System development methodology using LOGOS

Abstract

The development of applications written in APL has traditionally both benefited by and suffered from the freedom offered by the environment. A consequence of this freedom is that few applications are designed from the perspectives of consistency, modularity, and structure. This paper describes how LOGOS, a programming environment for APL, helps improve the development and maintenance of APL applications. Through the use of basic support facilities and integrated tools, LOGOS encourages a modular design within applications and a greater consistency among them. The support facilities provide such functionality as the paging of large applications, or the parallel testing of multiple versions of software, with minimal effort. Specific examples of system design and development are given in the paper. Programming methodologies in widespread practice are examined, and their application to APL with LOGOS is described. The use of LOGOS in top-down design and in application prototyping is also discussed.