I would like to check the type compatibility between the output of one function and the input of another. I know mypy does static type checking but I couldn't find anything on running it from python. Here is an example of what I am trying to do:
from typing import Union, Callable
import inspect
def gt_4(num: Union[int, float]) -> bool:
return num > 4
def add_2(num: Union[int, float]) -> float:
return num + 2.0
def types_are_compatible(type1, type2):
""" return True if types are compatible, else False """
# how to do this in a clean way?
# some kind of MyPy API would be nice here to not reinvent the wheel
# get annotations for output of func1 and input of func2
out_annotation = inspect.signature(gt_4).return_annotation
in_annotation = inspect.signature(add_2).parameters.get('num').annotation
# check if types are compatible,
types_are_compatible(out_annotation, in_annotation)
I found a small github project called typegaurd that seems to do something similar but I am really reluctant to use a small 3rd party library for the code I am working on. What is the cleanest way to do this? Is there anything built in to the standard library or MyPy that I can just use directly?