[Zope-CMF] Re: RFC: browser views and memoization

[yuppie]

Hi Whit!


whit wrote:
> yuppie wrote:
>>
>> I ended up using this method as decorator for most methods:
>>
>> def memoize(func):
>>     memo = {}
>>     def memoized_func(*args):
>>         if args not in memo:
>>             memo[args] = func(*args)
>>         return memo[args]
>>     return memoized_func
>>
>>
>> Are there better ways to resolve this?
>>
>> Will those memo dicts be removed together with the view object or does 
>> this create a potential memory leak? (I'm not very familiar with 
>> decorators.)
> 
> that's pretty elegant compared to shoving a multitude of values into the 
> view.  The closest thing to it would be a PEAK binding, but even that 
> can't handle the variety of situations that keing the memo by function 
> signature gives you. very nice.

Besides the fact it doesn't work :(

> that looks safe; as far as I can tell when the decorated method is 
> garbage collected with the view, all refs to 'memo' should be reaped..

Digging a bit deeper it looks like decoraters are created on class 
level, not on instance level. So 'memo' is not garbage collected with 
the view, it's the same for all instances and grows with each request. 
That's not exactly the behavior I want.

Have to think about it a bit more. Any input is welcome.

> In python 2.4 you could use frozenset to have keyword support too.  I 
> think something like this would work:
> 
>  > def memoize(func):
>  >     memo = {}
>  >     def memoized_func(*args, **kwargs):
>  >         sig = (args, frozenset(kwargs.items()))
>  >         if sig not in memo:
>  >             memo[sig] = func(*args, **kwargs)
>  >         return memo[sig]
>  >     return memoized_func

Thanks, I'll keep that in mind. For now this is not my problem.


Cheers,

	Yuppie