def class_method_wrapper(method, pre=None, post=None):
“””Given a class METHOD and two wrapper function, a PRE-function and
POST-function, first calls the pre-wrapper, calls the wrapped class method,
and then calls the post-wrapper.
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All wrappers should have the parameters (self, rv, *args). However,
pre-wrappers will always have `None` passed in as `rv`, since a return
value has not been evaluated yet.
>>> def pre_wrapper(instance, rv, *args):
… print(‘Pre-wrapper called: {0}’.format(args))
>>> def post_wrapper(instance, rv, *args):
… print(‘Post-wrapper called: {0} -> {1}’.format(args, rv))
>>> class Foo:
… def __init__(self):
… self.bar = 20
… def method(self, var1, var2):
… print(‘Original method called’)
… return var1 + var2 + self.bar
>>> Foo.method = class_method_wrapper(Foo.method, pre_wrapper, post_wrapper)
>>> f = Foo()
>>> x = f.method(1, 2)
Pre-wrapper called: (1, 2)
Original method called
Post-wrapper called: (1, 2) -> 23
def wrapped_method(self, *args):
pre(self, None, *args) if pre else None
rv = method(self, *args)
post(self, rv, *args) if post else None
return wrapped_method
def print_expired_insects(self, rv, *args):
“””Post-wrapper for Insect.reduce_health, and will print a message if the
insect has expired (health reduced to 0).
>>> from ants import Insect, Bee, ThrowerAnt, Place
>>> Insect.reduce_health = class_method_wrapper(Insect.reduce_health,
… pre=print_expired_insects)
>>> place = Place(‘Test’)
>>> bee = Bee(3)
>>> place.add_insect(bee)
>>> bee.reduce_health(2)
>>> bee.reduce_health(1)
Bee(Test) ran out of health and expired
>>> thrower = ThrowerAnt()
>>> place.add_insect(thrower)
>>> thrower.reduce_health(1)
ThrowerAnt(Test) ran out of health and expired
if self.health <= args[0]:
print('{0}({1}) ran out of health and expired'.format(
type(self).__name__, self.place))
def print_thrower_target(self, rv, *args):
"""Prints the target of a ThrowerAnt, if the ThrowerAnt found a target.
>>> from ants import *
>>> beehive = Hive(AssaultPlan())
>>> dimensions = (1, 9)
>>> gamestate = GameState(None, beehive, ant_types(), dry_layout, dimensions)
>>> ThrowerAnt.nearest_bee = class_method_wrapper(ThrowerAnt.nearest_bee,
… post=print_thrower_target)
>>> thrower = ThrowerAnt()
>>> short = ShortThrower()
>>> bee = Bee(5)
>>> gamestate.places[‘tunnel_0_1’].add_insect(short)
>>> gamestate.places[‘tunnel_0_0’].add_insect(thrower)
>>> gamestate.places[‘tunnel_0_5’].add_insect(bee)
>>> thrower.action(gamestate)
ThrowerAnt(1, tunnel_0_0) targeted Bee(5, tunnel_0_5)
>>> short.action(gamestate) # Bee not in range of ShortThrower
>>> bee.action(gamestate) # Bee moves into range
>>> short.action(gamestate)
ShortThrower(1, tunnel_0_1) targeted Bee(4, tunnel_0_4)
if rv is not None:
print(‘{0} targeted {1}’.format(self, rv))
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