def test_applying_with_left_in_second_arg(self):
self.assertEqual(
Either.apply(common_tests.add).to_arguments(Right(1), Left('')),
Left(''))
def test_insert(self):
self.assertEqual(Either.insert(1), Right(1))
def pipeline(steps, value) -> Either:
return reduce(lambda either, step: either.then(step), steps, Either.insert(value))
def test_exceptions_wrapped_in_left_kleisli_function(self):
self.assertEqual(str(Either.insert(1).then(lambda x: Right(x / 0))),
str(Left(ZeroDivisionError('division by zero'))))
def handleError(e: Exception):
if isinstance(e, TooHigh):
return "Value too high"
elif isinstance(e, Odd):
return "The number must be even"
else:
raise e
@curry(2)
def pipeline(steps, value) -> Either:
return reduce(lambda either, step: either.then(step), steps, Either.insert(value))
def getValue(value):
return value
if __name__ == "__main__":
# myValue = Either.insert(2)\
# .then(mustBeEven)\
# .then(mustBeLowerThan(5))\
# .either(handleError, getValue)
process = pipeline([mustBeEven, mustBeLowerThan(5)])
myValue = Either.insert(2).then(process).either(handleError, getValue)
print(myValue)