NOTE: this was fun to implement and I learned a lot about Python type metadata, but if you are looking for a runtime type checker look at Pydantic -----------------
Checks that a value satisfies a Python 3.6 type at runtime
This code uses Python 3.6 type hints and the typing package to provide a simple runtime type check.
The check can be done explicitly calling the check_type function or with the @check_args function decorator which raises an exception when the argument passed to the function do not match the type hints
Example:
from runtime_typechecker import check_type, check_args
from typing import Tuple
assert check_type((1, 67), Tuple[int, int])
assert not check_type((1, "new york"), Tuple[int, int])
@check_args
def dummy_fun(a: int = 0, b: str = '', c: Tuple[int, str] = (0, '')) -> int:
return a + len(b) + c[0] + len(c[1]) + 7
# this will throw a TypeException with the list of the issues. The decorated function is not even called in this case
dummy_fun(a='1', c=(1,42))
# this will work
dummy_fun(a=3)Currently not all of the components of Python 3.6 typing module are supported, more coming.