The Coroutine Model of Computation

Abstract

This paper presents a general denotational formalism called the Coroutine Model of Computation for control-oriented computational models. This formalism characterizes atomic elements with control behavior as Continuation Actors, giving them a static semantics with a functional interface. Coroutine Models are then defined as networks of Continuation Actors, representing a set of control locations between which control traverses during execution. This paper gives both a strict and non-strict denotational semantics for Coroutine Models in terms of compositions of Continuation Actors and their interfaces. In the strict form, the traversal of control locations forms a control path producing output values, whereas in the non-strict form, execution traverses a tree of potential control locations producing partial information about output values. Furthermore, the given non-strict form of these semantics is claimed to have useful monotonicity properties.