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PyOptional.py
50 lines (37 loc) · 1.24 KB
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PyOptional.py
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from typing import Callable, TypeVar, Type, Optional, Generic
T = TypeVar('T')
class PyOptional(Generic[T]):
value: T
@classmethod
def empty(cls):
return PyOptional[T](None)
def __init__(self, value: Optional[T]) -> None:
self.value = value
def get(self) -> Optional[T]:
return self.value
def or_else(self, default: T) -> T:
return self.value or default
def or_else_do(self, _lambda: Callable) -> T:
if self.value:
return self.value
else:
return _lambda()
def or_raise(self, exception: Exception) -> T:
if self.value:
return self.value
else:
raise exception
def is_present(self) -> bool:
return self.value is not None
def is_none(self) -> bool:
return self.value is None
def if_present(self, _lambda: Callable, default: T) -> T:
if self.is_present():
return _lambda(self.value)
else:
return default
def if_present_or_raise(self, _lambda: Callable, exception: Exception) -> T:
if self.is_present():
return _lambda(self.value)
else:
raise exception