Welcome to strongtyping

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strongtyping gives you a handy decorator which checks at runtime whether a function has been called with the correct parameter types.
It raises TypeMisMatch if the parameters used in a function call are invalid.

The Problem

Even if you use an advanced IDE which can highlight typing issues, in bigger projects you'll probably find yourself struggling through long debugging sessions before realising the issue was due to the wrong type of argument. These bugs are tricky to spot because they don't necessarily crash the program, but the output is still unexpected or just plain wrong. For example:

>>> def multiplier(a: int, b: int):
...     return a * b

>>> product = multiplier(3, 4)

>>> product_2 = multiplier('Hello', 'World') # Will be highlighted in some IDE's

>>> product_3 = multiplier('Hello', 4)
# No Exception but the result isn’t really what we expect

Without strongtyping you have to check for every valid type of every parameter in every function, which creates a lot of noisy/bloated code and begs the questions "Why use Python type hinting at all?":

>>> def multipler(a: int, b: int):
...     if isinstance(a, int) and isinstance(b, int):
...         return a * b

The Solution

I love Python and its freedom, but with the new option of adding type hints I wanted to get rid of writing if isinstance(value, whatever) repeatedly in my programs, so I decided to create strongtyping...

My solution is a simple decorator called @match_typing which will check at runtime whether the parameters you provide to a function are valid, based on type hints you've already defined in the def line. Here are some examples:

from typing import List, Union
import datetime
from strongtyping.strong_typing import match_typing

def func_a(a: str, b: int, c: list):

func_a('1', 2, [i for i in range(5)])
# >>> True

func_a(1, 2, [i for i in range(5)])
# >>> will raise a TypeMismatch Exception

def func_e(a: List[Union[str, int]], b: List[Union[str, int, tuple]]):
    return f'{len(a)}-{len(b)}'

func_e([1, '2', 3, '4'], [5, ('a', 'b'), '10'])
# >>> '4-3'

func_e([5, ('a', 'b'), '10'], [1, '2', 3, datetime.date])
# >>> will raise a TypeMismatch Exception


Python 3.7, 3.8, 3.9

  • ujson
  • pytest

What's included

from strongtyping.strong_typing import

  • @match_typing
  • @match_class_typing
  • @getter
  • @setter
  • @getter_setter

from strongtyping.type_namedtuple import

  • typed_namedtuple

from strongtyping.docs_from_typing import

  • @class_docs_from_typing
  • @rest_docs_from_typing
  • @numpy_docs_from_typing

from strongtyping.types import

  • Validator
  • IterValidator



  • A package I wrote in Cython to speed up parameter checking. This package provides a speed boost of over 300%.
  • you can simply install this package with pip install strongtyping-modules
  • for more detailed information please check out the README