Created
December 7, 2016 07:42
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callable default func
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from typing import TYPE_CHECKING | |
if TYPE_CHECKING: | |
from typing import List, Callable, TypeVar, Optional | |
T = TypeVar('T') | |
def test(func: Callable[[str], T]) -> List[T]: | |
list(map(func, "1")) | |
print(test(str)) # OK | |
print(test(int)) # OK | |
def test1(func: Callable[[str], T]=str) -> List[T]: | |
# error: Incompatible types in assignment (expression has type "str", variable has type Callable[[str], T]) | |
return list(map(func, "1")) | |
print(test1()) # OK | |
print(test1(str)) # OK | |
print(test1(int)) # OK | |
def _to_str(elem: str) -> str: | |
return str(elem) | |
def test2(func: Callable[[str], T]=_to_str) -> List[T]: | |
# error: Incompatible types in assignment (expression has type Callable[[str], str], variable has type Callable[[str], T]) | |
return list(map(func, "1")) | |
print(test2()) # OK | |
print(test2(str)) # OK | |
print(test2(int)) # OK | |
def test3(func: Callable[[str], str]=str) -> List[str]: | |
return list(map(func, "1")) | |
print(test3()) # OK | |
print(test3(str)) # OK | |
print(test3(int)) # OK cause error |
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