Execution continues at the first action in the specified rule. Form 8 is a return action. It causes a return from the procedure rule in which it appears. A procedure rule may return explicitly by executing a return action or implicitly by reaching the end of the rule. Form 9 is a rule choice.
Execution continues with the first action of the alternative whose label matches the returned value.
If none of the alternative labels matches the value, the otherwise alternative is taken. Following execution of the last action in the chosen alternative, execution continues following the choice. Each alternative label in a rule choice must be a value of the result type of the choice rule. A label can not be repeated nor appear on more than one alternative. Form 10 is a valued return action.