polymethod 1.0.0

Library to enable function overloading in Python

Introduction

This library is enables method overloading in Python taking care of the method resolution without additional user required code given sufficient typehints on the various functions. It brings no additional requirements and can be easily integrated into existing codebases.

License and Copyright Information

This library is distributed under the MIT License, see LICENSE.

Installation

This project has no dependencies and can be installed with pip either locally

git clone https://github.com/steinmig/polymethod.git
pip install ./polymethod

or from PyPI

pip install polymethod

Building documentation

The dependencies for building the documentation can be installed with

pip install -r docs/requirements.txt

The documentation can then be built and opened with

sphinx-build docs/source docs/build
firefox docs/build/index.html

Example Usage

This package allows you to overload functions, i.e. give multiple functions the same name, but let them require different number and/or types of arguments. This allows to provide simple APIs that can handle various inputs. Currently, the overloading feature is limited to methods, i.e. functions of a class. The overloaded methods can be regular methods, classmethods, or staticmethods. An example class would be

from polymethod import overload, OverloadMeta, NoMatchingOverload
from typing import Tuple

class API(metaclass=OverloadMeta):

    @classmethod
    @overload
    def provide_id(cls, user_name: str) -> int:
        # some function body
        return 0

    @classmethod
    @overload
    def provide_id(cls, birthday: Tuple[int, int, int]) -> int:
        # another function body
        return 1

assert API.provide_id("A user name") == 0
assert API.provide_id((4, 7, 1776)) == 1
try:
    API.provide_id(0)
except NoMatchingOverload as e:
    print(str(e))