Tools for modular programming: Finding out what's needed

Abstract

Modularity, in our view,1 deals with how to structure programs so that specified purposes are more easily attained. Our current work deals with three purposes—modifiability, reliability, and efficiency—and seeks to identify what structural properties, tools, and language features facilitate the attainment of these purposes. Our approach is to study the structure of three actual programs to see how their structure makes the programs more or less modifiable, reliable, and efficient. The first program is a 1,000 statement PL/I program written in top-down style with levels of abstraction. The second is a large circuit analysis program (AEDCAP). The third is a general purpose package for processing list structured data in a fashion that permits changing details of the data structure representation without revising high level algorithms operating on the data. The case study results will be used to assess the potential utility of possible programming tools and language features. 2