OAA-like Agents

Depending on the application, it may be useful to have agents that are reactive or proactive, but not both. Here are the descriptions of such alternatives for IndiGolog OAA agents.

Creating OAA-like reactive or proactive agents in IndiGolog does not differ much from creating OAA agents in Prolog. Since current IndiGolog interpreter is written in Prolog, most of the interfacing code for an IndiGolog agent is exactly the same as for a pure Prolog agent. The only difference is that the callbacks not only can be Prolog predicates, but also IndiGolog procedures:

oaa_AppDoEvent(<name of user-defined solvable>, _GoalParams) :-
indigolog(<name of IndiGolog procedure to handle the request>).


Reactive Agents



To create a simple reactive IndiGolog agent the programmer needs to declare procedure solvables, specify which IndiGolog procedures will be the corresponding callbacks and enter the OAA event loop by executing oaa_MainLoop(true). The callback procedures will be called whenever some OAA agents require services of this particular IndiGolog agent. All the other OAA events (e.g. updates to data solvables) are handled by the OAA library, and the developer does not need to worry about them.

All the functionality of OAA is accessible from within the primitive actions. IndiGolog agent can in turn call oaa_Solve to request services of other agents.

This way the OAA Prolog library will have full control over the execution of the program. The agent becomes a purely reactive one.

Proactive Agents



At another end of the spectrum, one can create a purely proactive IndiGolog OAA agent. This is again quite the same as creating a proactive OAA agent in Prolog. Here, instead of entering OAA event loop by executing oaa_MainLoop(true), one can just connect to the OAA facilitator and start executing an IndiGolog procedure:

oaa_Ready(true),
indigolog(<name of IndiGolog procedure>).

This way the IndiGolog part of the system has full control over the execution of the program. We must note that if the controller has declared some procedure solvables, their callbacks will never be called since the OAA library does not have control over the execution of the program and cannot monitor for incoming messages from other OAA agents in the system. OAA library can only deliver answers to the queries asked within IndiGolog procedures through calls to oaa_Solve.