from collections.abc import Callable, Mapping
from typing import Any, TypeVar

_S = TypeVar("_S")
_T = TypeVar("_T")

def identity(x: _T) -> _T: ...
def exhaust(rule: Callable[[_T], _T]) -> Callable[[_T], _T]: ...
def memoize(rule: Callable[[_S], _T]) -> Callable[[_S], _T]: ...
def condition(cond: Callable[[_T], bool], rule: Callable[[_T], _T]) -> Callable[[_T], _T]: ...
def chain(*rules: Callable[[_T], _T]) -> Callable[[_T], _T]: ...
def debug(rule, file=...) -> Callable[..., Any]: ...
def null_safe(rule: Callable[[_T], _T | None]) -> Callable[[_T], _T]: ...
def tryit(rule: Callable[[_T], _T], exception) -> Callable[[_T], _T]: ...
def do_one(*rules: Callable[[_T], _T]) -> Callable[[_T], _T]: ...
def switch(key: Callable[[_S], _T], ruledict: Mapping[_T, Callable[[_S], _S]]) -> Callable[[_S], _S]: ...
def minimize(*rules: Callable[[_S], _T], objective=...) -> Callable[[_S], _T]: ...