Concatenation of program modules an algebraic approach to the semantic and implementation problems

Abstract

The paper studies the semantic and implementation problems of programming languages which allow module concatenation. Three known languages of that class are Simula-67, Smalltalk and Loglan. The structure of program modules is treated as an algebra. A concise set of algebraic axioms defining this structure is given. The addressing problem is formulated in algebraic terms. The identifier binding rule is reduced to the evaluation of terms in the algebra of modules. The normal form theorem solves the question of this evaluation. The results allow to develop two efficient updating algorithms going beyond standard Dijkstra's algorithm and relevant for this class of languages. The paper ends with the detailed implementation techniques. The correctness of this implementation is proved. All of this allow to construct a new family of running-systems for languages with module concatenation.