def decode_as_tuple(
type_: Type[Decoded], json: Any, path: Path
) -> Union[Decoded, DecodingError]:
from typedjson.annotation import args_of
from typedjson.annotation import origin_of
def _required_length(args: Tuple[Type, ...]) -> int:
return len(args) - 2 if args[-1] is ... else len(args)
def _iter_args(args: Tuple[Type, ...]) -> Iterator[Type]:
last: Optional[Type] = None
for type_ in args:
if type_ is ...:
if last is None:
raise
else:
while True:
yield last
else:
yield type_
last = type_
if origin_of(type_) is tuple:
if json is None:
return DecodingError(TypeMismatch(path))
list_decoded: List[Any] = []
length = len(json)
if _required_length(args_of(type_)) > length:
return DecodingError(TypeMismatch(path))
for (index, (type_, element)) in enumerate(
zip(_iter_args(args_of(type_)), json)
):
decoded = decode(type_, element, path + (str(index),))
if isinstance(decoded, DecodingError):
return decoded
list_decoded.append(decoded)
return tuple(list_decoded) # type: ignore
else:
return DecodingError(UnsupportedDecoding(path))
def decode_as_union(type_: Type[Decoded], json: Any,
path: Path) -> Union[Decoded, DecodingError]:
from typedjson.annotation import args_of
from typedjson.annotation import origin_of
if origin_of(type_) is Union:
args = args_of(type_)
for type_ in args:
if type_.__class__ is TypeVar:
return DecodingError(UnsupportedDecoding(path))
for type_ in args:
decoded = decode(type_, json, path)
if not isinstance(decoded, DecodingError):
break
return decoded
else:
return DecodingError(UnsupportedDecoding(path))
def decode_as_list(type_: Type[Decoded], json: Any,
path: Path) -> Union[Decoded, DecodingError]:
from typedjson.annotation import args_of
from typedjson.annotation import origin_of
if origin_of(type_) is list:
Element = args_of(type_)[0]
list_decoded: List[Any] = []
for index, element in enumerate(json):
decoded = decode(Element, element, path + (str(index), ))
if isinstance(decoded, DecodingError):
return decoded
list_decoded.append(decoded)
return list(list_decoded) # type: ignore
else:
return DecodingError(UnsupportedDecoding(path))
def test_cannot_obtain_args_of_non_generics() -> None:
expectation: Tuple[Type, ...] = tuple()
assert args_of(NameJson) == expectation
def test_can_obtain_args_of_generics() -> None:
expectation = (int, str)
assert args_of(GenericJson[int, str]) == expectation