Confused about expressions in Prime RPN stack

[pinkman]

Like the others I think you’ll have to force yourself to think Prime, not 48.
But of course you can use the RPN mode with its limitations, especially hitting the [' '] key before copying an algebraic object from the stack.
If the 48 had this constraint you would never have posted any complaint!

Examples:
2: 5*X
1: X
CAS.diff(2) [Enter]
The result is 5 as expected.

2: 5*X
1: F1
[Sto]
The F1 is now 5*X (or whatever expression the 2nd level of the stack holds).

It works very well, but it cannot be compared to RPL or classic RPN behavior. It only has the reverse polish logic in common, nothing more.

Regards.