147 lines
5.4 KiB
Python
147 lines
5.4 KiB
Python
# Taken from https://github.com/rossmacarthur/typing-compat/
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# TODO: Remove once the minimum python version is increased to 3.8
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#
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# Licensed under the MIT license
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in all
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# copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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# SOFTWARE.
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#
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# flake8: noqa
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import collections
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import typing
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__all__ = ['get_args', 'get_origin']
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__title__ = 'typing-compat'
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__version__ = '0.1.0'
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__url__ = 'https://github.com/rossmacarthur/typing-compat'
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__author__ = 'Ross MacArthur'
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__author_email__ = 'ross@macarthur.io'
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__description__ = 'Python typing compatibility library'
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try:
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# Python >=3.8 should have these functions already
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from typing import get_args as _get_args # novermin
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from typing import get_origin as _get_origin # novermin
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except ImportError:
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if hasattr(typing, '_GenericAlias'): # Python 3.7
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def _get_origin(tp):
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"""Copied from the Python 3.8 typing module"""
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if isinstance(tp, typing._GenericAlias):
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return tp.__origin__
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if tp is typing.Generic:
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return typing.Generic
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return None
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def _get_args(tp):
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"""Copied from the Python 3.8 typing module"""
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if isinstance(tp, typing._GenericAlias):
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res = tp.__args__
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if (
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get_origin(tp) is collections.abc.Callable
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and res[0] is not Ellipsis
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):
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res = (list(res[:-1]), res[-1])
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return res
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return ()
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else: # Python <3.7
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def _resolve_via_mro(tp):
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if hasattr(tp, '__mro__'):
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for t in tp.__mro__:
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if t.__module__ in ('builtins', '__builtin__') and t is not object:
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return t
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return tp
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def _get_origin(tp):
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"""Emulate the behaviour of Python 3.8 typing module"""
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if isinstance(tp, typing._ClassVar):
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return typing.ClassVar
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elif isinstance(tp, typing._Union):
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return typing.Union
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elif isinstance(tp, typing.GenericMeta):
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if hasattr(tp, '_gorg'):
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return _resolve_via_mro(tp._gorg)
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else:
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while tp.__origin__ is not None:
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tp = tp.__origin__
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return _resolve_via_mro(tp)
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elif hasattr(typing, '_Literal') and isinstance(tp, typing._Literal): # novermin
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return typing.Literal # novermin
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def _normalize_arg(args):
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if isinstance(args, tuple) and len(args) > 1:
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base, rest = args[0], tuple(_normalize_arg(arg) for arg in args[1:])
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if isinstance(base, typing.CallableMeta):
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return typing.Callable[list(rest[:-1]), rest[-1]]
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elif isinstance(base, (typing.GenericMeta, typing._Union)):
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return base[rest]
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return args
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def _get_args(tp):
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"""Emulate the behaviour of Python 3.8 typing module"""
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if isinstance(tp, typing._ClassVar):
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return (tp.__type__,)
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elif hasattr(tp, '_subs_tree'):
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tree = tp._subs_tree()
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if isinstance(tree, tuple) and len(tree) > 1:
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if isinstance(tree[0], typing.CallableMeta) and len(tree) == 2:
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return ([], _normalize_arg(tree[1]))
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return tuple(_normalize_arg(arg) for arg in tree[1:])
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return ()
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def get_origin(tp):
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"""
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Get the unsubscripted version of a type.
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This supports generic types, Callable, Tuple, Union, Literal, Final and
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ClassVar. Returns None for unsupported types.
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Examples:
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get_origin(Literal[42]) is Literal
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get_origin(int) is None
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get_origin(ClassVar[int]) is ClassVar
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get_origin(Generic) is Generic
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get_origin(Generic[T]) is Generic
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get_origin(Union[T, int]) is Union
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get_origin(List[Tuple[T, T]][int]) == list
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"""
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return _get_origin(tp)
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def get_args(tp):
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"""
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Get type arguments with all substitutions performed.
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For unions, basic simplifications used by Union constructor are performed.
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Examples:
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get_args(Dict[str, int]) == (str, int)
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get_args(int) == ()
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get_args(Union[int, Union[T, int], str][int]) == (int, str)
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get_args(Union[int, Tuple[T, int]][str]) == (int, Tuple[str, int])
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get_args(Callable[[], T][int]) == ([], int)
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"""
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return _get_args(tp)
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