Help Understanding weakref (lazyloader)

[Ripter]

I found this script at http://www.pygame.org/wiki/LazyImage...arent=CookBook
And I can't quite figure out how it works. I was wondering if someone
could clarify it for me.
The Code is:

import pygame
import weakref

class ResourceController(object):
def __init__(self, loader):
self.__dict__.update(dict(
names = {},
cache = weakref.WeakValueDictionary(),
loader = loader
))

def __setattr__(self, name, value):
self.names[name] = value

def __getattr__(self, name):
try:
img = self.cache[name]
except KeyError:
img = self.loader(self.names[name])
self.cache[name] = img
return img
class ImageController(ResourceController):
def __init__(self):
ResourceController.__init__(self, pygame.image.load)
My question is why does the __setattr__ set the value to
self.names[name] instead of self.cache[name]?

[Ripter]

On Sep 3, 10:46*pm, Ripter <[e-mail]:

I found this script athttp://www.pygame.org/wiki/LazyImageLoading?parent=CookBook
And I can't quite figure out how it works. I was wondering if someone
could clarify it for me.
The Code is:

import pygame
import weakref

class ResourceController(object):
* * def __init__(self, loader):
* * * * self.__dict__.update(dict(
* * * * * * names = {},
* * * * * * cache = weakref.WeakValueDictionary(),
* * * * * * loader = loader
* * * * ))

* * def __setattr__(self, name, value):
* * * * self.names[name] = value

* * def __getattr__(self, name):
* * * * try:
* * * * * * img = self.cache[name]
* * * * except KeyError:
* * * * * * img = self.loader(self.names[name])
* * * * * * self.cache[name] = img
* * * * return img

class ImageController(ResourceController):
* * def __init__(self):
* * * * ResourceController.__init__(self, pygame.image.load)

My question is why does the __setattr__ set the value to
self.names[name] instead of self.cache[name]?

I feel stupid, I figured it out. (Don't program while watching Back to
the Future)
The reason would be the 'lazy' part. self.names holds the file name,
and when you get the property back (__getattr__) it checks to see if
it already got the value or not, and uses the name to get the value if
it hasn't already.

Duh. Sorry.