(RPL) percentage function % not preserving stack level 2

[Joe Horn]

(01-06-2019 06:16 AM)RMollov Wrote:  

(01-06-2019 03:48 AM)cdmackay Wrote:  Thanks, but the point of the DUP (or double ENTER) was to preserve the first number

DUP is not double ENTER, it is just another name for a single ENTER.

cdmackay: No, that's not correct. During digit entry, one DUP in RPL has the same effect as a double ENTER in RPL, and has a different effect than a single ENTER, as can be seen in these RPL keystroke sequences:

CLEAR 5 DUP 6 % + --> 5.3 alone on stack
CLEAR 5 ENTER ENTER 6 % + --> 5.3 alone on stack [One DUP has same effect as two ENTERs]
CLEAR 5 ENTER 6 % + --> Error: Too Few Arguments [One ENTER fails]

Reason: RPL's ENTER *either* terminates numeric entry *or* performs a DUP, but never both at the same time, unlike the ENTER key in 4-level-stack RPN machines. Also, RPL does not have any "stack lift disable" feature. Hence the necessary differences shown above.