> This looks like something that could easily adapted to, and better
> demonstrated
> with Pygame. Any reason why you aren't doing this?
>
> André
>
I want to use pure Python without a lot of extra library stuff. The
understanding kids develop will rely on the imagination a lot, with
the foreground remaining essentially lexical (just like a science
fiction novel is mostly just words on a page).
You can picture all those little bunnies hopping around in your mind's
eye. We don't need the overhead of actual graphical bunnies -- though
some puppeting programs may provide them.
Here's some working code except there's something not yet right -- no
fox is eating a bunny yet. I haven't figured out why.
from random import randint
class Mammal (object):
def __init__(self, name, eco):
self.name = name
self.stomach = []
self.alive = True
self.eco = eco
self.timetolive = 100
self.clock = 0
self.xpos = randint(-3,3)
self.ypos = randint(-3,3)
def update(self):
self.clock += 1
self.move()
if self.clock > self.timetolive:
self.alive = False
self.die()
def move(self):
self.xpos += randint(-1, 1)
self.ypos += randint(-1, 1)
class Bunny (Mammal):
def iseaten(self, fox):
self.alive = False
print '%s is eaten by %s.' % (self, fox)
def die(self):
print '%s dies of old age.' % self
def __repr__(self):
return 'Bunny %s age: %s @ (%s, %s)' % (self.name, self.clock,
self.xpos, self.ypos)
class Fox (Mammal):
def eat(self):
for bunny in self.eco.bunnies.values():
if (self.xpos == bunny.xpos) and (self.ypos == bunny.ypos):
self.stomach.append( bunny )
bunny.iseaten(self)
def die(self):
print '%s dies of old age.' % self
def __repr__(self):
return 'Fox %s age: %s @ (%s, %s)' % (self.name, self.clock,
self.xpos, self.ypos)
class Ecosystem(object):
def __init__(self):
self.bunnies = {}
self.foxes = {}
def update(self):
# state change
for bunny in self.bunnies.values():
bunny.update()
for fox in self.foxes.values():
fox.update()
# cull
for i, bunny in self.bunnies.items():
if not bunny.alive:
self.bunnies.pop(i)
for i, fox in self.foxes.items():
if not fox.alive:
self.foxes.pop(i)
def main():
eco = Ecosystem()
for i in range(100):
eco.bunnies[i] = Bunny(i, eco)
for i in range(100):
eco.foxes[i] = Fox(i, eco)
print 'Bunnies:', eco.bunnies
print 'Foxes: ', eco.foxes
for cycle in range(200):
eco.update()
Kirby
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