23 lines
633 B
Python
23 lines
633 B
Python
"""Useful internal functions."""
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from typing import Any, Callable, NoReturn, Type, TypeVar
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from ._compat import TypeAlias
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from .errors import StructureHandlerNotFoundError
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T = TypeVar("T")
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Predicate: TypeAlias = Callable[[Any], bool]
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"""A predicate function determines if a type can be handled."""
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def identity(obj: T) -> T:
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"""The identity function."""
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return obj
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def raise_error(_, cl: Type) -> NoReturn:
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"""At the bottom of the condition stack, we explode if we can't handle it."""
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msg = f"Unsupported type: {cl!r}. Register a structure hook for it."
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raise StructureHandlerNotFoundError(msg, type_=cl)
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