2407 lines
80 KiB
Python
2407 lines
80 KiB
Python
"""
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The typing module: Support for gradual typing as defined by PEP 484.
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At large scale, the structure of the module is following:
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* Imports and exports, all public names should be explicitly added to __all__.
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* Internal helper functions: these should never be used in code outside this module.
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* _SpecialForm and its instances (special forms):
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Any, NoReturn, ClassVar, Union, Optional, Concatenate
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* Classes whose instances can be type arguments in addition to types:
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ForwardRef, TypeVar and ParamSpec
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* The core of internal generics API: _GenericAlias and _VariadicGenericAlias, the latter is
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currently only used by Tuple and Callable. All subscripted types like X[int], Union[int, str],
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etc., are instances of either of these classes.
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* The public counterpart of the generics API consists of two classes: Generic and Protocol.
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* Public helper functions: get_type_hints, overload, cast, no_type_check,
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no_type_check_decorator.
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* Generic aliases for collections.abc ABCs and few additional protocols.
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* Special types: NewType, NamedTuple, TypedDict.
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* Wrapper submodules for re and io related types.
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"""
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from abc import abstractmethod, ABCMeta
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import ast
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import collections
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import collections.abc
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import contextlib
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import functools
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import operator
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import re as stdlib_re # Avoid confusion with the re we export.
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import sys
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import types
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from types import WrapperDescriptorType, MethodWrapperType, MethodDescriptorType, GenericAlias
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# Please keep __all__ alphabetized within each category.
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__all__ = [
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# Super-special typing primitives.
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'Annotated',
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'Any',
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'Callable',
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'ClassVar',
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'Concatenate',
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'Final',
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'ForwardRef',
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'Generic',
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'Literal',
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'Optional',
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'ParamSpec',
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'Protocol',
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'Tuple',
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'Type',
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'TypeVar',
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'Union',
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# ABCs (from collections.abc).
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'AbstractSet', # collections.abc.Set.
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'ByteString',
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'Container',
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'ContextManager',
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'Hashable',
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'ItemsView',
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'Iterable',
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'Iterator',
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'KeysView',
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'Mapping',
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'MappingView',
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'MutableMapping',
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'MutableSequence',
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'MutableSet',
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'Sequence',
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'Sized',
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'ValuesView',
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'Awaitable',
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'AsyncIterator',
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'AsyncIterable',
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'Coroutine',
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'Collection',
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'AsyncGenerator',
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'AsyncContextManager',
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# Structural checks, a.k.a. protocols.
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'Reversible',
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'SupportsAbs',
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'SupportsBytes',
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'SupportsComplex',
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'SupportsFloat',
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'SupportsIndex',
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'SupportsInt',
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'SupportsRound',
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# Concrete collection types.
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'ChainMap',
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'Counter',
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'Deque',
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'Dict',
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'DefaultDict',
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'List',
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'OrderedDict',
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'Set',
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'FrozenSet',
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'NamedTuple', # Not really a type.
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'TypedDict', # Not really a type.
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'Generator',
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# One-off things.
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'AnyStr',
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'cast',
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'final',
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'get_args',
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'get_origin',
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'get_type_hints',
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'is_typeddict',
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'NewType',
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'no_type_check',
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'no_type_check_decorator',
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'NoReturn',
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'overload',
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'runtime_checkable',
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'Text',
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'TYPE_CHECKING',
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'TypeAlias',
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]
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# The pseudo-submodules 're' and 'io' are part of the public
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# namespace, but excluded from __all__ because they might stomp on
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# legitimate imports of those modules.
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def _type_convert(arg):
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"""For converting None to type(None), and strings to ForwardRef."""
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if arg is None:
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return type(None)
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if isinstance(arg, str):
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return ForwardRef(arg)
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return arg
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def _type_check(arg, msg, is_argument=True):
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"""Check that the argument is a type, and return it (internal helper).
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As a special case, accept None and return type(None) instead. Also wrap strings
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into ForwardRef instances. Consider several corner cases, for example plain
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special forms like Union are not valid, while Union[int, str] is OK, etc.
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The msg argument is a human-readable error message, e.g::
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"Union[arg, ...]: arg should be a type."
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We append the repr() of the actual value (truncated to 100 chars).
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"""
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invalid_generic_forms = (Generic, Protocol)
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if is_argument:
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invalid_generic_forms = invalid_generic_forms + (ClassVar, Final)
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arg = _type_convert(arg)
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if (isinstance(arg, _GenericAlias) and
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arg.__origin__ in invalid_generic_forms):
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raise TypeError(f"{arg} is not valid as type argument")
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if arg in (Any, NoReturn):
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return arg
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if isinstance(arg, _SpecialForm) or arg in (Generic, Protocol):
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raise TypeError(f"Plain {arg} is not valid as type argument")
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if isinstance(arg, (type, TypeVar, ForwardRef, types.Union, ParamSpec)):
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return arg
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if not callable(arg):
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raise TypeError(f"{msg} Got {arg!r:.100}.")
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return arg
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def _type_repr(obj):
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"""Return the repr() of an object, special-casing types (internal helper).
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If obj is a type, we return a shorter version than the default
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type.__repr__, based on the module and qualified name, which is
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typically enough to uniquely identify a type. For everything
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else, we fall back on repr(obj).
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"""
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if isinstance(obj, types.GenericAlias):
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return repr(obj)
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if isinstance(obj, type):
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if obj.__module__ == 'builtins':
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return obj.__qualname__
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return f'{obj.__module__}.{obj.__qualname__}'
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if obj is ...:
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return('...')
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if isinstance(obj, types.FunctionType):
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return obj.__name__
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return repr(obj)
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def _collect_type_vars(types):
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"""Collect all type variable-like variables contained
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in types in order of first appearance (lexicographic order). For example::
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_collect_type_vars((T, List[S, T])) == (T, S)
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"""
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tvars = []
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for t in types:
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if isinstance(t, _TypeVarLike) and t not in tvars:
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tvars.append(t)
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if isinstance(t, (_GenericAlias, GenericAlias)):
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tvars.extend([t for t in t.__parameters__ if t not in tvars])
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return tuple(tvars)
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def _check_generic(cls, parameters, elen):
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"""Check correct count for parameters of a generic cls (internal helper).
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This gives a nice error message in case of count mismatch.
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"""
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if not elen:
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raise TypeError(f"{cls} is not a generic class")
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alen = len(parameters)
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if alen != elen:
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raise TypeError(f"Too {'many' if alen > elen else 'few'} parameters for {cls};"
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f" actual {alen}, expected {elen}")
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def _prepare_paramspec_params(cls, params):
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"""Prepares the parameters for a Generic containing ParamSpec
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variables (internal helper).
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"""
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# Special case where Z[[int, str, bool]] == Z[int, str, bool] in PEP 612.
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if len(cls.__parameters__) == 1 and len(params) > 1:
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return (params,)
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else:
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_params = []
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# Convert lists to tuples to help other libraries cache the results.
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for p, tvar in zip(params, cls.__parameters__):
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if isinstance(tvar, ParamSpec) and isinstance(p, list):
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p = tuple(p)
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_params.append(p)
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return tuple(_params)
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def _deduplicate(params):
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# Weed out strict duplicates, preserving the first of each occurrence.
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all_params = set(params)
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if len(all_params) < len(params):
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new_params = []
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for t in params:
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if t in all_params:
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new_params.append(t)
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all_params.remove(t)
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params = new_params
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assert not all_params, all_params
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return params
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def _remove_dups_flatten(parameters):
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"""An internal helper for Union creation and substitution: flatten Unions
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among parameters, then remove duplicates.
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"""
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# Flatten out Union[Union[...], ...].
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params = []
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for p in parameters:
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if isinstance(p, (_UnionGenericAlias, types.Union)):
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params.extend(p.__args__)
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elif isinstance(p, tuple) and len(p) > 0 and p[0] is Union:
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params.extend(p[1:])
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else:
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params.append(p)
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return tuple(_deduplicate(params))
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def _flatten_literal_params(parameters):
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"""An internal helper for Literal creation: flatten Literals among parameters"""
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params = []
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for p in parameters:
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if isinstance(p, _LiteralGenericAlias):
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params.extend(p.__args__)
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else:
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params.append(p)
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return tuple(params)
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_cleanups = []
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def _tp_cache(func=None, /, *, typed=False):
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"""Internal wrapper caching __getitem__ of generic types with a fallback to
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original function for non-hashable arguments.
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"""
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def decorator(func):
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cached = functools.lru_cache(typed=typed)(func)
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_cleanups.append(cached.cache_clear)
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@functools.wraps(func)
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def inner(*args, **kwds):
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try:
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return cached(*args, **kwds)
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except TypeError:
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pass # All real errors (not unhashable args) are raised below.
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return func(*args, **kwds)
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return inner
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if func is not None:
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return decorator(func)
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return decorator
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def _eval_type(t, globalns, localns, recursive_guard=frozenset()):
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"""Evaluate all forward references in the given type t.
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For use of globalns and localns see the docstring for get_type_hints().
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recursive_guard is used to prevent prevent infinite recursion
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with recursive ForwardRef.
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"""
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if isinstance(t, ForwardRef):
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return t._evaluate(globalns, localns, recursive_guard)
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if isinstance(t, (_GenericAlias, GenericAlias)):
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ev_args = tuple(_eval_type(a, globalns, localns, recursive_guard) for a in t.__args__)
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if ev_args == t.__args__:
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return t
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if isinstance(t, GenericAlias):
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return GenericAlias(t.__origin__, ev_args)
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else:
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return t.copy_with(ev_args)
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return t
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class _Final:
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"""Mixin to prohibit subclassing"""
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__slots__ = ('__weakref__',)
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def __init_subclass__(self, /, *args, **kwds):
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if '_root' not in kwds:
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raise TypeError("Cannot subclass special typing classes")
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class _Immutable:
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"""Mixin to indicate that object should not be copied."""
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__slots__ = ()
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def __copy__(self):
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return self
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def __deepcopy__(self, memo):
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return self
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# Internal indicator of special typing constructs.
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# See __doc__ instance attribute for specific docs.
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class _SpecialForm(_Final, _root=True):
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__slots__ = ('_name', '__doc__', '_getitem')
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def __init__(self, getitem):
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self._getitem = getitem
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self._name = getitem.__name__
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self.__doc__ = getitem.__doc__
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def __mro_entries__(self, bases):
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raise TypeError(f"Cannot subclass {self!r}")
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def __repr__(self):
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return 'typing.' + self._name
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def __reduce__(self):
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return self._name
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def __call__(self, *args, **kwds):
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raise TypeError(f"Cannot instantiate {self!r}")
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def __instancecheck__(self, obj):
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raise TypeError(f"{self} cannot be used with isinstance()")
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def __subclasscheck__(self, cls):
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raise TypeError(f"{self} cannot be used with issubclass()")
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@_tp_cache
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def __getitem__(self, parameters):
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return self._getitem(self, parameters)
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class _LiteralSpecialForm(_SpecialForm, _root=True):
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@_tp_cache(typed=True)
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def __getitem__(self, parameters):
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return self._getitem(self, parameters)
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@_SpecialForm
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def Any(self, parameters):
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"""Special type indicating an unconstrained type.
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- Any is compatible with every type.
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- Any assumed to have all methods.
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- All values assumed to be instances of Any.
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Note that all the above statements are true from the point of view of
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static type checkers. At runtime, Any should not be used with instance
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or class checks.
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"""
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raise TypeError(f"{self} is not subscriptable")
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@_SpecialForm
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def NoReturn(self, parameters):
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"""Special type indicating functions that never return.
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Example::
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from typing import NoReturn
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def stop() -> NoReturn:
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raise Exception('no way')
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This type is invalid in other positions, e.g., ``List[NoReturn]``
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will fail in static type checkers.
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"""
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raise TypeError(f"{self} is not subscriptable")
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@_SpecialForm
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def ClassVar(self, parameters):
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"""Special type construct to mark class variables.
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An annotation wrapped in ClassVar indicates that a given
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attribute is intended to be used as a class variable and
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should not be set on instances of that class. Usage::
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class Starship:
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stats: ClassVar[Dict[str, int]] = {} # class variable
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damage: int = 10 # instance variable
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ClassVar accepts only types and cannot be further subscribed.
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Note that ClassVar is not a class itself, and should not
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be used with isinstance() or issubclass().
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"""
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item = _type_check(parameters, f'{self} accepts only single type.')
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return _GenericAlias(self, (item,))
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|
|
@_SpecialForm
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def Final(self, parameters):
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"""Special typing construct to indicate final names to type checkers.
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A final name cannot be re-assigned or overridden in a subclass.
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For example:
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MAX_SIZE: Final = 9000
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MAX_SIZE += 1 # Error reported by type checker
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class Connection:
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TIMEOUT: Final[int] = 10
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class FastConnector(Connection):
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TIMEOUT = 1 # Error reported by type checker
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|
There is no runtime checking of these properties.
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"""
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item = _type_check(parameters, f'{self} accepts only single type.')
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return _GenericAlias(self, (item,))
|
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|
|
@_SpecialForm
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def Union(self, parameters):
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"""Union type; Union[X, Y] means either X or Y.
|
|
|
|
To define a union, use e.g. Union[int, str]. Details:
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- 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.::
|
|
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|
Union[Union[int, str], float] == Union[int, str, float]
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|
|
|
- Unions of a single argument vanish, e.g.::
|
|
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|
Union[int] == int # The constructor actually returns int
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|
|
|
- Redundant arguments are skipped, e.g.::
|
|
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|
Union[int, str, int] == Union[int, str]
|
|
|
|
- When comparing unions, the argument order is ignored, e.g.::
|
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|
Union[int, str] == Union[str, int]
|
|
|
|
- You cannot subclass or instantiate a union.
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|
- You can use Optional[X] as a shorthand for Union[X, None].
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|
"""
|
|
if parameters == ():
|
|
raise TypeError("Cannot take a Union of no types.")
|
|
if not isinstance(parameters, tuple):
|
|
parameters = (parameters,)
|
|
msg = "Union[arg, ...]: each arg must be a type."
|
|
parameters = tuple(_type_check(p, msg) for p in parameters)
|
|
parameters = _remove_dups_flatten(parameters)
|
|
if len(parameters) == 1:
|
|
return parameters[0]
|
|
return _UnionGenericAlias(self, parameters)
|
|
|
|
@_SpecialForm
|
|
def Optional(self, parameters):
|
|
"""Optional type.
|
|
|
|
Optional[X] is equivalent to Union[X, None].
|
|
"""
|
|
arg = _type_check(parameters, f"{self} requires a single type.")
|
|
return Union[arg, type(None)]
|
|
|
|
@_LiteralSpecialForm
|
|
def Literal(self, parameters):
|
|
"""Special typing form to define literal types (a.k.a. value types).
|
|
|
|
This form can be used to indicate to type checkers that the corresponding
|
|
variable or function parameter has a value equivalent to the provided
|
|
literal (or one of several literals):
|
|
|
|
def validate_simple(data: Any) -> Literal[True]: # always returns True
|
|
...
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|
|
|
MODE = Literal['r', 'rb', 'w', 'wb']
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|
def open_helper(file: str, mode: MODE) -> str:
|
|
...
|
|
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|
open_helper('/some/path', 'r') # Passes type check
|
|
open_helper('/other/path', 'typo') # Error in type checker
|
|
|
|
Literal[...] cannot be subclassed. At runtime, an arbitrary value
|
|
is allowed as type argument to Literal[...], but type checkers may
|
|
impose restrictions.
|
|
"""
|
|
# There is no '_type_check' call because arguments to Literal[...] are
|
|
# values, not types.
|
|
if not isinstance(parameters, tuple):
|
|
parameters = (parameters,)
|
|
|
|
parameters = _flatten_literal_params(parameters)
|
|
|
|
try:
|
|
parameters = tuple(p for p, _ in _deduplicate(list(_value_and_type_iter(parameters))))
|
|
except TypeError: # unhashable parameters
|
|
pass
|
|
|
|
return _LiteralGenericAlias(self, parameters)
|
|
|
|
|
|
@_SpecialForm
|
|
def TypeAlias(self, parameters):
|
|
"""Special marker indicating that an assignment should
|
|
be recognized as a proper type alias definition by type
|
|
checkers.
|
|
|
|
For example::
|
|
|
|
Predicate: TypeAlias = Callable[..., bool]
|
|
|
|
It's invalid when used anywhere except as in the example above.
|
|
"""
|
|
raise TypeError(f"{self} is not subscriptable")
|
|
|
|
|
|
@_SpecialForm
|
|
def Concatenate(self, parameters):
|
|
"""Used in conjunction with ``ParamSpec`` and ``Callable`` to represent a
|
|
higher order function which adds, removes or transforms parameters of a
|
|
callable.
|
|
|
|
For example::
|
|
|
|
Callable[Concatenate[int, P], int]
|
|
|
|
See PEP 612 for detailed information.
|
|
"""
|
|
if parameters == ():
|
|
raise TypeError("Cannot take a Concatenate of no types.")
|
|
if not isinstance(parameters, tuple):
|
|
parameters = (parameters,)
|
|
if not isinstance(parameters[-1], ParamSpec):
|
|
raise TypeError("The last parameter to Concatenate should be a "
|
|
"ParamSpec variable.")
|
|
msg = "Concatenate[arg, ...]: each arg must be a type."
|
|
parameters = tuple(_type_check(p, msg) for p in parameters)
|
|
return _ConcatenateGenericAlias(self, parameters)
|
|
|
|
|
|
class ForwardRef(_Final, _root=True):
|
|
"""Internal wrapper to hold a forward reference."""
|
|
|
|
__slots__ = ('__forward_arg__', '__forward_code__',
|
|
'__forward_evaluated__', '__forward_value__',
|
|
'__forward_is_argument__')
|
|
|
|
def __init__(self, arg, is_argument=True):
|
|
if not isinstance(arg, str):
|
|
raise TypeError(f"Forward reference must be a string -- got {arg!r}")
|
|
|
|
# Double-stringified forward references is a result of activating
|
|
# the 'annotations' future by default. This way, we eliminate them in
|
|
# the runtime.
|
|
if arg.startswith(("'", '\"')) and arg.endswith(("'", '"')):
|
|
arg = arg[1:-1]
|
|
|
|
try:
|
|
code = compile(arg, '<string>', 'eval')
|
|
except SyntaxError:
|
|
raise SyntaxError(f"Forward reference must be an expression -- got {arg!r}")
|
|
self.__forward_arg__ = arg
|
|
self.__forward_code__ = code
|
|
self.__forward_evaluated__ = False
|
|
self.__forward_value__ = None
|
|
self.__forward_is_argument__ = is_argument
|
|
|
|
def _evaluate(self, globalns, localns, recursive_guard):
|
|
if self.__forward_arg__ in recursive_guard:
|
|
return self
|
|
if not self.__forward_evaluated__ or localns is not globalns:
|
|
if globalns is None and localns is None:
|
|
globalns = localns = {}
|
|
elif globalns is None:
|
|
globalns = localns
|
|
elif localns is None:
|
|
localns = globalns
|
|
type_ =_type_check(
|
|
eval(self.__forward_code__, globalns, localns),
|
|
"Forward references must evaluate to types.",
|
|
is_argument=self.__forward_is_argument__,
|
|
)
|
|
self.__forward_value__ = _eval_type(
|
|
type_, globalns, localns, recursive_guard | {self.__forward_arg__}
|
|
)
|
|
self.__forward_evaluated__ = True
|
|
return self.__forward_value__
|
|
|
|
def __eq__(self, other):
|
|
if not isinstance(other, ForwardRef):
|
|
return NotImplemented
|
|
if self.__forward_evaluated__ and other.__forward_evaluated__:
|
|
return (self.__forward_arg__ == other.__forward_arg__ and
|
|
self.__forward_value__ == other.__forward_value__)
|
|
return self.__forward_arg__ == other.__forward_arg__
|
|
|
|
def __hash__(self):
|
|
return hash(self.__forward_arg__)
|
|
|
|
def __repr__(self):
|
|
return f'ForwardRef({self.__forward_arg__!r})'
|
|
|
|
class _TypeVarLike:
|
|
"""Mixin for TypeVar-like types (TypeVar and ParamSpec)."""
|
|
def __init__(self, bound, covariant, contravariant):
|
|
"""Used to setup TypeVars and ParamSpec's bound, covariant and
|
|
contravariant attributes.
|
|
"""
|
|
if covariant and contravariant:
|
|
raise ValueError("Bivariant types are not supported.")
|
|
self.__covariant__ = bool(covariant)
|
|
self.__contravariant__ = bool(contravariant)
|
|
if bound:
|
|
self.__bound__ = _type_check(bound, "Bound must be a type.")
|
|
else:
|
|
self.__bound__ = None
|
|
|
|
def __or__(self, right):
|
|
return Union[self, right]
|
|
|
|
def __ror__(self, right):
|
|
return Union[self, right]
|
|
|
|
def __repr__(self):
|
|
if self.__covariant__:
|
|
prefix = '+'
|
|
elif self.__contravariant__:
|
|
prefix = '-'
|
|
else:
|
|
prefix = '~'
|
|
return prefix + self.__name__
|
|
|
|
def __reduce__(self):
|
|
return self.__name__
|
|
|
|
|
|
class TypeVar( _Final, _Immutable, _TypeVarLike, _root=True):
|
|
"""Type variable.
|
|
|
|
Usage::
|
|
|
|
T = TypeVar('T') # Can be anything
|
|
A = TypeVar('A', str, bytes) # Must be str or bytes
|
|
|
|
Type variables exist primarily for the benefit of static type
|
|
checkers. They serve as the parameters for generic types as well
|
|
as for generic function definitions. See class Generic for more
|
|
information on generic types. Generic functions work as follows:
|
|
|
|
def repeat(x: T, n: int) -> List[T]:
|
|
'''Return a list containing n references to x.'''
|
|
return [x]*n
|
|
|
|
def longest(x: A, y: A) -> A:
|
|
'''Return the longest of two strings.'''
|
|
return x if len(x) >= len(y) else y
|
|
|
|
The latter example's signature is essentially the overloading
|
|
of (str, str) -> str and (bytes, bytes) -> bytes. Also note
|
|
that if the arguments are instances of some subclass of str,
|
|
the return type is still plain str.
|
|
|
|
At runtime, isinstance(x, T) and issubclass(C, T) will raise TypeError.
|
|
|
|
Type variables defined with covariant=True or contravariant=True
|
|
can be used to 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)
|
|
|
|
Note that only type variables defined in global scope can be pickled.
|
|
"""
|
|
|
|
__slots__ = ('__name__', '__bound__', '__constraints__',
|
|
'__covariant__', '__contravariant__', '__dict__')
|
|
|
|
def __init__(self, name, *constraints, bound=None,
|
|
covariant=False, contravariant=False):
|
|
self.__name__ = name
|
|
super().__init__(bound, covariant, 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)
|
|
try:
|
|
def_mod = sys._getframe(1).f_globals.get('__name__', '__main__') # for pickling
|
|
except (AttributeError, ValueError):
|
|
def_mod = None
|
|
if def_mod != 'typing':
|
|
self.__module__ = def_mod
|
|
|
|
|
|
class ParamSpec(_Final, _Immutable, _TypeVarLike, _root=True):
|
|
"""Parameter specification variable.
|
|
|
|
Usage::
|
|
|
|
P = ParamSpec('P')
|
|
|
|
Parameter specification variables exist primarily for the benefit of static
|
|
type checkers. They are used to forward the parameter types of one
|
|
callable to another callable, a pattern commonly found in higher order
|
|
functions and decorators. They are only valid when used in ``Concatenate``,
|
|
or s the first argument to ``Callable``, or as parameters for user-defined
|
|
Generics. See class Generic for more information on generic types. An
|
|
example for annotating a decorator::
|
|
|
|
T = TypeVar('T')
|
|
P = ParamSpec('P')
|
|
|
|
def add_logging(f: Callable[P, T]) -> Callable[P, T]:
|
|
'''A type-safe decorator to add logging to a function.'''
|
|
def inner(*args: P.args, **kwargs: P.kwargs) -> T:
|
|
logging.info(f'{f.__name__} was called')
|
|
return f(*args, **kwargs)
|
|
return inner
|
|
|
|
@add_logging
|
|
def add_two(x: float, y: float) -> float:
|
|
'''Add two numbers together.'''
|
|
return x + y
|
|
|
|
Parameter specification variables defined with covariant=True or
|
|
contravariant=True can be used to declare covariant or contravariant
|
|
generic types. These keyword arguments are valid, but their actual semantics
|
|
are yet to be decided. See PEP 612 for details.
|
|
|
|
Parameter specification variables can be introspected. e.g.:
|
|
|
|
P.__name__ == 'T'
|
|
P.__bound__ == None
|
|
P.__covariant__ == False
|
|
P.__contravariant__ == False
|
|
|
|
Note that only parameter specification variables defined in global scope can
|
|
be pickled.
|
|
"""
|
|
|
|
__slots__ = ('__name__', '__bound__', '__covariant__', '__contravariant__',
|
|
'__dict__')
|
|
|
|
args = object()
|
|
kwargs = object()
|
|
|
|
def __init__(self, name, bound=None, covariant=False, contravariant=False):
|
|
self.__name__ = name
|
|
super().__init__(bound, covariant, contravariant)
|
|
try:
|
|
def_mod = sys._getframe(1).f_globals.get('__name__', '__main__')
|
|
except (AttributeError, ValueError):
|
|
def_mod = None
|
|
if def_mod != 'typing':
|
|
self.__module__ = def_mod
|
|
|
|
|
|
def _is_dunder(attr):
|
|
return attr.startswith('__') and attr.endswith('__')
|
|
|
|
class _BaseGenericAlias(_Final, _root=True):
|
|
"""The central part of internal API.
|
|
|
|
This represents a generic version of type 'origin' with type arguments 'params'.
|
|
There are two kind of these aliases: user defined and special. The special ones
|
|
are wrappers around builtin collections and ABCs in collections.abc. These must
|
|
have 'name' always set. If 'inst' is False, then the alias can't be instantiated,
|
|
this is used by e.g. typing.List and typing.Dict.
|
|
"""
|
|
def __init__(self, origin, *, inst=True, name=None):
|
|
self._inst = inst
|
|
self._name = name
|
|
self.__origin__ = origin
|
|
self.__slots__ = None # This is not documented.
|
|
|
|
def __call__(self, *args, **kwargs):
|
|
if not self._inst:
|
|
raise TypeError(f"Type {self._name} cannot be instantiated; "
|
|
f"use {self.__origin__.__name__}() instead")
|
|
result = self.__origin__(*args, **kwargs)
|
|
try:
|
|
result.__orig_class__ = self
|
|
except AttributeError:
|
|
pass
|
|
return result
|
|
|
|
def __mro_entries__(self, bases):
|
|
res = []
|
|
if self.__origin__ not in bases:
|
|
res.append(self.__origin__)
|
|
i = bases.index(self)
|
|
for b in bases[i+1:]:
|
|
if isinstance(b, _BaseGenericAlias) or issubclass(b, Generic):
|
|
break
|
|
else:
|
|
res.append(Generic)
|
|
return tuple(res)
|
|
|
|
def __getattr__(self, attr):
|
|
# We are careful for copy and pickle.
|
|
# Also for simplicity we just don't relay all dunder names
|
|
if '__origin__' in self.__dict__ and not _is_dunder(attr):
|
|
return getattr(self.__origin__, attr)
|
|
raise AttributeError(attr)
|
|
|
|
def __setattr__(self, attr, val):
|
|
if _is_dunder(attr) or attr in ('_name', '_inst', '_nparams'):
|
|
super().__setattr__(attr, val)
|
|
else:
|
|
setattr(self.__origin__, attr, val)
|
|
|
|
def __instancecheck__(self, obj):
|
|
return self.__subclasscheck__(type(obj))
|
|
|
|
def __subclasscheck__(self, cls):
|
|
raise TypeError("Subscripted generics cannot be used with"
|
|
" class and instance checks")
|
|
|
|
|
|
# Special typing constructs Union, Optional, Generic, Callable and Tuple
|
|
# use three special attributes for internal bookkeeping of generic types:
|
|
# * __parameters__ is a tuple of unique free type parameters of a generic
|
|
# type, for example, Dict[T, T].__parameters__ == (T,);
|
|
# * __origin__ keeps a reference to a type that was subscripted,
|
|
# e.g., Union[T, int].__origin__ == Union, or the non-generic version of
|
|
# the type.
|
|
# * __args__ is a tuple of all arguments used in subscripting,
|
|
# e.g., Dict[T, int].__args__ == (T, int).
|
|
|
|
|
|
class _GenericAlias(_BaseGenericAlias, _root=True):
|
|
def __init__(self, origin, params, *, inst=True, name=None):
|
|
super().__init__(origin, inst=inst, name=name)
|
|
if not isinstance(params, tuple):
|
|
params = (params,)
|
|
self.__args__ = tuple(... if a is _TypingEllipsis else
|
|
() if a is _TypingEmpty else
|
|
a for a in params)
|
|
self.__parameters__ = _collect_type_vars(params)
|
|
if not name:
|
|
self.__module__ = origin.__module__
|
|
|
|
def __eq__(self, other):
|
|
if not isinstance(other, _GenericAlias):
|
|
return NotImplemented
|
|
return (self.__origin__ == other.__origin__
|
|
and self.__args__ == other.__args__)
|
|
|
|
def __hash__(self):
|
|
return hash((self.__origin__, self.__args__))
|
|
|
|
def __or__(self, right):
|
|
return Union[self, right]
|
|
|
|
def __ror__(self, right):
|
|
return Union[self, right]
|
|
|
|
@_tp_cache
|
|
def __getitem__(self, params):
|
|
if self.__origin__ in (Generic, Protocol):
|
|
# Can't subscript Generic[...] or Protocol[...].
|
|
raise TypeError(f"Cannot subscript already-subscripted {self}")
|
|
if not isinstance(params, tuple):
|
|
params = (params,)
|
|
params = tuple(_type_convert(p) for p in params)
|
|
if any(isinstance(t, ParamSpec) for t in self.__parameters__):
|
|
params = _prepare_paramspec_params(self, params)
|
|
_check_generic(self, params, len(self.__parameters__))
|
|
|
|
subst = dict(zip(self.__parameters__, params))
|
|
new_args = []
|
|
for arg in self.__args__:
|
|
if isinstance(arg, _TypeVarLike):
|
|
arg = subst[arg]
|
|
elif isinstance(arg, (_GenericAlias, GenericAlias)):
|
|
subparams = arg.__parameters__
|
|
if subparams:
|
|
subargs = tuple(subst[x] for x in subparams)
|
|
arg = arg[subargs]
|
|
# Required to flatten out the args for CallableGenericAlias
|
|
if self.__origin__ == collections.abc.Callable and isinstance(arg, tuple):
|
|
new_args.extend(arg)
|
|
else:
|
|
new_args.append(arg)
|
|
return self.copy_with(tuple(new_args))
|
|
|
|
def copy_with(self, params):
|
|
return self.__class__(self.__origin__, params, name=self._name, inst=self._inst)
|
|
|
|
def __repr__(self):
|
|
if self._name:
|
|
name = 'typing.' + self._name
|
|
else:
|
|
name = _type_repr(self.__origin__)
|
|
args = ", ".join([_type_repr(a) for a in self.__args__])
|
|
return f'{name}[{args}]'
|
|
|
|
def __reduce__(self):
|
|
if self._name:
|
|
origin = globals()[self._name]
|
|
else:
|
|
origin = self.__origin__
|
|
args = tuple(self.__args__)
|
|
if len(args) == 1 and not isinstance(args[0], tuple):
|
|
args, = args
|
|
return operator.getitem, (origin, args)
|
|
|
|
def __mro_entries__(self, bases):
|
|
if self._name: # generic version of an ABC or built-in class
|
|
return super().__mro_entries__(bases)
|
|
if self.__origin__ is Generic:
|
|
if Protocol in bases:
|
|
return ()
|
|
i = bases.index(self)
|
|
for b in bases[i+1:]:
|
|
if isinstance(b, _BaseGenericAlias) and b is not self:
|
|
return ()
|
|
return (self.__origin__,)
|
|
|
|
|
|
# _nparams is the number of accepted parameters, e.g. 0 for Hashable,
|
|
# 1 for List and 2 for Dict. It may be -1 if variable number of
|
|
# parameters are accepted (needs custom __getitem__).
|
|
|
|
class _SpecialGenericAlias(_BaseGenericAlias, _root=True):
|
|
def __init__(self, origin, nparams, *, inst=True, name=None):
|
|
if name is None:
|
|
name = origin.__name__
|
|
super().__init__(origin, inst=inst, name=name)
|
|
self._nparams = nparams
|
|
if origin.__module__ == 'builtins':
|
|
self.__doc__ = f'A generic version of {origin.__qualname__}.'
|
|
else:
|
|
self.__doc__ = f'A generic version of {origin.__module__}.{origin.__qualname__}.'
|
|
|
|
@_tp_cache
|
|
def __getitem__(self, params):
|
|
if not isinstance(params, tuple):
|
|
params = (params,)
|
|
msg = "Parameters to generic types must be types."
|
|
params = tuple(_type_check(p, msg) for p in params)
|
|
_check_generic(self, params, self._nparams)
|
|
return self.copy_with(params)
|
|
|
|
def copy_with(self, params):
|
|
return _GenericAlias(self.__origin__, params,
|
|
name=self._name, inst=self._inst)
|
|
|
|
def __repr__(self):
|
|
return 'typing.' + self._name
|
|
|
|
def __subclasscheck__(self, cls):
|
|
if isinstance(cls, _SpecialGenericAlias):
|
|
return issubclass(cls.__origin__, self.__origin__)
|
|
if not isinstance(cls, _GenericAlias):
|
|
return issubclass(cls, self.__origin__)
|
|
return super().__subclasscheck__(cls)
|
|
|
|
def __reduce__(self):
|
|
return self._name
|
|
|
|
def __or__(self, right):
|
|
return Union[self, right]
|
|
|
|
def __ror__(self, right):
|
|
return Union[self, right]
|
|
|
|
class _CallableGenericAlias(_GenericAlias, _root=True):
|
|
def __repr__(self):
|
|
assert self._name == 'Callable'
|
|
args = self.__args__
|
|
if len(args) == 2 and (args[0] is Ellipsis
|
|
or isinstance(args[0], (ParamSpec, _ConcatenateGenericAlias))):
|
|
return super().__repr__()
|
|
return (f'typing.Callable'
|
|
f'[[{", ".join([_type_repr(a) for a in args[:-1]])}], '
|
|
f'{_type_repr(args[-1])}]')
|
|
|
|
def __reduce__(self):
|
|
args = self.__args__
|
|
if not (len(args) == 2 and (args[0] is Ellipsis
|
|
or isinstance(args[0], (ParamSpec, _ConcatenateGenericAlias)))):
|
|
args = list(args[:-1]), args[-1]
|
|
return operator.getitem, (Callable, args)
|
|
|
|
|
|
class _CallableType(_SpecialGenericAlias, _root=True):
|
|
def copy_with(self, params):
|
|
return _CallableGenericAlias(self.__origin__, params,
|
|
name=self._name, inst=self._inst)
|
|
|
|
def __getitem__(self, params):
|
|
if not isinstance(params, tuple) or len(params) != 2:
|
|
raise TypeError("Callable must be used as "
|
|
"Callable[[arg, ...], result].")
|
|
args, result = params
|
|
# This relaxes what args can be on purpose to allow things like
|
|
# PEP 612 ParamSpec. Responsibility for whether a user is using
|
|
# Callable[...] properly is deferred to static type checkers.
|
|
if isinstance(args, list):
|
|
params = (tuple(args), result)
|
|
else:
|
|
params = (args, result)
|
|
return self.__getitem_inner__(params)
|
|
|
|
@_tp_cache
|
|
def __getitem_inner__(self, params):
|
|
args, result = params
|
|
msg = "Callable[args, result]: result must be a type."
|
|
result = _type_check(result, msg)
|
|
if args is Ellipsis:
|
|
return self.copy_with((_TypingEllipsis, result))
|
|
if not isinstance(args, tuple):
|
|
args = (args,)
|
|
args = tuple(_type_convert(arg) for arg in args)
|
|
params = args + (result,)
|
|
return self.copy_with(params)
|
|
|
|
|
|
class _TupleType(_SpecialGenericAlias, _root=True):
|
|
@_tp_cache
|
|
def __getitem__(self, params):
|
|
if params == ():
|
|
return self.copy_with((_TypingEmpty,))
|
|
if not isinstance(params, tuple):
|
|
params = (params,)
|
|
if len(params) == 2 and params[1] is ...:
|
|
msg = "Tuple[t, ...]: t must be a type."
|
|
p = _type_check(params[0], msg)
|
|
return self.copy_with((p, _TypingEllipsis))
|
|
msg = "Tuple[t0, t1, ...]: each t must be a type."
|
|
params = tuple(_type_check(p, msg) for p in params)
|
|
return self.copy_with(params)
|
|
|
|
|
|
class _UnionGenericAlias(_GenericAlias, _root=True):
|
|
def copy_with(self, params):
|
|
return Union[params]
|
|
|
|
def __eq__(self, other):
|
|
if not isinstance(other, _UnionGenericAlias):
|
|
return NotImplemented
|
|
return set(self.__args__) == set(other.__args__)
|
|
|
|
def __hash__(self):
|
|
return hash(frozenset(self.__args__))
|
|
|
|
def __repr__(self):
|
|
args = self.__args__
|
|
if len(args) == 2:
|
|
if args[0] is type(None):
|
|
return f'typing.Optional[{_type_repr(args[1])}]'
|
|
elif args[1] is type(None):
|
|
return f'typing.Optional[{_type_repr(args[0])}]'
|
|
return super().__repr__()
|
|
|
|
def __instancecheck__(self, obj):
|
|
return self.__subclasscheck__(type(obj))
|
|
|
|
def __subclasscheck__(self, cls):
|
|
for arg in self.__args__:
|
|
if issubclass(cls, arg):
|
|
return True
|
|
|
|
|
|
def _value_and_type_iter(parameters):
|
|
return ((p, type(p)) for p in parameters)
|
|
|
|
|
|
class _LiteralGenericAlias(_GenericAlias, _root=True):
|
|
|
|
def __eq__(self, other):
|
|
if not isinstance(other, _LiteralGenericAlias):
|
|
return NotImplemented
|
|
|
|
return set(_value_and_type_iter(self.__args__)) == set(_value_and_type_iter(other.__args__))
|
|
|
|
def __hash__(self):
|
|
return hash(frozenset(_value_and_type_iter(self.__args__)))
|
|
|
|
|
|
class _ConcatenateGenericAlias(_GenericAlias, _root=True):
|
|
pass
|
|
|
|
|
|
class Generic:
|
|
"""Abstract base class for generic types.
|
|
|
|
A generic type is typically declared by inheriting from
|
|
this class parameterized with one or more type variables.
|
|
For example, a generic mapping type might be defined as::
|
|
|
|
class Mapping(Generic[KT, VT]):
|
|
def __getitem__(self, key: KT) -> VT:
|
|
...
|
|
# Etc.
|
|
|
|
This class can then be used as follows::
|
|
|
|
def lookup_name(mapping: Mapping[KT, VT], key: KT, default: VT) -> VT:
|
|
try:
|
|
return mapping[key]
|
|
except KeyError:
|
|
return default
|
|
"""
|
|
__slots__ = ()
|
|
_is_protocol = False
|
|
|
|
@_tp_cache
|
|
def __class_getitem__(cls, params):
|
|
if not isinstance(params, tuple):
|
|
params = (params,)
|
|
if not params and cls is not Tuple:
|
|
raise TypeError(
|
|
f"Parameter list to {cls.__qualname__}[...] cannot be empty")
|
|
params = tuple(_type_convert(p) for p in params)
|
|
if cls in (Generic, Protocol):
|
|
# Generic and Protocol can only be subscripted with unique type variables.
|
|
if not all(isinstance(p, _TypeVarLike) for p in params):
|
|
raise TypeError(
|
|
f"Parameters to {cls.__name__}[...] must all be type variables "
|
|
f"or parameter specification variables.")
|
|
if len(set(params)) != len(params):
|
|
raise TypeError(
|
|
f"Parameters to {cls.__name__}[...] must all be unique")
|
|
else:
|
|
# Subscripting a regular Generic subclass.
|
|
if any(isinstance(t, ParamSpec) for t in cls.__parameters__):
|
|
params = _prepare_paramspec_params(cls, params)
|
|
_check_generic(cls, params, len(cls.__parameters__))
|
|
return _GenericAlias(cls, params)
|
|
|
|
def __init_subclass__(cls, *args, **kwargs):
|
|
super().__init_subclass__(*args, **kwargs)
|
|
tvars = []
|
|
if '__orig_bases__' in cls.__dict__:
|
|
error = Generic in cls.__orig_bases__
|
|
else:
|
|
error = Generic in cls.__bases__ and cls.__name__ != 'Protocol'
|
|
if error:
|
|
raise TypeError("Cannot inherit from plain Generic")
|
|
if '__orig_bases__' in cls.__dict__:
|
|
tvars = _collect_type_vars(cls.__orig_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 cls.__orig_bases__:
|
|
if (isinstance(base, _GenericAlias) and
|
|
base.__origin__ is Generic):
|
|
if gvars is not None:
|
|
raise TypeError(
|
|
"Cannot inherit from Generic[...] multiple types.")
|
|
gvars = base.__parameters__
|
|
if gvars is not None:
|
|
tvarset = set(tvars)
|
|
gvarset = set(gvars)
|
|
if not tvarset <= gvarset:
|
|
s_vars = ', '.join(str(t) for t in tvars if t not in gvarset)
|
|
s_args = ', '.join(str(g) for g in gvars)
|
|
raise TypeError(f"Some type variables ({s_vars}) are"
|
|
f" not listed in Generic[{s_args}]")
|
|
tvars = gvars
|
|
cls.__parameters__ = tuple(tvars)
|
|
|
|
|
|
class _TypingEmpty:
|
|
"""Internal placeholder for () or []. Used by TupleMeta and CallableMeta
|
|
to allow empty list/tuple in specific places, without allowing them
|
|
to sneak in where prohibited.
|
|
"""
|
|
|
|
|
|
class _TypingEllipsis:
|
|
"""Internal placeholder for ... (ellipsis)."""
|
|
|
|
|
|
_TYPING_INTERNALS = ['__parameters__', '__orig_bases__', '__orig_class__',
|
|
'_is_protocol', '_is_runtime_protocol']
|
|
|
|
_SPECIAL_NAMES = ['__abstractmethods__', '__annotations__', '__dict__', '__doc__',
|
|
'__init__', '__module__', '__new__', '__slots__',
|
|
'__subclasshook__', '__weakref__', '__class_getitem__']
|
|
|
|
# These special attributes will be not collected as protocol members.
|
|
EXCLUDED_ATTRIBUTES = _TYPING_INTERNALS + _SPECIAL_NAMES + ['_MutableMapping__marker']
|
|
|
|
|
|
def _get_protocol_attrs(cls):
|
|
"""Collect protocol members from a protocol class objects.
|
|
|
|
This includes names actually defined in the class dictionary, as well
|
|
as names that appear in annotations. Special names (above) are skipped.
|
|
"""
|
|
attrs = set()
|
|
for base in cls.__mro__[:-1]: # without object
|
|
if base.__name__ in ('Protocol', 'Generic'):
|
|
continue
|
|
annotations = getattr(base, '__annotations__', {})
|
|
for attr in list(base.__dict__.keys()) + list(annotations.keys()):
|
|
if not attr.startswith('_abc_') and attr not in EXCLUDED_ATTRIBUTES:
|
|
attrs.add(attr)
|
|
return attrs
|
|
|
|
|
|
def _is_callable_members_only(cls):
|
|
# PEP 544 prohibits using issubclass() with protocols that have non-method members.
|
|
return all(callable(getattr(cls, attr, None)) for attr in _get_protocol_attrs(cls))
|
|
|
|
|
|
def _no_init(self, *args, **kwargs):
|
|
if type(self)._is_protocol:
|
|
raise TypeError('Protocols cannot be instantiated')
|
|
|
|
|
|
def _allow_reckless_class_checks():
|
|
"""Allow instance and class checks for special stdlib modules.
|
|
|
|
The abc and functools modules indiscriminately call isinstance() and
|
|
issubclass() on the whole MRO of a user class, which may contain protocols.
|
|
"""
|
|
try:
|
|
return sys._getframe(3).f_globals['__name__'] in ['abc', 'functools']
|
|
except (AttributeError, ValueError): # For platforms without _getframe().
|
|
return True
|
|
|
|
|
|
_PROTO_ALLOWLIST = {
|
|
'collections.abc': [
|
|
'Callable', 'Awaitable', 'Iterable', 'Iterator', 'AsyncIterable',
|
|
'Hashable', 'Sized', 'Container', 'Collection', 'Reversible',
|
|
],
|
|
'contextlib': ['AbstractContextManager', 'AbstractAsyncContextManager'],
|
|
}
|
|
|
|
|
|
class _ProtocolMeta(ABCMeta):
|
|
# This metaclass is really unfortunate and exists only because of
|
|
# the lack of __instancehook__.
|
|
def __instancecheck__(cls, instance):
|
|
# We need this method for situations where attributes are
|
|
# assigned in __init__.
|
|
if ((not getattr(cls, '_is_protocol', False) or
|
|
_is_callable_members_only(cls)) and
|
|
issubclass(instance.__class__, cls)):
|
|
return True
|
|
if cls._is_protocol:
|
|
if all(hasattr(instance, attr) and
|
|
# All *methods* can be blocked by setting them to None.
|
|
(not callable(getattr(cls, attr, None)) or
|
|
getattr(instance, attr) is not None)
|
|
for attr in _get_protocol_attrs(cls)):
|
|
return True
|
|
return super().__instancecheck__(instance)
|
|
|
|
|
|
class Protocol(Generic, metaclass=_ProtocolMeta):
|
|
"""Base class for protocol classes.
|
|
|
|
Protocol classes are defined as::
|
|
|
|
class Proto(Protocol):
|
|
def meth(self) -> int:
|
|
...
|
|
|
|
Such classes are primarily used with static type checkers that recognize
|
|
structural subtyping (static duck-typing), for example::
|
|
|
|
class C:
|
|
def meth(self) -> int:
|
|
return 0
|
|
|
|
def func(x: Proto) -> int:
|
|
return x.meth()
|
|
|
|
func(C()) # Passes static type check
|
|
|
|
See PEP 544 for details. Protocol classes decorated with
|
|
@typing.runtime_checkable act as simple-minded runtime protocols that check
|
|
only the presence of given attributes, ignoring their type signatures.
|
|
Protocol classes can be generic, they are defined as::
|
|
|
|
class GenProto(Protocol[T]):
|
|
def meth(self) -> T:
|
|
...
|
|
"""
|
|
__slots__ = ()
|
|
_is_protocol = True
|
|
_is_runtime_protocol = False
|
|
|
|
def __init_subclass__(cls, *args, **kwargs):
|
|
super().__init_subclass__(*args, **kwargs)
|
|
|
|
# Determine if this is a protocol or a concrete subclass.
|
|
if not cls.__dict__.get('_is_protocol', False):
|
|
cls._is_protocol = any(b is Protocol for b in cls.__bases__)
|
|
|
|
# Set (or override) the protocol subclass hook.
|
|
def _proto_hook(other):
|
|
if not cls.__dict__.get('_is_protocol', False):
|
|
return NotImplemented
|
|
|
|
# First, perform various sanity checks.
|
|
if not getattr(cls, '_is_runtime_protocol', False):
|
|
if _allow_reckless_class_checks():
|
|
return NotImplemented
|
|
raise TypeError("Instance and class checks can only be used with"
|
|
" @runtime_checkable protocols")
|
|
if not _is_callable_members_only(cls):
|
|
if _allow_reckless_class_checks():
|
|
return NotImplemented
|
|
raise TypeError("Protocols with non-method members"
|
|
" don't support issubclass()")
|
|
if not isinstance(other, type):
|
|
# Same error message as for issubclass(1, int).
|
|
raise TypeError('issubclass() arg 1 must be a class')
|
|
|
|
# Second, perform the actual structural compatibility check.
|
|
for attr in _get_protocol_attrs(cls):
|
|
for base in other.__mro__:
|
|
# Check if the members appears in the class dictionary...
|
|
if attr in base.__dict__:
|
|
if base.__dict__[attr] is None:
|
|
return NotImplemented
|
|
break
|
|
|
|
# ...or in annotations, if it is a sub-protocol.
|
|
annotations = getattr(base, '__annotations__', {})
|
|
if (isinstance(annotations, collections.abc.Mapping) and
|
|
attr in annotations and
|
|
issubclass(other, Generic) and other._is_protocol):
|
|
break
|
|
else:
|
|
return NotImplemented
|
|
return True
|
|
|
|
if '__subclasshook__' not in cls.__dict__:
|
|
cls.__subclasshook__ = _proto_hook
|
|
|
|
# We have nothing more to do for non-protocols...
|
|
if not cls._is_protocol:
|
|
return
|
|
|
|
# ... otherwise check consistency of bases, and prohibit instantiation.
|
|
for base in cls.__bases__:
|
|
if not (base in (object, Generic) or
|
|
base.__module__ in _PROTO_ALLOWLIST and
|
|
base.__name__ in _PROTO_ALLOWLIST[base.__module__] or
|
|
issubclass(base, Generic) and base._is_protocol):
|
|
raise TypeError('Protocols can only inherit from other'
|
|
' protocols, got %r' % base)
|
|
cls.__init__ = _no_init
|
|
|
|
|
|
class _AnnotatedAlias(_GenericAlias, _root=True):
|
|
"""Runtime representation of an annotated type.
|
|
|
|
At its core 'Annotated[t, dec1, dec2, ...]' is an alias for the type 't'
|
|
with extra annotations. The alias behaves like a normal typing alias,
|
|
instantiating is the same as instantiating the underlying type, binding
|
|
it to types is also the same.
|
|
"""
|
|
def __init__(self, origin, metadata):
|
|
if isinstance(origin, _AnnotatedAlias):
|
|
metadata = origin.__metadata__ + metadata
|
|
origin = origin.__origin__
|
|
super().__init__(origin, origin)
|
|
self.__metadata__ = metadata
|
|
|
|
def copy_with(self, params):
|
|
assert len(params) == 1
|
|
new_type = params[0]
|
|
return _AnnotatedAlias(new_type, self.__metadata__)
|
|
|
|
def __repr__(self):
|
|
return "typing.Annotated[{}, {}]".format(
|
|
_type_repr(self.__origin__),
|
|
", ".join(repr(a) for a in self.__metadata__)
|
|
)
|
|
|
|
def __reduce__(self):
|
|
return operator.getitem, (
|
|
Annotated, (self.__origin__,) + self.__metadata__
|
|
)
|
|
|
|
def __eq__(self, other):
|
|
if not isinstance(other, _AnnotatedAlias):
|
|
return NotImplemented
|
|
return (self.__origin__ == other.__origin__
|
|
and self.__metadata__ == other.__metadata__)
|
|
|
|
def __hash__(self):
|
|
return hash((self.__origin__, self.__metadata__))
|
|
|
|
|
|
class Annotated:
|
|
"""Add context specific metadata to a type.
|
|
|
|
Example: Annotated[int, runtime_check.Unsigned] indicates to the
|
|
hypothetical runtime_check module that this type is an unsigned int.
|
|
Every other consumer of this type can ignore this metadata and treat
|
|
this type as int.
|
|
|
|
The first argument to Annotated must be a valid type.
|
|
|
|
Details:
|
|
|
|
- It's an error to call `Annotated` with less than two arguments.
|
|
- Nested Annotated are flattened::
|
|
|
|
Annotated[Annotated[T, Ann1, Ann2], Ann3] == Annotated[T, Ann1, Ann2, Ann3]
|
|
|
|
- Instantiating an annotated type is equivalent to instantiating the
|
|
underlying type::
|
|
|
|
Annotated[C, Ann1](5) == C(5)
|
|
|
|
- Annotated can be used as a generic type alias::
|
|
|
|
Optimized = Annotated[T, runtime.Optimize()]
|
|
Optimized[int] == Annotated[int, runtime.Optimize()]
|
|
|
|
OptimizedList = Annotated[List[T], runtime.Optimize()]
|
|
OptimizedList[int] == Annotated[List[int], runtime.Optimize()]
|
|
"""
|
|
|
|
__slots__ = ()
|
|
|
|
def __new__(cls, *args, **kwargs):
|
|
raise TypeError("Type Annotated cannot be instantiated.")
|
|
|
|
@_tp_cache
|
|
def __class_getitem__(cls, params):
|
|
if not isinstance(params, tuple) or len(params) < 2:
|
|
raise TypeError("Annotated[...] should be used "
|
|
"with at least two arguments (a type and an "
|
|
"annotation).")
|
|
msg = "Annotated[t, ...]: t must be a type."
|
|
origin = _type_check(params[0], msg)
|
|
metadata = tuple(params[1:])
|
|
return _AnnotatedAlias(origin, metadata)
|
|
|
|
def __init_subclass__(cls, *args, **kwargs):
|
|
raise TypeError(
|
|
"Cannot subclass {}.Annotated".format(cls.__module__)
|
|
)
|
|
|
|
|
|
def runtime_checkable(cls):
|
|
"""Mark a protocol class as a runtime protocol.
|
|
|
|
Such protocol can be used with isinstance() and issubclass().
|
|
Raise TypeError if applied to a non-protocol class.
|
|
This allows a simple-minded structural check very similar to
|
|
one trick ponies in collections.abc such as Iterable.
|
|
For example::
|
|
|
|
@runtime_checkable
|
|
class Closable(Protocol):
|
|
def close(self): ...
|
|
|
|
assert isinstance(open('/some/file'), Closable)
|
|
|
|
Warning: this will check only the presence of the required methods,
|
|
not their type signatures!
|
|
"""
|
|
if not issubclass(cls, Generic) or not cls._is_protocol:
|
|
raise TypeError('@runtime_checkable can be only applied to protocol classes,'
|
|
' got %r' % cls)
|
|
cls._is_runtime_protocol = True
|
|
return cls
|
|
|
|
|
|
def cast(typ, val):
|
|
"""Cast a value to a type.
|
|
|
|
This returns the value unchanged. To the type checker this
|
|
signals that the return value has the designated type, but at
|
|
runtime we intentionally don't check anything (we want this
|
|
to be as fast as possible).
|
|
"""
|
|
return val
|
|
|
|
|
|
def _get_defaults(func):
|
|
"""Internal helper to extract the default arguments, by name."""
|
|
try:
|
|
code = func.__code__
|
|
except AttributeError:
|
|
# Some built-in functions don't have __code__, __defaults__, etc.
|
|
return {}
|
|
pos_count = code.co_argcount
|
|
arg_names = code.co_varnames
|
|
arg_names = arg_names[:pos_count]
|
|
defaults = func.__defaults__ or ()
|
|
kwdefaults = func.__kwdefaults__
|
|
res = dict(kwdefaults) if kwdefaults else {}
|
|
pos_offset = pos_count - len(defaults)
|
|
for name, value in zip(arg_names[pos_offset:], defaults):
|
|
assert name not in res
|
|
res[name] = value
|
|
return res
|
|
|
|
|
|
_allowed_types = (types.FunctionType, types.BuiltinFunctionType,
|
|
types.MethodType, types.ModuleType,
|
|
WrapperDescriptorType, MethodWrapperType, MethodDescriptorType)
|
|
|
|
|
|
def get_type_hints(obj, globalns=None, localns=None, include_extras=False):
|
|
"""Return type hints for an object.
|
|
|
|
This is often the same as obj.__annotations__, but it handles
|
|
forward references encoded as string literals, adds Optional[t] if a
|
|
default value equal to None is set and recursively replaces all
|
|
'Annotated[T, ...]' with 'T' (unless 'include_extras=True').
|
|
|
|
The argument may be a module, class, method, or function. The annotations
|
|
are returned as a dictionary. For classes, annotations include also
|
|
inherited members.
|
|
|
|
TypeError is raised if the argument is not of a type that can contain
|
|
annotations, and an empty dictionary is returned if no annotations are
|
|
present.
|
|
|
|
BEWARE -- the behavior of globalns and localns is counterintuitive
|
|
(unless you are familiar with how eval() and exec() work). The
|
|
search order is locals first, then globals.
|
|
|
|
- If no dict arguments are passed, an attempt is made to use the
|
|
globals from obj (or the respective module's globals for classes),
|
|
and these are also used as the locals. If the object does not appear
|
|
to have globals, an empty dictionary is used.
|
|
|
|
- If one dict argument is passed, it is used for both globals and
|
|
locals.
|
|
|
|
- If two dict arguments are passed, they specify globals and
|
|
locals, respectively.
|
|
"""
|
|
|
|
if getattr(obj, '__no_type_check__', None):
|
|
return {}
|
|
# Classes require a special treatment.
|
|
if isinstance(obj, type):
|
|
hints = {}
|
|
for base in reversed(obj.__mro__):
|
|
if globalns is None:
|
|
base_globals = sys.modules[base.__module__].__dict__
|
|
else:
|
|
base_globals = globalns
|
|
ann = base.__dict__.get('__annotations__', {})
|
|
for name, value in ann.items():
|
|
if value is None:
|
|
value = type(None)
|
|
if isinstance(value, str):
|
|
value = ForwardRef(value, is_argument=False)
|
|
value = _eval_type(value, base_globals, localns)
|
|
hints[name] = value
|
|
return hints if include_extras else {k: _strip_annotations(t) for k, t in hints.items()}
|
|
|
|
if globalns is None:
|
|
if isinstance(obj, types.ModuleType):
|
|
globalns = obj.__dict__
|
|
else:
|
|
nsobj = obj
|
|
# Find globalns for the unwrapped object.
|
|
while hasattr(nsobj, '__wrapped__'):
|
|
nsobj = nsobj.__wrapped__
|
|
globalns = getattr(nsobj, '__globals__', {})
|
|
if localns is None:
|
|
localns = globalns
|
|
elif localns is None:
|
|
localns = globalns
|
|
hints = getattr(obj, '__annotations__', None)
|
|
if hints is None:
|
|
# Return empty annotations for something that _could_ have them.
|
|
if isinstance(obj, _allowed_types):
|
|
return {}
|
|
else:
|
|
raise TypeError('{!r} is not a module, class, method, '
|
|
'or function.'.format(obj))
|
|
defaults = _get_defaults(obj)
|
|
hints = dict(hints)
|
|
for name, value in hints.items():
|
|
if value is None:
|
|
value = type(None)
|
|
if isinstance(value, str):
|
|
value = ForwardRef(value)
|
|
value = _eval_type(value, globalns, localns)
|
|
if name in defaults and defaults[name] is None:
|
|
value = Optional[value]
|
|
hints[name] = value
|
|
return hints if include_extras else {k: _strip_annotations(t) for k, t in hints.items()}
|
|
|
|
|
|
def _strip_annotations(t):
|
|
"""Strips the annotations from a given type.
|
|
"""
|
|
if isinstance(t, _AnnotatedAlias):
|
|
return _strip_annotations(t.__origin__)
|
|
if isinstance(t, _GenericAlias):
|
|
stripped_args = tuple(_strip_annotations(a) for a in t.__args__)
|
|
if stripped_args == t.__args__:
|
|
return t
|
|
return t.copy_with(stripped_args)
|
|
if isinstance(t, GenericAlias):
|
|
stripped_args = tuple(_strip_annotations(a) for a in t.__args__)
|
|
if stripped_args == t.__args__:
|
|
return t
|
|
return GenericAlias(t.__origin__, stripped_args)
|
|
return t
|
|
|
|
|
|
def get_origin(tp):
|
|
"""Get the unsubscripted version of a type.
|
|
|
|
This supports generic types, Callable, Tuple, Union, Literal, Final, ClassVar
|
|
and Annotated. Return None for unsupported types. Examples::
|
|
|
|
get_origin(Literal[42]) is Literal
|
|
get_origin(int) is None
|
|
get_origin(ClassVar[int]) is ClassVar
|
|
get_origin(Generic) is Generic
|
|
get_origin(Generic[T]) is Generic
|
|
get_origin(Union[T, int]) is Union
|
|
get_origin(List[Tuple[T, T]][int]) == list
|
|
"""
|
|
if isinstance(tp, _AnnotatedAlias):
|
|
return Annotated
|
|
if isinstance(tp, (_BaseGenericAlias, GenericAlias)):
|
|
return tp.__origin__
|
|
if tp is Generic:
|
|
return Generic
|
|
if isinstance(tp, types.Union):
|
|
return types.Union
|
|
return None
|
|
|
|
|
|
def get_args(tp):
|
|
"""Get type arguments with all substitutions performed.
|
|
|
|
For unions, basic simplifications used by Union constructor are performed.
|
|
Examples::
|
|
get_args(Dict[str, int]) == (str, int)
|
|
get_args(int) == ()
|
|
get_args(Union[int, Union[T, int], str][int]) == (int, str)
|
|
get_args(Union[int, Tuple[T, int]][str]) == (int, Tuple[str, int])
|
|
get_args(Callable[[], T][int]) == ([], int)
|
|
"""
|
|
if isinstance(tp, _AnnotatedAlias):
|
|
return (tp.__origin__,) + tp.__metadata__
|
|
if isinstance(tp, (_GenericAlias, GenericAlias)):
|
|
res = tp.__args__
|
|
if (tp.__origin__ is collections.abc.Callable
|
|
and not (res[0] is Ellipsis
|
|
or isinstance(res[0], (ParamSpec, _ConcatenateGenericAlias)))):
|
|
res = (list(res[:-1]), res[-1])
|
|
return res
|
|
if isinstance(tp, types.Union):
|
|
return tp.__args__
|
|
return ()
|
|
|
|
|
|
def is_typeddict(tp):
|
|
"""Check if an annotation is a TypedDict class
|
|
|
|
For example::
|
|
class Film(TypedDict):
|
|
title: str
|
|
year: int
|
|
|
|
is_typeddict(Film) # => True
|
|
is_typeddict(Union[list, str]) # => False
|
|
"""
|
|
return isinstance(tp, _TypedDictMeta)
|
|
|
|
|
|
def no_type_check(arg):
|
|
"""Decorator to indicate that annotations are not type hints.
|
|
|
|
The argument must be a class or function; if it is a class, it
|
|
applies recursively to all methods and classes defined in that class
|
|
(but not to methods defined in its superclasses or subclasses).
|
|
|
|
This mutates the function(s) or class(es) in place.
|
|
"""
|
|
if isinstance(arg, type):
|
|
arg_attrs = arg.__dict__.copy()
|
|
for attr, val in arg.__dict__.items():
|
|
if val in arg.__bases__ + (arg,):
|
|
arg_attrs.pop(attr)
|
|
for obj in arg_attrs.values():
|
|
if isinstance(obj, types.FunctionType):
|
|
obj.__no_type_check__ = True
|
|
if isinstance(obj, type):
|
|
no_type_check(obj)
|
|
try:
|
|
arg.__no_type_check__ = True
|
|
except TypeError: # built-in classes
|
|
pass
|
|
return arg
|
|
|
|
|
|
def no_type_check_decorator(decorator):
|
|
"""Decorator to give another decorator the @no_type_check effect.
|
|
|
|
This wraps the decorator with something that wraps the decorated
|
|
function in @no_type_check.
|
|
"""
|
|
|
|
@functools.wraps(decorator)
|
|
def wrapped_decorator(*args, **kwds):
|
|
func = decorator(*args, **kwds)
|
|
func = no_type_check(func)
|
|
return func
|
|
|
|
return wrapped_decorator
|
|
|
|
|
|
def _overload_dummy(*args, **kwds):
|
|
"""Helper for @overload to raise when called."""
|
|
raise NotImplementedError(
|
|
"You should not call an overloaded function. "
|
|
"A series of @overload-decorated functions "
|
|
"outside a stub module should always be followed "
|
|
"by an implementation that is not @overload-ed.")
|
|
|
|
|
|
def overload(func):
|
|
"""Decorator for overloaded functions/methods.
|
|
|
|
In a stub file, place two or more stub definitions for the same
|
|
function in a row, each decorated with @overload. For example:
|
|
|
|
@overload
|
|
def utf8(value: None) -> None: ...
|
|
@overload
|
|
def utf8(value: bytes) -> bytes: ...
|
|
@overload
|
|
def utf8(value: str) -> bytes: ...
|
|
|
|
In a non-stub file (i.e. a regular .py file), do the same but
|
|
follow it with an implementation. The implementation should *not*
|
|
be decorated with @overload. For example:
|
|
|
|
@overload
|
|
def utf8(value: None) -> None: ...
|
|
@overload
|
|
def utf8(value: bytes) -> bytes: ...
|
|
@overload
|
|
def utf8(value: str) -> bytes: ...
|
|
def utf8(value):
|
|
# implementation goes here
|
|
"""
|
|
return _overload_dummy
|
|
|
|
|
|
def final(f):
|
|
"""A decorator to indicate final methods and final classes.
|
|
|
|
Use this decorator to indicate to type checkers that the decorated
|
|
method cannot be overridden, and decorated class cannot be subclassed.
|
|
For example:
|
|
|
|
class Base:
|
|
@final
|
|
def done(self) -> None:
|
|
...
|
|
class Sub(Base):
|
|
def done(self) -> None: # Error reported by type checker
|
|
...
|
|
|
|
@final
|
|
class Leaf:
|
|
...
|
|
class Other(Leaf): # Error reported by type checker
|
|
...
|
|
|
|
There is no runtime checking of these properties.
|
|
"""
|
|
return f
|
|
|
|
|
|
# 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.
|
|
# Internal type variable used for Type[].
|
|
CT_co = TypeVar('CT_co', covariant=True, bound=type)
|
|
|
|
# A useful type variable with constraints. This represents string types.
|
|
# (This one *is* for export!)
|
|
AnyStr = TypeVar('AnyStr', bytes, str)
|
|
|
|
|
|
# Various ABCs mimicking those in collections.abc.
|
|
_alias = _SpecialGenericAlias
|
|
|
|
Hashable = _alias(collections.abc.Hashable, 0) # Not generic.
|
|
Awaitable = _alias(collections.abc.Awaitable, 1)
|
|
Coroutine = _alias(collections.abc.Coroutine, 3)
|
|
AsyncIterable = _alias(collections.abc.AsyncIterable, 1)
|
|
AsyncIterator = _alias(collections.abc.AsyncIterator, 1)
|
|
Iterable = _alias(collections.abc.Iterable, 1)
|
|
Iterator = _alias(collections.abc.Iterator, 1)
|
|
Reversible = _alias(collections.abc.Reversible, 1)
|
|
Sized = _alias(collections.abc.Sized, 0) # Not generic.
|
|
Container = _alias(collections.abc.Container, 1)
|
|
Collection = _alias(collections.abc.Collection, 1)
|
|
Callable = _CallableType(collections.abc.Callable, 2)
|
|
Callable.__doc__ = \
|
|
"""Callable type; Callable[[int], str] is a function of (int) -> str.
|
|
|
|
The subscription syntax must always be used with exactly two
|
|
values: the argument list and the return type. The argument list
|
|
must be a list of types or ellipsis; the return type must be a single type.
|
|
|
|
There is no syntax to indicate optional or keyword arguments,
|
|
such function types are rarely used as callback types.
|
|
"""
|
|
AbstractSet = _alias(collections.abc.Set, 1, name='AbstractSet')
|
|
MutableSet = _alias(collections.abc.MutableSet, 1)
|
|
# NOTE: Mapping is only covariant in the value type.
|
|
Mapping = _alias(collections.abc.Mapping, 2)
|
|
MutableMapping = _alias(collections.abc.MutableMapping, 2)
|
|
Sequence = _alias(collections.abc.Sequence, 1)
|
|
MutableSequence = _alias(collections.abc.MutableSequence, 1)
|
|
ByteString = _alias(collections.abc.ByteString, 0) # Not generic
|
|
# Tuple accepts variable number of parameters.
|
|
Tuple = _TupleType(tuple, -1, inst=False, name='Tuple')
|
|
Tuple.__doc__ = \
|
|
"""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, ...].
|
|
"""
|
|
List = _alias(list, 1, inst=False, name='List')
|
|
Deque = _alias(collections.deque, 1, name='Deque')
|
|
Set = _alias(set, 1, inst=False, name='Set')
|
|
FrozenSet = _alias(frozenset, 1, inst=False, name='FrozenSet')
|
|
MappingView = _alias(collections.abc.MappingView, 1)
|
|
KeysView = _alias(collections.abc.KeysView, 1)
|
|
ItemsView = _alias(collections.abc.ItemsView, 2)
|
|
ValuesView = _alias(collections.abc.ValuesView, 1)
|
|
ContextManager = _alias(contextlib.AbstractContextManager, 1, name='ContextManager')
|
|
AsyncContextManager = _alias(contextlib.AbstractAsyncContextManager, 1, name='AsyncContextManager')
|
|
Dict = _alias(dict, 2, inst=False, name='Dict')
|
|
DefaultDict = _alias(collections.defaultdict, 2, name='DefaultDict')
|
|
OrderedDict = _alias(collections.OrderedDict, 2)
|
|
Counter = _alias(collections.Counter, 1)
|
|
ChainMap = _alias(collections.ChainMap, 2)
|
|
Generator = _alias(collections.abc.Generator, 3)
|
|
AsyncGenerator = _alias(collections.abc.AsyncGenerator, 2)
|
|
Type = _alias(type, 1, inst=False, name='Type')
|
|
Type.__doc__ = \
|
|
"""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.
|
|
"""
|
|
|
|
|
|
@runtime_checkable
|
|
class SupportsInt(Protocol):
|
|
"""An ABC with one abstract method __int__."""
|
|
__slots__ = ()
|
|
|
|
@abstractmethod
|
|
def __int__(self) -> int:
|
|
pass
|
|
|
|
|
|
@runtime_checkable
|
|
class SupportsFloat(Protocol):
|
|
"""An ABC with one abstract method __float__."""
|
|
__slots__ = ()
|
|
|
|
@abstractmethod
|
|
def __float__(self) -> float:
|
|
pass
|
|
|
|
|
|
@runtime_checkable
|
|
class SupportsComplex(Protocol):
|
|
"""An ABC with one abstract method __complex__."""
|
|
__slots__ = ()
|
|
|
|
@abstractmethod
|
|
def __complex__(self) -> complex:
|
|
pass
|
|
|
|
|
|
@runtime_checkable
|
|
class SupportsBytes(Protocol):
|
|
"""An ABC with one abstract method __bytes__."""
|
|
__slots__ = ()
|
|
|
|
@abstractmethod
|
|
def __bytes__(self) -> bytes:
|
|
pass
|
|
|
|
|
|
@runtime_checkable
|
|
class SupportsIndex(Protocol):
|
|
"""An ABC with one abstract method __index__."""
|
|
__slots__ = ()
|
|
|
|
@abstractmethod
|
|
def __index__(self) -> int:
|
|
pass
|
|
|
|
|
|
@runtime_checkable
|
|
class SupportsAbs(Protocol[T_co]):
|
|
"""An ABC with one abstract method __abs__ that is covariant in its return type."""
|
|
__slots__ = ()
|
|
|
|
@abstractmethod
|
|
def __abs__(self) -> T_co:
|
|
pass
|
|
|
|
|
|
@runtime_checkable
|
|
class SupportsRound(Protocol[T_co]):
|
|
"""An ABC with one abstract method __round__ that is covariant in its return type."""
|
|
__slots__ = ()
|
|
|
|
@abstractmethod
|
|
def __round__(self, ndigits: int = 0) -> T_co:
|
|
pass
|
|
|
|
|
|
def _make_nmtuple(name, types, module, defaults = ()):
|
|
fields = [n for n, t in types]
|
|
types = {n: _type_check(t, f"field {n} annotation must be a type")
|
|
for n, t in types}
|
|
nm_tpl = collections.namedtuple(name, fields,
|
|
defaults=defaults, module=module)
|
|
nm_tpl.__annotations__ = nm_tpl.__new__.__annotations__ = types
|
|
return nm_tpl
|
|
|
|
|
|
# attributes prohibited to set in NamedTuple class syntax
|
|
_prohibited = frozenset({'__new__', '__init__', '__slots__', '__getnewargs__',
|
|
'_fields', '_field_defaults',
|
|
'_make', '_replace', '_asdict', '_source'})
|
|
|
|
_special = frozenset({'__module__', '__name__', '__annotations__'})
|
|
|
|
|
|
class NamedTupleMeta(type):
|
|
|
|
def __new__(cls, typename, bases, ns):
|
|
assert bases[0] is _NamedTuple
|
|
types = ns.get('__annotations__', {})
|
|
default_names = []
|
|
for field_name in types:
|
|
if field_name in ns:
|
|
default_names.append(field_name)
|
|
elif default_names:
|
|
raise TypeError(f"Non-default namedtuple field {field_name} "
|
|
f"cannot follow default field"
|
|
f"{'s' if len(default_names) > 1 else ''} "
|
|
f"{', '.join(default_names)}")
|
|
nm_tpl = _make_nmtuple(typename, types.items(),
|
|
defaults=[ns[n] for n in default_names],
|
|
module=ns['__module__'])
|
|
# update from user namespace without overriding special namedtuple attributes
|
|
for key in ns:
|
|
if key in _prohibited:
|
|
raise AttributeError("Cannot overwrite NamedTuple attribute " + key)
|
|
elif key not in _special and key not in nm_tpl._fields:
|
|
setattr(nm_tpl, key, ns[key])
|
|
return nm_tpl
|
|
|
|
|
|
def NamedTuple(typename, fields=None, /, **kwargs):
|
|
"""Typed version of namedtuple.
|
|
|
|
Usage in Python versions >= 3.6::
|
|
|
|
class Employee(NamedTuple):
|
|
name: str
|
|
id: int
|
|
|
|
This is equivalent to::
|
|
|
|
Employee = collections.namedtuple('Employee', ['name', 'id'])
|
|
|
|
The resulting class has an extra __annotations__ attribute, giving a
|
|
dict that maps field names to types. (The field names are also in
|
|
the _fields attribute, which is part of the namedtuple API.)
|
|
Alternative equivalent keyword syntax is also accepted::
|
|
|
|
Employee = NamedTuple('Employee', name=str, id=int)
|
|
|
|
In Python versions <= 3.5 use::
|
|
|
|
Employee = NamedTuple('Employee', [('name', str), ('id', int)])
|
|
"""
|
|
if fields is None:
|
|
fields = kwargs.items()
|
|
elif kwargs:
|
|
raise TypeError("Either list of fields or keywords"
|
|
" can be provided to NamedTuple, not both")
|
|
try:
|
|
module = sys._getframe(1).f_globals.get('__name__', '__main__')
|
|
except (AttributeError, ValueError):
|
|
module = None
|
|
return _make_nmtuple(typename, fields, module=module)
|
|
|
|
_NamedTuple = type.__new__(NamedTupleMeta, 'NamedTuple', (), {})
|
|
|
|
def _namedtuple_mro_entries(bases):
|
|
if len(bases) > 1:
|
|
raise TypeError("Multiple inheritance with NamedTuple is not supported")
|
|
assert bases[0] is NamedTuple
|
|
return (_NamedTuple,)
|
|
|
|
NamedTuple.__mro_entries__ = _namedtuple_mro_entries
|
|
|
|
|
|
class _TypedDictMeta(type):
|
|
def __new__(cls, name, bases, ns, total=True):
|
|
"""Create new typed dict class object.
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This method is called when TypedDict is subclassed,
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or when TypedDict is instantiated. This way
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TypedDict supports all three syntax forms described in its docstring.
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Subclasses and instances of TypedDict return actual dictionaries.
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"""
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for base in bases:
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if type(base) is not _TypedDictMeta:
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raise TypeError('cannot inherit from both a TypedDict type '
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'and a non-TypedDict base class')
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tp_dict = type.__new__(_TypedDictMeta, name, (dict,), ns)
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annotations = {}
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own_annotations = ns.get('__annotations__', {})
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own_annotation_keys = set(own_annotations.keys())
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msg = "TypedDict('Name', {f0: t0, f1: t1, ...}); each t must be a type"
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own_annotations = {
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n: _type_check(tp, msg) for n, tp in own_annotations.items()
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}
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required_keys = set()
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optional_keys = set()
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for base in bases:
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annotations.update(base.__dict__.get('__annotations__', {}))
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required_keys.update(base.__dict__.get('__required_keys__', ()))
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optional_keys.update(base.__dict__.get('__optional_keys__', ()))
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annotations.update(own_annotations)
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if total:
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required_keys.update(own_annotation_keys)
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else:
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optional_keys.update(own_annotation_keys)
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tp_dict.__annotations__ = annotations
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tp_dict.__required_keys__ = frozenset(required_keys)
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tp_dict.__optional_keys__ = frozenset(optional_keys)
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if not hasattr(tp_dict, '__total__'):
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tp_dict.__total__ = total
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return tp_dict
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__call__ = dict # static method
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def __subclasscheck__(cls, other):
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# Typed dicts are only for static structural subtyping.
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raise TypeError('TypedDict does not support instance and class checks')
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__instancecheck__ = __subclasscheck__
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def TypedDict(typename, fields=None, /, *, total=True, **kwargs):
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"""A simple typed namespace. At runtime it is equivalent to a plain dict.
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TypedDict creates a dictionary type that expects all of its
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instances to have a certain set of keys, where each key is
|
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associated with a value of a consistent type. This expectation
|
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is not checked at runtime but is only enforced by type checkers.
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Usage::
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|
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class Point2D(TypedDict):
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x: int
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y: int
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label: str
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a: Point2D = {'x': 1, 'y': 2, 'label': 'good'} # OK
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b: Point2D = {'z': 3, 'label': 'bad'} # Fails type check
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|
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assert Point2D(x=1, y=2, label='first') == dict(x=1, y=2, label='first')
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|
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The type info can be accessed via the Point2D.__annotations__ dict, and
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the Point2D.__required_keys__ and Point2D.__optional_keys__ frozensets.
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TypedDict supports two additional equivalent forms::
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|
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Point2D = TypedDict('Point2D', x=int, y=int, label=str)
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Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str})
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|
|
By default, all keys must be present in a TypedDict. It is possible
|
|
to override this by specifying totality.
|
|
Usage::
|
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|
|
class point2D(TypedDict, total=False):
|
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x: int
|
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y: int
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|
|
|
This means that a point2D TypedDict can have any of the keys omitted.A type
|
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checker is only expected to support a literal False or True as the value of
|
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the total argument. True is the default, and makes all items defined in the
|
|
class body be required.
|
|
|
|
The class syntax is only supported in Python 3.6+, while two other
|
|
syntax forms work for Python 2.7 and 3.2+
|
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"""
|
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if fields is None:
|
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fields = kwargs
|
|
elif kwargs:
|
|
raise TypeError("TypedDict takes either a dict or keyword arguments,"
|
|
" but not both")
|
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|
|
ns = {'__annotations__': dict(fields)}
|
|
try:
|
|
# Setting correct module is necessary to make typed dict classes pickleable.
|
|
ns['__module__'] = sys._getframe(1).f_globals.get('__name__', '__main__')
|
|
except (AttributeError, ValueError):
|
|
pass
|
|
|
|
return _TypedDictMeta(typename, (), ns, total=total)
|
|
|
|
_TypedDict = type.__new__(_TypedDictMeta, 'TypedDict', (), {})
|
|
TypedDict.__mro_entries__ = lambda bases: (_TypedDict,)
|
|
|
|
|
|
def NewType(name, tp):
|
|
"""NewType creates simple unique types with almost zero
|
|
runtime overhead. NewType(name, tp) is considered a subtype of tp
|
|
by static type checkers. At runtime, NewType(name, tp) returns
|
|
a dummy function that simply returns its argument. Usage::
|
|
|
|
UserId = NewType('UserId', int)
|
|
|
|
def name_by_id(user_id: UserId) -> str:
|
|
...
|
|
|
|
UserId('user') # Fails type check
|
|
|
|
name_by_id(42) # Fails type check
|
|
name_by_id(UserId(42)) # OK
|
|
|
|
num = UserId(5) + 1 # type: int
|
|
"""
|
|
|
|
def new_type(x):
|
|
return x
|
|
|
|
new_type.__name__ = name
|
|
new_type.__supertype__ = tp
|
|
return new_type
|
|
|
|
|
|
# Python-version-specific alias (Python 2: unicode; Python 3: str)
|
|
Text = str
|
|
|
|
|
|
# Constant that's True when type checking, but False here.
|
|
TYPE_CHECKING = False
|
|
|
|
|
|
class IO(Generic[AnyStr]):
|
|
"""Generic base class for TextIO and BinaryIO.
|
|
|
|
This is an abstract, generic version of the return of open().
|
|
|
|
NOTE: This does not distinguish between the different possible
|
|
classes (text vs. binary, read vs. write vs. read/write,
|
|
append-only, unbuffered). The TextIO and BinaryIO subclasses
|
|
below capture the distinctions between text vs. binary, which is
|
|
pervasive in the interface; however we currently do not offer a
|
|
way to track the other distinctions in the type system.
|
|
"""
|
|
|
|
__slots__ = ()
|
|
|
|
@property
|
|
@abstractmethod
|
|
def mode(self) -> str:
|
|
pass
|
|
|
|
@property
|
|
@abstractmethod
|
|
def name(self) -> str:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def close(self) -> None:
|
|
pass
|
|
|
|
@property
|
|
@abstractmethod
|
|
def closed(self) -> bool:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def fileno(self) -> int:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def flush(self) -> None:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def isatty(self) -> bool:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def read(self, n: int = -1) -> AnyStr:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def readable(self) -> bool:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def readline(self, limit: int = -1) -> AnyStr:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def readlines(self, hint: int = -1) -> List[AnyStr]:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def seek(self, offset: int, whence: int = 0) -> int:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def seekable(self) -> bool:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def tell(self) -> int:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def truncate(self, size: int = None) -> int:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def writable(self) -> bool:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def write(self, s: AnyStr) -> int:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def writelines(self, lines: List[AnyStr]) -> None:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def __enter__(self) -> 'IO[AnyStr]':
|
|
pass
|
|
|
|
@abstractmethod
|
|
def __exit__(self, type, value, traceback) -> None:
|
|
pass
|
|
|
|
|
|
class BinaryIO(IO[bytes]):
|
|
"""Typed version of the return of open() in binary mode."""
|
|
|
|
__slots__ = ()
|
|
|
|
@abstractmethod
|
|
def write(self, s: Union[bytes, bytearray]) -> int:
|
|
pass
|
|
|
|
@abstractmethod
|
|
def __enter__(self) -> 'BinaryIO':
|
|
pass
|
|
|
|
|
|
class TextIO(IO[str]):
|
|
"""Typed version of the return of open() in text mode."""
|
|
|
|
__slots__ = ()
|
|
|
|
@property
|
|
@abstractmethod
|
|
def buffer(self) -> BinaryIO:
|
|
pass
|
|
|
|
@property
|
|
@abstractmethod
|
|
def encoding(self) -> str:
|
|
pass
|
|
|
|
@property
|
|
@abstractmethod
|
|
def errors(self) -> Optional[str]:
|
|
pass
|
|
|
|
@property
|
|
@abstractmethod
|
|
def line_buffering(self) -> bool:
|
|
pass
|
|
|
|
@property
|
|
@abstractmethod
|
|
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 = _alias(stdlib_re.Pattern, 1)
|
|
Match = _alias(stdlib_re.Match, 1)
|
|
|
|
class re:
|
|
"""Wrapper namespace for re type aliases."""
|
|
|
|
__all__ = ['Pattern', 'Match']
|
|
Pattern = Pattern
|
|
Match = Match
|
|
|
|
|
|
re.__name__ = __name__ + '.re'
|
|
sys.modules[re.__name__] = re
|