[Python-Dev] caching in the stdlib?

[Stefan Behnel]

I think this is better suited for python-ideas, so moving it there.

Guido van Rossum, 28.07.2010 16:31:
> On Tue, Jul 27, 2010 at 10:29 PM, Stefan Behnel  wrote:
>> What about actually putting it visibly into the stdlib? Except for files, I
>> didn't see much about caching there, which seems like a missing battery to
>> me. Why not do it as with the collections module and add stuff as it comes
>> in?
>
> Caching is a rather large topic to focus on in a single stdlib module
> or package. It means radically different things to different people.

Sure. All I would like to see in the stdlib is a dict based cache with a 
bounded size and a set of different policies that keep it at that size.

Maybe a BoundedDict would match that need.


> The pattern we're talking about there is probably more something like
> memoization, so 'memo' or 'memoization' could b a reasonable module
> name.

That would be a second interface to it, I'd say. The normal interface would 
just be the regular mapping interface, maybe even just a .get() method 
instead of a KeyError raising lookup.


> Maybe it could provide a decorator that you configure with
> things like how many entries max, the expiration policy (or different
> policies could have different decorators), and how to compute the memo
> key from the arguments to the function (the default could be the
> repr() of the argument tuple).

Absolutely.

Stefan