typed-everywhere 1.0.1

Runtime type checking and not only for function arguments and class variables but even for the ordinary local and global variables!

typed-everywhere

Runtime type checking and not only for function arguments and class variables but even for the ordinary local and global variables!

Installation

pip install typed-everywhere

How To Use

We have a proxy class:

class Typed(wrapped)

This class inherits a variant of ObjectProxy from wrapt. Along with all augmented assignment operators, this class also overloads the normal assignment operator (=) thanks to assign-overload. wrapped can be any object and the resulting instance of this class will act like wrapped in every way. If you use this class, you need to call typed_everywhere.patch_and_reload_module(). This function only exposed in this package as a convenience, actually it is the exact copy of assign_overload.patch_and_reload_module() and you can find documentation about it in assign-overload. Usage example:

import typed_everywhere

def main():
    a = typed_everywhere.Typed(10)
    a = 20 # Ok
    print(a) # prints 20
    a = "abc" # Error

if typed_everywhere.patch_and_reload_module():
    main()

One thing to note is if you assign a variable holding a Typed instance to a new variable, new variable takes the value of the Typed instance, not the value of its underlying object. However, most operators return the underlying object. Example:

import typed_everywhere

def main():
    a = typed_everywhere.Typed(10)
    print(type(a+5)) # prints int
    b = a
    print(type(b)) # prints Typed

if typed_everywhere.patch_and_reload_module():
    main()

If you want to access the underlying object, use the __wrapped__ attribute:

import typed_everywhere

def main():
    a = typed_everywhere.Typed(10)
    b = a.__wrapped__
    print(type(b)) # prints int

if typed_everywhere.patch_and_reload_module():
    main()

Typed is also compatible with typeguard. Function argument type enforcement example:

import typeguard
import typed_everywhere

@typeguard.typechecked
def test4(a: typed_everywhere.Typed[int]):
    pass

def main():
    a = typed_everywhere.Typed(10)
    b = typed_everywhere.Typed("abc")
    test4(a) # Ok
    test4(b) # Error

if typed_everywhere.patch_and_reload_module():
    main()