[beothorn]

I did not know about this project, I will look into it, thanks for linking :)

But, from a quick peek, I think my motivation is different.

My intention when creating this was not profiling exactly each operation, but understanding the logic (what each function calls do and what parameters are passed). I see that this, apparently, does not capture argument values and return values (I may be wrong).

If you are profiling, that makes sense. Calling toString on every argument obviously affect the performance.

Another thing is that this is pretty simple, there are not many tweaks you need to do, as the goal is just to glance at the values being passed around at runtime.

If you look at the example page, with the sort algorithms, you will see that you can follow exactly how each one works by looking at the values being passed and returned. You don't get this from only looking at the calls.