Multi - A LISP based multiprocessing system

A package of LISP functions, collectively called MULTI, which extends LISP 1.5 to multiprogramming is presented. MULTI defines the notion of a process within a LISP implementation using function invocation as the only control primitive. A process is an executable entity consisting of a process template and a set of register values. The process template defines the operations the process carries out. Process environments are saved in what can be viewed as function call instances, i.e. LISP forms which have the name of a process template in functional position and the register values following it. The flexibility of this simple conceptualization of processes is demonstrated by several examples which use MULTI to Implement recursion, backtracking, generators, agendas and AND/OR graph searching. The implementation of MULTI does not assume that the host LISP system provides any data or control environment saving mechanisms such as FUNARG or INTERLISP's spaghetti stack. Thus, MULTI is portable to other LISP systems.