Open Constraint Programming

A new model for high-level concurrent programming is presented. Designed for implementing programs which manipulate and react to shared data which is highly structured, its main elements are: a shared constraint store, deened as a theory-update system a notion of reactor, which is a program fragment written in a generic reactive programming language; a general use of agents, deened as arbitrary (possibly parallel) programs, which contain embedded reactors; a trigger model, representing an abstract architecture addressing the key implementation challenges. This paper presents a \wrapper" framework as the outermost framework toward the deenition and implementation of constraint stores and a suuciently rich set of agents. A constraint store is formalized as in traditional constraint programming as a theory with an intended model. These theories are updatable, and the update functions are available externally via reactive programs. These programs , called reactors, are used to update and synchronize with the store, and are embedded within user programs. In summary, the entire framework provides high-level reasoning on the domain of discourse via its constraint system, provides expressive synchronization and update operations via updates to the constraints, and nally, it provides exibility via the embedding of reactors in arbitrary agent programs, ie: it is an open system.