A rule-based approach to modular system design

The author proposes an approach to the development of software systems based on ideas and techniques from the algebraic theory of graph grammars. Given an initial specification, SPEC productions (SPEC is an algebraic specification) are applied sequentially or in parallel to generate another specification: if the productions are the interfaces of module specifications from a library, then the derivation sequence can be translated into a modular system. The results obtained are intended as a formal support for a rule-based (expert) system to aid the systematic development of large software systems from a library of reusable components. The author discusses the notions of derivability and translation of a derivation sequence into an interconnection of modules, and he indicates how to anticipate the application of a production using the parallelism theorem. This equivalence of derivations translates into provably equivalent modular systems