |
| def __instancecheck__(self, obj): |
| if not super().__instancecheck__(obj): |
| return False |
| itemtype = self.__parameters__[0] |
| for x in obj: |
| if not isinstance(x, itemtype): |
| return False |
| return True |
| |
| |
| class List(list, MutableSequence, metaclass=_ListMeta): |
| pass |
| |
| |
| class _SetMeta(GenericMeta): |
| |
| def __instancecheck__(self, obj): |
| if not super().__instancecheck__(obj): |
| return False |
| itemtype = self.__parameters__[0] |
| for x in obj: |
| if not isinstance(x, itemtype): |
| return False |
| return True |
| |
| |
| class Set(set, MutableSet, metaclass=_SetMeta): |
| pass |
| |
| |
| class MappingView(Sized, Iterable, extra=collections_abc.MappingView): |
| pass |
| |
| |
| class KeysView(MappingView, Set[KT], extra=collections_abc.KeysView): |
| pass |
| |
| |
| # TODO: Enable Set[Tuple[KT, VT]] instead of Generic[KT, VT]. |
| class ItemsView(MappingView, Generic[KT, VT], extra=collections_abc.ItemsView): |
| pass |
| |
| |
| class ValuesView(MappingView, extra=collections_abc.ValuesView): |
| pass |
| |
| |
| class _DictMeta(GenericMeta): |
| |
| def __instancecheck__(self, obj): |
| if not super().__instancecheck__(obj): |
| return False |
| keytype, valuetype = self.__parameters__ |
| for key, value in obj.items(): |
| if not (isinstance(key, keytype) and |
| isinstance(value, valuetype)): |
| return False |
| return True |
| |
| |
| class Dict(dict, MutableMapping, metaclass=_DictMeta): |
| pass |
| |
| |
| 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) |
| return cls |
| |
| |
| 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. |
| """ |
| |
| @abstractproperty |
| def mode(self) -> str: |
| pass |
| |
| @abstractproperty |
| def name(self) -> str: |
| pass |
| |
| @abstractmethod |
| def close(self) -> None: |
| pass |
| |
| @abstractmethod |
| def closed(self) -> bool: |
| pass |
| |
| @abstractmethod |
| def fileno(self) -> int: |
| pass |
| |
| @abstractmethod |
| def flush(self) -> None: |
| pass |
| |
| @abstractmethod |
| def isatty(self) -> bool: |
| pass |
| |
| @abstractmethod |
| def read(self, n: int = -1) -> AnyStr: |
| pass |
| |
| @abstractmethod |
| def readable(self) -> bool: |
| pass |
| |
| @abstractmethod |
| def readline(self, limit: int = -1) -> AnyStr: |
| pass |
| |
| @abstractmethod |
| def readlines(self, hint: int = -1) -> List[AnyStr]: |
| pass |
| |
| @abstractmethod |
| def seek(self, offset: int, whence: int = 0) -> int: |
| pass |
| |
| @abstractmethod |
| def seekable(self) -> bool: |
| pass |
| |
| @abstractmethod |
| def tell(self) -> int: |
| pass |
| |
| @abstractmethod |
| def truncate(self, size: int = None) -> int: |
| pass |
| |
| @abstractmethod |
| def writable(self) -> bool: |
| pass |
| |
| @abstractmethod |
| def write(self, s: AnyStr) -> int: |
| pass |
| |
| @abstractmethod |
| def writelines(self, lines: List[AnyStr]) -> None: |
| pass |
| |
| @abstractmethod |
| def __enter__(self) -> 'IO[AnyStr]': |
| pass |
| |
| @abstractmethod |
| def __exit__(self, type, value, traceback) -> None: |
| pass |
| |
| |
| class BinaryIO(IO[bytes]): |
| """Typed version of the return of open() in binary mode.""" |
| |
| @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.""" |
| |
| @abstractproperty |
| def buffer(self) -> BinaryIO: |
| pass |
| |
| @abstractproperty |
| def encoding(self) -> str: |
| pass |
| |
| @abstractproperty |
| def errors(self) -> str: |
| pass |
| |
| @abstractproperty |
| def line_buffering(self) -> bool: |
| pass |
| |
| @abstractproperty |
| def newlines(self) -> Any: |
| pass |
| |
| @abstractmethod |
| def __enter__(self) -> 'TextIO': |
| pass |
| |
| |
| class io: |
| """Wrapper namespace for IO generic classes.""" |
| |
| __all__ = ['IO', 'TextIO', 'BinaryIO'] |
| IO = IO |
| TextIO = TextIO |
| BinaryIO = BinaryIO |
| |
| io.__name__ = __name__ + '.io' |
| sys.modules[io.__name__] = io |
| |
| |
| Pattern = _TypeAlias('Pattern', AnyStr, type(stdlib_re.compile('')), |
| lambda p: p.pattern) |
| Match = _TypeAlias('Match', AnyStr, type(stdlib_re.match('', '')), |
| lambda m: m.re.pattern) |
| |
| |
| class re: |
| """Wrapper namespace for re type aliases.""" |
| |
| __all__ = ['Pattern', 'Match'] |
| Pattern = Pattern |
| Match = Match |
| |
| re.__name__ = __name__ + '.re' |
| sys.modules[re.__name__] = re |
