Python function overloading

>>> from multipledispatch import dispatch
>>> from collections import namedtuple
>>> from types import *  # we can test for lambda type, e.g.:
>>> type(lambda a: 1) == LambdaType
True

>>> Sprite = namedtuple('Sprite', ['name'])
>>> Point = namedtuple('Point', ['x', 'y'])
>>> Curve = namedtuple('Curve', ['x', 'y', 'z'])
>>> Vector = namedtuple('Vector', ['x','y','z'])

>>> @dispatch(Sprite, Point, Vector, int)
... def add_bullet(sprite, start, direction, speed):
...     print("Called Version 1")
...
>>> @dispatch(Sprite, Point, Point, int, float)
... def add_bullet(sprite, start, headto, speed, acceleration):
...     print("Called version 2")
...
>>> @dispatch(Sprite, LambdaType)
... def add_bullet(sprite, script):
...     print("Called version 3")
...
>>> @dispatch(Sprite, Curve, int)
... def add_bullet(sprite, curve, speed):
...     print("Called version 4")
...

>>> sprite = Sprite('Turtle')
>>> start = Point(1,2)
>>> direction = Vector(1,1,1)
>>> speed = 100 #km/h
>>> acceleration = 5.0 #m/s**2
>>> script = lambda sprite: sprite.x * 2
>>> curve = Curve(3, 1, 4)
>>> headto = Point(100, 100) # somewhere far away

>>> add_bullet(sprite, start, direction, speed)
Called Version 1

>>> add_bullet(sprite, start, headto, speed, acceleration)
Called version 2

>>> add_bullet(sprite, script)
Called version 3

>>> add_bullet(sprite, curve, speed)
Called version 4

Source: stackoverflow.com

Python function overloading

registry = {}


class MultiMethod(object):
    def __init__(self, name):
        self.name = name
        self.typemap = {}

    def __call__(self, *args):
        types = tuple(arg.__class__ for arg in args)  # a generator expression!
        function = self.typemap.get(types)
        if function is None:
            raise TypeError("no match")
        return function(*args)

    def register(self, types, function):
        if types in self.typemap:
            raise TypeError("duplicate registration")
        self.typemap[types] = function


def multimethod(*types):
    def register(function):
        name = function.__name__
        mm = registry.get(name)
        if mm is None:
            mm = registry[name] = MultiMethod(name)
        mm.register(types, function)
        return mm

    return register

###### usage ######
from multimethods import multimethod

# 'overload' makes more sense in this case
overload = multimethod


@overload(str, int)
def do_smth(a, b):
    print(a + b)


@overload(str)
def do_smth(a):
    print(a)

Source: stackoverflow.com

Similar codes

1 vote102 views1 answer
Django sites framework
Python
12 votes115 views2 answers
Is python object oriented language
Python
0 vote108 views1 answer
Django password field encryption
Python
2 votes105 views2 answers
Numpy array_equal
Python
0 vote103 views1 answer
Get param function python
Python
0 vote164 views1 answer
Python randomly chose user agent
Python
0 vote115 views1 answer
Get all environment variables python
Python
0 vote102 views2 answers
Connect to mysql database jupyter
Python
0 vote109 views1 answer
ModuleNotFoundError: No module named 'django.db.models.enums'
Python
-1 vote155 views1 answer
ImportError: DLL load failed while importing win32file: The specified module could not be found.
Python