The Basics of Metacomputation

When we use the Refal machine for computation, we load a program into it, put the expression to evaluate into the view-field, and switch the machine on. The Refal machine works on its own; we do not interfere with its operation. After a while it comes up (or does not come up) with the desired (or not exactly desired) result. Metacomputation is an operation mode of the Refal machine where it is not left to itself, but is run under the supervision and control of a higher authority, which can be the user, i.e. a human being, or another machine. The purpose of this is to explore the behavior of the Refal machine with an initial view-field which is not completely defmed, but can be represented by an expression with free variables. The program is defmite and remaines fixed. The ultimate goal of metacomputation is to construct a formal model of the Refal machine working under these circumstances, a model which could serve as the machine's alternative defmition for that special case.