Abstract: Interactive services with multiple interfaces are realized by employing a modular approach to their implementation. Such an approach facilitates supporting natural language understanding interaction with users through use of interfaces that at least allow the user to provide information beyond what is currently being requested by the service, and/or different ordering of inputs, and/or incomplete information, and/or correction of information, and/or the return of control to prior points in the service. This is realized, in an embodiment of the invention, by employing an interactive service logic that uses “reactive constraint graphs”, i.e., a form of event-driven graph in which nodes contain constraints on events, in conjunction with a service monitor. The service monitor manages the communication between the service logic and the multiple user interfaces.

Abstract: Interactive services are provided by employing a modular approach to implementing interactive services with multiple interfaces. Such an approach facilitates supporting natural language understanding interaction with users through use of interfaces that allow at least different ordering of inputs, and/or incomplete information, and/or correction of information, and/or the return of control to prior points in the service. This is realized, in an embodiment of the invention, by employing a single interactive service logic that uses “reactive constraint graphs”, i.e., a form of event-driven graph, in which nodes contain a set of constraints on events. Specifically, control progresses from a node to a derivative node, i.e., “child”, only when all the constraints in the set on the node have been satisfied. A single set of constraints implicitly supports a significant number of the possible different orderings of inputs.