This function operates implicitly on the active instance (see section 9.4.1.1) for a message, and thus can only be called from within the body of a message-handler. This function directly deletes the active instance and is the one used to implement the delete handler attached to class USER (see section 9.4.5.2). This function returns the symbol TRUE if the instance was successfully deleted, otherwise the symbol FALSE.
Syntax
(delete-instance)