herpetologist, Dynamic parameter type checking for Python 3.6 and above. This able to detect deep nested variables.
problem statement
Let say you want to detect dynamically argument types for a function,
def greeting(name: str):
# we want to throw exception if name is not `str`.
print(name) There is existing library called typeguard, it is already good enough but when comes to nested checking, it failed.
List[List[int]] # failed
List[Tuple[int, float, str]] # failed
Tuple[List[int], Tuple[List[int]]] # failed
List[Dict[str, Dict[str, List[str]]]] # failed
Tuple(List[int, float], Tuple[float, float]) # failed
Tuple[Tuple[List[Dict[int, str]]], Tuple[List[int]]] # failed
Tuple[Tuple[List[Dict[int, str]]], Tuple[List[int], str]] # failedand list goes on, but this simple decorator check_type can helps you, any depth of nested and positions.
I know, who is going to pass that kind of parameter?
Installing from the PyPI
pip install herpetologistOnly supports Python 3.6 and above.
how-to
from herpetologist import check_type
@check_type
def greeting(name: str):
print(name)@check_type
def greeting(name: Tuple[Tuple[List[Dict[int, str]]], Tuple[List[int]]]):
pass
greeting((([{1: 'str'}],), ([1], [1]))) # no error
greeting((([{1: 'str'}],), ([1], [1.1]))) # error@check_type
def greeting(name: List[Dict[str, Dict[str, List[str]]]]):
pass
greeting([{'a': {'b': ['a', 'a']}}]) # no error
greeting([{'a': {'b': ['a', 1]}}]) # errorSupport custom types
class ClassA:
def __init__(self):
pass
@check_type
def greeting(name: str, foo: ClassA):
print(foo)Ignore checking
Just simply skip type hinting,
def greeting(name: str, foo):
print(foo)default value
herpetologist will never checked default value, snake is a snake (concept from duck typing)!
@check_type
def greeting(name: List[Dict[str, Dict[str, List[str]]]] = None):
if name is None:
print('name is None!')
greeting([{'a': {'b': ['a', 'a']}}]) # no error
greeting() # no errorexample
Simply read more at example.ipynb.
