decorator example

evil.py

import threading
import time

from collections import defaultdict 

class Effect(object):
    '''
    class styled decorator because you need to have some way for the
    effects.starter to find the effects.stopper
    The "easiest" way of doing so is a class method that registers the stopper
    functions in a dictionary, but it is a bit of a pita
    '''

    stoppers = {}


    @classmethod
    def starter(cls, name):
        print('start called w. {} for {}'.format(cls, name))
        def wrap(method):
            print('start wrapping {}'.format(method))
            def inner(obj, duration):
                print('inner start running {}, {}'.format(obj, duration))
                method(obj, duration)
                print('looking for stopper: {}'.format(name))
                stop_function = cls.stoppers[name]
                print('stopper found {}'.format(stop_function))
                thread = threading.Thread(target=stop_function,
                     args = (obj, duration))
                obj.effects['freeze'].add(thread)
                thread.start()
            return inner
        return wrap

    @classmethod
    def stopper(cls, name):
        print('stopper called w. {} for {}'.format(cls, name))
        def wrap(method):
            print('stop wrap called with method:{}'.format(method))
            def inner(obj, *args):
                print('stop inner called obj: {}, args = {}'.format(obj, args))
                return method(obj, *args)
            print('registering {} as stopper for {}'.format( wrap, name))
            cls.stoppers[name] = inner
        return wrap

class Player:
    def __init__(self):
        self.speed = 1.0
        self.hot = 10
        self.effects = defaultdict(set)

    @Effect.starter('freeze')
    def freeze(self, duration):
        print('freeze called')
        self.speed = 0.0
        #thread = threading.Thread(target=self._unfreeze, 
                #args = (duration,))
        #self.effects['freeze'].add(thread)
        #thread.start()

    @Effect.stopper('freeze')
    def _unfreeze(self, duration):
        print('unfreeze called')
        time.sleep(duration)
        print('done sleeping')
        self.speed = 1.0

    @Effect.starter('heat')
    def heat(self, duration):
        print('heating player')
        self.hot *= 2

    @Effect.stopper('heat')
    def _unheat(self, duration):
        time.sleep(duration) # note, could move this into the Effects decorator
        #class
        self.hot /= 2
        print('player cooled off')


p = Player()
p.freeze(.25)
p.heat(.5)
start = time.time()
while time.time() - start < 1:
    print(p.speed, p.hot)
    time.sleep(.1)