DUP2


Synopsis


Duplicate the objects on level 1 and level 2 of the stack

Stack Diagram


Input Stack Output Stack
O2 O1 O2 O1 O2 O1
Level 2 Level 1 Level 4 Level 3 Level 2 Level 1
Type Command
Parallel list processing Group 2
Affected by flags None

Description


The DUP2 command creates a duplicate of the objects on the first two levels of the stack.

Compatibility


This command is fully compatible with userRPL.

Usage


3:            "This is a string"
2:               { 'X' 'Y' 'Z' }
1:                           1_m
……………………………………………………………………………………
DUP2

will result in

5:            "This is a string"
4:               { 'X' 'Y' 'Z' }
3:               { 'X' 'Y' 'Z' }
2:                           1_m
1:                           1_m
……………………………………………………………………………………

Related Commands


Stack manipulation 27 5 NEW

Command Short Description
CLEAR Remove all objects from the stack
DEPTH Get the current stack depth
DROP Remove an object from the stack
DROP2 Remove two objects form the stack
DROPN Remove N objects from the stack
DUP Duplicate an object on the stack
DUP2 Duplicate two objects on the stack
DUPDUP Duplicate the same object twice on the stack
DUPN Duplicate a group of N objects
NDUPN Replicate one object N times and return N
NIP Remove object at level 2 on the stack
OVER Duplicate object at level 2 on the stack
PICK Duplicate object at position N on the stack
PICK3 Duplicate object at level 3 on the stack
ROLL Move object at level N to level 1
ROLLD Move object from level 1 to level N
ROT Move object from level 3 to level 1
SWAP Exchange objects in levels 1 and 2
UNPICK Move object from level 1 to level N.
UNROT Move object from level 1 to level 3
IFT Evaluate objects on the stack conditionally
IFTE Evaluate objects on the stack conditionally
STKPUSH Push a snapshot of the current stack on the undo stack NEW
STKPOP Pop a stack snapshot from the undo stack NEW
STKDROP Drop a snapshot from the undo stack NEW
STKPICK Copy snapshot in level N to the current stack NEW
STKDEPTH Get the depth of the undo stack NEW
  • manual/chapter6/stack/cmd_dup2.txt
  • Last modified: 2019/10/22 14:56
  • by jojo1973