PROGRAM QUERY & TRANSFORMATION SYSTEM FOR SOFTWARE RE-ENGINEERING PROJECTS

Abstract

Over years of maintenance, programs often go through phases of corrections, modifications and additions, and therefore become harder and harder to understand and modify. In many situations, these programs are re-engineered to use new languages or concepts to ease the maintenance effort. In this project, a Program Query and Transformation Language, PQTL for short, was designed, implemented and evaluated through examples. PQTL is a general-purpose, end-user level language for specifying program transformations. PQTL provides a basis for automating program transformations in software re-engineering projects. In PQTL, we write program transformations in terms of conceptual models or program design. Separation or conceptual program design models from the physical program representation facilitates the design of a generic program transformation tool. A generic tool can be customized to the needs of a specific software re-engineering project to the source language to specific program transformation rules, and to an internal program representation. In the thesis, we classily program transformations that occur in software re-engineering projects, show how we express the various classes or program transformations in PQTL, describe our prototype implementation of a PQTL-based generic transformation system, and evaluate the system by using a subset of COBOL85. By using the PQ, system users can automate data restructuring and the deletion of dead code. Users can also modify the program without delving into the source code. The key benefits are reduced time and effort by the users accuracy of the modification and therefore lower cost or re-engineering.