A Universal Modular ACTOR Formalism for Artificial Intelligence

A Universal Modular ACTOR Formalism for A r t i f i c i a l Intelligence Carl Hewitt Peter Bishop Richard Steiger Abstract This paper proposes a modular ACTOR architecture and definit ional method for a r t i f i c i a l intelligence that is conceptually based on a single kind of object: actors [or, if you w i l l , v i r tual processors, activation frames, or streams]. The formalism makes no presuppositions about the representation of primitive data structures and control structures. Such structures can be programmed, micro-coded, or hard wired 1n a uniform modular fashion. In fact it is impossible to determine whether a given object is "really" represented as a l i s t , a vector, a hash table, a function, or a process. The architecture w i l l e f f ic ient ly run the coming generation of PLANNER-like a r t i f i c i a l intelligence languages including those requiring a high degree of parallelism. The efficiency is gained without loss of programming generality because it only makes certain actors more e f f ic ient ; it does not change their behavioral characteristics. The architecture is general with respect to control structure and does not have or need goto, interrupt, or semaphore primitives. The formalism achieves the goals that the disallowed constructs are intended to achieve by other more structured methods. PLANNER Progress