Memoize/cache partial function

I would like to suggest to not cache the output of a function, if the output is None. This could be made optional by some argument to the @cache decorator, i.e. partial. That allows the possibility to cache the value only if the function “succeeded”. Otherwise the input is “burned” with a None value.

I think this might be a powerful feature in the streamlit paradigm, addressing some of the use cases that depend on some more complex state.

This is possible. You can use the fact that throwing an exception in a cached function prevents storing the result. I’m writing up a demonstration now and will share… :slight_smile:

So the quick answer is that you can throw an exception in your cached function (which prevents caching) and then catch it in your code. If you want to get all fancy, you can hermetically seal this logic away by copy-pasting the partial_cache decorator in this gist.

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