How to capture the execution of a playground?

Hi,

I would like to store the object resulting from executing a playground.
This would imply two steps:

- Knowing that the playground content was executed (via the play button
or its shortcuts Ctrl + Shift + g or Ctrl + g).
- Getting the results of that execution. For example if the result at
the end is a string or a dictionary, I would like to get that string or
dictionary.

Any pointers on how to make that will be welcomed.

Cheers,

Offray

Ps: I still get lost when I search by myself trying to answer questions
like the ones above. I imagine that in some way is related with
evaluationAction and presentations, by looking for the source code of
"do it and go", but still I can't get a functional code snippet to start
prototyping.