A hybrid knowledge representation as a basis of requirement specification and specification analysis

A formal requirement specification language, the frame-and-rule oriented requirement specification language FRORL, developed to facilitate the specification, analysis, and development of a software system is presented. The surface syntax of FRORL is based on the concepts of frames and production rules that may bear hierarchical relationships to each other, relying on multiple inheritance. To provide thorough semantic foundations, FRORL is based on a nonmonotonic variant of Horn-clause logic. Using the machinery of Horn-clause logic, various properties of a FRORL specification can be analyzed. Among the external properties of FRORL are formality, object-orientedness, and a wide spectrum of life cycle phases. Intrinsic properties are modularity, provision for incremental development, inheritance, refinement, reusability, prototyping, and executability. A software development environment based on FRORL has been implemented using the C language on a Sun workstation