>>>>Does that answer the question ?
>>>
>>>IMO, it does not - it's the full list of how passing parameters in Fox works, from the caller's side. What we need here is the callee side, where I don't know of a way to distinguish between a passed value and a passed reference. Either way, the callee receives a pointer to a memory block where the value resides; it's the actual status of the value (is it a value of a variable, or a copy of a value assigned to a parameter) that I don't see how to distinguish, without knowing Fox source code.
>>
>>Yes, exactly - I don't see a way and doubt there is one.
>
>Once upon a time, I remember that list memory would show the variable passed by reference in a special way... as a sort of invisible. Not sure whether this is worth trying to check, specially if you have a dozen parameters.

I agree. Many versions back, I thought that the List Memory did indicate that a parameter was passed by reference (I think).

The problem with current List Memory format is even if the caller argument is passed by reference and List Memory hides it. The callee can not check this because it would not know the caller's argument variable name.