Abstract
To control the operation of large application suites or to tailor a special purpose application to particular need, developers frequently use application specific languages, such as batch, scripting, and query languages. These languages which are also referred to as Fourth Generation Languages (4GLs) therefore play an important role in today's economy. Incompatibilities between different versions of 4GLs and changing requirements may make massive changes on a company's library of 4GL programs necessary. In this paper, we explore possibilities for performing mass changes on 4GLs and show how the transformation of programs written in 4GLs compares to the transformation of mainstream programming languages.