CoCreate OneSpace Designer - Commands Reference Manual

UNDO terminate action

UNDO reverses the effects of a specified number of previous steps.

Syntax


               +----------------------<---------------------+
               |                                            |
---->(UNDO)----+----(:BACKWARD)-----------------------------+---->
               |                                            |
               +----(:FORWARD)------------------------------+
               |                                            |
               -+----(:NUM_STEPS)----|number of steps|------+
               |                                            |
               +----(:NEXT)---------------------------------+
               |                                            |
               +----(:MAX_BACK)----|number of steps|--------+
               |                                            |
               +----(:MAX_FORWARD)----|number of steps|-----+
               |                                            |
               +----(:KEEP_STEPS)----|number of steps|------+
               |                                            |
               +----(:AUTO_REMOVE)----+----(:ON)----+-------+
                                      |             |
                                      +----(:OFF)---+

Options

The following options are available to undo or redo a number of design steps.

:BACKWARD - performs a backward undo.
:FORWARD - performs a forward undo.
:NUM_STEPS - undoes the specified number of steps at the next :OK or :NEXT.
:NEXT - performs the UNDO operation, without terminating the command.
:MAX_BACK - specifies the number of steps to be kept in the backward history. All older steps are automatically deleted.
:MAX_FORWARD - specifies the number of steps to be kept in the forward history. All newer steps are automatically deleted.
:YES - completes the operation.
:NO - cancels the operation.
KEEP_STEPS - specifies the number of steps you want to keep.
AUTO_REMOVE - chooses whether or not to automatically remove a specified number of undo steps.
ON - chooses to automatically remove a specified number of undo steps.
OFF - chooses to keep a specified number of undo steps.

When to use

Use this action to reverse the effects of any number of previous operations.

Example

In the following diagram, five steps are available in both the backward (steps 0 to 4), and forward (steps 6 to 10), direction.


0----1----2----3----4----5----6----7----8----9----10
^                   ^    ^    ^                    ^
|----past steps-----|    |    |----future steps----|
                         |
                      current
                       posn.

Entering UNDO :MAX_BACK 2 will throw away steps 0 to 2, and keep steps 3 and 4.
Entering UNDO :MAX_FORWARD 2 will throw away steps 8 to 10, and keep steps 6 and 7.