47 lines
1.1 KiB
Python
47 lines
1.1 KiB
Python
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"""
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Dummy contextvars implementation, to make prompt_toolkit work on Python 3.6.
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As long as there is only one application running at a time, we don't need the
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real contextvars. So, stuff like the telnet-server and so on requires 3.7.
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"""
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from typing import Any, Callable, Generic, Optional, TypeVar
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def copy_context() -> "Context":
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return Context()
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_T = TypeVar("_T")
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class Context:
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def run(self, callable: Callable[..., _T], *args: Any, **kwargs: Any) -> _T:
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return callable(*args, **kwargs)
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class Token(Generic[_T]):
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pass
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class ContextVar(Generic[_T]):
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def __init__(self, name: str, *, default: Optional[_T] = None) -> None:
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self._name = name
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self._value = default
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@property
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def name(self) -> str:
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return self._name
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def get(self, default: Optional[_T] = None) -> _T:
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result = self._value or default
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if result is None:
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raise LookupError
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return result
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def set(self, value: _T) -> Token[_T]:
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self._value = value
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return Token()
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def reset(self, token: Token[_T]) -> None:
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pass
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