Semantics of multiway dataflow constraint systems

Multiway dataflow constraint systems (MDCS) is a programming model where statements are not executed in a predetermined order. Rather, individual methods are selected from specific method sets and then executed to achieve a desired global state. The selection is done by a planner, which typically bases the choice of methods on the history of updates to the global state. MDCS is well suited for describing user interface logic where choosing what code to execute depends in complicated ways on the history of user interactions and on data availability. User interfaces are the domain of examples in this paper.