Progress
Programming
Handbook
Rules About UNDO
Within an ON ERROR, ON ENDKEY, ON STOP, or ON QUIT phrase, you can specify a block to be undone. This is the syntax for the UNDO option:
Within this syntax, you can name the block to be undone, label1. The block you name must be the current block or a block that contains the current block. If you omit label1, Progress determines the block to undo. It chooses the innermost containing block with the error property. The following blocks have the error property:
Optionally, you can specify the action Progress takes after undoing the block:
- LEAVE that block or an enclosing block.
- Perform the NEXT iteration of the the block or an enclosing block.
- RETRY the current iteration of the block.
- RETURN to the calling procedure. If you are within a user-interface trigger, you can return NO–APPLY to cancel the action. In any other context, you can return ERROR to raise the ERROR condition in the caller. You can also pass a return string back to the caller. The caller can read that string by invoking the RETURN–VALUE function.
The default action is to retry the block that was undone.
For more information on UNDO, see the Progress Language Reference .
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