Caching GeneratorType results
veyesecurity opened this issue · 1 comments
veyesecurity commented
Please consider the example below:
class Foo(object):
def __init__(self, items):
self.items = items
@cached_property
def squares(self):
for item in self.items:
yield item * item
foo = Foo([1, 2, 3])
print list(foo.squares)
print list(foo.squares)
It will produce the following output:
[1, 4, 9]
[]
To fix this we have modified cached_property
decorator:
class cached_property(object):
def __init__(self, func):
self.func = func
def __get__(self, obj, cls):
value = self.func(obj)
if isinstance(value, GeneratorType):
value = list(value)
obj.__dict__[self.func.__name__] = value
return value
But now we loose the laziness of the method and also change its return type. Do you have in mind any elegant way to implement cached decorator that will cache items yielded so far, so when the property will be called second time it will first yield cached items and then continue with items yielded by the original (cached) method?
pydanny commented
Not closing yet this as it adds excellent historical context for any work done on #100. Thanks @veyesecurity!