Cancel changes (CANCEL)

The cancel changes operator completely clears the current change session.

Clearing the session reverts every change accumulated in it: data property values (including local ones) go back to what they were at the start of the session, newly created objects disappear, and class changes of existing objects are undone.

As with other session management operators, you can explicitly specify nested local properties for the cancel operator.

warning

This operator works differently if executed during an apply transaction — for example, inside the applied action or inside a global synchronous event handler. In that case, instead of clearing the session, it cancels the apply that is currently running.

Language

To declare an action that implements cancellation, use the CANCEL operator.

Examples

CLASS Sku;
in = DATA LOCAL BOOLEAN (Sku);

// drop everything accumulated in the current session
dropChanges()  { CANCEL; }

// drop changes but preserve the `in[Sku]` local property
dropChangesKeepIn()  {
    CANCEL NESTED (in[Sku]);
}