[Python-ideas] Re: Additional LRU cache introspection facilities

Actually you can get the cache data from the python version, for that you need to force the use of the python version of functools def get_cache(f): freevars = f.__code__.co_freevars index = freevars.index('cache') return f.__closure__[index].cell_contents import importlib.abc class ForcePythonLruCache(importlib.abc.MetaPathFinder): def find_spec(self, fullname, path, target=None): if fullname == '_functools': raise ImportError('_functools not available') import sys del sys.modules['functools'] del sys.modules['_functools'] import functools @functools.lru_cache def test(x): return x test(1) test(2) test('a') test('foo') print(list(get_cache(test).keys())) On Tue, Jan 12, 2021 at 4:09 PM Paul Moore wrote:

On Tue, 12 Jan 2021 at 17:16, Christopher Barker wrote:

...

Is the implementation of lru_cache too opaque to poke into it without an

existing method? Or write a quick monkey-patch?

...

Sorry for not checking myself, but the ability to do that kind of thing

is one of the great things about a dynamic open source language.

I've only looked at the Python implementation, but the cache is a local variable in the wrapper, unavailable from outside. The cache information function is a closure that references that local variable, assigned as an attribute of the wrapped function.

It's about as private as it's possible to get in Python (not particularly because it's *intended* to hide anything, as far as I can tell, more likely for performance or some other implementation reason).

Paul _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-leave@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/C6YULK... Code of Conduct: http://python.org/psf/codeofconduct/

-- Sebastian Kreft