memoizable | Memoize method return values | Runtime Evironment library

I'm looking for a way to cache properties of an object. In my case, I suppose the object can change over the time, so the memoized value for the property should be flushable. In pure python, I want to have a behaviour like:

I postes this question because I didn't find any related answer on stackoverflow. I did everything. I will explain what I have tried. When I start the Rails server using rails s, I get the following output:

I'm trying to create a "reactive and memoizable" version of an existing function by leveraging functions from shiny - but for usage outside of a shiny context.

The cool thing about relying on shiny::reactive() is that

1. it "automagically" knows about its reactive dependencies
2. it handles the decision "return cache or re-execute underlying expresssion" for us

While my approach of handing the function's body (instead of the function itself) to shiny::reactive() works per se, it makes me give up things that only work for functions such as missing() or match.arg().

But I can't seem to find a way of handing the function itself to shiny::reactive() while still making use of its built-in caching/memoization. To see this, note that foo() is actually executed each time we call foo_react() and thus no caching comes into play in the second approach

Here's my code for a concurrent cache: