Name

Action -- supertype of actions performed by an action plan

Synopsis

//
// Action -- messages shared by ActionCall, ActionTo, and ActionForEach
//
@deftype Action <GetOwner>
- (int)		getNArgs;
- (void)	setArg1: arg1;
-		getArg1;
- (void)	setArg2: arg2;
-		getArg2;
- (void)	setArg3: arg3;
-		getArg3;
@end

//
// ActionCall -- an action defined by calling a C function
//
@deftype ActionCall <Action>
- (void)	setFunctionPointer: (func_t)fptr;
- (func_t)	getFunctionPointer;
@end

//
// ActionTo -- an action defined by sending an Objective C message
//
@deftype ActionTo <Action>
- (void)	setTarget: target;
-		getTarget;
- (void)	setMessageSelector: (SEL)aSel;
- (SEL)		getMessageSelector;
@end

//
// ActionForEach -- an action defined by sending to every member of a collection
//
@deftype ActionForEach <ActionTo>
@end

Description

Action is a common supertype of all action types which may be created within an action plan. Each action is always controlled by a single action plan to which it belongs. This action plan is referred to as its owner. Given the action object, its owner plan may be obtained using the inherited getOwner message.

Actions are allocated in the same zone as their owner plan, and may be created only using one of the createAction messages on an ActionGroup or Schedule. Each of these messages returns the action that was created as its return value. Actions in an action plan may also be obtained by processing the plan using any of its messages inherited from its underlying collection. Actions may also be removed from an action plan using a remove message on the underlying collection.

(.. Note: currently, an action cannot be removed while it is currently being executed. This means that the function or message called by an action cannot itself remove that same action from its action plan. This restriction will be removed in the future.) No matter what the type of action, the default ordering constraints established by its membership in an owning plan may be supplemented by explicit specification. These specifications are made directly between actions in the same plan, or between actions in different plans if they are suitably qualified. Given any action belonging to any plan, the set of specific explicit ordering constraints in which it participates may be obtained by one of the messages getSuccessors, getPredecessors, getCostarts, and Coends inherited from the KeyedCollection type.

Separate subtypes of Action are defined for each of the various forms of createAction messages that create them. The current representation of these actions will be undergoing change as support for their parameter and return types is migrated into more basic support from the defobj library. Each action type provides messages to retrieve and set the values of all argument values bound into the action. These capabilities will remain, but different messages will eventually be supported. This documentation will be completed once the messages supported on Action types are finalized.

Roger Burkhart <rmb@santafe.edu>
Last modified: