A sequential abstract machine for flat concurrent prolog

AbstractThis paper describes a uniprocessor implementation of Flat Concurrent Prolog, based on an abstract machine and a compiler for it. The machine instruction set includes the functionality necessary to implement efficiently the parallel semantics of the language. In addition, the design includes a novel approach to the integration of a module system into a language. Both the compiler and the emulator for the abstract machine have been implemented and form the basis of Logix, a practical programming environment for Flat Concurrent Prolog. Its performance suggests that a process-oriented language need not be less efficient then a procedure-oriented language, even on a uniprocessor. In particular, it shows that a process queue and process spawning can be implemented as effectively as an activation stack and procedure calling, and thus debunks the “expensive-process-spawn myth”