STKPUSH
Synopsis
Push a snapshot of the current stack on the Undo stack
Description
The STKPUSH
command creates a snapshot of the stack and pushes it on the top of the Undo stack. The Undo stack may contain up to 8 snapshots: each time a ninth is pushed on it, the snapshot on level 8 is lost.
The command has little utility in interactive mode, since each time a command is typed and XEQ
ted a snapshot of the stack is already pushed on the Undo stack: the only effect of STKPUSH
would be to duplicate the latest snapshot.
Compatibility
This command is new in newRPL and does not exist in userRPL.
Usage
The following program
« 123 456 789 STKPUSH CLEAR »
leaves an empty stack. If LF is pressed, the previous stack will be restored.
3: 123 2: 456 1: 789 ……………………………………………………………………………………
Related Commands
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 |