MilmanRonV / Python-Method-Overloading

Metaclass & descriptor based method overloading

Python Method Overloading

This Python script demonstrates method overloading using a metaclass and a descriptor. It dispatches functions based on the types/type hints of their arguments.

The script defines the following classes:

• OverloadMeta: A metaclass that provides a MethodOverloadDict to __new__ instead of a regular namespace.
• MethodOverloadDict: A dictionary subclass that handles method registration using FunctionDispatcher.
• FunctionDispatcher: An abstract base class that defines the interface for a function dispatcher.
• DictionaryFunctionDispatcher: A descriptor that dispatches a callable responsible for selecting the right function based on registered functions and the provided arguments' types.
• overload: A decorator that marks methods as overloads.

Usage

You can find an example usage below.

pip install git+https://github.com/MilmanRonV/Python-Method-Overloading.git

from __future__ import annotations
from pyoverload import OverloadMeta, overload

class Foo(metaclass=OverloadMeta):
    @overload
    def bar(self, x: int):
        print(f"Bar function with integer argument: {x}")

    @overload
    def bar(self, s: str):
        print(f"Bar function with string argument: {s}")


f = Foo()
f.bar(42)  # Output: Bar function with integer argument: 42
f.bar("Hello")  # Output: Bar function with string argument: Hello

In this example, the Foo class demonstrates method overloading with the bar method. The bar method can be called with either an integer or a string argument. Depending on the argument type, the corresponding overloaded version of the function will be dispatched.

Note: Similar functionality can be achieved using functools.singledispatchmethod, but this implementation offers a more precise dispatching mechanism.

Enjoy exploring function overloading with this script!

Happy Coding!